PRINCIPIUM The Newsletter of the Initiative for Interstellar Studies Issue 20 | February 2018

ISSN 2397-9127

■ Project Lyra : mission to ʻOumuamua ■ Preparing for the next Interstellar Object ■ Interstellar News ■ The Orbits of Seveneves ■ Tsiolkovsky - Interstellar Pioneer ■ NEWS FEATURES ■ Work on the interstellar asteroid and i4is Project Lyra R ■ Pete Worden, Breakthrough Initiatives, at i4is HQ O F E ■ Sir Arthur C Clarke Centenary V I

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S T U D I E S www.i4is.org Scientia ad sidera Knowledge to the stars

Principium | Issue 20 | February 2018 1 what Kelvin Long and Rob Swinney did on their recent USA visit including giving addresses at Editorial NASA Goddard and the University of Maryland. We Welcome to Principium, the quarterly newsletter also report interstellar-related work including the about all things interstellar from i4is, the Initiative Primitive Object Volatile Explorer (PrOVE) for Interstellar Studies - and our US-based Institute proposal, upcoming ideas from Darryl Seligman for Interstellar Studies. And a special welcome if of Yale University and the work of the team at you are a new reader . Please tell us if we have your Technical University of Dresden. We celebrate the details incorrect ([email protected]). BIS Scotland relaunch and we'll be working with Our Introduction feature for Principium 20 is them to deliver more outreach in Scotland. We have Project Lyra: A feasibility study for a mission to the an update on Project Glowworm and finally we interstellar asteroid ʻOumuamua by i4is Executive enjoy some Christmas tree sailcraft from our major Director Andreas M Hein. We are featuring the i4is 2017 contributor Dmitry Novoseltsev. Project Lyra strongly in this issue. Our first known Neal Stephenson has always been an interesting interstellar visitor, barren though it may be, is a novelist and thinker. This time we consider the momentous event and the Project Lyra is typical astrodynamical side of his latest novel in the first of our team's ability to bring world-class technical part of The Orbits of Seveneves by new contributor resources rapidly to bear upon issues important to Sander Elvik. the interstellar community. If you would like to be I have always been fascinated by Konstantin involved, by technical or by material contribution to Tsiolkovsky and his famous equation. In Tsiolkovsky our work then get in touch with us via [email protected]. - Interstellar Pioneer I hope to show how his maths, Our front cover this time is by Efflam Mercier physics and engineering broaden to imagine our (efflammercier.com). We asked him to imagine a interstellar future. crewed mission to ʻOumuamua and the view of the We have two News Features - on work in progress Earth-Moon system at its closest approach to our on i4is Project Lyra and the interstellar asteroid planet. It did not happen, of course, but we may generally and on the visit of Pete Worden of anticipate that, with progress in human capabilities, Breakthrough Initiatives to the i4is HQ. it may be possible with a future interstellar object. I ʻOumuamua has obvious parallels with the hope readers find it as inspirational as I do! eponymous object in Rendezvous with Rama and we Last time I misattributed that magnificent Sputnik recently saw Arthur C Clarke's centenary. Patrick image to our colleague Robert Kennedy. In fact he Mahon reminds us of his interstellar vision. and others have used it in many contexts, including As promised we include a glimpse of our HQ Wikipedia. I have tried to track down the artist, interior concentrating on Models and art at the Mill. Gregory R Todd, without success. If anyone knows Next time we will have The Orbits of Seveneves him then please put me in touch so I can add my - Part 2 - the orbits explained, a review of Going thanks to all those he has had and should have had Interstellar - a Baen anthology of new fiction and over the years! non-fiction on interstellar travel and a major feature Our back cover this time is the three French ExTrA introducing Z-pinch fusion propulsion based on the telescopes at the European Southern Observatory, Project Icarus Firefly concept. La Silla, Chile. They look for exoplanets transiting across their local star (www.eso.org/public/teles- Comments on i4is and all matters interstellar are instr/lasilla/extra). always welcome, And we do need to be ready for the next interstellar John I Davies, Editor, [email protected] object so Marshall Eubanks has analysed this in Preparing for the next Interstellar Object. Marshall Join in the conversation by following the i4is on our Facebook page www.facebook.com/InterstellarInstitute is CEO at Asteroid Initiatives LLC, the Asteroid and in our professional network on LinkedIn www. Prospecting Company, and was a key member of the linkedin.com/groups/4640147 - and check the i4is blog, The Starship Log www.i4is.org/the-starship-log. Project Lyra team. Follow us on Twitter at @I4Interstellar and seek out our Our Interstellar News this time includes some words followers too! from Andreas Hein on i4is in 2017, a summary of Contact us on email via [email protected]. All issues of Principium are at www.i4is.org/Principium.

The views of our writers are their own. We aim for sound science but not editorial orthodoxy.

Principium | Issue 20 | February 2018 2 Project Lyra: A feasibility INTRODUCTION study for a mission to the interstellar asteroid

ʻOumuamua Andreas M Hein

Andreas Hein describes how an i4is technical team responded to the detection of the interstellar asteroid ’Oumuamua. Their paper, Project Lyra: Sending a Spacecraft to 1I/'Oumuamua (former A/2017 U1), the Interstellar Asteroid received wide attention and sparked interest in interception of interstellar objects

In 2017, a yet unseen, mysterious visitor from our solar system to date. At this speed, you our galaxy has entered our solar system. On would get from the Earth to the Moon in 1.3 October 19th 2017, the University of Hawaii’s hours. Pan-STARRS 1 telescope on Haleakala Its speed will gradually decrease while leaving discovered a fast-moving object near the Earth, the solar system and finally reach about 26 FEATURE initially named A/2017 U1, but now designated km/s in interstellar space, when it has left the as ’Oumuamua [1]. The object’s trajectory is Sun’s gravitational pull. hyperbolic, which means that it is not bound to But this is not the only novelty. It gets far more the solar system. It flew into the solar system mysterious. The luminosity change pattern from interstellar space and after having been of ʻOumuamua over time indicates that it has pulled close to the Sun by its gravity, it is now on a remarkable shape, never observed before its way to leaving it again. At its closest approach in a small body: It looks like a cigar and has to the Sun, it had a velocity of over 80 km/s, roughly the length and width of the Empire faster than any object that has been observed in State Building. Another mystery: We still do not know what ʻOumuamua actually is. Is it a comet or an asteroid? First observations indicated that it didn’t develop a cometary tail when it approached the Sun, which means that it is an asteroid. But later publications hypothesized Artist’s impression of `Oumuamua. that if ʻOumuamua has Credit: ESO/M. Kornmesser travelled through interstellar http://www.eso.org/public/hungary/ space for millions of years, images/eso1737a/ it might have developed a

[1] MPEC 2017-V17 : New Designation Scheme for Interstellar Objects, minorplanetcenter.net/mpec/K17/K17V17.html

Principium | Issue 20 | February 2018 3 “crust” around a potentially icy core, which might explain why Figure 1: Time-distance graph of 'Oumuamua and spacecraft launched no tail was observed. The crust 5 and 10 years after its discovery at different speeds. prevented a tail from forming. From the beginning, discussions about a non-natural origin of ʻOumuamua abound. Due to its odd shape and trajectory, there was a very low probability that this object was actually of artificial origin. A low probability but very high impact event merits further investigation and therefore Breakthrough Listen attempted to capture signals that might be emitted by ʻOumuamua, to no avail. wanted to answer, the simplest order to select the more realistic At this point, it should be clear way of approaching this problem options. You can easily cut the that ʻOumuamua is probably one is to assume that ʻOumuamua graph on the x-axis (time) and of the most exciting objects that travels at 26 km/s and now you define the latest and earliest date were discovered in 2017 and need to chase it. The later you you want to launch the probe since its discovery, one question start the chase, the faster you (between 2013 and 2028). If has been repeatedly asked: Can need to be, as ʻOumuamua will you look at the intersection of we get there? And can we get fly farther and farther away from the line for 'Oumuamua and the there with current or near-future us. The farther ʻOumuamua is line for the spacecraft you can technologies? These are exactly away when a spacecraft reaches immediately see when you will the questions the team from i4is it, the more difficult will it be to reach ʻOumuamua (one to a few asked itself. We immediately observe it. ʻOumuamua is a very decades) and at which distance formed a team of volunteers faint object and the farther it gets (100s of astronomical units). The (Kelvin Long, Nikolaos Perakis, from the Sun, the more and more slope of the line is the required Adam Crowl, Robert Kennedy, difficult it is to collect light that velocity (40, 50, 60 km/s) for Richard Osborne, Andreas Hein) is reflected from it, which means reaching Oumuamua at a specific on the 31st of October, 12 days you need a larger telescope that time and distance. after ʻOumuamua’s discovery and can collect more light. Another Now, the obvious challenge is baptised the project “Lyra”; the disadvantage is that the longer to reach the required velocities star constellation in the direction you have to wait for the scientific of several dozens of km/s. You from which ʻOumuamua came data to return, the less interesting need a lot of energy for that. The from. Intense design activities it gets for scientists to promote fastest human-made object is started during which further a mission. Developing an Voyager 1 with a current velocity external people joined our efforts interplanetary spacecraft already of about 16.6 km/s at a distance such as eminent astronomer takes about a decade. If it takes of 122 AU. We need to be several Marshall Eubanks, former Ariane further 30 years to get the data, times faster than that. Although 4 guidance engineer Adam a young scientist is essentially challenging, there are ways of Hibberd and aerospace engineer close to retirement when the data reaching such high velocities Kieran Heyward. What we arrives. using existing and near-future wanted to know is if we can get to We can easily visualize this technologies. In the following, I ʻOumuamua within a reasonable problem. With a time-distance present three possibilities that we timeframe of a few decades with graph, as shown in Figure 1, have considered. a launch in the next 5-10 years. you can easily see that there are For the first option, we use This much time is realistically the infinite possible trajectories that a mission concept that has minimum duration for developing will reach ʻOumuamua sooner or been previously proposed by an interplanetary spacecraft. later. What we do as engineers a Keck Institute for Space Regarding the first question we is to select realistic constraints in Studies report for exploring Principium | Issue 20 | February 2018 4 the interstellar medium. It is shield is used which is similar to this mission concept already essentially a rollercoaster ride. the heat shield of the NASA Solar exist today. The Falcon Heavy The spacecraft is first sent on Orbiter mission, which will fly is scheduled for a launch in a trajectory out of the Earth’s close to similar distances to the 2018, the heat shield will soon gravitational field using a large Sun and is currently undergoing be launched into space with the rocket, for example the Falcon testing. Now, at the closest point Solar Orbiter probe, solid rocket Heavy, Space Launch System, to the Sun, the spacecraft ignites engines are routinely used in or the Big Falcon Rocket. The a solid propellant engine it has space, and the spacecraft itself spacecraft is accelerated to such been carrying all the way. In could be based on the heritage of high velocities that it is not only orbital mechanics, you get the the New Horizons probe that has thrown out of the Earth’s gravity biggest “bang for the buck” for flown past Pluto. field but has enough energy to a rocket engine, if you ignite it An alternative to this fly out to Jupiter. At Jupiter, the at the closest point to the central “conventional” mission is to use planet’s gravity decelerates the body. Hence, the whole idea of more advanced technologies. spacecraft with respect to the falling so closely to the Sun is to “Advanced” means here that these Sun. This manoeuvre is called ignite the engine at the closest technologies have not yet been “sling shot”. The advantage is point of approach and then to flown in space but laboratory that it can be used for accelerating be propelled away from the Sun experiments have shown that they and braking spacecraft by using with the maximum “bang”. The work in principle. One possibility the planet’s gravity. Hence, spacecraft flies away from the is to use laser sail-propelled you get this acceleration and Sun at the incredible speed of spacecraft. Laser sail-propelled deceleration “for free” without about 370 km/s. At this speed spacecraft use a laser sail, which using propellant. The acceleration you would get from London to is essentially a thin, reflective and deceleration is achieved by New York in 15 seconds. Note surface that reflects the photons a tiny reduction or increase in that this is the speed you would of the laser beam. The photons the orbital energy of the planet. need for a mission duration to exchange momentum with the sail As the mass of the planet is ʻOumuamua of 8 years and a and the spacecraft is accelerated. vastly higher than the mass of launch in 2021. The spacecraft Think about a sail ship and the spacecraft, it is essentially will have a velocity at infinity of replace the wind by photons and negligible. To continue, our 55 km/s and is therefore much the sail by a reflective surface. spacecraft has been decelerated faster than ʻOumuamua with In 2016 Breakthrough Starshot so much by exploiting Jupiter’s 26 km/s. The spacecraft would announced the development of gravity field that it is now on a fly past ʻOumuamua in 2029, a laser-sail propelled interstellar trajectory that it is falling towards taking images using a telescope mission, based on a terrestrial the Sun in an almost straight line, at a distance from the Sun of laser infrastructure with a beam an extreme roller-coaster ride, 69 AU (Earth-Sun distances). power of several dozens of GW although it takes over a year to At this point ʻOumuamua will and gram-sized spacecraft that are fall. Of course the spacecraft will be a black object in front of the accelerated to 20% of the speed of not fall into the Sun but would blackness of space. Where the light. Now, could we downscale move away from the Sun once human eye would fail, a telescope this infrastructure to launch a it has passed its closest point to and other instruments will suck spacecraft to ʻOumuamua? The the Sun. The spacecraft gets very in the electromagnetic waves spacecraft would be launched close to the Sun, about 3 solar that are nevertheless emitted into space, manoeuvred into radii or about 1.5 million km. At by ʻOumuamua. The data will the line of sight of the laser such a distance, the solar radiation then be sent back to Earth with infrastructure based on Earth is about 20,000 times higher an antenna powered by nuclear and are then “shot” away by the than what you receive during a radioisotopic generators, a laser. We did calculations on such sunny day. Converted to Watts per chunk of Plutonium whose heat a downscaled infrastructure. It square meters, the power per area is transformed into electricity. turns out that a 2 to 4 MW-class is about 15 MW/m². This is higher Finally, the data is transformed laser infrastructure would be than the power per area inside into images. What will we see? sufficient to accelerate a one gram a fusion reactor. To avoid the It is important to note that all spacecraft to the same velocity at spacecraft melting away, a heat technologies that are used for infinity as the sling shot mission.

Principium | Issue 20 | February 2018 5 However, one gram is obviously advantage is the flexibility of such seen, there are ways of flying not much. If we would like to an infrastructure of launching to 'Oumuamua. We could either launch a CubeSat-class (1 kg, 10 spacecraft to promising targets use existing technologies or cm cube) spacecraft, we would without much advanced warning. technologies that are currently need about 2 to 4 GW of laser Imagine a “mothership” with under development. Who will power. But what’s the advantage 3-4 CubeSats in space. Once be first to unravel the secrets of of building a large laser beaming the next interstellar asteroid is 'Oumaumua? Or will we be too infrastructure to send a chip-sized detected, the mothership releases late? In that case, let us prepare or a 10 cm cube to ʻOumuamua? the CubeSats which are then for the next interstellar object! First, this could be an opportunity launched towards its target within The Lyra paper is Project for a mission that can be done days, thereby minimizing the Lyra: Sending a Spacecraft to with a smaller version of the time between discovery and data 1I/'Oumuamua (former A/2017 Starshot beaming infrastructure, return. Compare that with the U1), the Interstellar Asteroid providing a justification for mission based on conventional Andreas M Hein, Nikolaos these intermediate infrastructures technologies before. It takes years Perakis, Kelvin F Long, Adam before the full-scale interstellar- to perform the manoeuvres to get Crowl, Marshall Eubanks, Robert capable infrastructure is the spacecraft up to speed. G Kennedy III, Richard Osborne operational. Second, the real Let us summarize. As you have arxiv.org/abs/1711.03155

Laser sail probes at ʻOumuamua Credit: Maciej Rebisz

About Andreas Hein and the team Dr Andreas Hein is Executive Director of the Initiative for Interstellar Studies (i4is) and chairs its technical committee. His PhD is from the Technical University of Munich (TUM). He is a Researcher / System Architect - Autonomous Driving System of Systems at CentraleSupelec, Paris. Kelvin F Long is President of i4is and founded the organisation with Rob Swinney in 2012. He is the author of Deep Space Propulsion: A Roadmap to Interstellar Flight (Springer, 2012) and is a member of the Advisory Committee of Breakthrough Starshot. Robert Kennedy is President of i4is-USA. He is Senior Systems Engineer at Tetra Tech and co-founded the Tennessee Valley Interstellar Workshops (TVIW). Marshall Eubanks is CEO at Asteroid Initiatives LLC, the Asteroid Prospecting Company, and has held senior positions at JPL and the Internet Engineering Task Force (IETF). Nikolaos Perakis is a postgraduate at TUM working on a PhD in combustion modelling and simulation of rocket engines. Richard Osborne is a Systems Consultant and rocket scientist. He has worked for many companies in space technology including Reaction Engines and Commercial Space Technologies. He is a Council Member of the British Interplanetary Society. Adam Crowl is Project Officer at Queensland Health, Australia. He is the author of numerous papers on interstellar flight and was a member of the original Project Icarus study group. Adam Hibberd is a freelance software engineer and musician/composer. He worked on software for Ariane 4 guidance and Airbus flight simulation at EASAMS and other aerospace companies. Kieran Hayward is an Avionics Validation Engineer at Thales Alenia Space UK. He has an MSc in aerospace engineering from Cranfield University.

Principium | Issue 20 | February 2018 6 Sir Arthur C Clarke Centenary Celebrations Thoughts on a mighty imagination and his envisaged interstellar object by Patrick Mahon

is the resemblance between the huge alien spaceship, over 50 The name of Sir Arthur C Clarke interstellar asteroid ‘Oumuamua kilometres long and 20 kilometres FBIS is, I imagine, a familiar and the alien spaceship featured in in diameter. ‘Oumuamua is only one for most i4is supporters. his 1973 novel ‘Rendezvous with around 180 metres in length1, Clarke’s science fiction Rama’. For those who haven’t nearly 300 times smaller than novels are filled with realistic read it, the story focuses on a Clarke’s ship. In addition, portrayals of the science and mission to rendezvous with and attempts by the Breakthrough engineering of spaceflight, while study a long, cylindrical object Listen project to detect any his collaboration with Stanley after it enters the solar system artificial signals emanating from Kubrick on the 1968 film ‘2001: from interstellar space. Sound it have been unsuccessful, and A Space Odyssey’ led to the familiar? the current consensus is that creation of one of the most iconic Unfortunately, that’s where ‘Oumuamua is an interstellar spacecraft designs in film history, the similarities end. Rama is a asteroid of natural origin, rather ‘Discovery’ – a model of which is on display at i4is HQ. Although Sir Arthur is sadly no longer with us, 16 December 2017 marked the centenary of his birth. This anniversary was Book covers almost marked by several organisations, invariably show the including our friends at the British interior of the Rama Interplanetary Society, who held object - where much of the action takes place. a dinner to celebrate Clarke’s life This rare exception is at the end of the ‘Reinventing an ancient audiobook Space’ conference in Glasgow (on cassettes). Credit: Chivers Audio in late October , and whose Books Christmas Get Together included an illustrated talk about Sir Arthur by BIS Fellow and special effects designer Mat Irvine, who knew him well. BIS also dedicated the 50th issue of their e-magazine ‘Odyssey’ to Clarke in November. Clarke was an active and involved member of BIS for much of his life, joining at the age of 18, becoming a Fellow and twice serving as Chairman. What makes the centenary of Clarke’s birth particularly relevant [1] Estimates of length vary from 180m (www.noao.edu/news/2017/pr1706.php) to to the current issue of Principium about 1km (www.nature.com/articles/nature25020)

Principium | Issue 20 | February 2018 7 than an alien spacecraft. Even so, plausible fusion-powered need for chemical rockets, thus the first detection of an interstellar passenger liner which travels massively reducing the cost of visitor to our solar system shortly between the Earth and Mars. space travel, was explored at before the centenary of Sir • Quantum vacuum energy drive – length in Clarke’s 1979 novel Arthur’s birth seems singularly in ‘The Songs of Distant Earth’ ‘The Fountains of Paradise’. appropriate. (1986), Clarke wanted to show Rama may be the most topical a realistic form of interstellar For me, the centenary of Clarke’s of Clarke’s creations right now, travel at sub-light speed, as a birth provides an opportunity but it is far from being the only contrast to the fantastical faster- to give thanks for the life of one relevant to i4is. Those who than-light space drives of ‘Star someone who wrote science have attended one of our ‘Starship Trek’ and ‘Star Wars’. He posited fiction that was always informed Engineer’ courses will be familiar a futuristic but conceivable by science fact – gained initially with several of Clarke’s other propulsion system based on through being awarded a fictional spacecraft and related using the quantum zero-point First Class honours degree in technologies, all of which are energy which pervades all space, Mathematics and Physics by based on sound engineering an idea which was the subject of King’s College London in 1948, principles. A small subset would much academic speculation at following his wartime service in include: that time. the RAF. I have recently dug out my copies • Solar sails – the use of sunlight • Space Elevators – the to accelerate a large reflective of several of the books listed construction of a super-strong above, and am re-reading them sail was explored in Clarke’s orbital tower, reaching from 1963 short story, ‘Sunjammer’ with great pleasure. If you want to the surface of the Earth up explore some novels which depict (later renamed ‘The Wind from into space, so that people and the Sun’). interstellar spacecraft realistically cargo could travel to and from I’d recommend Clarke as an • Fusion propulsion – Clarke’s geostationary orbit without the excellent starting point. first published novel ‘The Sands of Mars’ (1951) includes a

Image was created using descriptions from the original Rendezvous with Rama and its sequel Rama II. 3D artist: James A Ciomperlik. Credit: Monomorphic at English Wikipedia

Principium | Issue 20 | February 2018 8 Interstellar News John Davies and Patrick Mahon with the latest interstellar-related news i4is in 2017 second year. the aerospace department on The Our Executive Director, • We had numerous educational Application of Extreme Aerospace Andreas Hein, reminds us of the events in schools and colleges Engineering to Interstellar Flight. achievements of the Initiative for throughout the year. There was an opportunity to Interstellar Studies in the past • Principium is enjoying a larger observe a full scale test of Wide year - and larger readership within the Field Infrared Survey Telescope • The opening of our HQ, which interstellar community. (WFirst), a proposed space makes us the first dedicated telescope with some exciting interstellar organization with a Kelvin & Rob in the USA objectives from exoplanet building. The opening event in i4is President Kelvin F Long and imaging to gravitational physics itself has been an unforgettable Deputy Director Rob Swinney wfirst.gsfc.nasa.gov. were in the USA again in recent experience with Apollo astronaut Here is Kelvin at GSFC Al Worden. weeks. Kelvin spoke at NASA Goddard Spaceflight Center witnessing the vacuum chamber • We had the honour to welcome (GSFC) on Interstellar Flight - thermal testing of the Parker Solar Pete Worden, the Executive The Benefits to Astronomy and Probe spacecraft due for launch to Director of the Breakthrough Astrophysics. He also addressed the Sun in July. Initiatives to our HQ in the University of Maryland At closest approach it will be November and hear about their AIAA chapter associated with travelling at approximately latest activities. More in Patrick Mahon's report in this issue. • i4is-US has organised the Foundations of Interstellar Studies Workshop in collaboration with the New York City College of Technology. We spent four marvellous days with presentations spanning the whole width of interstellar propulsion technologies. • Project Lyra: Our concept study for reaching the interstellar asteroid ‘Oumuamua has been a huge success with over 40 websites (Scientific American, Buzzfeed, MIT Technology Review, Universe Today, etc) in more than six languages featuring our project. Even the London Review of Books has picked up the project. i4is.org/what-we-do/ technical/project-lyra/ • Andromeda Study: Our Andromeda probe study from 2016 has been featured by the MIT Technology Review and The Times. • The Interstellar module at the International Space University (ISU) which we delivered for the

Principium | Issue 20 | February 2018 9 Twitter illustration of a proposed impact mission to ʻOumuamua. We especially liked the three axis views. Credit: @darryl_seligman - Darryl Seligman, Yale University

700,000 km/hr and will require discussing Interstellar Probe: More interstellar thinking several gravitational "slingshots" First Step to the Stars and Much of this issue is devoted to around Venus to get closer to the Anthony Freeman from the Jet our study of an intercept mission, Sun than any previous probe. Propulsion Laboratory on The Project Lyra but others are Recall it takes just as much First Interstellar Explorer: What thinking along similar lines. "push" to get close to the Sun as Should it Do when it Arrives at its The Primitive Object Volatile to get away from it! In December Destination. Explorer (PrOVE) www.lpi. Kelvin also attended the American Kelvin also visited the gravitation- usra.edu/sbag/meetings/jan2018/ Geophysical Union which held al wave detector LIGO Livingston presentations/1010-Hewagama. its fall meeting in New Orleans, near New Orleans pdf is a comet interceptor idea Louisiana, at the Ernest N Morial which pre-dates our interstellar Presentations by Andreas Hein Convention Center. 25,000 asteroid but by lurking at a series delegates attended. For the first i4is Executive Director Dr Andreas Hein has presented our of "way-points" could intercept an time in its history the meeting unexpected visitor. organized an interstellar session, Project Lyra work to - • "Raumfahrtkolloquium der FH We have also heard of a paper titled 'from the Heliosphere to by Darryl Seligman of Yale Interstellar Exploration Beyond: Aachen" (30th space symposium of the University of Applied University (astronomy.yale.edu/ IMAP and Interstellar Probe'. people/darryl-seligman) submitted This was organized by the primary Sciences Aachen) in November 2017 to AAS Journals around the end convener Pontus C Brandt from of January. Thanks to Marshall Johns Hopkins University Applied • 22nd Winter Seminar at Bad Eubanks of Asteroid Initiatives for Physics Laboratory. Kelvin F Honnef in January 2018 spotting this. A Twitter image (see Long presented a Historical • the Paris observatory in above) gives a good illustration Review of Interstellar Probe December 2017 of a proposed impact mission to Concepts and Examination of ʻOumuamua. We look forward to Payload Mass considerations for the paper. Different System Architectures. We also noticed Developing Among the many speakers were Revolutionary Propulsion at Marc G Millis from the Tau Zero TU Dresden, a paper from last Foundation discussing Long year's International Astronautical Term Perspectives on Interstellar Congress in Adelaide, Australia. Flight, Ralph L McNutt Jnr Since 2012 there has been a from Johns Hopkins University Principium | Issue 20 | February 2018 10 dedicated breakthrough propulsion the BIS. Why not join this, the system using minimal resources. physics group at the Institute world's longest-established space The project is also going to be of Aerospace Engineering at advocacy organisation (www.bis- completed in the first half of Technical University of Dresden, space.com/eshop/why-join)? 2018, again resulting in a report Germany and in this paper they Project Glowworm Update and a paper for the International discuss ideas for Propellantless Project Glowworm has made Astronautical Congress. propulsion, the EMDrive and the significant progress mostly in • We are also reaching out to Mach-Effect Thruster. They are developing our own ChipSat, a other universities and the Chipsat concentrating on the latter and fingernail-sized spacecraft. The community to establish mutual building very sensitive thrust project is currently in its early ways of working. balances to detect the tiny thrusts phase of development but we • We have started working on which may be expected. aim at rapidly entering hardware developing a ChipSat prototype Education and Outreach development in 2018. Here are that we can use for testing basic It was good to re-make contact some of the results from 2017 and functionalities of our ChipSat and with Space Studio West London plans for 2018 - to gain practical experience with and their enthusiastic students and • ISU white paper on ChipSat- them. teachers at their Careers event on based interstellar mission. If you would like to get involved 6 February 2018. We are working Professor Chris Welch from the please contact our technical team with their physics and maths International Space University via the usual address info@i4is. departments on new ways of and Rob Swinney of i4is working org and tell us how you can help. interesting their students in space, with a group of ISU Masters' Christmas Sailcraft interstellar and the physics and students has completed a report on maths of space. A little belated but we thought how ChipSats could be used for a you would like the Christmas We have also been talking to the minimal interstellar mission that tree from Dmitry Novoseltsev famous Royal Institution (www. requires minimal funding. (Дмитрий Новосельцев). Dmitry rigb.org)in London about getting • ISU white paper on foldable gave us a vast vision of possible involved in their Masterclass structures for ChipSats: Another futures in his piece Engineering programme. report by ISU students addresses New Worlds: Creating the Future BIS Scotland relaunch how small foldable structures in P17-19. Here we see his more We were not able to be at City of could be used for enhancing the playful side. Lets adopt his idea Glasgow College for the relaunch capabilities of ChipSats. for a Christmas tree decorated of the Scottish chapter of the • Glowworm mission ISU with solar sails, laser sails, British Interplanetary Society on Individual Project: Chris Welch E-sails and magsails of different 30 January 2018 so all we can (ISU) and Nikolas Perakis (i4is) designs. Maybe for a children’s do is congratulate this renewed are currently supervising an Christmas party or adult New Year branch of our good friend and Individual Project on different celebrations next year? "older sibling", the BIS and mission architectures for the signpost them at www.bis-space. final Glowworm mission (laser com/branches/regional/bis- CubeSat + laser sail ChipSat). scotland The project is going to be The principal movers of this completed in the first half of renewal are Graham Paterson 2018, resulting in a report and of City of Glasgow College and a paper for the International Matjaz Vidmar of the Royal Astronautical Congress. Observatory Edinburgh. You • Minimal ChipSat interstellar can contact them via scotland@ mission ISU Individual Project: bis-space.com. They are keen Another Individual Project, to include i4is in their work and supervised by Chris Welch we'll be working with them to (ISU) and co-supervised achieve this in 2018. by Elena Ancona (i4is) is All the founding members of i4is addressing how a ChipSat are long-established members of could be sent out of our solar

Principium | Issue 20 | February 2018 11 The Initiative for Interstellar Studies

image: ©ALEX STORER Working towards the real Final Frontier

Help us to realise our mission to reach the stars - we need your help - physics to software engineering, graphic design to project management - and rocket science of course! ...and much more....

We have a great team. But we need more talent in all departments. Come and join us! Here is just some of our team - » Dr Andreas Hein: i4is Executive Director, System Architect & Engineer » John Davies: Project Manager & Editor, Principium, the i4is quarterly » Kelvin Long: i4is President, Advisory Council of Project Starshot, author Deep Space Propulsion, A Roadmap to Interstellar Flight (Springer) » Paul Campbell: Software Engineer » Richard Osborne: Rocket Scientist » Rob Swinney: i4is Education Director, Project Leader, Project Icarus » Terry Regan: creator of the BIS Daedalus model and the i4is 2001 Monolith » Tishtrya Mehta: Astrophysics Researcher

Web: i4is.org Twitter: @I4Interstellar R Contact: [email protected] O F Facebook: InterstellarInstitute E V I

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Principium | Issue 20 | February 2018 12 NEWS FEATURE Dr Pete Worden, Breakthrough Initiatives, at i4is HQ Patrick Mahon Our Principium Deputy Editor was privileged to be present at a historic meeting and public lecture by Dr Pete Worden, former Director of the NASA Ames Research Centre, Mountain View. He is now the Executive Director of Breakthrough Initiatives, and specifically of Breakthrough Starshot, with which i4is has been associated since its launch.

On Monday 20 November 2017, i4is HQ received a visit from Dr Pete Worden, former Director of the NASA Ames Research Centre in California, who is now the Executive Director of Breakthrough Initiatives, the set of interstellar challenges launched by US/Russian billionaire Yuri Milner and Professor Stephen Hawking in July 2015. Dr Worden was on a whistle-stop tour of Europe, so we were delighted that he found time in his busy schedule to meet with i4is’s leadership, discuss our work and give a public lecture. Pete Worden has had a long and varied career. After gaining a Intense discussion at the Mill. LtoR Angelo Gonovese, Rob Swinney, Patrick Mahon, PhD in astronomy he joined the Stefan Zeidler, Pete Worden. Credit: Kelvin Long United States Air Force, where he Pete arrived at lunchtime and, latest developments at the worked for nearly thirty years on following a quick tour of the Breakthrough Initiatives. Our the Strategic Defence Initiative building and a sandwich, he President, Kelvin Long, took and many other space-related spent the afternoon meeting the opportunity during these programmes, rising to the rank of with several members of the i4is meetings to present Pete with a Brigadier General. After retiring team, including Kelvin F Long, copy of the i4is book ‘Beyond from the USAF, Worden became Rob Swinney, Angelo Genovese, the Boundary’ and an i4is lapel a Professor of Astronomy at his Stefan Zeidler, Terry Regan pin, both of which were warmly alma mater, the University of and Patrick Mahon. Pete was received. Arizona, before becoming the briefed on i4is’s current projects, Following a tea break, Pete Director of NASA Ames in 2006, including Project Lyra, Project then delivered a public lecture a role he held for nine years Glowworm, Project Dragonfly in the grand conference room. before leaving NASA to join the and our education programme, He prefaced his remarks Breakthrough Initiatives. and, in turn, told us about the by showing a short video Principium | Issue 20 | February 2018 13 address delivered to a recent Chinese space conference by Breakthrough Initiatives Board member Stephen Hawking, in which Hawking explained why he believes that humanity should develop the capability to travel beyond the solar system and colonise planets around other stars. [Editor’s note: See the review of ‘A Search for a New Earth’ in P19 for further details of Hawking’s arguments.] He co-founded the Breakthrough Initiatives to do the early research and development work that Pete Worden addresses the meeting. Credit Kelvin Long will be a necessary precursor to any manned interstellar flight capability in the coming centuries, aiming to answer three fundamental questions: is there other life in the Universe? If so, is any of it intelligent? And is it possible for mankind to develop the technology to enable travel between the stars? Pete summarised the four main projects that fall under the banner of the Breakthrough Initiatives: • Breakthrough Listen – a $100 million programme of astronomical observations, searching for evidence of intelligent life beyond Earth. It will look for artificial radio or optical signals coming from the 1,000,000 nearest stars, the plane and centre of our own galaxy, and the 100 nearest Kelvin, Pete and Angelo. Credit Patrick Mahon galaxies. • Breakthrough Watch – a multi- last one took place at Stanford Pete explained that the key million dollar astronomical University in April 2017. problem for interstellar, rather programme to develop Earth- • Breakthrough Starshot – a than interplanetary, flight was and space-based technologies $100 million research and speed. The fastest probes we have that can find Earth-like planets engineering programme aiming yet launched from the Earth are in our cosmic neighbourhood, to demonstrate proof of concept the Voyager spacecraft, and these to see if they host life. This will for a new technology, enabling would take tens of thousands start with observations of the ultra-light unmanned space flight of years to get to our nearest Alpha Centauri system. at 20% of the speed of light, neighbour, Alpha Centauri. The • Breakthrough Discuss – an ultimately laying the foundations chemical rockets we currently use academic conference focused on for a flyby mission to Alpha simply aren’t up to the challenge. life in the Universe and novel Centauri within a generation. Breakthrough Starshot is instead ideas for space exploration. The Expanding on the last of these, investigating an alternative approach: laser-powered solar Principium | Issue 20 | February 2018 14 to achieving interstellar travel. i4is President Kelvin F Long thanked Pete for his inspiring lecture, and soon afterwards Pete was whisked away by taxi, headed for the University of Cambridge, where he was scheduled to see Lord Martin Rees, the British Astronomer Royal who is, like Kelvin, a member of the Breakthrough Initiatives’ advisory committee. It was a great pleasure to host Dr Pete Worden. We thank him for his time and insights, and hope to see him at our headquarters again in the near future.

Angelo explains i4is technical team laser sail propulsion and chipsat work. Credit Kelvin Long sails, where a powerful laser is focused on a large reflective sail carrying a tiny, low mass payload known as a ‘chipsat’. Freed from having to carry, and accelerate, their own fuel, such craft have the potential to reach very high speeds. [Editor’s note: This is, of course, the same propulsion technology that is at the heart of i4is’s own Project Glowworm.] He noted that one possible destination for an early solar/ laser sail technology demonstrator mission could be Saturn’s moon Enceladus, to follow up the Cassini mission’s recent discovery of a sub-surface ocean of liquid water. There followed a brief question and answer session, during which Pete was asked for more detail about the possible mission Relaxing in The Swan at the end of an exciting and to Enceladus, his views on highly productive day. LtoR Rob Swinney, Angelo Genovese, Gill Norman (Executive Secretary, BIS), colonising Mars, and what he Terry Regan, Sue Morris, Patrick Mahon, Kelvin believes to be the key challenges Long, Stefan Zeidler.

About Patrick Mahon Patrick Mahon is Deputy Editor of Principium and Programme Manager, i4is.

Principium | Issue 20 | February 2018 15 The Orbits of Seveneves A book review with a touch of orbital dynamics Sander Elvik

Sander reviews Seveneves by Neil Stephenson, a fiction by an acclaimed writer who has a strong technical backgound. This is part one of two. The second part, explaining the orbits and trajectories, will appear in the next issue of Principium.

“Why didn’t they just send everything up here?” “Plane-change maneuvers are expensive. It’s not too bad if the only thing plane-changing is Sean and Larz and a Drop Top, but it would be ridiculously wasteful to send the whole expedition package up here only to plane-change later.” Dinah didn’t mention the other reason, which was that the biggest part of Sean’s package was so screamingly radioactive that it couldn’t be allowed anywhere near them. “Okay. But we’re still talking geocentric, right?” “Correct, we’re still just a few hundred miles high.” “So, how do they get from the rendezvous point to a heliocentric situation?” “There’s a bunch of different ways to do it,” Dinah said, “but if I know Sean he’ll go through the L1 gateway.”

And so starts the description of capabilities. find yourself thinking “hey, that the orbital mechanics that are in By almost immediately is cool, but how then about…” play for Sean and his crew on the making it clear that the Earth is And again and again Stephenson Ymir, off on a private, improvised doomed, and giving a tight but proves the thoroughness of his mission to improve the odds of uncertain timeline for its demise, work by addressing these issues humanity surviving the inevitable Stephenson ensures you keep as well, but a bit further on in the doom that has been brought upon turning the pages. In the first part, book. the Earth. we follow the main characters of Although the presence of Seveneves, by Neal Stephenson the story as they work their roles technology is made very explicit is a science fiction novel with in the preparations to make a in the book, it is often more of a very realistic feel to it. The safe haven for humanity outside a backdrop in which the tale book is divided into three parts, the atmosphere. The tension is told. Just like contemporary of which the first two read like a builds up relentlessly by both technology usage is. Being a work technology thriller. Although no the race against a loosely defined of science fiction however, new date is used, the book is set in the clock, and by the new challenges strides in technology are required near future. A reader with more being introduced along the way. to meet the need of the characters, than average interest in space, These are not only the fictional such as long term provision of such as the readers of Principium, challenges the characters need energy, waste reuse and food can enjoy recognizing current to deal with, but also the ones production. While the latter comes orbital hardware, see a certain the readers are allowed to come to play a pivotal role in the story, NASA mission having been up with by themselves. Time unfortunately none of the three are completed, and observe further and time again, parts of the plan discussed in significant detail. At progress in the New Space unfolding are introduced and you the time of the events in the book,

Principium | Issue 20 | February 2018 16 important strides have been set in using them in a very action through the delicates of ΔV (delta robotics however, and these play packed and exciting part of the vee), apogee and perigee, the an interesting and entertaining book, where the team flying a matter of changing these and the role throughout the book. But spacecraft is faced with “so many effects on orbital periods, the time the real focus of the book is on imponderables, a well-managed it takes a spacecraft to make a full orbital dynamics, starting with aerospace engineering project orbit. the traditional orbits that current would have called a halt to all In the citation used in the space travel technology work further work and devoted several introduction of this review, he also with. years to analysing the problem throws in the very imaginative “I can’t drift far, confined as I down…” Their challenge is to notion of the “L1 gateway”. am to the pressure hull. But you match their highly elliptical orbit Although maybe the L2 gateway can imagine that if I hadn’t been to a circular low-Earth orbit, but would inspire the readers of able to stop - if I’d been out on a by rather unconventional means. Principium more, as it is our space walk - I might have drifted The author takes the reader way out of the solar system. a long way. And what the science of orbital mechanics tells is that no two objects in orbit can have the same six numbers, except in the special case I just showed you, where I was inside the hollow arklet so that both of our centres of gravity could coincide.” Hence the basics of orbital parameters and their influence on formation flight in space is introduced by one of the main characters of the book: Doc, a “famous astronomer and science pundit”. Stephenson has put much effort into making the real effects of orbital mechanics play an important role as the story is told. More or less all variations come into play, such as the basic class book circular low-earth orbit. Particularly interesting is how large orbital structures behave under the stresses of a low-earth circular orbit and the implication for formation flying, both of which play important roles in the story. Being thorough in his use of orbital dynamics, Stephenson also elegantly weaves into the story the aspects of orbital rendezvous, the matter of plane changes and the impact of an orbit’s inclination on the location of launch facilities on the ground. Even tethered flight and atmosphere skipping is touched upon. Stephenson then broadens UK cover Credits: Cover layout design ©HarperCollinsPublishers Ltd 2016 the subject to elliptical orbits,

Principium | Issue 20 | February 2018 17 Unfortunately, the specifics of this branch of orbital dynamics do not receive as much scrutiny by Stephenson as they deserve. In my opinion, these gateways are even cooler than they sound. They are solutions to the so-called three-body problem, which in astronautics is used to determine the motion of a spacecraft under the gravitational influence of two celestial bodies, like the Earth and the Moon. Stephenson’s orbital work is accurate, but at times brief or tightly interwoven into the story. To be able to grasp the finesse of what is described, good visual imagination power or some pre-knowledge comes in handy. Though it remains entertaining either way. And rest assured, the book is by no means an introduction to orbital dynamics only. Despite Neal Stephenson at Science Foo Camp 2008 all good intentions by the powers Credit: By Bob Lee; cropped by Beyond My Ken (talk) 20:21, 14 June 2010 (UTC) - originally posted to Flickr as Neal Stephenson, CC BY 2.0, https://commons.wikimedia.org/w/index. at work in the novel, politics php?curid=10637917 finds itself a way to orbit as well. The role of orbital dynamics was published in 2016 by Harper This provides for some attractive diminishes in this part of the Collins Publishers (ISBN: 978-0- conflicts. Often the wisdom of book. The reader’s curiosity as to 00-813254-5). It counts 867 pages knowledgeable subject matter what happened to humanity in the and can be found in various online experts is challenged by strongly five millennia between part 2 and stores with a list price of 14.99 opinionated politicians, backed by part 3 is rewarded piece by piece USD. UK price £9.99. social media influencers. Luckily, as the story further unfolds. It it is only the survival of the Neal Stephenson makes for a very rewarding read, human species which is at stake... Stephenson was born on but being more heavily a work The outcome of these conflicts October 31, 1959 in Fort Meade, of fiction and less a technology echoes on in part 3 of the book, Maryland, US, and had his first thriller as the first two parts, it is which takes place 5000 years novel published in 1984. Many also a different read. later, and form the new backdrop of his books combine high-tech In conclusion: a great read that of the story. Of course humanity themes with sociological ideas. will, if you like me like to read in by now have mastered Clarke’s Among other prizes, his novel bed, deprive you of some hours space elevator. There are grand Cryptonomicon (2013) won the of sleep. However, you will be space stations in orbit and several Prometheus Hall of Fame Award, awarded with an excellent tale of ingenious ways for people to and Seveneves was nominated for space travel and the joy of orbital travel between them and the the Hugo Award for Best Novel, mechanics. Earth. One of which uses 19th a prize he’d previously won in Seveneves by Neal Stephenson century whip technology. 1995. is a science fiction novel and About Sander Elvik Sander Elvik is a Systems Engineer and Systems Integrator based in The Netherlands, specialised in mission critical facility infrastructure for data centres. He holds a Masters in Aerospace Engineering from Delft University of Technology.

Principium | Issue 20 | February 2018 18 Models and art at the Mill

The Initiative for Interstellar Studies has always cherished the imaginative as an inspiration and sometimes even an exemplar of what we are striving to achieve. Our headquarters, informally "The Mill", give us an opportunity and a location to show visual imagination in all its forms. Here is a small sample of what you will see when you visit The Mill. Chosen to show the diversity of what we have gathered. There is far more and we'll be showing more of our collection in later issues of Principium. But there is no substitute for seeing it yourself - so come and visit us either at one of our of events or by pre-arrangement. You can always reach us on [email protected].

The reception and bar features a display of magazine covers, a Star Trek poster by Joshua Budich and on the right a NASA poster showing a Shuttle launch. Relax with coffee and a snack or wander further and see more...

Opposite the bar you will find globes of the Moon, Mars and Earth and portraits of UK space travellers - European Space Agency astronaut Tim Peake (Soyuz TMA-19M and ISS, 2015) and Project Juno cosmonaut Helen Sharman (Soyuz TM-12 and Mir space station, 1989).

Principium | Issue 20 | February 2018 19 Terry Regan holding the finished Discovery model (2001: A Space Odyssey) with Rob Swinney. Much enhanced from a kit model it now hangs in our HQ. "To Boldly Go" by Joshua Budich www.joshuabudich.com/star-trek "I was honored when CBS asked me to participate in their Star Trek: 50 Artists. 50 Years Art Exhibition".

Star Trek has been an inspiration to all at i4is. Here a specially significantly named starship, USS Kelvin.

The BIS Project Daedalus Fusion Starship model was sponsored by i4is and built by Terry. Normally residing at BIS, HQ, London, but loaned to i4is on special occasions.

Terry also led the team which built our 2001 monolith. Here Rob and Terry move half of it into storage in our HQ basement.

Principium | Issue 20 | February 2018 20 Tsiolkovsky - Interstellar Pioneer John Davies Principium Editor John Davies considers one of his heroes and his contribution to rocketry and the interstellar endeavour.

Introduction I first encountered Konstantin Eduardovitch Tsiolkovsky (Константи́ н Эдуа́рдович Циолко́вский) in my early teens. I was reading popular books about space travel following on from the adventures of Dan Dare "Pilot of the Future" in the UK comic Eagle. I read books like The Conquest of Space and Rockets, Missiles and Space Travel, both by Willy Ley and The Exploration of Space by Arthur C Clarke. And others now forgotten, by me at least! Amongst the Goddards and Von Brauns I came across a mention of a mysterious Russian, Tsiolkovsky; A man with a long beard and small glasses who was around at the time of Jules Verne and H G Wells but who did "real space", if only in calculation. I later discovered that he wrote science fiction too. He's been around my space career, both professional and amateur, ever since. Most recently I have done some work for schools with his famous equation but I was especially struck last year with this quotation which was blazed across the exit room of the exhibition, Cosmonauts: Birth of the Space Age, at the London Science Museum "Earth is the cradle of humanity, but one cannot live in a cradle forever". I was aware of Tsiolkovsky as a visionary as well Konstantin Eduardovitch Tsiolkovsky - without the long beard and small glasses! as a mathematician and engineer but Credit Archive of Russian Academy of Sciences. I had an impression that he had had

Tsiolkovsky quotation at London Science Museum

Principium | Issue 20 | February 2018 21 an interstellar vision. I decided Brief Biography • First international recognition - to investigate. This article is the To set the scene, here are the from the Society for Space Travel, result. main facts and milestones of Germany, Herman Oberth wrote My wider sources are referenced Tsiolkovsky's life (culled from to Tsiolkovsky in 1929: "You have in the text but you may be the Biographies listed below and kindled a fire, and we shall not especially interested in the final online sources) - let it die out, but will bend every effort to make the greatest dream sections of this piece, Biographies • Konstantin Eduardovich and Works (of Tsiolkovsky). The of mankind come true." (see Tsiolkovsky, Константи́ н latter is a translation of his papers Biographies: Sokolsky) Эдуа́рдович Циолко́вский which has been especially useful. • Death 1935 in Kaluga, Russian • Born 1857 in Izhevsk, Ryazan SFSR, Soviet Union. Age 78. Tsiolkovsky was driven through- Province, Russian Empire, son of out his life by that Onward and Eduard Ignatyevich Tsiolkovsky The Equation Upward urge which drives many and Mariya Ivanova Yumasheva Amongst his numerous of us, great and small, to consider • Early life - made deaf by an achievements, both visionary the future of our species beyond infection at age 9 and took to and practical, perhaps his most its beautiful cradle. His vision private study famous, simple and striking result extended to the stars but his is the Ideal Rocket Equation. This mathematical and engineering • Work - Aerospace Engineering, defines the performance of all intellect also drove him to dream Mathematics, Physics, reaction-propelled vehicles from too of "explosive pipes" governed Philosophy, popularisation of all fireworks to fusion rockets. by equations to enable us to get these through writings including there. science fiction The equation first appears in • Profession - Schoolteacher "Investigation of World Spaces by Reactive Vehicles (1903)" (see Works below). The date is important in the title because he uses the same title in later works - which also used the equation. Tsiolkovsky wrote the equation -

Where V is added velocity, V1 is exhaust velocity, Tsiolkovsky writes "Let us denote the mass of the vehicle and everything it contains, with the exception of the supply of explosives, by M1; the total mass of explosives by M2" A bit of algebra shows this to be equivalent to our more usual -

Where m0 is total initial mass and

mf is the final mass. Tsiolkovsky used conservation of momentum to derive the equation but a simpler though much less rigorous derivation can be done Tsiolkovsky's drawings of liquid fuelled rockets showing how his thinking evolved. directly from Newton's Second Credit: ESA / Museum of Flight, Seattle. law (using computing notation). Principium | Issue 20 | February 2018 22 insects and bacteria—do not all these activities create about man a situation that is purely As propellant is expelled the mass of the artificial? rocket falls and at constant exhaust velocity Tsiolkovsky's equation shows how velocity (see Works below for source) increases exponentially. Credit: John Davies / i4is.org Here his philosophy opposes the reaction of cultural critics like John Ruskin (1819 – 1900) who lamented the artificiality of industrial civilisation. In ethereal space this artificiality will simply be Newton's Second law - force mathematics and physics extended to the very limit, but equals mass times acceleration - wherever they assisted his then man too will find himself f = m*a objective. His equation gave in conditions that are most favourable for him. Transposing us the fundamental limits of "reactive vehicles". Physics Here Tsiolkovsky sees our species a = f/m can set frustrating limits to as finding its natural environment Integrating acceleration against engineers. American engineer- in space. What has subsequently the time from initial to final astronaut Don Pettit expressed been called an "ecological niche". velocity and mass from initial this frustration in "The Tyranny Over the course of the mass to final mass - with force of the Rocket Equation" (www. centuries, new conditions kept constant and directly nasa.gov/mission_pages/station/ will create a new species of proportional to the exhaust expeditions/expedition30/tryanny. beings, and the artificiality velocity of the rocket (since the html) and Scotty put it more which surrounds them will be exhaust velocity does not change) generally but very succinctly, diminished and perhaps will ∫a dt = f * ∫(1/m) dm telling Captain Kirk "I canna disappear completely. Wasn't Performing the integrations - change the laws of physics!" it like this that aquatic animals noting that the indefinite integral Imagination once crawled out upon the land of 1/x is ln x (log to base e of x)- and little by little turned into Tsiolkovsky was not only amphibians and then into land Change in velocity = exhaust concerned with the "nuts and animals; the latter, but perhaps velocity * ln (initial mass/final bolts" of leaving the earth and also the aquatic animals (flying mass). getting to other parts of the fish, for example) started the Which is the equation as we universe, he also had visions line of animals of the air, the usually quote it today. of the future of humanity and flying birds, insects, and bats. I stress again that this is not a sentient beings in general. Here rigorous derivation but it may be the themes of cosmism much He envisages a process of gradual helpful in showing how Newton discussed during his time and change to suit the new conditions. leads to Tsiolkovsky. especially in Russia, overlap He goes on to argue that "The Reactive Vehicle will save us from Having noticed that any with the practical scientist and engineer. Here's a quote from calamities that await the Earth" derivation of the equation requires both from catastrophic volcanic integration and that this is not "Investigation of World Spaces by Reactive Vehicles" (1911-1912) - activity and from impact of bodies taught in UK schools except to from "stellar space" - science specialists I developed At the present time, the more an incremental solution using a advanced layers of humanity If an aerolite several versts spreadsheet, Please contact me if strive to put their life in [approximately kilometres] you would like details. frameworks that are more and across hit the earth, it more artificial. Does not this would kill many people; Tsiolkovsky's objective was and this could happen quite to achieve spaceflight. His represent progress? The fight against inclement weather, high unexpectedly, for such an motivation was practical but aerolite as a non-periodic like all good engineers he used and low temperatures, the force of gravity, beasts and harmful comet coming from the murky Principium | Issue 20 | February 2018 23 depths of stellar space along century terrestrial energy period of time is of course a hyperbolic path cannot consumption looks fairly modest! very great, but for the whole be foreseen by astronomers He looks further - of humanity and for the light- much in advance of the But there is not one sun, there giving life of our sun it is catastrophe. People will perish are numberless luminaries and negligible. During tens of because of earthquakes, rising therefore not only limitless thousands of years in its trip temperature of the earth and space will be captured, but to another star, the human air, and due to a multitude of also limit- less energy of the race will live by the stores of other causes. rays of numberless suns will potential energy borrowed from We have, of course, recently seen be available for the life of our sun. such a "nonperiodic comet" on creatures. There are indeed "numberless a hyperbolic path, the asteroid That it is possible to reach luminaries". He remarks that ʻOumuamua - discussed elsewhere other suns is seen from the "several tens of thousands of in this issue of Principium. It following reasoning: suppose years" will be required to reach was only about half a kilometre a reactive vehicle is in uniform the nearest stars at a mere 30 in length but NASA anticipates motion at a velocity of only 30 km/sec or 1/10,000 of c but he that interstellar objects may be km/sec, which is 10,000 times mentions elsewhere that greater fairly common (www.nasa.gov/ slower than the speed of light. velocities may be obtained by planetarydefense/faq/interstellar). That is the speed of the earth other means, as we will see. So Tsiolkovsky produced early moving round the sun; such And unless the Bussard ramjet can arguments for moving beyond also is the speed of certain be made to work then "reactive" our planet and solar system. He aerolites, from which it is worldships will certainly need imagined how we might do it - evident that this speed is to "live by the stores of potential Reactive vehicles will conquer possible (without decrease) energy borrowed from our sun". limitless spaces for us human for small bodies as well. Since If transportation of mankind Bond/Martin Dry and Wet World Ship Concepts, Credit: Adrian Mann / BIS See 1984 papers including A. Bond and A.R. Martin, “World Ships – An Assessment of the Engineering Feasibility”, JBIS, 37, pp.254–266, 1984

beings and will provide two from the closest stars it takes to another sun is possible, thousand million times more. light several years to reach then why our fears about the solar energy than that which us, reactive trains will travel light-giving span of life of our humanity has here on earth. that distance in the course of presently bright sun? Let it Tsiolkovsky does not "show several tens of thousands of grow dim and become extinct! working" but 2*10^9 times years. During hundreds of millions greater than very early 20th For the life of one person this of years of its glory and Principium | Issue 20 | February 2018 24 brilliance man will be able to build up supplies of energy and emigrate with them to another seat of life. Tsiolkovsky envisaged an unlimited future for our species. He was sceptical about the contemporary view that the Sun would suffer thermodynamic "heat death" - The gloomy views of scientists about the inevitable end of all living beings on the earth and its cooling off due to the loss of the heat of the sun should not now have the merits of indisputable truth.

Lord Kelvin and others in the late affairs. But Tsiolkovsky is an First i4is laser-propelled interstellar probe concept, 19th century expected the Sun to optimist Project Dragonfly Credit: David Hardy cool as a result of the operation of Thus, there is no end to life, thermodynamics. We now know to reason and to perfection size does not exceed a few that nuclear processes give us of mankind. Its progress is tens of centimetres, this reason to expect a much longer, eternal. And if that is so, one electromagnetic "light" can but still finite, life for the Sun. cannot doubt the attainment of be directed as a parallel beam Tsiolkovsky puts one of the key immortality. with the aid of a large concave long-term arguments for human (parabolic) mirror to a flying Interstellar Propulsion expansion beyond the solar aeroplane and there perform system - There is currently little dissension the work needed for ejecting from the view that our earliest particles of air or supplies of In all likelihood, the better hope for propulsion of interstellar "dead" material in order to part of humanity will never probes is via some version of high acquire cosmic velocity while perish but will move from sun energy external electromagnetic still in the atmosphere. to sun as each one dies out in radiation acting on a sail. succession. Many decillion (see Works below for source) Tsiolkovsky envisaged this in his years hence we may be living This is beamed power to drive paper "The Spaceship" (1924- near a sun which today has not on-board reaction mass. He goes 1926). It is worth quoting at some yet even flared up but exists further - length. After discussing a number only in the embryo, in the form of high energy rocket propulsion This parallel beam of electric of nebulous matter designed ideas he goes on - or even light (solar) rays for eternity and for high should exert pressure by itself And finally, the third and most purposes. (there can be no doubt that attractive method of obtaining And he expects us to do even such pressure exists [see note speed. This is to transmit better when "our knowledge and on Lebedev below]) such energy to the vehicle from reason will have increased" pressure can give the vehicle outside, from the earth. The a sufficient speed. In that If today we are able to believe vehicle itself need not store case, one would not need any somewhat in the infinitude of up material energy (that is, supplies for ejection. The last mankind, what will it be like ponderable energy—in the method would seem to be the several thousand years from form of explosive or fuel). most refined. now when our knowledge and The energy is transmitted reason will have increased? to it from the planet in the Refined indeed - since this Though we may now be a little form of a parallel beam avoids the need for reaction less confident in the influence of of electromagnetic rays of mass and makes Tsiolkovsky's "knowledge and reason" in human short wave-length. If its own equation irrelevant. This is, Principium | Issue 20 | February 2018 25 Daedalus staging. Credit: Adrian Mann. Like all "reaction vehicles" a fusion rocket is subject to the Tsiolkovsky equation and, like all extant launch vehicles, requires multiple stages. of course, the subject of much The editors of this translation add radiation on four square recent work by several groups a footnote to justify Tsiolkovsky's meters hardly equals the worldwide including Lubin's team "refined method" - weight of one-tenth of a gram. at UCSB and by the Initiative The effect of light pressure was So, in "The Spaceship" one for Interstellar Studies - and, of experimentally established by Russian engineer, Tsiolkovsky, course, the major work driven the noted Russian physicist P. speaks to another, Yuri Milner by Breakthrough Starshot. N. Lebedev in 1899 (Editors). of Breakthrough Starshot, across Tsiolkovsky goes on to consider Lebedev's paper is 100 years. And to the rest of us as energy sources. "Untersuchungen über die we work towards our interstellar Indeed, on the earth we could Druckkräfte des Lichtes" goals. build a power station of (Investigations on the pressure Our other greatest hope for almost unlimited size with the forces of light) (it.wikisource. interstellar propulsion was also generation of many millions org/wiki/Scientia_-_Vol._VII/ anticipated by Tsiolkovsky. Recall of units of electric energy. Die_Druckkr%C3%A4fte_des_ that nuclear fission was decades The station transmits energy Lichtes) from proof, that fusion was a to a flying vehicle which Lebedev describes the effect, distant dream and see an inkling does not need to carry any supporting Maxwell's conclusion of what might be possible in this supplies of special energy that - from "Investigation of World (energy to produce speed). …the rays of light must exert Spaces by Reactive Vehicles" The vehicle would only carry pressure on those bodies on (1911-1912). passengers and life-support which they fall. The fact that First he reminds us of his rocket facilities for the trip or for this property of light escaped equation - permanent residence in the the researchers was easily ether. This would greatly … it is seen that an increase in explained by the exceptionally simplify the problem of [exhaust velocity] brings about low behaviour of these forces: interplanetary communications a proportional increase in the Maxwell calculated (1873) that and colonization of the solar velocity of the rocket, V2, for in the clear sky at lunchtime system. the same relative consumption the compressive force of solar of explosive mate-(M2/M1). Principium | Issue 20 | February 2018 26 He then considers the early results solar system. of course, and Arthur C Clarke from the study of radioactive All this from a single page in the remarked that either a positive elements - translation of his paper. or a negative answer to this It is believed that as radium Only someone with the great question would be equally disintegrates continually into combination of imagination, staggering. more elementary matter it drive, practical engineering Tsiolkovsky's 1911-1912 paper liberates particles of different thinking, up-to-date scientific "Investigation of World Spaces by masses moving with amazing, knowledge and mathematical Reactive Vehicles" ends with an unconceivable velocities close capability could have come up exhortation - to that of light. For example, with this intelligent speculation at Advance boldly, great and helium atoms are released here this time. The world of 1912 was small workers of the human with speeds from 30 to 100 even more unready for this than race, and you may be assured thousand km/sec. the ideas of Goddard ("A Method that not a single bit of your He mentions other particle of Reaching Extreme Altitudes" labours will vanish without velocities and goes on - 1919), Oberth (Die Rakete zu a trace but will bring to you These speeds (in km) are 6 to den Planetenräumen "The Rocket great fruit in infinity. 50 thousand times greater than into Planetary Space", 1923) May we, mostly "small workers", those of gases emerging from and the lunar visionaries of the also retain an optimistic view of the muzzle of our reaction pipe. British Interplanetary Society our human future! So he concludes that his rocket, 2 or 3 decades later (BIS Lunar Spaceship, 1939). Biographies the "reaction pipe", can employ Red Cosmos, K E Tsiolkovskii, propellants using similar Vision Grandfather of Soviet Rocketry, processes - Tsiolkovsky was a dreamer - By James T Andrews Ph.D, Texas .. if it were possible to although a very practical one. A&M University Press. 2009, accelerate the disintegration Some of his other ideas include - muse.jhu.edu/book/2784 of radium or other radioactive • All metal airships - lifted by an A biography putting Tsiolkovsky bodies, and probably all internal vacuum into a historical and cultural bodies are of this kind, then its • Steering rockets either by using context. employment might yield—all graphite vanes in the exhaust other conditions being equal, Konstantin Tsiolkovsky or by pointing the whole rocket His Life and Work, see formula (35) [a version of motor the rocket equation from his Arkadiĭ Aleksandrovich 1903 paper]—a velocity of • Cooling the outer surface Kosmodemyansky. English the reactive vehicle such that of a high velocity vehicle by translation X Danko published to reach the closest sun (star) circulating fuel through a double Dec 2000 University Press of the would be possible in 10 to 40 skin Pacific, Honolulu years. • Similarly cooling the rocket A more technical biography from It is a coincidence, of course, motor a Soviet point of view that the BIS Daedalus study led • Advocacy of liquid fuel rockets The Life and Work of Konstantin to a similar mission duration in an era of solid fuel rocketry E Tsiolkovsky, V N Sokolsky in K but clearly Tsiolkovsky was - in essence larger versions E Tsiolkovsky Selected Works anticipating mission durations of firework rockets - with A brief biography included in which are in the same range as suggestions for liquid oxygen and Selected Works, see below in Bond, Martin and the BIS team hydrogen as ideal propellants Sources anticipated many decades later. • The space elevator There are also many useful He goes on - • And, as we have seen, the sources on the web - here are two Then only a handful of radium, destiny of our species beyond our I have found most useful - see formula (16) [a different planet Konstantin E Tsiolkovsky www. version of the rocket equation And he believed that nasa.gov/audience/foreducators/ from his 1903 paper], would be consciousness must exist rocketry/home/konstantin- enough for a rocket weighing throughout the universe. We a ton to break all ties with the still don't know if we are alone,

Principium | Issue 20 | February 2018 27 tsiolkovsky.html • A High-Speed Train, 1927 Conclusion Konstantin Tsiolkovsky: Russian • Cosmic Rocket Trains, 1929 I have only touched on the Father of Rocketry, Nola Taylor • A New Aeroplane, 1929 range of work produced by Redd, Space.com Contributor, • Reactive Aeroplane, 1930 this remarkable member of our February 27, 2013, www. • To Astronauts, 1930 species. There is much more to space.com/19994-konstantin- • Semi-Reactive Stratoplane, say. We lack a thorough technical/ tsiolkovsky.html 1932 scientific biography, at least in • Reaching the Stratosphere, 1932 English or English translation. Works • Astroplane, 1932 And I have said nothing of My principal source has been - • The Astroplane and the his science fiction - which K E TSIOLKOVSKY Selected Machines That Preceded It, was deliberately didactic and Works, compiled by V N Manuscript dated 1933 inspirational. Sokolsky, General editor Acad. A • Maximum Rocket Speed, From I would welcome additions, A Blagonravov, translated from the manuscript dated 1935 corrections and comments from the Russian by G Yankovsky, Principium readers. University Press of the Pacific, Honolulu, Hawaii, 1968-2004 It contains two background pieces. The first by the great Sergei Pavlovich Korolev, director of the Soviet space programme till his premature death in 1966. Sergei Pavlovich Korolev (Серге́й Па́влович Королёв) On the Practical Significance Credit: London Science Museum of the Scientific and Engineering Propositions of Tsiolkovsky in Rocketry - S P Korolyov, 1957 The second the short biography already cited above - The life and work of Konstaniin E Tsiolkovsky, V N Sokolsky - and the following works by Tsiolkovsky- • From the manuscript "Free Space", 1883 • Tsiolkovsky's First Description of his Wind Tunnel, 1897 • Investigation of World Spaces by Reactive Vehicles, 1903 • Investigation of World Spaces by Reactive Vehicles, 1911-1912 • Investigation of World Spaces by Reactive Vehicles, Supplement to first and second parts, 1914 • The Spaceship, 1924-1926

John I Davies is a retired software engineer and mobile telecomms consultant. He was briefly in the UK space industry with small parts in an early design study for the Hubble telescope and in the last stages of the ultimately cancelled European ELDO launcher. His main work has been in communications software and in mobile data communications. He has been active in the Initiative for Interstellar Studies since soon after its foundation in 2012. He is a career-long member of the British Interplanetary Society.

Principium | Issue 20 | February 2018 28 Preparing for the next

Interstellar Object T M Eubanks*

Marshall Eubanks, CEO of Asteroid Initiatives LLC and a key member of the i4is Project Lyra team, considers the challenges of intercepting and examining future interstellar objects.

The recent discovery of the first has been learned from efforts 1. Introduction high velocity hyperbolic object to design a mission to 1I. Two 1I is a difficult, but not impossi- passing through the Solar System basic types of such missions have ble, target for a spacecraft mission [1], 1I/2017 U1 ’Oumuamua (or been proposed to date, pursuit with existing technology. 1I was simply 1I), opens the possibilities missions, where a spacecraft only discovered after its periheli- of near term interstellar missions, would be sent to chase and catch on (closest approach to the Sun) not to distant stars, but to up to an ISO after its discovery, and is rapidly leaving the solar considerably closer objects and prepositioned missions, system on a hyperbolic orbit, passing through the solar system. where spacecraft would be with a velocity “at infinity” (i.e.

Material orbiting in the galaxy launched and positioned in far from the Sun), v∞, of 26.3 km tests to migrate widely over time stable orbital regions, such as at s−1, or ~5.5 Astronomical Units and thus 1I, or any other visiting Lagrange points, in advance of (AU) per year, where one AU is InterStellar Object (ISO), would the discovery of any particular the distance between the Earth likely have formed very far from ISO. The prepositioned spacecraft and the Sun. 1I will thus be many the solar system in both space and would then wait and attempt AU from the Sun by the time any time, in another solar system or to intercept ISOs in the inner probe could be launched to over- maybe independently from stellar solar system, should some be take it; such a probe would need a outflows or ejecta in interstellar discovered and pass within range. v∞ considerably larger than 1I’s to space. These objects are thus It is not realistic to expect that a have a reasonable mission dura- likely to be very different from heavy lift booster would be kept tion. 1I will, for example, be at a any solar system asteroid, and on standby to send a probe to a distance of 36.2 AU on July 18th, from each other; determining their incoming ISO on short notice, 2023. A probe with a v∞ of 6.5 composition in detail would thus and it is highly unlikely that even AU per year would have a closing be of intense scientific interest. a very active interstellar comet velocity of only 1 AU per year, 1I is, however, an asteroidal would be detected much before and would take roughly 36 years ISO, not emitting any gas to one year before its perihelion to flyby 1I if it started its pursuit inform astronomers about its passage, and so any mission on that date. A more reasonable composition; in situ spacecraft initiated after the discovery of mission duration of under 18 exploration will be necessary to a new ISO will inevitably be a years would require a v∞ ≥ 7.5 AU determine details of the structure pursuit mission. Prepositioned per year, or ≥ 36 km s−1. This is and chemical composition of this missions are a newer idea offering substantially faster than the fastest or any other asteroidal ISO. a number of advantages but human spacecraft to date, Voyager −1 This note describes how also some formidable technical 1, which has a v∞ =16.86 km s . spacecraft exploration of challenges; more attention will be The various propulsion asteroidal ISOs can be paid here to pursuit missions. technologies capable of pursuing accomplished based on what and reaching 1I deep in the * Asteroid Initiatives LLC, P.O. Box 141, Clifton Virginia 20124, [email protected]

Principium | Issue 20 | February 2018 29 outer solar system have been the Catalina Sky Survey. These this uncertainty will be resolved surveyed by Hein et al. [2]; these surveys in aggregate have a total by the middle of the next decade, technologies can be in principle survey time of about 30 years; a when the LSST should be in full applied to any incoming asteroidal naive estimate for the detection operation. or cometary ISO. With chemical rate of 1I type objects would thus −1 3. Likely Velocities of Visiting rockets the necessary velocities be ~0.03 yr . Interstellar Objects require a combination of gravity The upcoming Large Synoptic As objects with densities assists together with powered Survey Telescope (LSST) will comparable to solar system Oberth maneuvers close to the reach a limiting survey magnitude bodies and diameters »1 cm will Sun to gain orbital energy; these as faint as r = 24.5, and so should not be significantly perturbed complicated orbital maneuvers be able to detect an incoming ISO by drag from the Interstellar inevitably restrict the timing of with a photometric magnitude Medium (ISM) even on billion such flyby missions even if a comparable to 1I at a distance of year time-scales [9], the v of an heavy lift booster, such as NASA’s ~ 1 AU, possibly several months ∞ incoming ISO provides a strong Space Launch System (SLS) [3] before perihelion. The LSST indication of which galactic were dedicated to the mission. survey should have a depth per population it belongs to. The unit time better than one order of 2. Finding More Interstellar Sun and most of the nearby magnitude better that the existing Asteroids stars are in the galactic thin surveys, leading to a naive 1I/’Oumuamua was discovered disk, orbiting very close to the estimate of a discovery rate for on October 18 by Pan-STARRS1 plane of the galaxy. The relative interstellar asteroids of ~0.2 per with a visual magnitude of velocities of objects in the thin year [7]. Cook et al. [8] looked 19.8 at a distance from Earth of disk are effectively randomized by at constraints on the number ~0.208 AU [1]. 1I photometric mutual gravitational interactions, density of interstellar comets and observations [4, 5, 6] reveal an with nearly Gaussian velocity concluded that the LSST could average absolute visual magnitude dispersions with a root mean detect as many as 1 or as few as of about 23, a tumbling non- square (rms) in the galactic plane 10−4 interstellar comets per year principal axis rotation with of ~40 km s−1 relative to the Local (with the primary uncertainty rotation periods of ~8.1 - 8.3 Standard of Rest (LSR)*, together being the uncertainty in their hours and surprisingly large with a rms of only 16.5 km s−1 number density). The discovery magnitude changes of > 2 for the W velocity component rates of both sorts of ISO are thus magnitudes during a rotation (the velocity in the direction still quite uncertain; it is not clear period. 1I was discovered by one orthogonal to the galactic plane) if the next decade will lead to the of the three most capable current [10]. (Note that these velocities discovery of no ISOs, a few, or asteroid surveys, the others being are all relative to the local potentially a flood. Hopefully, the Mt. Lemmon Survey, and orbital motion of ~255 km s−1

Table 1: Velocity Vector Components in the galactic U, V, W system, where U is radial, V is along the direction of galactic rotation, and W is orthogonal to the galactic disk. The final column provides the vector magnitude . The 1I inbound velocity is of course the incoming velocity of the asteroid relative to the Sun; the other velocities are thus expressed as the velocity of the LSR relative to the Sun. [10] provides the standard deviation of the stellar velocities, which is also included. The final row provides, as a reference, the difference of the 1I and Gaia DR1 velocity estimates.

Source U V W |v| km s−1 km s−1 km s−1 km s−1 1I inbound [13] -11.33 ± 0.07 -22.38 ± 0.08 -7.63 ± 0.09 26.18

New Hipparcos -7.5 ± 1.0 -13.5 ± 0.3 -6.8 ± 0.1 16.9 Reduction[10]

NHR standard deviation 32.6 22.4 16.5 [10] Gaia DR1 [14] -8.19 ± 0.74 -9.28 ± 0.92 -8.79 ± 0.74 15.18 1I - Gaia DR1 -3.14 ± 0.74 -13.10 ± 0.92 1.16 ± 0.75 13.52

* the mean motion of material in the Milky Way in the neighborhood of the Sun (en.wikipedia.org/wiki/Local_standard_of_rest) Principium | Issue 20 | February 2018 30 about the center of the galaxy.) about 40 km s−1). If a new visitor Stars (and presumably thus also is a thin disk object, the chances assist for the pursuit. asteroids and comets) from other thus are roughly equal that it Figure 1 shows the complicated trajectory required for a sample populations also speed through will have a smaller or a larger v∞ the galactic disk, with typical rms than 1I; only the objects with a pursuit mission to a body with the relative velocities of ~50 -100 comparable or smaller outgoing same timing and velocity as 1I, −1 but assumed for simplicity to be km s for objects from the thick v∞ are likely to be reachable disk, and ~300 km s−1 for objects with near term space flight entirely in the ecliptic plane. This from the galactic Halo [11]. technology. The directions of the sample mission involves a launch Intergalactic asteroids and comets outgoing velocity vectors will be in the Spring of 2021 into a high- are also a possibility; these would changed by their passage near energy transfer trajectory reaching be expected to have velocities the Sun, and will be effectively Jupiter a little over 1 year later, an relative to the Sun > 500 km s−1 randomized with respect to the unpowered Jupiter gravity assist [12]. All of these higher velocity ecliptic. The effective outbound to remove most of the probe’s objects should have near random inclination (the angle between the orbital angular momentum so that inclinations, and thus on average outgoing v vector and the plane it drops in close to the Sun, where ∞ * large velocities out of the galactic of the ecliptic) will thus also be an Oberth maneuver, with a δV −1 plane. an important factor in mission of 3.2 km s , would be performed Table 1 provides, in galactic planning, as only targets that only 2.4 million km from the Sun on July 18th, 2023, yielding a v coordinates, the inbound happen to have relatively small ∞ = 43.2 km s−1 and a flyby in late 1I v∞, together with recent effective outbound inclinations are determinations of the LSR likely to be reachable by a pursuit 2040. Solar shielding at least as velocity and, for reference, the mission. good as that for the Parker Solar Probe [17] would be required difference between the 1I inbound 4. Pursuit Missions velocity and the recent Gaia DR1 to survive the close passage by To reach an ISO in a pursuit the Sun during these Oberth LSR determination [14]. 1I has mission using chemical propulsion an incoming v of ~26.3 km s−1, maneuvers (at the minimum ∞ within a reasonable amount of largely in the galactic plane. distance of this sample mission time would require both a launch the solar flux would be over 5 This velocity is quite consistent reasonably soon after perihelion with it being a long term resident Megawatts per square meter, passage and a spacecraft v∞ 35 almost 4000 times the flux here at of the galactic thin disk, but is −1 km s . Attaining this velocity the Earth). much too small for it to be a thick ≳ with chemical propulsion is Note that there are two fairly disk or halo object. Clearly, with only possible in practice with a existing or near term technology, small angles in the trajectory combination of gravity assists, shown in Figure 1, one being pursuit missions will not be able at a minimum a Jupiter or Saturn to reach thick disk or halo objects, the angle between the incoming gravity assist to remove almost and outgoing velocity vectors at as these should have v∞ > 100 −1 all of the spacecraft’s orbital Jupiter, and the second, called the km s , and it is reasonable to angular momentum and leave its assume that any potential pursuit opening angle, being between the velocity vector pointing almost incoming and outgoing velocity target will be a thin disk object. directly at the Sun, followed by an Prepositioning missions are not vectors at the Sun. The latter Oberth maneuver (an impulsive angle (~ 30◦ for this particular subject to the same limitations, velocity change) at the time of and seem to be the only way at trajectory) sets a stringent limit the closest approach to the Sun on the effective inclination range present to explore high-velocity [15, 16]. After perihelion passage objects from outside the thin disk that can be targeted by these and the Oberth maneuver the maneuvers. To fall from Jupiter at close range. probe would execute a ballistic The incoming velocity vectors to close to the Sun the orbital pursuit, possibly decades long, angular momentum must be of thin-disk visitors to the solar to catch up with and flyby the system are likely to be in the target. Pursuit missions thus * Delta V - the change in velocity required. galactic plane with v ~ being See Tsiolkovsky - Interstellar Pioneer ∞ depend in practice on a favorable on average close to the velocity elsewhere in this issue for Delta V as planetary alignment, with Jupiter provided by rockets. There are other ways of of the local standard of rest (16.9 (or potentially Saturn) being at a achieving Delta V, of course, including laser −1 propelled sails km s , but with a variation of longitude suitable for a gravity

Principium | Issue 20 | February 2018 31 quite small (5.4 AU km s−1 in this case), which means that the Jupiter gravity assist cannot provide any significant velocity out of the ecliptic and the incoming velocity vector will be close to the ecliptic plane. The out-of-plane velocity required to reach high inclination targets thus must come from the Oberth maneuver, which typically have a small opening angle, or from a subsequent second giant planet gravity assist, which requires a possible but Figure 1: An intercept trajectory for an object in the ecliptic, but otherwise with the orbital parameters of 1I/’Oumuamua. After a launch into a fast Jupiter trajectory in April unlikely favorable alignment of 28, 2021, the probe would execute an unpowered gravity assist at Jupiter on May 22, two planets. 2022, passing within 30,000 km of the Jupiter surface, followed by a 3.2 km s−1 Oberth maneuver near the Sun (at 3.5 R [sun radii])on July 18th, 2023. This combination of The particular Oberth maneuver ☉ maneuvers would allow a heavy lift booster, such as NASA’s SLS [3], to deliver a 500 kg shown in Figure 1 thus cannot probe to the target with a fast flyby in early 2043. Credit: Marshall Eubanks. reach objects with effective would increase the mission target detection will have to be outbound inclinations 30 duration) or increasing δV (by performed optically or in the near- degrees unless a giant planet using either larger rockets or a IR with a telescope or telescopes happens to lie at the correct≳ less massive payload, or both). carried on the pursuit probe. The longitude for a second, post- The combination of realistic limits terminal navigation problem for Oberth, gravity assist. Of course, on mission duration and rocket 1I, for example, will be severe; the opening angle resulting size will mean that high velocity with an absolute magnitude of from the Oberth maneuver can and high effective inclination ~22 magnitude, 1I will be very be changed, but only at the cost ISOs will not make good pursuit dim as it recedes from the Sun, of other mission parameters. targets. By combining the velocity and an intercept in the late 2030’s Let ψ be half the opening angle and inclination restrictions it is or early 2040’s would be based, (technically, the angle between thus possible to predict that only with present data, on ephemeris the perihelion vector and the roughly one quarter of the ISOs information from 2017-2018, outbound v vector), and δV ∞ found are likely to be suitable leading to ephemeris uncertainties be the velocity imparted by targets for a pursuit mission. of many 10s or even 100s of the rocket thrust in the Oberth It is fortunate that the first one thousands of km. maneuver (i.e. along the velocity found, 1I, happens to be a suitable The apparent magnitude, m, vector at perihelion). Then, for a pursuit target and it is very of an asteroid depends on its relatively small v ∞ unclear when the next such target absolute magnitude, H, the will be found. distance between the body and (1) the observer, d , and the distance 5.The End of the Chase; Finding BO between body and the Sun, d . where ψ is of course in radians. the Target in a Pursuit Mission BS Ignoring the phase factor, which Equation 1 shows an inverse ISO pursuit missions will be will be effectively a constant in relation between v and ψ; a unusual in that they will almost ∞ the geometry of a pursuit mission, larger v can be obtained by a certainly be “ flying blind,” ∞ the apparent magnitude is given closer passage by the Sun, which aimed at a target that neither by results in a narrower hyperbolic the probe nor any terrestrial or (2) trajectory and a smaller ψ space telescope can see for most angle. To reach a large effective of the duration of the mission. outbound inclination (i.e. a large Unfortunately, radar or lidar will If the spacecraft has a telescope ψ) requires either reducing v not help with target detection ∞ with a limiting magnitude of m by moving the Oberth maneuver at distances of millions of km; SC then the target can be detected at a further from the Sun (which Principium | Issue 20 | February 2018 32 distance 6. Prepositioning Spacecraft 7. Conclusions It is possible that small spacecraft We now know for certain that (3) could be prepositioned in the interstellar asteroids exist and

inner solar system at relatively from time to time come through stable locations, such as Lagrange the solar system; it is inevitable with both d and d being BO BS points, to attempt ISO flybys in that missions will eventually measured in AU. Equation 3 the inner solar system, as has be mounted to directly observe encapsulates the discovery been proposed for comets [18]. these scientifically interesting difficulty that a pursuit mission These spacecraft, not having bodies. There is much that can will face. 1I, for example, has an any particular launch windows, be done to prepare for the next absolute magnitude that varies could be launched on a “space such visitor before its discovery. between ~ 22.5 and 25 depending available” basis, or under a A program to send future probes on its rotational phase [5, 6]. A program such as the NASA to future visiting ISOs would 40 cm optical telescope in space Small Innovative Missions for benefit from finding numerous should be able to detect a object Planetary Exploration (SIMPLEx) such objects, finding them as with a predictable motion at m SC program (part of SALMON, Stand early as possible, and improving ~23.5. As the exponential factor Alone Missions of Opportunity). the technology available to reach in Equation 3 would thus be near Prepositioning would avoid them. Clearly, anything that would zero on approach to 1I, and as launch scheduling problems substantially improve the depth d would be of order 100 AU BS and decades long pursuit times. and number of asteroid surveys or more even for high energy However, to have a good should improve the chances of Oberth maneuvers, 1I would not probability of success, such a finding interstellar objects; these be detected until the spacecraft mission would likely need a δV surveys should make sure that is a few hundredths of an AU, capability of order 1 - 5 km s−1, in their software allows for the or a few million km, away, a order to traverse distances of order high angular rate of motion of day or two at best from the time 0.1 AU in times of order of a few ISOs when they are close to the of the fast flyby*. As the target months. Prepositioned spacecraft Earth. Solar electric propulsion ephemeris uncertainty at that will likely need be small to lower rapidly loses effectiveness as point is likely to be ~50,000 km, costs, which seems in tension with probes on fast hyperbolic orbits the probe will need a terminal the δV required on such missions. move away from the Sun; pursuit guidance δV of order 0.5 to 1 This interesting possibility would missions would benefit from km s−1 in order to do a close clearly benefit from a detailed the availability of high-specific flyby of the target, releasing a design study for the ISO case, as impulse (ISP ) propulsion, such small impact probe to generate intercept mission characteristics as nuclear-electric rockets, that vapor for spectral analysis. As will be considerably different for do not require the availability the communication Round Trip interstellar asteroids than for long of solar power. Pursuit missions Time (RTT) at that time would period comets. will require a very high level be > one day, the probe would of independence in the flyby have to detect the target, perform spacecraft, and thus will terminal navigation, execute the benefit from the development terminal guidance maneuver and of spacecraft autonomous target the impact probe entirely operations. ISO missions are autonomously, without any active likely to make use of impacting feedback from its controllers on sub-probes to gain information Earth. about composition in the absence of cometary activity. These hypervelocity impacts would produce a significant amount

* The question of the limiting magnitude of a spacecraft telescope is a complicated one, as it depends on more than just the size of the telescope. Other factors include the nature and temperature of the detector, the stability of the platform and the length of maximum duration of exposures. The latter is exemplified by the increased exposure time for the Long Range Reconnaissance Imager (LORRI) on the New Horizons spacecraft which added an apparent magnitude (from 20 to 21) to the sensitivity of the imager as it headed out beyond Pluto (www. planetary.org/blogs/emily-lakdawalla/2018/0124-new-horizons-prepares-for-2014mu69.html). Note that such magnitudes are logarithmic - en.wikipedia.org/wiki/Apparent_magnitude - and this more than doubles the sensitivity of the imager. Principium | Issue 20 | February 2018 33 of Extreme Ultraviolet (EUV) [3] H. P. Stahl, R. C. Hopkins, A. [9] K. Scherer, Drag forces radiation on very short time Schnell, D. A. Smith, A. Jackman, on interplanetary dust grains scales, and these missions would K. R. Warfield, Designing induced by the interstellar thus benefit from improvements astrophysics missions for NASA’s neutral gas, J. Geophys. Res. in flash EUV spectroscopy. Space Launch System, Journal 105 (2000) 10329–10342. Prepositioned missions to of Astronomical Telescopes, doi:10.1029/1999JA900343. intercept ISOs are at present Instruments, and Systems 2 (4) poorly characterized and are at a (2016) 041213. doi:10.1117/1. [10] C. Francis, E. Anderson, low overall Technical Readiness JATIS.2.4.041213. Calculation of the local standard Level (TRL); these missions thus of rest from 20 574 local stars in require basic work to improve [4] W. C. Fraser, P. Pravec, A. the New Hipparcos Reduction their TRL before they can be Fitzsimmons, P. Lacerda, M. with known radial velocities, New seriously proposed. T. Bannister, C. Snodgrass, Astronomy 14 (2009) 615–629. I. Smoli’c, 1I/’Oumuamua arXiv:0812.4032, doi:10.1016/j. Acknowledgements. is tumbling, ArXiv newast.2009.03.004. This work used the JPL Small- eprintsarXiv:1711.11530. Body Database Browser, the JPL [11] P. E. Nissen, W. J. Schuster, HORIZONS system, the Minor [5] D. Jewitt, J. Luu, J. Rajagopal, Two distinct halo populations in Planet Center database and the R. Kotulla, S. Ridgway, W. Liu, T. the solar neighborhood. Evidence NIST Atomic Spectra Database. Augusteijn, Interstellar Interloper from stellar abundance ratios and TME was supported by Asteroid 1I/2017 U1: Observations from kinematics, Astron. Astrophys. Initiatives, S.A. Eubanks and a the NOT and WIYN Telescopes, 511 (2010) L10. arXiv:1002.4514, grant from NASA Innovative ArXiv e-printsarXiv:1711.05687. doi:10.1051/0004- Advanced Concepts (NIAC). 6361/200913877. [6] M. T. Bannister, M. E. References Schwamb, W. C. Fraser, M. [12] B. W. Carney, D. W. [1] P. Bacci, M. Maestripieri, Marsset, A. Fitzsimmons, S. D. 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L. Seaman, F. Trujillo, S. Navarro-Meza, L. galaxy from OB stars with C. Shelly, H. Sato, D. Abreu, M. Glaspie, Implications for proper motions from the Gaia M. Micheli, D. Koschny, M. Planetary System Formation from DR1 catalogue, Astronomy Busch, A. Knoefel, E. Schwab, Interstellar Object 1I/2017 U1 Letters 43 (2017) 159–166. G. V. Williams, Comet C/2017 (’Oumuamua), Ap. J. Lett. 850 arXiv:1611.00794, doi:10.1134/ u1 (panstarrs), Minor Planet (2017) L38. arXiv:1711.01344, S1063773717030021. Electronic Circulars 2017-U181. doi:10.3847/2041-8213/aa9989. [15] R. Adams, G. Richardson, [2] A. M. Hein, N. Perakis, K. F. [8] N. V. Cook, D. Ragozzine, Using the two-burn escape Long, A. Crowl, M. Eubanks, R. M. Granvik, D. C. Stephens, maneuver for fast transfers G. Kennedy, III, R. Osborne, Realistic Detectability of Close in the solar system and Project Lyra: Sending a Interstellar Comets, Ap. J. 825 beyond, in: 46th AIAA/ASME/ Spacecraft to 1I/’Oumuamua (2016) 51. arXiv:1607.08162, SAE/ASEE Joint Propulsion (former A/2017 U1), the doi:10.3847/0004-637X/825/1/51. Conference & Exhibit, American Interstellar Asteroid, arxiv.org/ Institute of Aeronautics abs/1711.03155. and Astronautics, 2010. Principium | Issue 20 | February 2018 34 doi:doi:10.2514/6.2010-6595. [17] N. J. Fox, M. C. Velli, S. D. [18] S. Aslam, M. F. A’Hearn, URL https://doi. Bale, R. Decker, A. Driesman, P. Clark, M. Daly, L. Feaga, D. org/10.2514/6.2010-6595 R. A. Howard, J. C. Kasper, J. Folta, N. Gorius, T. Hewagama, Kinnison, M. Kusterer, D. Lario, T. Hurford, M. Keidar, T. [16] L. A. Alkalai, N. A. Arora, M. K. Lockwood, D. J. McComas, Livengood, B. Malphrus, M. S. T. Turyshev, M. S. Shao, N. E. Raouafi, A. Szabo, The Mumma, C. A. Nixon, C. Proulx, L. F. Friedman, Solar Gravity Solar Probe Plus Mission: J. Sunshine, G. 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Apparent trajectory of ʻOumuamua as seen from Earth (from en.wikipedia.org/wiki/ʻOumuamua) showing origin in Lyra, closest approach to Earth in October 2017 and destination in Pegasus. See front cover of this issue for a hypothetical view of the Earth-Moon system at closest approach of ʻOumuamua.

Image credit:Tomruen/Wikipedia (trajectory data from JPL Horizons, ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_ group=sb&sstr=3788040)

About Marshall Eubanks Marshall Eubanks is CEO at Asteroid Initiatives LLC, the Asteroid Prospecting Company, and has held senior positions at JPL and the Internet Engineering Task Force (IETF). He holds a Master of Science (M.S.) in Physics and an M.S. in Planetary Physics from the Massachusetts Institute of Technology. Asteroid Initiatives is dedicated to exploring the economic potential of Near-Earth asteroids. Email address: [email protected] (T.M. Eubanks) Marshall would like to acknowledge Adam Crowl (i4is) and Demetrios Matsakis (U.S. Naval Observatory) for discussions and comments on the draft manuscript.

Principium | Issue 20 | February 2018 35 NEWS FEATURE Work on the interstellar asteroid and i4is Project Lyra

John Davies and Andreas Hein

Principium editor and i4is Project Lyra team leader consider the present state and future of ’Oumuamua and Project Lyra.

The Initiative for Interstellar Project Lyra and the initial of-oumaumau notably that Studies, i4is, announced Project paper of 8 November 2017 `Oumuamua is tumbling, Lyra on the 30 October 2017, received a great deal of attention unlike most asteroids in our 11 days after the discovery of including mentions in scientific Solar System and that given its 1I/’Oumuamua by the team publications- elongated shape this means that it at the University of Hawaii’s • IEEE Spectrum: How We is almost certainly a solid object, Pan-STARRS 1 telescope. The Could Explore That Interstellar unlike some of the "rubble pile" goal of the project is to assess Asteroid spectrum.ieee.org/tech- irregular objects in the Solar the feasibility of a mission to talk/aerospace/space-flight/how- System. 1I/’Oumuamua using current we-could-explore-that-interstellar- There is a fine animation of the and near-term technology and asteroid hyperbolic path of `Oumuamua to propose mission concepts for • Scientific American: SpaceX’s within the solar system by achieving a flyby or rendezvous. Planned Giant Rocket Could video originator "Tomruen" at - On 8 Nov 2017 i4is published the Chase Down Interstellar Asteroid commons.wikimedia.org/wiki/ first paper Project Lyra: Sending www.scientificamerican.com/ File:Oumuamua_trajectory_ a Spacecraft to 1I/’Oumuamua article/spacex-rsquo-s-planned- animation.gif based on trajectory ( former A/2017 U1) , the giant-rocket-could-chase-down- data from JPL Horizons. Interstellar Asteroid arxiv.org/ftp/ interstellar-asteroid/ The American Astronomical arxiv/papers/1711/1711.03155.pdf • Universe Today: Project Society (AAS) has a January 2018 Early work and reception Lyra, A Mission to Chase Down Update on an Interstellar Asteroid Recall that ’Oumuamua has a That Interstellar Asteroid www. by Susanna Kohler, aasnova. hyperbolic excess velocity of 26 universetoday.com/137960/ org/2018/01/19/update-on-an- km/s. This is much faster than project-lyra-mission-chase- interstellar-asteroid. any object humanity has ever interstellar-asteroid-1/ A couple of highlights from the launched into space. Voyager 1, There are also many references AAS piece- the fastest object humanity has to Project Lyra in popular and • Jason Wright (The Pennsylvania ever built, has a hyperbolic excess "serious" press and in academic State University) demonstrates velocity of 16.6 km/s. As it enters papers. via a series of calculations that no interstellar space ’Oumuamua Research on ’Oumuamua and known solar system body could covers 5.5 AU/year. In other interstellar objects have scattered ‘Oumuamua onto words it is travelling fast enough Here is just a small sample of its current orbit - nor could any across the diameter of Earth's published work - still unknown object bound to orbit more than twice a year. To The SETI Institute explains our solar system. The paper is reach it is a challenge close to some remarkable findingsThe On Distinguishing Interstellar the technical limits of our current Three Surprises of 'Oumuamua Objects Like 'Oumuamua civilisation. www.seti.org/three-surprises- From Products of Solar System

Principium | Issue 20 | February 2018 36 Scattering iopscience.iop.org/ • A travel time of 1013 years There is a Project Lyra Wikipedia article/10.3847/2515-5172/ (10,000,000,000,000 years!) page en.wikipedia.org/wiki/ aa9f23/meta at a speed comparable to its Project_Lyra. Please feel free to • Gregory Laughlin (Yale) and relative motion through the solar edit (but kindly avoid anonymous Konstantin Batygin (Caltech) neighbourhood. editing!) argue that its current passage, Manasvi Lingam and Abraham Coming soon if it’s not a fluke, suggests (Avi) Loeb look at Implications of i4is president Kelvin F Long and the presence of an enormous Captured Interstellar Objects For other members of the Lyra team number (1027) of such objects Panspermia and Extraterrestrial are working on a paper discussing in our galaxy alone — enough Life arxiv.org/pdf/1801.10254. the potential for an artificial origin to account for two Earth-masses pdf. They estimate the capture of ‘Oumuamua. They conclude, as of material for every star in the rate of interstellar objects by have other authoritative experts, galaxy. means of three-body gravitational that this is highly unlikely. They also argue that flinging interactions for Sun-Jupiter However given - asteroids like ‘Oumuamua out into system and the Alpha Centauri • the curious shape of the object interstellar space isn’t easy. The A&B binary system concluding • therefore the parallels with necessary multi-body interaction that the radius of the largest Arthur C Clarke's story requires the system to contain a captured object is a few tens of • the exploratory purpose of giant and long-period planet like km and Earth-sized respectively. Project Lyra Neptune or Jupiter and suggests They look at the implications of - they have called their paper, that every star in the galaxy may this model for the transfer of life Rendezvous with ‘Oumuamua. host a Neptune-like planet at a by means of rocky material by Look out for announcements Neptune-like distance. objects captured by this “fishing on our website, Twitter and The Laughlin/Batygin paper net” of the Solar system. Facebook. is On the Consequences of the Avi Loeb is Professor at the Detection of an Interstellar Center for Astrophysics, Future of Project Lyra Asteroid iopscience.iop.org/ Harvard, and chairs the Advisory Work on Project Lyra continues article/10.3847/2515-5172/ Committee for the Breakthrough and we are currently working aaa02b/meta Starshot Initiative. on refined mission scenarios, Looking for origins of the At the more speculative including the potential for asteroid, a paper 1I/2017 U1 end of things N Chandra advanced technologies such (‘Oumuamua) is Hot: Imaging, Wickramasinghe of University as laser, solar, electric sails for Spectroscopy And Search Of of Buckingham, UK, and acceleration and magnetic and Meteor Activity by Quan-Zhi international collaborators electric sails for deceleration Ye et al (Caltech, University suggest a vindication of his work that may allow for a rendezvous of Maryland, University of with Fred Hoyle, the Hoyle- with ‘Oumuamua. Furthermore, Western Ontario) arxiv.org/ Wickramasinghe theory of the we have also started using pdf/1711.02320.pdf origin and evolution of cosmic life trajectory otpimization tools for It suggests - in Oumuamua (A/2017U1) – A finding optimal trajectories to • The velocity and trajectory of Confirmation of Links between ‘Oumuamua using the Oberth ‘Oumuamua is consistent with a Galactic Planetary Systems in maneuver (powered slingshot typical interstellar object (ISO) Advances in Astrophysics tinyurl. at the Sun). Furthermore, our given the velocity distribution com/ACoLbGS public outreach continues with of the local stellar population, For other papers and the latest Project Lyra features to appear in but they found no definite star of publications try - scholar.google. the Dutch technology magazine origin com and search for Oumuamua. KIJK and the French astronomy • A scan of stellar close and aerospace magazine “Ciel et Where do I find out more? Espace” (Sky and Space). approaches to the nominal The i4is website has Project Lyra trajectory with the Gliese star – A Mission to ‘Oumuamua i4is. catalogue ( Gliese & Jahreiß org/what-we-do/technical/project- 1991) also reveals no obvious lyra which summarises the candidates in the immediate project and includes links to six vicinity of the solar system videos and 41 media mentions.

Principium | Issue 20 | February 2018 37 NEXT ISSUE

The Orbits of Seveneves - Part 2 - the orbits explained Book review 'Going Interstellar' - a Baen anthology new fiction & non-fiction on interstellar travel Z-pinch and Icarus Firefly

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Principium | Issue 20 | February 2018 38 Principium | Issue 20 | February 2018 39 Mission The mission of the Initiative for Interstellar Studies is to foster and promote education, knowledge and technical capabilities which lead to designs, technologies or enterprise that will enable the construction and launch of interstellar spacecraft.

Vision We aspire towards an optimistic future for humans on Earth and in space. Our bold vision is to be an organisation that is central to catalysing the conditions in society over the next century to enable robotic and human exploration of the frontier beyond our Solar System and to other stars, as part of a long-term enduring strategy and towards a sustainable space- based economy.

Values To demonstrate inspiring leadership and ethical governance, to initiate visionary and bold programmes co-operating with partners inclusively, to be objective in our assessments yet keeping an open mind to alternative solutions, acting with honesty, integrity and scientific rigour.

Editor: John I Davies Deputy Editors : Andreas Hein, Patrick Mahon

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Scientia ad sidera Knowledge to the stars

Front cover: Hypothetical Astronaut sees Earth-Moon system from ʻOumuamua, Credit: Efflam Mercier, efflammercier.com Back cover: ExTrA telescopes at La Silla Credit: ESO/Emmanuela Rimbaud

Principium | Issue 20 | February 2018 i4is.org 40