See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/323458920 Nanospacecraft Fleet for Multi-asteroid Touring with Electric Solar Wind Sails Article in IEEE Aerospace Conference Proceedings · March 2018 CITATIONS READS 0 302 19 authors, including: Andris Slavinskis P. K. Toivanen NASA Finnish Meteorological Institute 27 PUBLICATIONS 94 CITATIONS 64 PUBLICATIONS 418 CITATIONS SEE PROFILE SEE PROFILE Maria Gritsevich David Mauro University of Helsinki NASA 147 PUBLICATIONS 534 CITATIONS 9 PUBLICATIONS 28 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: ESTCube-2 View project Multi-Asteroid Touring View project All content following this page was uploaded by Andris Slavinskis on 28 February 2018. The user has requested enhancement of the downloaded file. Nanospacecraft Fleet for Multi-asteroid Touring with Electric Solar Wind Sails Andris Slavinskis Pekka Janhunen Karri Muinonen Tartu Observatory Petri Toivanen Antti Penttila¨ NASA Ames Research Center Finnish Meteorological Institute Mikael Granvik Moffett Field Erik Palmenin´ aukio 1 Tomas Kohout Mountain View, CA 94035 00560 Helsinki, Finland Maria Gritsevich Mobile: +16505375099 [pekka.janhunen, petri.toivanen] Department of Physics [email protected] @fmi.fi P.O. Box 64, FI-00014 University of Helsinki, Finland Andris Slavinskis Mihkel Pajusalu [karri.muinonen, Mihkel Pajusalu Massachusetts Institute of Technology antti.i.penttila, mikael.granvik, Indrek Sunter¨ Department of Earth, Atmospheric, tomas.kohout, Hendrik Ehrpais and Planetary Sciences maria.gritsevich]@helsinki.fi Janis Dalbins 77 Massachusetts Ave Iaroslav Iakubivskyi Cambridge, MA 02139 Karri Muinonen Tonis˜ Eenmae¨ [email protected] Finnish Geospatial Tartu Observatory, University of Tartu Research Institute FGI Observatooriumi 1, Toravere˜ Erik Ilbis National Land Survey of Finland 61602 Tartu county, Estonia Hendrik Ehrpais Geodeetinrinne 2 Mobile: +37258284333 Estonian Student Satellite Foundation 02430 Masala, Finland [andris.slavinskis, mihkel.pajusalu, W. Ostwaldi 1-D601 indrek.sunter, hendrik.ehrpais, 50411 Tartu, Estonia Maria Gritsevich janis.dalbins, iaroslav.iakubivskyi, [[email protected], Ural Federal University tonis.eenmae]@ut.ee hendrik.ehrpais]@estcube.eu Institute of Physics and Technology Mira str. 19, 620002 David Mauro Andrew S. Rivkin Ekaterinburg, Russia Jan Stupl The Johns Hopkins University Stinger Ghaffarian Technologies Inc. Applied Physics Laboratory William F. Bottke NASA Ames Research Center 11100 Johns Hopkins Rd Southwest Research Institute Moffett Field Laurel, MD 20723-6099 1050 Walnut St, Suite 300 Mountain View, CA 94035 [email protected] Boulder, CO 80302 [jan.stupl, david.mauro]@nasa.gov [email protected] Abstract—We propose a distributed close-range survey of hun- dreds of asteroids representing many asteroid families, spec- tral types and sizes. This can be implemented by a fleet of nanospacecraft (e.g., 4–5-unit CubeSats) equipped with minia- ture imaging and spectral instruments (from near ultraviolet to near infrared). To enable the necessary large delta-v, each spacecraft carries a single electric sail tether which taps the momentum from the solar wind. Data are stored in a flash memory during the mission and downlinked at an Earth flyby. This keeps deep-space network telemetry costs down, despite the large number of individual spacecraft. To navigate without the use of the deep-space network, optical navigation is required to track stars, planets and asteroids. The proposed mission architecture is scalable both scientifically and financially. A TABLE OF CONTENTS fleet of 50 spacecraft will be able to obtain images and spectral data from 200 to 300 near-Earth and main belt asteroids. It 1. INTRODUCTION ................................... 2 allows study of those asteroid families and spectroscopic types for which currently no close-range observations are available. 2. SCIENCE OBJECTIVES ........................... 3 This paper presents science objectives, overall science traceabil- 3. SCIENCE TRACEABILITY MATRIX ............... 5 ity matrix, example targets and technical challenges associated with the mission. We open to discuss preliminary requirements, 4. EXAMPLE TARGETS .............................. 5 mission and spacecraft designs. 5. TECHNOLOGICAL CHALLENGES ................ 7 6. PRELIMINARY REQUIREMENTS .................. 8 7. PRELIMINARY MISSION DESIGN ................. 9 8. SUMMARY ........................................ 16 ACKNOWLEDGMENTS ............................... 16 REFERENCES ........................................ 17 978-1-5386-2014-4/18/$31:00 c 2018 IEEE BIOGRAPHY ......................................... 19 1 1. INTRODUCTION composition and structure of planetesimals from which, e.g., The motivations to study asteroids range from understanding the Earth once formed. Therefore we should have a reliable of the early evolution of the Solar System to plans of in- statistical view to size and compositional distributions of at space resource utilization. As remnants from Solar System least the largest asteroid families. An asteroid family (a group formation, they are studied to understand the delivery of of asteroids with similar orbital parameters and spectra) is water and organics to the Earth and other planets, and to thought to correspond to collisional fragments of a single determine the evolution and composition of the asteroids original parent body. themselves, of the planets, and the Solar System as a whole. During the mission, asteroids belonging to different families, As the largest population of Solar System objects, asteroids different spectral types and size classes are characterized. A and meteoroids regularly impact the Earth and its atmosphere, causing meteor showers, scientifically valuable meteorite fleet of small spacecraft tour multiple asteroids and gather impacts and devastating asteroid impacts [1]. As rich and remote measurements of a much larger number of asteroids accessible resources, asteroids could be used for extraction of than have thus far been studied at a close range. Each water and for mining of platinum group metals and building spacecraft is equipped with a small electric solar wind sail (E-sail) tether to give it large (in principle unlimited) ∆v materials. capability so that it can tour the asteroid belt indefinitely There are two principal ways the asteroids are studied. First, (i.e., limited only by the mission and spacecraft lifetime) and via distant, typically point-source observations with ground- return data to the ground during one or more Earth flybys. based and space telescopes. Second, via space missions with The science payload on board each spacecraft is lightweight close-range observation, in situ measurements and sample – a Near UltraViolet-VISual-Near InfraRed (NUV-VIS-NIR) instrument for high-resolution imaging at short wavelengths return. The first method allows the study of thousands of µ µ objects using a single instrument at a time. By doing so, we (e.g., 0.3–0.5 m) and up to 3.7- m spectral imaging. gain overall knowledge about orbits, albedos, colors, spectra The mission provides a unique contribution to the closing of and sizes of asteroids. On the other hand, a single spacecraft can study one or, in some cases, a few objects in detail. Space the knowledge gap between a large number of surveyed aster- missions can provide maps of albedos, colors, spectra and oids and a handful of closely studied asteroids by performing morphological features (craters, faults, fractures, boulders, flybys to tens of primary targets (two flybys per target) and hundreds of secondary targets. This allows collection etc.), three-dimensional models, precise mass and density < estimates, physical properties and chemical composition of of close-range ( 1000 km) high-resolution (10–20 m/px) the surface material, as well as infer the internal composition. imagery and spectra (45–170 m/px in the range from 1 to 3.7 µm). With such a simple measurement strategy, resolved As of today, there are more than 752,000 known asteroids [2], observations are obtained from asteroids over all spectral at least 138,000 of which have size and albedo estimates [3]. types and 10+ families, including all known active asteroids Information on the taxonomic class has been derived for and 10+ potentially hazardous objects. The mission also about 4,000 asteroids based on their low-resolution spec- contributes to determination of the evolution of the current tra. Using the broad-band photometry, tens of thousands population of asteroids, detection of hydration features, deter- of asteroids have been classified. The number of spectrally mination of mass and density of binaries, finding of signs of classified asteroids will increase to hundreds of thousands in material transfer between binaries, and mapping of potential the upcoming decade thanks to Gaia, Euclid and other large sample return targets and sites. scientific telescopes that are currently in development [4]. The MAT concept was proposed for the European Space Since the beginning of 1990s, six close-range, in situ and sample return missions have flown and performed detailed Agency’s (ESA’s) Announcement of Opportunity (AO) “New study of ten asteroids. The upcoming decade will double Science Ideas” [7]. Consequently ESA selected the theme of the number thanks to Hayabusa-2, OSIRIS-REx, DART, using nanospacecraft in small body missions and studied it