Commercial Spaceflight and Advanced Propulsion Commercial Crew Development (CCDev1) • Sierra Nevada Corporaon (SpaceDev) – Development of the Dream Chaser spaceplane – $20M for building and tes>ng Engineering Test Arcle – Leverages NASA HL-20 airframe – Launch vehicle: Atlas V – Hybrid Rocket – Seven crew members • Robert Bigelow • Expandable Space Staon Modules – Inflatable modules are easier to launch – Based on technology developed at NASA: TransHab Program • Prototypes: – Genesis I • 1/3 size inflatable structure • Launched July 12, 2006 • Expanded to twice its diameter (4.4 m) – Genesis II • Same size as Genesis I • Launched June 28, 2007 • Enhanced sensors • Addi>onal layer for thermal control • Increased reliability Sundancer/BA 330 • Occupancy – 3 people – long term – 6 people – short term • Protec>on – Radiaon – Ballis>c • Four large windows • Environmental Systems • Solar Power • Propulsion – Manuevering – De-orbing • Es>mated launch: 2014? Space Ship Two • Spaceplane – VSS Enterprise – VSS Voyager (planned) • Hybrid Rockets • Peak Al>tude: 110 mi White Knight Two • Jet powered aircra – VMS EVE – VMS Spirit of Steve Fossed • Launch Al>tude: 9.5 mi • Suborbital Space Tourism – Ticket: $200 K – Down payment: $20 K • Spaceport – Partnership with New Mexico – $200 million – Training ground for tourists Lynx • Two person • $95k ($20k deposit) >cket price • Al>tude 100 mi. • Take off/lands like airplane • Mark I test flight: 2014? • Poten>ally four flights/day • Kerosene and LOX engines X-Racer • Designed for Rocket Racing League • Two seats – Pilot – Flight Engineer • 230 mi/hr Advanced Propulsion/Concepts 8 Surface Reactors • Need power for astronauts on Moon or Mars • Nuclear power is the only viable solu>on for powering manned missions • NASA Glenn is currently working on developing a 40 kW fission reactor • Small scale compared to terrestrial power plants • Design must be very different (heat, size, materials…) • Test (without nuclear material) is expected 2012-13 9 Innovave Nuclear Space Power and Propulsion Ins>tute • Research space nuclear reactor concepts • Research space nuclear thrusters • Research materials/ components for space nuclear power • Mixture of theore>cal, computaonal, and experimental work 10 What we’re going to talk about We’re going to talk about propulsion that involves physics • Bussard Ramjet that is understood. • Solar Sails This does not mean that all of the • Magne>c Sails engineering problems are solved • Beamed Energy Propulsion We will not discuss propulsion that requires new physics to be • Laser Propulsion discovered or invented. • Tethers If you are interested in “new • Space Elevator physics” propulsion: hdp://www.daviddarling.info/ • An>maer encyclopedia/A/ advanced_propulsion_concepts.html 11 Fuel-less Propulsion We’ve talked a lot about chemical, electric, and nuclear rockets. In all of these systems, you’re rocket must accelerate its fuel for later parts of the mission. This led us to the rocket equaon. Remember that the fuel mass has an exponen>al dependence on the spacecra velocity. If we could leave the fuel behind, this would improve performance dramacally. This is an exponen>al mass savings. 12 Bussard Ramjet The Bussard Ramjet picks up fuel from interstellar space as it flies that it then “burns” in a nuclear reac>on to provide power and thrust. Ini>al design was mechanical structure. However, for a 1000 ton spacecra, a ramjet needed to be over 104 km2 Magne>c fields can be used instead, but we can only collect ionized H and not atomic H Technical challenges remain: difficult to get H into engine; collec>ng p not D 13 Solar Sails A solar sail uses a large sail and is pushed by photons from the Sun. Photons carry momentum and transfer No fuel is required. their momentum to the spacecra when they collide with the sail. Conceptually simple design. Can move spacecra towards and away from the sun Photon pressure at Earth: 10-5 N/m2 Large scale structure required in space (several square km) Thrust decreases as you move farther from the Sun since intensity falls off like 1/r2 14 Solar Sails A solar sail uses a large sail and is pushed by photons from the Sun. Research is currently underway to develop solar sail technology. NASA JPL: Nano Sail D tested in JAXA in space solar sail 15 large vacuum chamber () deployment (7.5 µm thick) Recent Solar Sails • Japanese Ikaros Project – Launch: May 2010 – Diagonal 20 m – Thickness: 7.5 µm – Next step: 50m sail to Jupiter/Trojans • NASA Nanosail-D – Cubesat – Nov 2010 – Area: 100 m2 16 Magne>c Sails A magne4c sail uses a large extended magne>c field, which interacts with the solar wind. The force of the solar wind plasma on the sail provides thrust. Magne>c field and plasma pressure balance. As spacecra gets farther away, size of the sail changes, but the thrust does not decrease Generang a large scale magne>c field has challenges: 1. requires superconduc>ng magnets 2. large structures in space Mini-Magnetosphere Plasma Propulsion (M2P2) Uses plasma to “inflate” magne>c field Only small structures and no superconduc>ng magnets are required 17 M2P2 Research Dipole magne>c field generated by large current loop Magne>c field looks like a mini- magnetosphere Test M2P2 constructed here at UW Tested at NASA Glenn Ini>al results on magne>c field inflaon look promising Currently unfunded Similar research currently funded by ESA 18 M2P2 19 MagBeam 20 ISS to Mars? • Plans to deorbit the ISS pushed back from 2016 to 2020 • ISS cost approximately $150 billion to construct in total • Unclear what it would require or cost to move the ISS out of orbit • Thermal, radiaon issues designed for being at Earth Laser Propulsion A laser pushed lightsail is similar to a solar sail, except the photons come from a laser on a staon instead of the Sun. Idea proposed and analyzed by Robert Forward in 1989. No fuel or large quan>>es of onboard power are required. More control of system since laser is controlled on Earth. Similar issues as solar sail: large structures in space; light falls off like 1/r2; low force A lightcra> has a parabolic mirror that is hit by a laser on the ground. The laser causes the air under the cra to heat violently, which generates thrust. Requires high power lasers (100 kW for sounding rocket capabili>es). hp://www.youtube.com/watch?v=LAdj6vpYppA 22 Tethers Tethers Unlimited is currently inves>gang use of space tethers for propulsion, power generaon, orbital transfers, launch assist… Microsatellite Propulsionless Electrodynamic Tether (µPET): How it works: 1. Long tether is deployed 2. Current is run along the tether (on board power is required) 3. Current in the tether interacts with the Earth’s magne>c field 4. That current can be used to power something to provide thrust Tether deployment has been successfully tested on shudle missions hp://www.youtube.com/watch? v=pCAEFocoVdM 23 Tethers Tethers Unlimited is currently inves>gang use of space tethers for propulsion, power generaon, orbital transfers, launch assist… Tether Assisted Launch: How it works: 1. Spacecra is launched by low power rocket. 2. Satellite in orbit reaches down with tether and grabs the spacecra 3. Tether swings the spacecra into a higher orbit 4. The orbital al>tude of the Tethers are constructed satellite is decreased with mul>ple fibers to 5. Can use µPET to increase be a robust design the orbit 24 Space Elevator A space elevator stretches from the surface of the Earth to geosynchronous orbit and higher to a counterweight A “climber” ascends the cable to bring payloads from Earth’s surface to orbit Concept of space elevator was first invented by Konstan>n Tsiolkovsky 1895 Currently, material technology is not available to construct a space elevator There is speculaon that carbon nanotube material could be used in the future 25 Space Elevator Base staons come in two varie>es: 1. Mobile plaorms 2. Staonary Plaorms Climber: • Not a tradi>onal elevator • Must be able to climb variable cable size • Speed and mass must be carefully adjusted to minimize oscillaons and cable damage 26 When will we build one? “The space elevator will be built about 50 years aer everyone stops laughing.” -Arthur C. Clarke Tether Strength Compete>>on: • Breaking strength • Strength to weight rao • Tether length Power Beaming Climber Compe>>on: • The level 1 (2 m/s) challenge: LaserMo>ve ($900,000). • The level 2 (5 m/s) challenge remains unclaimed ($1,100,000). “This is no longer science fic>on. We came out of the workshop saying, ‘We may very well be able to do this.’” -David Smitherman (2000) NASA/Marshall’s Advanced Projects Office 27 .