Commercial Spaceflight and Advanced Propulsion Commercial Crew Development (CCDev1) • Sierra Nevada Corporaon (SpaceDev) – Development of the Dream Chaser spaceplane – $20M for building and tesng 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 • Addional layer for thermal control • Increased reliability Sundancer/BA 330 • Occupancy – 3 people – long term – 6 people – short term • Protecon – Radiaon – Ballisc • Four large windows • Environmental Systems • Solar Power • Propulsion – Manuevering – De-orbing • Esmated launch: 2014? Space Ship Two • Spaceplane – VSS Enterprise – VSS Voyager (planned) • Hybrid Rockets • Peak Altude: 110 mi

White Knight Two • Jet powered aircra – VMS EVE – VMS Spirit of Steve Fosse • Launch Altude: 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 • Altude 100 mi. • Take off/lands like airplane • Mark I test flight: 2014? • Potenally 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 soluon 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 Instute

• Research space nuclear reactor concepts • Research space nuclear thrusters • Research materials/ components for space nuclear power • Mixture of theorecal, 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 • Magnec 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: hp://www.daviddarling.info/ • Anmaer 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 exponenal dependence on the spacecra velocity.

If we could leave the fuel behind, this would improve performance dramacally. This is an exponenal mass savings. 12 Bussard Ramjet The Bussard Ramjet picks up fuel from interstellar space as it flies that it then “burns” in a nuclear reacon to provide power and thrust.

Inial design was mechanical structure.

However, for a 1000 ton spacecra, a ramjet needed to be over 104 km2

Magnec 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; collecng 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 Magnec Sails A magnec sail uses a large extended magnec field, which interacts with the solar wind. The force of the solar wind plasma on the sail provides thrust. Magnec 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 magnec field has challenges: 1. requires superconducng magnets 2. large structures in space Mini-Magnetosphere Plasma Propulsion (M2P2) Uses plasma to “inflate” magnec field

Only small structures and no superconducng magnets are required 17 M2P2 Research Dipole magnec field generated by large current loop

Magnec field looks like a mini- magnetosphere

Test M2P2 constructed here at UW

Tested at NASA Glenn

Inial results on magnec 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 quanes 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 capabilies). hp://www.youtube.com/watch?v=LAdj6vpYppA 22 Tethers Tethers Unlimited is currently invesgang 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 magnec field 4. That current can be used to power something to provide thrust Tether deployment has been successfully tested on shule missions

hp://www.youtube.com/watch? v=pCAEFocoVdM 23 Tethers Tethers Unlimited is currently invesgang 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 altude of the Tethers are constructed satellite is decreased with mulple 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 Konstann 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 variees: 1. Mobile plaorms 2. Staonary Plaorms

Climber: • Not a tradional 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 Competeon: • Breaking strength • Strength to weight rao • Tether length

Power Beaming Climber Compeon: • The level 1 (2 m/s) challenge: LaserMove ($900,000). • The level 2 (5 m/s) challenge remains unclaimed ($1,100,000).

“This is no longer science ficon. 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