ERAU Space Physics Program1 Space Physics Program College of Arts & Sciences ERAU-Prescott Dr. Darrel Smith World Space Congress October 17, 2002

ERAU Space Physics Program2 Outline 1. The Space Physics degree program 2. Motivation for advanced propulsion 3. Antimatter propulsion 4. Possible missions (timescales) 5. Experiment to measure I sp

ERAU Space Physics Program3 B.Sc. Space Physics Degree Program 1. Nick Devereux’s talk (yesterday) Space Science Education & Outreach 2. Program Starts Fall Four areas of concentration Embry-Riddle Aeronautical University

ERAU Space Physics Program4 Motivation Why Antimatter Propulsion ? The “long” mission

ERAU Space Physics Program5 Problems with the “long” mission 1. Prolonged zero-g environment Weightlessness triggers a reduction in density of weight-bearing bones 1-2% a month severe osteoporosis

ERAU Space Physics Program6 Problems with the “long” mission 2. Radiation Exposure Mars vehicle is no longer shielded from galactic and solar radiation

ERAU Space Physics Program7 Advanced Propulsion Systems Goal: Obtain the highest I sp Antimatter I sp ~ 10 7 sec. 1. Antiprotons 2. Positrons

ERAU Space Physics Program8 Antiprotons Momentum Thrust The production of massive particles reduces the thrust.

ERAU Space Physics Program9 Positrons Momentum Thrust The production of “massless” particles (e.g., photons) enhances the thrust. “Photon Drive”

ERAU Space Physics Program10 The Engine Positron-electron annihilation occurs behind an absorber/reflector at the rear of the spacecraft. thrust

ERAU Space Physics Program11 The Photon Drive

ERAU Space Physics Program12 Spacecraft Performance Specific Thrust: Thrust:

ERAU Space Physics Program13 Mission Parameters Minimum flight time for rendezvous (Mars, Jupiter) Use a Direct Trajectory Optimization Method (D.A. Kluever, 1997) Start in a heliocentric orbit with the same position, velocity vectors as the Earth. The spacecraft is transferred to heliocentric orbits around Mars and Jupiter

ERAU Space Physics Program14 Mission Parameters to Mars & Jupiter PlanetM rocket M propellant Travel time Mars400 Mt1.336 Mt3.84 days Jupiter400 Mt3.765 Mt10.8 days

ERAU Space Physics Program15 Mission Parameters to  -Centuari M rocket M propellant Velocityt t (years) t o (years) 400 Mt53.9 Mt0.10 c Mt170 Mt0.50 c Mt360 Mt0.98 c

ERAU Space Physics Program16 Measuring the specific thrust Store positrons in a Penning trap. G. Smith, LLL Release the positrons in a time window of 100  s. The positrons annihilate the electrons on a tungsten target which is mounted on a torsion pendulum. We expect to measure a force of ~1.3 mN by measuring the amplitude of motion of the torsion pendulum. This will be the first measurement of the specific thrust due to matter-antimatter annihilations.

ERAU Space Physics Program17 Conclusions Something like a “photon drive” engine will be required to achieve interplanetary and interstellar manned space travel. The major hurdle to overcome will be the technology required to produce and store many kilograms of positrons. High-flux, relatively low-energy accelerators will be needed to produce the volume of positrons required. New accelerator technology is needed. The need for compact, high-energy sources of fuel will be in high demand, so commercial markets may be the “driving force” in developing this breakthrough technology.

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