AAWSAP DIRD, Positron Aerospace Propulsion, March 2010

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Benefits of using positrons for a Mars mission include:
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The "disposable /:i.V" used to propel TMI stages into low-probability Earth or Mars
intercepts can be eliminated, reducing total propellant mass.
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Reduction in shielding and engine mass give lower initial mass low Earth orbit for
launch vehicles or faster transits for piloted missions.
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The ERV uses a positron engine instead of LOX/CH4. This gives significant mass
savings or an equivalent reduction in Mars-to-Earth return time for astronauts.
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The improvement in l sp translates to either a reduced launch payload mass for cargo
missions or reduced transit times for piloted missions to Mars.
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More chemical propellant can be stored on the lander to improve aerobraking or
landing strategies that reduce hazards for astronauts.
Launch dates are set for around 2030. Assuming minimum !:i.V for Mars opposition-class
missions, interplanetary scenarios are illustrated in Figure 16. The !:i.V for an insertion
trajectory into Mars for the manned mission (Figure 16b) is !:i.V = 3.7 km/sec. Each
manned trajectory assumes a 180-day transit time .
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Figures 16. Mars Trajectories (X-coordinates defined in direction of Aries): (a) 2029 cargo mission; (b)
2031 manned lander to Mars; (c) 2033 manned return to Earth; (d) 2035 manned lander to Mars, if necessary
(courtesy Positronics Research LLC) 52
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