High-Altitude Divert Architecture for Future Robotic and Human Mars Missions

Future robotic and human missions to Mars require improved landed precision and increased payload mass. Low ballistic coefficient entry vehicles decelerate high in the thin Mars atmosphere and may be used to deliver higher-mass payloads to the surface. A high-altitude supersonic propulsive divert maneuver is proposed as a means of precision landing for low ballistic coefficient entry vehicles that decelerate to supersonic speeds at altitudes of 20-60km. This divert maneuver compares favorably to traditional precision landing architectures with up to 100% improvement in range capability while saving over 30% in propellant mass. Through Monte Carlo simulations, it was found that architectures that use hypersonic vehicles with ballistic coefficients of 10kg/m2 can potentially land within 500m of a target with this maneuver alone. This high-altitude divert range capability is sensitive to altitude and flight-path angle variations at maneuver initiation, and it is relatively insensitive to velocity at initiation. The propellant mass fraction is relatively invariant to the initial conditions and correlates directly with the divert distance.