Preliminary study of rescue systems for Mars landing

Abstract

Entry, descent and landing (EDL) is probably the most difficult and risky phase of a human mission to Mars. Whatever the EDL systems for Mars, the qualification might be very difficult, very expensive and the risks could still be very high, especially for the first missions. Risks could nevertheless be mitigated if backup options existed during the final phase of EDL. If an important problem is encountered during the last minutes of the descent and if the velocity is lower than Mach 3, a possible option is to use an ejection seat, an individual parachute and small thrusters, which could be attached to the seat of the astronaut. The total mass of such a rescue system would be of the order of 230 kg, which does not include the mass of the astronaut. In the event of an emergency landing, the astronaut will still have to reach a safe haven quickly to survive because of his limited life support system autonomy. An automatic rover can be sent to rescue the astronaut and increase the maximum rescuing distance. A probabilistic risk assessment has been performed. Provided that the autonomy of the life support system is 8 h and that there is no insurmountable obstacle, it is shown that the probability of reachability is 0.9 at 50 km from the safe haven.