A 2007 Mars Sample Return Mission utilizing in-situ propellant production

Abstract

A system trade study was conducted to determine the feasibility of a 2007 Mars sample return (MSR) mission utilizing the Martian atmosphere for in-situ propellant production (ISPP). A hybrid zirconia and SabatierElectrolysis (S E) process ISPP system was assumed that produced liquid oxygen and liquid methane. The emphasis of the study was threefold. First, to determine what impact the choice in mixture ratio of the oxygedmethane propellant combination used for Mars ascent has on the overall injected mass from Earth of the MSR mission elements. Second, to ascertain if the 2003/2005 "workhorse" lander being designed for MSR missions can be modified to accommodate a 2007 ISPP MSR mission. Third, to identify what parameters and technologies have a significant impact on the overall injected mass of the MSR mission elements. This paper also summarizes the current status of ISPP work funded by the NASA through the Jet Propulsion Laboratory (JPL). It was determined that the choice in mixture ratio has a moderate impact on the overall injected mass from Earth of the MSR mission elements. Although it satisfies the injected mass constraint of an affordable medium"? launch vehicle, a 2007 ISPP MSR mission cannot be accomplished using a modified 2003/2005 "workhorse" lander due to configuration and packaging issues. Configuration, propulsion, power, and thermal control appear to be the four areas with the highest impact on the overall feasibility and injected mass for an ISPP MSR mission. Technology investment in these areas is required to make a 2007 ISPP MSR feasible.

Hybrid Rocket Propulsion and In-Situ Propellant Production for Future Mars Missions

“…In their 2007 MSR mission design, Thunissen et al 15 chose an operational O/F of 3.9, which is sensibly higher than the 3.45 optimal O/F of liquid methane and LOX shown on figure 2. That was because thanks to a slow decrease in performance at O/F ratios beyond the optimum, it was possible to replace some brought fuel by in-situ acquired oxidizer and further reduce the brought mass to Mars.…”

“…As explained in Part III, Zubrin's scenario reaches a higher propellant mass leverage than Stancati et al 10 and the hybrid at the cost of bringing liquid hydrogen and operating three different chemical reactors on Mars. The failed attempt of Thunissen et al 15 in designing a Zubrin MSR mission has demonstrated the danger of overcomplexification when it comes to ISPP. For the same reason that we do not believe that ISPP is relevant for MSR missions, we believe that the Zubrin ISPP presents too many unnecessary challenges for the first stage of medium to large-scale missions to Mars, for which one chemical reactor to be operated in-situ on Mars provides already enough challenges and propellant mass leverage.…”

“…It is to be noted that for methane/LOX engines, delivered performances of 342s and 350s were assumed for Sridhar's two MSR missions 19 . Also, the off-optimal-O/F design from Thunissen et al lead to a lower delivered specific impulse in the 330-335s range 15 . The delivered specific impulse levels for the hybrid and liquid engines used in ISPP mission designs for Mars are therefore of the very same magnitude.…”

“…This latter solution, requiring no less than three chemical reactors to be operated at the surface of Mars, was used in 1999 by Thunissen et al 15 for the design of a potential 2007 Mars Sample Return (MSR) mission.…”

“…Most ISPP mission designs carried out so far have concerned MSR missions 10,15,19 , missions that can now be achieved with much smaller payloads thanks to miniaturization and an Earth return vehicle that now remains in Martian orbit (Mars ascent vehicle (MAV) payload mass of 36 kg in 2010 6 against 240 kg in 1978 3 used until 1995 19 ). This evolution, as we will see in this article (Part VII), made ISPP rather irrelevant for MSR missions because it was unnecessarily complex and risky.…”