Letter: Mars Sample Return Key Link Still Missing
Recent news articles about uncertain NASA Mars budgets have repeatedly noted that the next rover or orbiter must lead to sample return, formalized last year as the highest priority among future planetary missions [“Former Mars Czar Tapped To Lead NASA’s Mars Reboot,” March 5, page 7; “NASA Seeks Ideas for Next Mars Mission,” April 16, page 3; and “$17.5B NASA Spending Bill Favors Planetary Probes over Crew Taxis,” April 30, page 1].
Reporters, scientists and taxpayers should pointedly ask about spending plans for a related costly flight program that is rarely mentioned. Compared with orbiters and rovers, testing rockets needed to actually return from Mars offers far more leverage toward the stated priority.
Aerospace conference presentations in March showed that the Mars ascent vehicle continues to languish as several competing “paper rocket” designs, with negligible progress during the past dozen years of brilliant successes for one-way missions. Why?
Status quo engineers confidently promise predictable results in order to compete for funding. This “design-build” assumption lets leaders continually choose to wait until work officially begins on the often-postponed sample-return mission.
Some engineers acknowledge that creating a tiny launch vehicle is an adventure into the unknown. Since the 1990s, the regular response has been that sample return is in the near future so there isn’t time to develop new technology, absurd in retrospect.
Smaller Mars ascent vehicles can reduce the overall scale and cost of sample-return missions. In a contrary move a few years ago, NASA’s conceptual mission design was expanded under an assumption of increasing budgets. The updated plan includes an extra Mars lander dedicated to delivering a relatively heavy 300-kilogram vehicle for launching from Mars to orbit. Even for that size, the required propulsive capability is far beyond anything ever flown.
A reasonable path would be to pay for Mars return technology sooner instead of perpetual postponement. If the optimists are right, would it be terrible to have a proven capability years before it is needed? More likely, setbacks should be expected.
Mars science leaders and NASA managers would do well to learn the technical reasons that it is challenging to build a launch vehicle barely larger than a person. To ensure success, they should scrutinize the various proposed designs more carefully. Is it really “just transportation,” or rather a very special science apparatus to convey fascinating new data? The collective intellect and influence of planetary scientists should be brought to bear, analogous to astronomers participating in the design and funding of new telescopes.