March 8, 2012
The recent release of the administration’s FY 2013 budget gave some scientists a bit of a shock. Planetary science (considered a “jewel in the crown” of the space agency) has been identified for cutting, over 20% during the next five years. A particularly painful cut comes to the agency’s robotic Mars exploration program. Planned missions in cooperation with the Europeans and future missions designed to lead up to the return of a surface sample from Mars were eliminated from the budget. In effect, the successful program of Mars missions created after the embarrassing failure of the Mars Polar Lander over a decade ago is being scrapped.
The administration digested the National Research Council (NRC) Decadal Survey in planetary science (released last spring) before writing their new budget. The study process for this report involves getting the relevant scientific communities to determine and lay out their priorities. The assumption is that the scientific community can best determine the most relevant goals and questions in planetary science and therefore design mission concepts to address them. Through a variety of working groups and forums, the desires of the community are made known and a report is written around them. Typically, planetary scientists organize their working groups around objects of study, such as the inner (rocky) planets, small bodies (asteroids and comets), and giant planets. For the latest Decadal Survey, the Mars community had its own separate group. Mars is, of course, a rocky, inner planet, and for decades has held sway in the planning process, both for robotic and human missions.
NASA’s highest scientific priority for Mars exploration is to determine if it has now, or has ever had life. The chosen mission concept to address this question is to return samples of the surface of Mars to the Earth. This is a very difficult task. Mars is a big planet with a deep gravity well. At its closest, it is several tens of millions of miles from the Earth, leaving robotic machines controlled from the Earth with long time delays (up to tens of minutes). Safely landing on Mars is hard enough – taking off again and navigating back to Earth with samples safely in hand, is at least an order of magnitude more difficult.
Yet the new Decadal Survey made Mars sample return its only priority in the area of Mars science – the report offered no alternative missions for consideration. Moreover, the sample return mission concept presented by the Decadal Survey required not one, but three separate “Flagship” missions (i.e., those having total costs exceeding $1 billion). In a complex scenario, the mission concept called for a Mars lander to deliver a rover, explore and collect samples and then store them on the surface. A second mission years later would rendezvous with the stored samples on the surface of Mars, transfer them to an ascent vehicle, and place the samples in orbit around the red planet. The third and final mission would rendezvous with this orbital vehicle, dock with it and return the samples to the Earth. From initial landing to sample return would take over a decade and cost many billions of dollars. Moreover, in this series of three sequential and very complex missions, one single-point failure could spell the end of the entire effort.
When the Office of Management and Budget saw this plan and its price tag, they thought it was too much money for too complicated a mission. Unfortunately, the Mars subgroup left no “back-up” options in the Decadal Survey – it was do the sample return trio or do nothing. Hence, the new budget proposes nothing. Of course, a big part of the reason that this mission trio was a non-starter was to preserve funding for the James Webb Space Telescope (JWST), which at its current estimated $8 billion cost (and counting), effectively makes most other space science endeavors non-starters.
Cry “Havoc!” and let slip the dogs of war! The planetary science community was stunned. The Planetary Society organized a letter writing campaign, demanding that Congress intervene and save the “Mars program.” Scientists complained that their highest priority as expressed in the Decadal Survey had been discarded without any real thought and debate (much as the Vision for Space Exploration had been thrown away two years ago). In partial response, the agency is setting up an ad hoc group to study some less expensive, interim Mars missions (something that the Decadal Survey should have done). Presently, all of planetary science is in danger of severe cutbacks. And the final bill for JWST has yet to be delivered.
What can be learned from this these events and applied to the exploration of the Moon? Like the Mars community, the lunar science community has made sample return the centerpiece of their mission wish list. A South Pole-Aitken (SPA) basin sample return has been proposed as a New Frontiers mission and studied in detail twice over the last nine years – and passed over for selection twice. Yet the new Decadal Survey once again makes this mission its top priority in lunar science. Moreover, for this mission to be scientifically successful in its goal of dating the impact that created the SPA basin (the biggest and oldest impact crater on the Moon) it must not only complete the sample return, it must collect samples whose context can be reconstructed and fully understood. As discussed here previously, given the difficulty of such reconstruction for the Apollo samples (which were carefully documented and collected by trained field observers), an unambiguous outcome for this robotic mission is exceedingly unlikely.
Certainly, returning a sample from the Moon is less difficult than doing it from Mars, so the two tasks are not directly comparable. Yet, there are a number of missions to both the Moon and Mars that could be done for less money and would significantly advance our understanding of their histories and processes. For example, an entirely new field of scientific study is the generation, movement and fate of water on the Moon, a problem rich in both scientific and exploration potential. This new field could be investigated profitably by a series of properly instrumented, small robotic missions.
These issues and questions were known at the time that the Decadal Survey was conducted, so there is little excuse for ignoring them, except for the community’s fixation on sample return missions. In part, this obsession exists because it provides a large part of the research community with something to do. NASA money has built many expensive laboratories to analyze extraterrestrial materials and new lunar and planetary samples are needed to keep them operating. But the full potential of remote, in situ analysis – coupled with careful and clever geological planning – has not been given enough thought by the scientific community.
Will the lunar science community also shoot itself in the foot? If so, it will simply be finishing a job started by this administration two years ago with the cancellation of the VSE. Fans of human spaceflight please take note: the process of undertaking these “Decadal Surveys” has been widely praised and advocated as a model for determining the goals and objectives of the human space program. Considering the consequences of this latest effort in planetary science, one might want to re-think that scenario.
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