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NASA’s decision last week to fly a near-twin of the Curiosity rover (above) in 2020 represents a dramatic change in policy back towards doing a sample return mission. (credit: NASA/JPL)

The resurrection of Mars Sample Return


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There had been rumors for a couple of weeks that NASA would make a big announcement about Mars at one of the largest annual meetings of scientists, the American Geophysical Union (AGU) conference in San Francisco. The rumors were about the possibility that NASA’s Curiosity rover had discovered something very interesting on Mars. As it turned out, the Curiosity science results, although interesting, were not nearly up to the hype. But NASA did make a major announcement at AGU: NASA is taking the first step towards the ultimate scientific goal for the red planet, Mars Sample Return.

You can be forgiven if you missed it, because NASA was careful not to use the words “Mars Sample Return” in their press release. Instead, they announced that they are going to build another rover, based on the successful Curiosity design and using some spare parts manufactured for Curiosity, to be launched in 2020. In the official press release, NASA stated that the instrument suite is still to be determined. But make no mistake, this is the first step toward sample return, and in many ways represents a major reversal for the Obama Administration.

But make no mistake, this is the first step toward sample return, and in many ways represents a major reversal for the Obama Administration.

To understand what happened, you have to know the context. To establish its goals for scientific exploration of the solar system, NASA turns to the National Research Council (NRC) of the National Academies and a process known as a “decadal survey.” (There are “decadal surveys” in other scientific areas as well.) The decadal survey is essentially a group of selected volunteers who meet over approximately two years and hash out a list of science priorities for the planetary science program. They develop a list of science missions in the large “flagship” class and the medium “New Frontiers” class.

The decadal survey is based upon implicit trust between the scientific community and NASA. The volunteers agree to devote their time, and other members of the community participate by submitting white papers and attending town hall meetings, with the expectation that NASA will make a good faith effort to follow the recommendations in the decadal survey and not pursue other goals. The end result of the two years of data collection, open meetings and closed-door deliberations, as well as an extensive peer review, is a final report that nearly everybody considers to be a “community-wide consensus” about what to do in the field of planetary science. The decadal survey is also highly-respected outside of the scientific community. Congress, and until recently, the Office of Management and Budget (OMB), treated the decadal survey as a sort of bible for the program, representing the collected wisdom of the planetary science community and an overall agreement on the goals for the planetary science program, and they too expected NASA to follow it.

In March 2011, the National Academies released the report “Visions and Voyages for Planetary Science in the Decade 2013–2022.” The report provided not only a priority-ranked list of flagship-class missions and a non-prioritized list of New Frontiers class missions, but also a set of decision rules on how NASA, OMB, and Congress should approach the program if funding was insufficient to produce the recommended program (see “Tough decisions ahead for planetary exploration”, The Space Review, April 4, 2011).

The top-ranked flagship mission in the planetary decadal survey was the Mars Astrobiology Explorer-Cacher (MAX-C), a Mars rover to collect and cache samples at Mars for eventual retrieval by a future spacecraft or set of spacecraft. Collectively, this was known as “Mars Sample Return,” or MSR. At the time of the report, NASA was already planning a 2016 orbiter and a 2018 rover mission to Mars along with the European Space Agency. The plan then underway involved using NASA’s “skycrane” landing system to place two rovers, an American one and a European rover known as ExoMars, on the surface of Mars. This was a risky design approach because the two rovers together would force changes on the landing system that would dramatically increase cost and program risk. So the decadal survey recommended that the sample collecting rover only be pursued if NASA could keep the cost below $2.5 billion (in 2015 dollars). The decadal survey’s own independent cost and technical risk evaluation process had indicated that this was possible. If the mission could not achieve that cost target, then NASA was directed to go to the second flagship mission on its prioritized list, a Europa orbiter, not invent a Mars mission of its own.

The decadal survey clearly stated that the scientific community firmly believed that Mars Sample Return was the next logical objective for the Mars science program. Over a decade of successful missions at Mars had developed sufficient technology, and gathered sufficient information about the Martian geochemistry, that the community believed that sample return was the only remaining Mars goal that was worthy of significant expense. Individual scientific teams could still propose their own Discovery-class missions to Mars, but they would have to stand on their own merits and were not part of a list selected by the decadal survey process.

In a risky move, the planetary decadal survey did not select any other Mars missions either as flagships or New Frontiers. They considered such options as rovers with advanced instrument suites that could take measurements, multiple small rovers, and even seismic networks, and determined that none of these rose to the level of a strategically-selected mission. The Mars sample caching rover was their only choice, and the community maintained a united front behind this choice.

According to one rumor, Secretary of State Hillary Clinton was angry about the ExoMars decision, because European governments complained to her about American unreliability.

The decadal survey debuted at a time that the planetary science budget had just started to be reduced. Although the people who make the budget decisions at OMB never talk in public, it is not hard to discern their overall decision-making process. First, they did not want to increase NASA’s budget for the Science Mission Directorate. Second, they did not want to reduce or cancel the expensive James Webb Space Telescope, especially considering the strong support it received from Barbara Mikulski, an influential Democratic senator from Maryland. Third, they did not want to reduce spending on Earth science spacecraft. That leaves only heliophysics (the study of the Sun and its interaction with the Earth’s magnetosphere), and planetary science. Heliophysics has a relatively small budget. Given that Earth science and astronomy and astrophysics were off-limits, and there was not much money to take from heliophysics, that left planetary science—the largest of the four scientific divisions at NASA—as the obvious choice to get cut, if only to support the higher-priority areas.

Throughout 2011, it was clear that NASA was backing out of its joint Mars mission with Europe. Privately, many European space experts accepted that the joint mission, which was often mistakenly referred to as ExoMars (which was technically only the name of the European part of the joint effort), would have to be redefined because ESA was hard-pressed to pay for their own part of it. The most likely de-scope would be to build a single rover, probably a European one carried to Mars on an American skycrane landing system. It was also clear to those who understood program management that NASA was running out of time to develop a sample collecting rover by the 2018 launch window once you considered the lead times required to secure funding and start design.

In February 2012, the President released his fiscal year 2013 NASA budget. This was technically the first budget of the period covered by the planetary decadal survey. The budget did not include any funding for the Mars sample collecting rover, and in fact included a $309 million cut in the NASA planetary science budget. That planetary cut included $226 million from the Mars budget, a 40% reduction. Part of these cuts would go to cover a $109 million increase for the James Webb Space Telescope and smaller increases for Earth science and heliophysics.

The Mars sample collecting rover was not provided with a new program start. There was no public explanation for this decision, but the explanation that emerged, largely via word of mouth, was that OMB had been unwilling to both start a new flagship class spacecraft mission and make the first step toward a Mars Sample Return mission campaign that would most likely commit the United States to two more expensive Mars missions during the following decade. Many in the Mars science community cried foul, stating that the other missions in Mars Sample Return—an ascent vehicle to bring the collected samples up to Mars orbit, and an orbiting vehicle with a return capsule that would rendezvous with the launched sample and return it to Earth—could be built partially or entirely by foreign partners that would have access to the returned samples. The administration’s decision to cancel the sample collecting rover, and the vehicle that would take it and the European ExoMars rover to the surface, shattered the cooperation that NASA had cultivated with ESA on Mars exploration. According to one rumor, Secretary of State Hillary Clinton was angry about the decision, because European governments complained to her about American unreliability.

If other members of the planetary science community interpreted the cancellation of the Mars rover as an indication that NASA would move on to the next mission in the planetary science decadal survey, the Europa orbiter, they were soon dissuaded from this thought. The president’s budget meant no new flagships, period, not simply a rejection of Mars Sample Return.

On February 13, NASA Administrator Charles Bolden announced that he was ordering NASA’s Science Mission Directorate to work with the Human Exploration and Operations Mission Directorate as well as the Office of the Chief Technologist to develop “an integrated strategy to ensure that the next steps for Mars exploration will support science as well as human exploration goals, and potentially take advantage of the 2018–2020 exploration window.” This integrated planning effort was dubbed “Mars Next Decade.”

At the MEPAG meeting, Grunsfeld faced what can best be described as a suspicious audience that was concerned that the new “Mars Next Decade” effort was essentially an end-run around the planetary science decadal survey.

If the Mars and planetary science communities felt battered by the disapproval of their top priority science mission and the substantial cuts to their budget, they soon received another shock. New Associate Administrator for the Science Mission Directorate John Grunsfeld announced that the integrated planning effort would look at missions that could be done by the 2018 or 2020 launch windows. NASA would have approximately $700 million available to support the earlier window, and perhaps $100 million additional to support a mission that was launched in 2020 instead. He said that the integrated planning effort would look at missions that could support science, human spaceflight, and technology.

Grunsfeld’s statement alarmed planetary scientists for two reasons. First, the planetary science decadal survey had been clear that they did not support any other missions at Mars other than the sample collecting rover and those missions that might win Discovery competitions, and now Grunsfeld was indicating that NASA was going to choose to do its own Mars mission that did not have the blessing of the scientific community. Second, Grunsfeld’s comments seemed to indicate that although the science budget was going to pay for the mission, it could serve non-science objectives, such as supporting a future human mission to Mars that had not been formally approved or even defined.

In late February 2012, the Mars Exploration Program Analysis Group, or MEPAG, met in Washington, DC. MEPAG is a “community forum” for providing input to NASA’s Mars program. MEPAG is funded by NASA, and in order to not violate the laws governing how NASA can receive formal advice and recommendations on its programs, MEPAG is an “analysis” group and does not issue recommendations. MEPAG can issue statements and white papers, however, and did provide extensive input to the decadal survey.

At the MEPAG meeting, Grunsfeld faced what can best be described as a suspicious audience that was concerned that the new “Mars Next Decade” effort was essentially an end-run around the planetary science decadal survey. Grunsfeld responded by stating that a new committee, known as the Mars Program Planning Group, or MPPG, would use the decadal survey as guidance in their own assessment, producing a plan for “Mars Next Decade.” But he also indicated that he had carved out the $700–800 million for Mars in the planetary budget, and specifically wanted a Mars mission, because of two reasons. First, he believed that Mars was particularly important to the public visibility of the agency. And second, he wanted to preserve the capabilities to conduct Mars missions, particularly entry, descent, and landing, which the United States had developed over many years. Many suspected that this was code for protecting JPL by directing a mission to the laboratory rather than leaving it to the uncertainties of mission competitions.

Grunsfeld announced that the MPPG would be headed by former NASA official Orlando Figueroa. But then Grunsfeld committed a serious error that led many to doubt his commitment to the MPPG process. According to Space News, Grunsfeld said “Probably what Orlando’s team will come up with is something like the [Lunar Reconnaissance Orbiter] experience.” To many assembled in the room, it seemed like Grunsfeld had simultaneously announced the creation of the team and stated his preferred conclusion to its efforts.

At the MEPAG meeting, Grunsfeld was followed by Steven Squyres, the principal investigator for the Spirit and Opportunity Mars rovers and the chairman of the planetary science decadal survey. Squyres demonstrated his ability to carefully choose his words when he explained the decadal survey’s mission priority list, stating succinctly that they had recommended a sample collecting rover, and nothing else. “This is the bottom line: New missions that lead directly to sample return have very high priority,” Squyres said. “New missions that do not lead directly to sample return should be openly competed via the Discovery program.” In response to a question, Squyres was blunt: “There is no Plan B for Mars.”

NASA administrator Charles Bolden said that the cuts had come from the Mars budget because “when we took a look at the portfolio, the area that seemed to be in the best shape was our Mars exploration.” This explanation was not warmly received by some members of Congress.

Although Orlando Figueroa has an excellent reputation among scientists, many in the Mars community and the wider planetary science community viewed his Mars Program Planning Group with skepticism, noting that it was not independent of NASA and fearing that it could produce a result that Grunsfeld or OMB desired, rather than one based upon the scientific advice that has driven previous Mars science mission decisions. Figueroa spoke at the annual meeting of the Lunar and Planetary Science Conference in Houston in March, and announced a June workshop at the Lunar and Planetary Institute to obtain input from a broad cross section of the global technical and scientific community.

But suspicion of the MPPG continued to increase and led to a highly-unusual development. In April, the House Appropriations Commerce-Justice-Science subcommittee produced a draft bill that added money to the Mars budget, but also included in the accompanying report some very specific language on how it could be spent:

“The Committee rectifies this situation by increasing the funds available for Mars Next Decade to $150,000,000, or $88,000,000 above the request, in order to allow for a more substantial mission concept to be developed. According to the decision rules of the decadal survey, however, that mission concept must lead to the accomplishment of sample return in order to remain a top funding priority. Because the Committee is unable to discern whether this condition is being met from the scant information provided to date about Mars Next Decade, NASA is directed to promptly submit its Next Decade mission concept to the NRC for evaluation. The recommendation includes language prohibiting the obligation of funds for the mission unless and until the NRC submits to the Committees on Appropriations a certification confirming that the mission concept will lead to the accomplishment of sample return as described in the Mars Astrobiology Explorer-Cacher section of the decadal survey. If the NRC instead determines that NASA’s chosen mission concept will not lead to the accomplishment of sample return, NASA is directed to immediately: (1) notify the Committees; (2) reallocate the funds provided for Mars Next Decade to the Outer Planets Flagship program in order to begin substantive work on the second priority mission, a descoped Europa orbiter; and (3) submit the Mars Next Decade mission concept, or any substitute Mars mission concept, for competition in the Discovery or New Frontiers programs.”

The congressional language was of course symptomatic of the larger deterioration in relations between Congress and the executive branch. Congress was concerned that the White House was ignoring scientific advice and longstanding policy to do what it wanted, so Congress was writing increasingly prescriptive language into its bills preventing NASA from subverting congressional intent. Although specific language about an ongoing study was apparently unprecedented, the sentiment was not. Congress has long distrusted NASA decision making and supported independent reviews of many of its programs. However, the draft bill did not get signed into law, and was therefore not binding upon NASA. It still indicated strong congressional skepticism of NASA’s actions.

Presidential science advisor John Holdren explained before a House committee hearing in late February that the Mars program had been targeted for cuts because the money was needed elsewhere. A few weeks later, on March 21, NASA administrator Charles Bolden said that the cuts had come from the Mars budget because “when we took a look at the portfolio, the area that seemed to be in the best shape was our Mars exploration.” This explanation was not warmly received by some members of Congress, who wondered why programs experiencing difficulties were rewarded with additional funding while programs that were successful got cut.

The MPPG continued to meet throughout the summer, and held what many Mars scientists considered to be a highly successful workshop in June, with over 400 paper abstracts submitted. Figueroa presented his group’s results to Grunsfeld in August, after the successful and highly-publicized landing of the Curiosity rover on Mars. Although some Mars scientists were aware of the MPPG’s conclusions, they did not speak about them publicly.

Finally, seven months after the controversy over the future of the Mars program had erupted, Figueroa presented the MPPG results to a meeting of the National Research Council’s Committee on Astrobiology and Planetary Science (CAPS) in Irvine, California, on September 23. The presentation to CAPS was not what the Congress had called for in its draft bill, because CAPS could not review the Mars Next Decade proposal and “certify” NASA’s mission choice.

For those still skeptical of the entire MPPG process, Figueroa’s presentation was surprising. In essence, the Mars Program Planning Group had spent nearly seven months considering the future of the Mars program, with a specific focus on the 2018 and 2020 Mars launch opportunities, and concluded that the best option was a Mars sample collecting rover, as had been recommended by the planetary science decadal survey. It was yet another demonstration of both the unanimity of the Mars science community and the power of the planetary science decadal survey.

Overall, the MPPG message to NASA was loud and clear: Do Mars Sample Return.

The MPPG presentation (which has been labeled a “final report,” although it is actually only a set of PowerPoint slides), included four notional rover options, ranging from a low-end rover that would be a near-clone of the Spirit and Opportunity solar-powered rovers, to a higher-end rover that would be a near-clone of Curiosity. All of the rovers would be capable of sample collection for future sample return. None of them could be done for the $700 million available for the 2018 opportunity, or the approximately $800 million available for the 2020 opportunity.

The MPPG presentation did include some other aspects that caused those present to scratch their heads. For instance, it referred to opportunities to include humans in a sample return campaign, essentially to “catch” the samples in space and return them to Earth aboard an Orion spacecraft. It also suggested the possibility of putting a collection rover, Mars ascent vehicle, and Earth return spacecraft all atop a Space Launch System rocket sometime in the 2020s or later and flying a single large, and undoubtedly expensive, mission to Mars. Such a sample return mission would bust open NASA’s science budget and seemed odd to be included in a report that resulted in part because the Mars program budget was being substantially reduced.

But overall, the MPPG message to NASA was loud and clear: Do Mars Sample Return.

Throughout October and November there was no news on NASA plans for a Mars mission in 2018 or 2020. This was to be expected, however, because the fiscal year 2014 budget was still in development. Science data started to flow from Curiosity on Mars, accompanied by incredible images in high definition. By late November there were rumors that Curiosity had made an important discovery on Mars. Those rumors increased expectations for a major announcement by NASA at the AGU meeting in December.

But when John Grunsfeld took the stage on Tuesday, December 4, at the Moscone Center in San Francisco, he had a bigger surprise than anybody expected. Grunsfeld announced that NASA would build a rover for launch in 2020. The rover would be a near-clone of Curiosity, and would cost approximately $1.5 billion. It would use spare parts left over from Curiosity’s assembly. This was “Option C” as identified in the Mars Program Planning Group’s final report.

The NASA press release that accompanied Grunsfeld’s announcement did not use the term “sample return.” NASA did not announce the beginning of a multi-mission sample return campaign, only that NASA would establish a “science definition team” to select the instruments that the rover would carry.

When asked about it, however, Grunsfeld said that because sample caching was a priority in the decadal survey, it would naturally be a high priority for the rover’s science definition team. “The decadal survey said the highest priority is caching for some future unspecified sample return,” Grunsfeld said. The science team “may decide to do that. They may decide they want to do in situ science including sample acquisition and characterization.” But Grunsfeld also announced that the team would be “front-loaded” for sample caching for a possible future “sample return.” Although he stopped short of saying so, the rover that NASA was announcing was for all intents and purposes the MAX-C rover that was prioritized in the decadal survey.

The rover announcement was a major, and welcome, surprise for Mars scientists. But it raises many questions. For starters, considering that Grunsfeld only expected to have $800 million available for a 2020 mission, how is NASA able to afford a $1.5 billion rover? NASA officials would only say that the money is “already in the budget.” But does this mean that it is being cut from other programs like New Frontiers, Discovery, and operational missions like Cassini? The planetary decadal survey addressed the entire solar system and one of its major recommendations was that NASA should seek to balance its program. If the 2020 rover comes at the expense of exploring the rest of the solar system, NASA will have simply found another way to subvert the planetary decadal survey, and the planetary science community’s wishes.

In addition, why was NASA announcing the mission now, especially given that announcements of new program starts are almost always made with the presentation of a new budget in February?

It seems entirely possible that President Obama asked his advisers what the agency’s next steps were for Mars, and was told that the Mars exploration budget was scheduled for substantial reductions. Maybe Obama himself told OMB, and NASA, to produce a better answer.

But most mysteriously, why has NASA, or more accurately, OMB, made a complete reversal and gone from opposing a sample collecting rover to supporting one that can serve as the first step in eventually bringing samples back to the Earth? There may be three answers to this last question. First, at least part of what OMB may have been objecting to with the original Mars rover plan was a multi-mission and international commitment. Perhaps OMB officials were convinced that this new rover would not lead to an international commitment and would not automatically commit NASA to funding two further expensive Mars missions. Mars scientists believe that a collection of samples on Mars can survive for many years before they have to be retrieved, so this new rover could roll around on Mars for a 687-day Mars year, collecting samples, and then deposit its sample canister for retrieval later in the 2020s.

Second, despite NASA efforts to find an answer for Mars other than sample return, the MPPG made it blatantly clear that the Mars community was not going to accept any other answer. They were not going to support further orbiters or rovers with limited instruments after many felt that important science had already been conducted by Mars Global Surveyor, Mars Odyssey, Mars Reconnaissance Orbiter, Spirit and Opportunity, Phoenix, and Curiosity. Additional orbiters, landers or rovers on their own would achieve substantially less science-per-dollar than an admittedly expensive sample return mission. Congress’ not-so-subtle signaling that appropriators would accept only a mission leading to sample return, or abandoning Mars to focus on another target such as Europa, substantially reduced NASA’s decision space. If they tried to pursue a different mission, Congress might eliminate the funding.

But the best answer is probably the Curiosity landing, which was one of the most widely viewed events in Internet history. There is an old saying that nothing succeeds like success, and Curiosity was an amazing demonstration of American technological capability. At a time when economic and political news is grim, Curiosity gave Americans something to be both proud and amazed by. It seems entirely possible that President Obama asked his advisers what the agency’s next steps were for Mars, and was told that the Mars exploration budget was scheduled for substantial reductions. Maybe Obama himself told OMB, and NASA, to produce a better answer.

The new rover is not officially a sample return cacher. But it seems highly unlikely that it could be funded without some kind of collecting and caching capability, even if it is not the primary instrument onboard. And any “science definition team” that NASA establishes for this rover will be composed of Mars scientists who served on the planetary decadal survey, are part of MEPAG, or worked on the MPPG, and all three groups have been consistent in supporting sample caching and return.


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