Recent comments by my longtime friend and colleague, former NASA Deputy Administrator Lori Garver, on the Mars 2020 mission require critical examination and correction. 

As heard on National Public Radio’s “The Diane Rehm Show” and reported by SpaceNews in the Jan. 6 issue [“Garver: NASA Should Cancel SLS and Mars 2020 Rover,” page 3], Lori characterized Mars 2020 as a “redo” of the Curiosity mission, suggested that there were better ways to explore Mars that “drive technology” and implicitly criticized the planetary community’s objectives as being more about funding Mars than ambitious science. None of these statements stands up to deeper scrutiny. In summary:

  • The science objectives of Mars 2020 are quite distinct from Curiosity.
  • While Mars 2020 will use elements of Curiosity to minimize cost and technical risk, the sample acquisition and caching system will definitely drive technology.
  • Exploring Mars is complex and challenging. Only one-third of the missions to the red planet have been fully successful. Introducing new technologies while building a mission, as was the case with Curiosity, yields schedule slip and cost overrun.
  • The decadal surveys by the National Academy of Sciences (which recommended the Mars caching mission) are the gold standard of advice to the nation — because extraordinary precautions are taken to minimize bias, seek competing opinions and utilize the peer review process to ensure a balanced report.

After the twin losses of Mars Climate Orbiter and Mars Polar Lander in 1999, I got the extraordinary opportunity to completely redesign a decade’s worth of Mars missions including Mars Science Lab/Curiosity. 

That decade was no haphazard collection of missions. Rather, the program was designed as an interrelated set of projects aimed at understanding Mars as a system and particularly the potential for past life on Mars. And, as was planned, the missions were also intentionally crafted to prepare for a Mars sample return in the following decade — including developing critical technologies such as precision entry, descent and landing. It is now clear that this stepwise and strategic approach has been extremely successful.

But why Mars and why sample return? Mars is the most Earth-like of the other planets, is the most likely to have developed life, is the ultimate target for human exploration and is accessible every two years. Bringing samples back to Earth is critical for three reasons that have stood the test of time: utilizing instruments that cannot be shrunk to spacecraft size; engaging hundreds of scientists across dozens of laboratories; and most importantly, being able to follow the pathways of discovery as new experiments are conducted. As capable as Curiosity is, the instrument suite is fixed.

But, it is argued, isn’t bringing back samples a daunting task with enormous risk? I agreed with that statement 14 years ago as NASA’s first “Mars czar” and as a consequence canceled the Mars sample return project then being studied. But built into the decade we restructured (Mars Odyssey to Curiosity) was a stepwise attack on the scientific, technical and cost risk. Those risks have now been largely retired and the stage is set for a sample return at an affordable cost.

As explained by the National Academy of Sciences in painstaking detail via the so-called planetary science decadal survey, the highest-priority strategic mission for the decade 2013-2022 is a Mars rover designed to identify and store (cache) scientifically compelling samples to begin the Mars sample return campaign. Notably, a mission to Europa was judged roughly equal in science value but came in second because of mission cost and accessibility. Missions to the outer planets typically take five or six years of travel time and the independent cost estimate at the time for Europa was far greater than for the Mars project.

The decadal process involved five panels meeting over a period of a year; almost 200 white papers with over 1,600 individual authors; a meticulously selected and balanced steering committee required to disclose all conflicts; and a final anonymous peer review. Having been a member of the steering committee, I can say without hesitation that of all the groups I have participated in the last 40 years, the decadal survey was the most scientifically rigorous. In scale, it was second only to my service on the Columbia Accident Investigation Board. Finally, the Mars Program Planning Group and the Science Definition Team established for Mars 2020 have now validated the fundamental conclusions of the decadal survey about next steps for Mars. 

Mars 2020 is the caching rover called for in the decadal and will utilize much of the capability developed for Curiosity in order to minimize technical and cost risk. The science objectives, though, will be quite distinct from Curiosity, and a new sample coring, drilling and caching technology will be needed. Having just successfully advised and graduated a brand new Ph.D. student from Stanford whose dissertation was on the challenges of autonomously coring and drilling samples on Mars, I know we are in fact pushing the frontiers of capability.

I am sympathetic to Lori’s call for advancing the technology of Mars exploration, but this laudable view must be tempered with real world evaluation of the cost and schedule risk. Recently an independent eight-month Mars Science Lab Lessons Learned study was conducted at the behest of NASA. The basic charter was to understand why the Mars Science Lab/Curiosity was two years late and about $900 million over budget. The key finding was that by incorporating so many new technologies such as the sky crane and titanium actuators and also selecting a science payload that was beyond the state of the art, an overrun and schedule slip was essentially guaranteed. To avoid this “budget busting” in the future, Mars 2020 must adopt a scope, including new technology, that is well defined and understood.

As a lifelong practitioner of technology research and development, project design and management — including my time in Silicon Valley at NASA Ames — I can state quite unequivocally that it is a lot easier to advocate “new technology” than it is to make it happen. Space exploration is often called a “one strike and you’re out” business. That makes it doubly hard when inserting new tools and techniques.

Let me finish with a few comments about the big picture for planetary science. Based on some reviews I chaired a year or so ago, there might well be a Europa mission that is now in the same cost bin as Mars 2020. And an analysis of funding profiles suggests that both Mars 2020 and a redesigned Europa mission (i.e., the Europa Clipper) may be started in this decade, but only if the Planetary Science Division at NASA is given a flat budget at the 2012 level of about $1.5 billion.

The success of planetary science in understanding the universe, exciting a new generation of students and leading the international community has been demonstrated time and again. Let’s keep it going.

Scott Hubbard is a consulting professor in the Department of Aeronautics and Astronautics at Stanford University, former director of NASA’s Ames Research Center in Silicon Valley and the first NASA “Mars czar” (Mars program director). His new book, “Exploring Mars: Chronicles from a Decade of Discovery,” details the program restructuring effort described above.

G. Scott Hubbard has held key roles at NASA, including director of Ames Research Center, first Mars Program director, founder of NASA's Astrobiology Institute, and the agency’s sole member of the Columbia Accident Investigation Board. Hubbard, now retired,...