James Green, Director, NASA Planetary Science Division


As a graduate student at the University of Iowa in the 1970s, Jim Green used to rub elbows with legendary scientist James Van Allen — that is, when he wasn’t rubbing elbows with a Univac mainframe in one of the buildings occupied by the university’s physics department. Green moonlighted as a computer operator to pay his way through graduate school.

The old Univac machine helped Green produce, in 1977, his first deliverable to the science community: a paper on the angular distribution of auroral kilometric radiation — radio emissions associated with the northern lights.

Green has spent his postacademic career almost exclusively with NASA. Since 2006, he has been in charge of the NASA Science Mission Directorate’s Planetary Science Division and its roughly $1.4 billion portfolio of unmanned probes and robotic explorers.

Green’s curriculum vitae, printed out on letter-sized stationary, would stretch about 11 meters, laid out end-to-end. The greater part of that is devoted to a sprawling list of more than 100 scientific and technical papers to which Green has laid his name since the late ’70s.

None of those papers deals with economics, politics or advocacy — subjects Green has become acutely cognizant of in his role as the top public-sector advocate for a planetary science community in crisis.

Recently, in his third-floor office at NASA headquarters in Washington, he spoke with Space News staff writer Dan Leone.


Some in the field have declared that this is a time of crisis for planetary science. Do you agree?

Yes. I don’t know if you’ve listened to the news lately, but indeed, the nation has a budget crisis. The concept that the government’s going to cut back on its activities will affect most every sector in the federal government, and that includes discretionary funding. That’ll be one of the first things that will be discussed. And in that is NASA. And within NASA there’s planetary science. We’re all quite interested in continuing to work with the White House Office of Science and Technology Policy and the Office of Management and Budget to determine the budget level that NASA will have over the next five years so that we can create an executable program.


So what is the Planetary Science Division’s belt-tightening strategy — across-the-board reductions or targeted cuts?

We have the National Research Council’s decadal survey of planetary science priorities to guide us and we’re trying to execute it in good faith. But the planetary decadal also provides us some decision-making rules — things that we need to be able to create a balanced program and move the whole field forward. That’s one of the first times I’ve ever seen, in any of the decadals, some well-crafted rules. For instance, it says you need a balanced program. A balanced program contains these elements: the principal investigator-led missions, which include Discovery and New Frontiers; a healthy research and analysis program; a technology program, so that you actually have a future in terms of folding out technology on future missions; and a flagship mission. Not 10 flagships. A flagship. The top flagship being a Mars sample return, and we’re working on that.


NASA’s 2012 budget request, released last winter just ahead of the decadal survey, includes several years of back-to-back cuts for planetary science. Didn’t the decadal survey advise NASA to descope its flagship missions if something like this happened?

It did, it did. But the decadal has a section in there addressing what you do with the program under a less favorable budget. That “balanced program” concept, as promoted by the decadal, is exactly what I’m planning on doing.


So what’s the plan for undertaking a flagship Mars sample return mission under a shrinking budget?

Under an austere budget, we partner. The first of a series of missions to accomplish Mars sample return will be occurring in 2018. For us to be able to effectively do that under a constrained budget, we’re working with our partner, the European Space Agency. Can we execute on that? We believe we can. Is it going to cost us billions for the next mission? It’s going to cost what it costs — provided the rest of the program is intact. Some of that is not in our control.


Meanwhile, the European Space Agency (ESA) is still awaiting definitive word from NASA regarding the U.S. agency’s role in its ExoMars mission, specifically NASA’s contribution to the jointly built rover that would launch in 2018. What’s the status?

Commitment to support ExoMars is being discussed at the highest levels. NASA Administrator Charlie Bolden and ESA Director-General Jean-Jacques Dordain have exchanged letters and we believe Charlie is committed to work with ESA. We are moving forward right now, in good faith, on both sides, as if that commitment will be confirmed. We’re trying to find the magic formula where all that comes together to allow us to create our part of the participation. And we’re planning out what the 2018 mission will look like, what the roles and responsibilities will be.


Which are NASA’s roles and responsibilities?

It starts from a perspective of, what are we good at? Should we do the entry, descent and landing, or should we let ESA do it? What nation on this world has been successful in entry, descent and landing on Mars? The United States. So NASA should do the entry, descent and landing.


How soon will scientists here on Earth have some martian rocks to examine?

Well, that depends. Will that happen in this decade? No. Will it happen in the next decade? Yeah, probably. It depends on budgets, it depends on the partnership roles and responsibilities, it depends on what we find. It’s going to take several Mars launch opportunities to launch the sample return campaign, and each opportunity is 26 months apart. We may need to miss an opportunity to have the funding necessary to be able to complete a particular activity. But this planetary decadal said, “We want you to do a Mars sample return mission for which getting a rover down on the ground and finding and caching samples is the first step in this decade.” And that’s what we’re going to do.


The decadal survey declared the flagship-class Jupiter Europa Orbiter mission unaffordable as currently conceived. Does NASA have a plan for descoping this mission?

We’ve already started working on it, right now. In fact, it’s going to be discussed, hotly, at the next Outer Planets Assessment Group meeting in October. We’re going to present what some of the initial findings are of a descoped Europa mission. We need an orbiter before we have a lander. So do we want to go into the ocean of Europa? The answer is yes, but we have a lot to learn before we get there, and orbiting before we land is a process that we’ve used a lot. That works. Well. There’s only been one thing that we’ve done that’s jumped over an orbiter, and that’s been the Huygens probe on Titan.


With flagship-class missions effectively off the table for the foreseeable future …

Did anybody read the decadal? I didn’t get that out of the decadal.


Your division said in March that it was unreasonable to expect new flagship starts.

Yes, based on the economic times.


So if a flagship start, aside from ExoMars, is out of the question, does that relieve any of the pressure to restart plutonium-238 production?

For the last five years, since I’ve been here, we’ve been working with the administration to try to restart plutonium production. We’re now further ahead than we’ve ever been before, because we’ve been given the authorization, and the appropriation, from Congress to restart it. This year, we provided the Department of Energy with funding to be able to begin the study of plutonium restart.


Will smaller-scale missions, like those in the Discovery or New Frontiers programs, be granted broader license to use plutonium-powered radioisotope power systems if they want them?

We’re trying to do major leaps in science within the budget constraints that we have. I could go through a litany of missions where plutonium is needed that are within the Discovery and New Frontiers budget. If we relegated plutonium only to our flagship missions, then we’re really stunting the growth of our opportunities in New Frontiers and Discovery to doing some really fabulous stuff. Plutonium, as a power source, is important for any mission where the light from the sun is low. We’re studying two Discovery missions for a 2016 launch opportunity: One goes to a comet and one goes to Titan. If we pick the Titan mission, we need plutonium for it. And by the way, what plutonium we do have is dwindling. We do believe planetary science is going to require plutonium in the future for its missions, and our stockpile continues to dwindle.