Challenges to Enabling a Richer Planetary Exploration Program

This article originally appeared on Van Kane's blog and is reposted here with permission.

This week has brought to the fore two challenges for NASA’s managers as they try to enable the richest possible mix of coming planetary missions. At stake are whether the agency will be able to select two (the default is one) Discovery missions from the current competition, and whether there will be the possibility of a mission selected for Enceladus and/or Titan in the next decade.

When I write these blog posts, it is always more fun to write about the exciting science or clever engineering solutions than to write about policy. Often, however, the richness of NASA’s planetary science program hangs on questions of management and policy. Can NASA’s managers find the flexibility in spending to allow the selection of two Discovery missions? Can they find a way to incorporate new scientific discoveries and a changed political landscape (a new Congressional mandate) in between Decadal Surveys? This is not glamorous stuff, but it is the essential background to what missions we’ll see in the coming decade.

The Discovery question probably is the simpler because it likely “only” involves solving a $150M or so problem. For this low cost ($450M) program, the space agency is currently conducting a competition among five finalist mission proposals. These competitions are expensive to conduct and arduous for both the agency and the proposers. As a result, NASA’s managers would like stage the competitions no more frequently than approximately every four years. To increase the number of missions flown, the agency would like to select two missions that would be launched two years apart, allowing a total of five launches in the coming decade. (This plan assumes that each competition provides at least two proposals that after extreme scrutiny are scientifically compelling, technically feasible, and can be done within the cost cap. It also assumes that the currently planned future budgets are provided by future Presidents and Congresses.)

The wrench in this plan is the two-year delay in the previously selected Discovery mission, the InSight Martian geophysical station. As you’ve probably heard, the key instrument for this mission wasn’t ready in time to allow the planned launch this year. Instead, under a just-announced new plan, the mission will lift off in 2018 when Earth and Mars next align for launch. As a result of the delay, the costs of launch and operating the mission that had been planned for the next two years are pushed out to 2018 to 2020. This is when NASA wants to start development on the next one or two Discovery missions. In addition, a substantial group of engineers and scientists need to be paid from now until launch in 2018 to fix the instrument problem and retain the core group needed to prepare the mission for launch and flight.

When NASA’s director for its planetary science program, Jim Green, announced the new InSight plan at a recent meeting, one of the earliest questions was whether or not this meant that NASA would still be able to select two Discovery missions. An article on the journal Nature’s website poses the same question.

NASA has not formally released an estimate of the additional costs required under the new plan, saying that those figures will be available this coming August. At a recent meeting, the InSight mission’s principal investigator stated that flying the mission later would cost $150M. It’s not clear from his statement what all is included in that figure. NASA had ~$150M budgeted for InSight for the next two years to cover launch and mission operations. Those costs will need to be shifted out two years. There will also be new costs for the 2016-2017 period to fix the instrument and to keep the core team together, and it’s not clear if this spending is included in the $150M estimate. 

Because the federal budget operates on a cash basis, any money not spent in the current fiscal year returns to the treasury. So NASA can't simply bank the money it had planned to spend in 2016-2017 and spend it two years later. The agency’s managers may have some flexibility, though, subject to many rules that I don’t pretend to understand in any detail:

NASA may be able to sign long term contracts with an outside company or organization (which would include the Jet Propulsion Laboratory, which is developing and will later operate the InSight mission). In some cases, money committed to a contractor counts as spent by the government when the contract is signed but the contractor can spend the transferred money later. 

NASA’s managers may be able to shift money among projects. For example, they might be able to spend money in the next two years originally earmarked for InSight on the Mars 2020 rover project. Then in 2018-2019, the agency might be able to spend money originally planned for the rover on InSight.

The $150M is less than half of what NASA is projected to be spending on Discovery mission development per year by the end of the decade. In theory, delaying the start of the next Discovery mission(s) by around six months might solve the cash flow problem and allow the selection of two Discovery missions. Jim Green has said that mission timing will be crucial, and all the teams currently in the Discovery competition have been asked to identify alternative launch dates.

I am convinced that NASA’s managers would like to fly InSight and select two new Discovery missions if fiscally possible. The kinds of options that I've mentioned above probably just scratch the surface on the kinds of ideas they are exploring. We will know more when NASA’s managers release the final budget plan for InSight this August and when they announce in late this year whether or not they selected one or two new Discovery missions.

In the meantime, veteran space reporter Jeff Foust has tweeted that Science Mission Directorate head John Grunsfeld (Jim Green’s boss) told him that the option to select two missions is still on the table. We can hope that he and his managers find a solution to select two.

The other problem, how to enable missions to Saturn’s moons Titan and Enceladus may not have such a clean path to a resolution. A spate of new discoveries have raised interest in exploring these worlds as possible abodes of life. These discoveries caught the attention of key members of Congress who have directed NASA to establish an Ocean Worlds program to explore these two moons along with Europa. (There are other ocean moons in the outer solar system, but they are less likely to be abodes of life or would be harder to explore.)

The Congressional mandate directed NASA to explore these worlds through a mixture of low-cost (Discovery program), medium cost (New Frontiers program, ~$850M), and high cost (Flagship, >$1B) missions. Planning for a Europa mission with a Flagship mission is underway (although there’s no agreement on when the mission should launch). NASA is left to find a way to send new missions to Titan and Enceladus to fulfill the Congressional mandate.

Unfortunately, neither of these moons was highly ranked as targets by the most recent Decadal Survey, which represents the consensus of the scientific community on exploration targets. (Europa was highly ranked.) The Survey examined missions to land on the lakes of Titan and decided that the scientific return for the estimated approximately $1B cost was not high enough. A mission to orbit Titan, land on a lake, and fly a balloon was estimated at an astronomical cost of $6.7B. Mission concepts, primarily orbiters, were examined for Enceladus, found to be expensive at $1.9B and were not a priority at that cost.

Fortunately, mission concepts such as multi-flyby spacecraft instead of more expensive orbiters have been more fully developed, giving mission planners lower cost options. In recent competitions for Discovery missions, two teams have proposed multi-flyby missions to fly through Enceladus’ plumes to search for clues to habitability and in one of the proposals to also map Titan’s surface at higher resolution. A third team proposed a lander for a Titan lake. All of these proposals were for missions at a fraction the cost of the Decadal Survey cost estimates for similar (but to be fair, more capable) missions. 

Unfortunately, per a comment by Green at a recent meeting, while these Discovery missions proposed compelling science, they were judged by reviewers of being unlikely to fit within the Discovery cost cap. Green implied that similar missions could fit within the New Frontiers budget cap (further implying costs substantially lower than their Decadal Survey cost estimates).

Given NASA’s current budget level and missions in development, the agency has no ability to add another major Flagship mission to the queue of missions before the mid-2020s. That leaves NASA’s New Frontiers program as the only potential home for an Enceladus and/or Titan mission in the next ten years or so. But there’s a problem using this program, too. While Discovery proposals can target any world in the solar system except the Earth and sun, candidate missions for the New Frontiers program competitions were pre-selected by the Decadal Survey. The list was carefully examined to ensure that the missions are scientifically compelling, affordable, and balance the wide interests of planetary scientists. Because NASA is mandated to follow the Decadal Survey in setting its priorities, the list of recommended missions carries weight. One purpose of the list is to prevent teams from lobbying outside the Decadal Survey for their favorite New Frontiers candidates to NASA’s senior managers and Congress. (There’s no mechanism to prevent Congress from imposing its favorites on NASA, though.)

NASA has just begun the process of starting the competition to select the next New Frontiers mission from among the candidates, with a target launch in the mid-2020s. The agency’s managers decided to add a mission to Enceladus and/or Titan to the list of candidate missions. Many scientists within the planetary community are not happy with this addition.

Last week, I listened in on the first day a meeting (the Planetary Science Subcommittee) of senior scientists discussing the issue with Jim Green. Their main objections boiled down to several points:

The New Frontiers current list was developed by the entire community and NASA’s managers should not arbitrarily change it. At a minimum, the addition should be vetted before the mid-term Decadal Survey review planned for next year. Doing otherwise undermines the credibility of the Decadal Surveys. Green’s response was that given the timing of the Congressional mandate and the planned start for the next New Frontiers competition, a discussion in the mid-term review wasn’t feasible. It was either now or wait for yet the next New Frontiers competition that would start in the early 2020’s. In Green’s words, the timing of the mandate sucked because it limited his ability to consult with the broader scientific community before having to tell the community what missions they could propose for the competition.

Many are concerned that rather than being an open competition, an Ocean World’s selection is pre-determined. There’s no point to teams proposing the other candidate missions. Green’s response was that NASA will run a clean competition.

Why these two moons and not Pluto or the asteroid Ceres where there have also been exciting new discoveries? Green’s response was that there are no credible New Frontiers-class follow up Pluto missions and teams have yet to propose cost-capped Ceres missions, but he expects them in the future.

At this meeting, scientists reported on discussions in analysis groups representing specific planetary science disciplines. Perhaps predictably, the report for the outer planets group was enthusiastic about the addition while reports for the small bodies and Venus groups – which have candidate New Frontiers missions – were troubled to upset by the addition. The Mars group – which has no New Frontiers candidates – was silent on the topic. The report from the lunar group – which has two candidate missions – was also silent on this topic, but this group meets the least frequently of the analysis groups and simply may not have had a chance to caucus and decide either way.

As the discussion on adding Enceladus and Titan to the New Frontiers candidate list continued, it became more nuanced. A few of the scientists wondered if an Enceladus/Titan proposal would be competitive given the lack of a mature list of scientific questions and design concepts. The Decadal Survey carefully defined the scientific goals for the missions on its candidate list. In addition, most of the missions on the New Frontiers candidate list have been proposed before or have similar Discovery proposals to draw on. Green noted that Enceladus/Titan proposals would also have Discovery proposals to draw on. He said that NASA was working on a plan to define the scientific goals for an Enceladus/Titan mission for this competition.

Green also talked more about NASA’s choices in response to the Congressional mandate. NASA’s managers could decide to consider a mission to these moons to be a strategic mandate outside of the Decadal Survey’s recommendations. The agency is planning for a Mars orbiter in the early 2020’s as a strategic mission to provide a communications relay to future missions, follow up on scientific questions raised since the last decadal survey, and prepare for future human missions. In a similar vein – and this is my speculation and wasn’t raised by Green – the agency could decide to substitute the selection of a planned New Frontiers competition in the early 2020s for a strategic Ocean Worlds mission. Instead, the agency has chosen to add a mission to the Saturn’s moons to the New Frontiers candidate list where it must beat out five other candidates on compelling science, feasibility, and cost.

NASA’s managers take the advice of the planetary science community seriously. They are actively seeking the response to their decision to add Ocean Worlds to the New Frontiers program (and at the same time selling their proposed solution).  No one in the meeting I listened to stated that they questioned the scientific importance of Enceladus and Titan. However, several would appeared to believe that these two worlds should compete in the next Decadal Survey (to be released in the early 2020s) for a place as prioritized missions. NASA's managers are arguing that the time is now to recognize their priority. 

This is a conversation likely to take at least a few weeks if not months to play out. 

As I said at the beginning of this post, these issues aren’t glamorous. They are simply the nuts and bolts issues NASA’s managers face as they work to create the richest possible program of planetary exploration within the resources the President’s budget office and Congress provide them.

Appendix: At the Planetary Sciences Subcommittee meeting, NASA's Jim Green presented these slides to make his case that and Enceladus/Titan mission should be added to the New Frontiers candidate list. The final slide is from the Small Bodies Analysis Group (SBAG) arguing that any addition should be made follow a review by senior members of the planetary science community.