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.)
In the current Discovery competition, NASA’s managers will select one or two missions from among three asteroid and two Venus mission proposals. Credit: NASA |
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:
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.)
For the fourth New Frontiers competition that is in its initial stages, the Decadal Survey reports said that a mission should be selected among these candidates. Credit: NASA |
For the fifth New Frontiers competition, currently planned for the early 2020s, the Decadal Survey recommended that two additional missions be added to the list of candidate missions. |
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.
Congressional language directing the creation of an Ocean Worlds program that would include Enceladus and Titan. |
Key discoveries at Enceladus since the priorities for the last Decadal Survey (in its Visions and Voyages (V&V)) priorities were set. |
More Enceladus discoveries |
Titan discoveries. |
SBAG's statement on how new candidate missions should be added. |