The Vision for Space Exploration included a strong component of HSF robotic precursor missions and robotic science missions to exploration destinations. Robotic precursor missions are a worthy topic, but today I'll discuss the status of robotic Planetary Science missions at NASA. The status of the Mars program has been well-publicized, with NASA's withdrawal from ExoMars participation, near-term cuts to Mars mission funding, and the decision to initiate Mars-2020, a mission like the one that delivered the Mars Surface Laboratory Curiosity rover, but with an instrument suite that is yet to be determined. The status of other NASA Planetary Science missions has not received nearly as much attention. However, with recent and expected budget cuts, there will be no outer planets flagship missions, and the smaller Discovery and New Frontiers mission lines will be slowed. Lunar Quest and Mars Scout small missions are already gone. Future Planetary Exploration gives some insight into the direction Discovery and New Frontiers are heading:
I picked up one
key point in Monday’s meeting while listening to James
Green, the head of NASA’s planetary science program. In reviewing his
program’s projected budget,
his team believes that it can start two additional New Frontiers
each) and a single Discovery mission ($500M) in the next ten years. The
balance between the two programs is NASA's choice; for approximately the
same funding it could select one New Frontiers and three Discovery
The recent Planetary Science
Decadal Survey anticipated 5 Discovery mission starts and 2 New
Frontier mission starts over the course of a decade. In its first
decade, the Discovery program was able to start even more missions than
that. Now we could be looking at only a single competitively selected
Discovery mission in a decade. That's a going-out-of-business pace for Discovery, the
backbone of NASA Planetary Science.
It is interesting
that NASA has decided to implement the highest priority Flagship mission
of the Decadal Survey. However, Flagship missions are not the highest
priority of the Survey:
It is also possible
that the budget picture could turn out to be less favorable than the
committee has assumed. This could happen, for example, if the actual
budget for solar system exploration is smaller than the projections the
committee used. If cuts to the program are necessary, the committee
recommends that the first approach should be descoping or delaying
Flagship missions. Changes to the New Frontiers or Discovery programs
should be considered only if adjustments to Flagship missions cannot
solve the problem. And high priority should be placed on preserving
funding for research and analysis programs and for technology
The bold is the Survey's, as this is one of their key points.
budget cuts are harming NASA Planetary Science, but ignoring the
Decadal Survey and implementing a Flagship mission at the expense of
most of the remnants of the Discovery mission line is not helpful.
we are already ignoring the Decadal Survey, I have a suggestion designed for these budget-challenged
times. That suggestion is to initiate a new line of "very small"
Planetary Science missions. With the possibility of a decade where
Mars-2020 and 3 other missions are the only new starts, and the prospect
of even more budget cuts to Planetary Science in the years ahead,
something drastic is needed to keep the program and the associated
science community in business once the missions that are currently in
operation and under construction go silent. Incoming data will be
needed in future years. Imagine if one of the rare future missions fails?
Something is needed for survival in the data-lean years, and I suggest
that be a new line of competitively selected, low-cost, highly-focused
Planetary Science missions. These would be cost-capped at a level that
is considerable lower than Discovery ($500M plus launch and possible
NASA-furnished equipment in some cases). Maybe the figure would be
$200M, or maybe even $50M or much lower. The goal would be to have
frequent new mission starts, perhaps one per year or 2. This mission
line could be like NASA's new orbital Earth Ventures line (the line
includes orbital, suborbital, and instrument mission series) or the
Heliophysics and Astrophysics Explorers. An example mission is CYGNSS. The line would be for independent missions, and not for adding instruments to
other organizations' planetary missions, since NASA already has such Missions of
Opportunity. In today's budget situation, implementing such a mission
series would likely mean sacrificing one of the large missions, like one
of the New Frontiers missions, which would certainly not be an easy
choice to make.
One objection to such a proposal is
that even though the cost of such missions would be lower, the
corresponding reduction in science returned would be even greater.
Either mission risk would be increased unacceptably, or mission
capability would decrease unacceptably. Small missions may work for
Astrophysics, Heliophysics, and Earth Science, but missions in those
fields have a much easier time because they don't need to go to other
planets, with all of the associated difficulties of communication
bandwidth, long mission life, propulsion requirements, and more for
flyby and orbiting planetary missions, let alone the challenges of
landers and sample return.
One response to that objection is that Planetary Missions don't all have to go far.
Discovery shows this. There could be "very remote" sensing missions
like Kepler or NASA's proposed Near Earth Asteroid survey instrument that don't come close to their subjects. There could be sample
missions like Genesis that don't need to approach a distant planetary body. A
mission could wait for a NEO to approach us. A lander could use a "less
gentle landing" style like the ill-fated Deep Space 2 impactors.
Starting a line of such competitive procurements would likely generate
many new low-cost mission ideas.
My main response
to this argument, however, may take a bit of a leap of faith for the
skeptical critic. That response is that mission capabilities for small
missions are increasing rapidly, and Planetary Science should not leave
itself out of this trend. Cubesats are becoming more powerful and a
low-cost industry is growing around that standard. Multiple cubes can
be combined for more ambitious missions. The Interplanetary Cubesat Workshop
is evidence of the effort to increase the reach of Cubesats. Planetary
Resources is a company developing low-cost spacecraft capable of
investigating asteroids. An announcement is expected tomorrow for Deep
Space Industries; we will have to wait to see what their vision is.
Multiple Google Lunar X PRIZE teams are striving to send missions to the
lunar surface. That is a largely private competition, but some teams
may also be interested in having a government customer. NASA has a
space technology program that may be interested in demonstrating
technologies like aerocapture or solar electric propulsion at other
planets. Perhaps some sort of collaboration could occur with that
organization on a small Planetary Science mission. Many other small
spacecraft efforts are in progress for Earth environment observation,
military, technology development, and other purposes, perhaps
representing a combined wave of efforts unlike any that has come
before. NASA Planetary Science can ride this wave, and at the same time
help it grow, or it can ignore it and struggle, perhaps successfully,
to scrape up the funding for each one of the small remaining handful of
large missions it now expects.