PASADENA,
Calif. -- Proposals for a multibillion dollar Mars sample return mission —
perhaps even a comprehensive sample return program — appear to be on the front
burner again, but not without controversy.
It turns
out, Alan Stern, NASA's new associate administrator for the Science Mission
Directorate, is a big proponent of Mars
sample return. But while many NASA planetary scientists share that
sentiment, a number of others also worry that such an ambitious mission — Stern
estimates it could cost from $3 billion to $4 billion — would suck up all the available
money for most
other Mars missions in the next decade and disrupt NASA's ability to send
at least one robotic mission to Mars every two years.
The Mars
sample return program and related proposals for the early caching of Mars
samples were big topics at the Seventh International Conference on Mars, held
here July 9-13 at the California Institute of Technology. The meeting brought
together some 500 leading experts on the red planet to discuss current and
future exploration plans.
In a July 10
long-distance telephone hookup between meeting attendees and Stern, he advised
that the Mars sample return undertaking would require "focus and discipline" to
locate requisite funds for the effort within the agency's budget.
Stern said
he is personally looking at the 2018-2020 time period for Mars sample
return activities. To help fund the initiative, he proposed skipping one Mars mission opportunity sometime during the next decade.
Stern also
is backing use of the nuclear-powered
Mars Science Laboratory to practice caching Mars specimens. That large
rover is under development here at the Jet Propulsion Laboratory. Putting a
caching capability on the Mars Science Laboratory rover, Stern said, would help
build the foundation of support for future Mars sample return activities, not
only in scientific and public circles, but also in Congress and the White House
Office of Management and Budget.
"I think
there's something concrete about putting your stake in the ground," Stern told
the meeting attendees.
Technology
demonstration
Stern has
asked a tiger team at NASA's Ames Research Center in Mountain View, Calif., to
design sample caching gear to be installed on the Mars Science Laboratory. A
small, hockey puck-sized device is being studied, seen as a "secondary payload"
to be attached to the rover.
The final
study results from the Ames team on the caching hardware are due by the end of
July or early August, reported Chris McKay, a planetary scientist at the space
agency field center who is helping to assess the feasibility of the Mars
Science Laboratory add-on. Preliminary discussions also are under way with
officials in the European Space Agency's ExoMars rover project to carry similar
sample caching equipment on board that 2013 mission.
These NASA
and European Space Agency (ESA) rovers would collect bits of Mars during their
respective exploration treks — preparatory to the landing of a sample return
craft designed to gather, then rocket
back to Earth a variety of select specimens of soil and rock from the red
planet.
"I think
there are things that we have to keep in mind as we move toward a sample return
program," McKay told SPACE.com. "It's not going to just be a sample
return. We're going to have a series of sample returns. We have to think of it
as a program. The first sample return ought to be a simple, pathfinder-like
sample return ... a technology demonstration."
Utilizing
the Mars Science Laboratory for caching samples collected by rovers would get
people focused and thinking about sample return, McKay said. "It ties sample
return to the ongoing program. There's a tendency to think of sample return as
something 'out there' ... it doesn't need to be. It can be something in the Mars
program," he said.
McKay also
said the sample return program has to connect, ultimately, with human
exploration of Mars.
A
careful, delicate balance
At the Mars
conference, placing an expensive sample return activity on the exploration
agenda, perhaps at the expense of other projects, sparked some anxieties.
"I'm
cautiously optimistic," said Philip Christensen, a leading Mars scientist and
professor in the Department of Geological Science at Arizona State University
in Tempe. "I am concerned that the sample return mission would take over the
Mars program. If you put that mission too far into the future, with not much in
between, then you lose a lot of momentum ... a lot of young talented scientists
and engineers," he said.
Christensen
added that he sees "a real serious challenge" in carving out enough money in
the near-term to pay for Mars sample return and still maintain
a dynamic program.
"It's going
to take a careful, delicate balance to be able to afford the sample return and
yet maintain some measure of a program," Christensen told SPACE.com at
the Mars meeting in Pasadena. "I have no expectation that the program will be
as dynamic and vigorous as it has been if we're going to pay for a sample
return. Something's got to give. But at the same time you can't just give up
everything."
Pragmatic
sample return
In a July
17 phone interview, NASA's Stern told SPACE.com that he has asked the
Mars Science Laboratory project to add sample caching to the mission rover's
duties. "It's a late but viable opportunity" and would explore techniques for
follow-on Mars sample return work, he said.
The full
life-cycle cost of the Mars Science Laboratory is $1.6 billion, according to Guy
Webster, a Jet Propulsion Laboratory spokesman. The price tag for the caching
apparatus, Stern noted, is $2 million for hardware, plus integration costs to
the Mars Science Laboratory.
"I want to
get serious about Mars sample return and this is the way to do it," Stern said.
"This has been going on all my life, waiting for Mars sample return and it
never gets there. We're going to do a pragmatic, but competent sample return."
Stern said
he also has requested that ESA consider adding the Mars Science Laboratory
sample caching equipment to their ExoMars mission. He said that he will discuss
the matter with Daniel Sacotte, ESA's director of human spaceflight,
microgravity and exploration in a meeting later this month at NASA
headquarters.
"I want to
be able to point up into the sky and say I already have a sample waiting up
there," Stern said. "I'm just opening possibilities."
It is not a
given, however, that those pre-selected Mars samples would later be robotically
picked up for return to Earth, Stern said.
Make
some history
Stern
emphasized that the NASA Mars exploration program currently occupies 46 percent
of the space agency's $1.4 billion planetary division budget.
"It won't
get larger ... and there's already pressure to make it smaller. We have to do
something worthy of that 46 percent. The Mars community has to thread a needle.
If they don't do Mars sample return, their budget is likely to shrink. They
have to do a Mars sample return, or get smaller.
That's my
analysis, not my wish ... that's my analysis of the way the politics will go,"
Stern said.
Stern said
he thinks that a $3 billion to $4 billion Mars sample return effort in 2018 is
affordable, although architecture studies that blueprint the concept must still
be done before the agency can seek a formal start to a sample return program
and budget for it.
"Let's get
this done ... make some history," Stern concluded.
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