Since its arrival on Mars in 2012, NA- SA’s Curiosity rover has zapped and rilled ancient rocks in the hopes of inding evidence for past life. But it may never get a chance to inves- tigate something far more exciting:
the possibility that martian microbes exist today. In the coming years, as the rover
trundles up the side of Aeolis Mons, it
will pass rocks that, seen from orbit, seem
to host mysteriously intermittent dark
streaks—perhaps marking seasonal water
seeps. But NASA’s planetary protection
office, charged with keeping earthly microbes from colonizing other bodies, has
said it may nix a visit. It fears that Curiosity could contaminate this so-called special
region because the rover was not fully sterilized before launch.
To Alberto Fairén, a planetary scientist
at Cornell University, that makes no sense.
Sooner or later humans—biped rovers that
can’t be sterilized—will set foot on the
planet, hopelessly confounding any hope
of finding indigenous life, he and several
colleagues argue in an op-ed in press in the
journal Astrobiology. “We need to investigate Mars’s special regions carefully and
fully prior to human missions,” he says.
Bureaucratic changes at NASA could create an opening for his view, which some
Curiosity team members share. In July, a
NASA job posting signaled that the planetary protection office was moving out of
its longtime home in the science directorate to NASA’s Office of Safety and Mission
Assurance in Washington, D.C., a place
more accustomed to working directly with
engineers. Cassie Conley, the planetary
protection office’s longtime chief, will face
competition to keep her job, and she could
be replaced by someone with less strict
views on sterilization requirements. Meanwhile, by the end of this year, the National
Academies of Sciences, Engineering, and
Medicine are expected to complete a head-to-toe examination of how the office works
and whether it keeps abreast with current
science, and later this year NASA is holding a major workshop that could lead to a
redefinition of special regions on Mars, the
warm and watery areas that are off-limits
for all but the most sterile of spacecraft.
The Viking landers of the 1970s were
the only missions to Mars ever to be com-
pletely cleaned to the highest standards of
planetary protection. They were baked in a
purpose-built giant oven, and the cost of do-
ing so is thought to have been roughly 10%
of the mission. Ever since then, says Conley,
researchers have complained about the of-
fice, as if it exists solely to burden them and
make their missions impossibly expensive.
“People like to have a villain,” she says.
The office has clashed in recent years
with the Jet Propulsion Laboratory (JPL) in
Pasadena, California, which assembled Cu-
riosity. JPL baked parts of the rover in ovens
at 110°C for nearly a week, to sterilize them
to a level where the rover could explore
special regions. But in 2011, weeks before
launch, JPL engineers decided that Curios-
ity should launch with one of its drill bits
mounted on its robotic arm. They opened
the already-sterilized bit box, a violation of
planetary protection protocols that caused
the office to downgrade Curiosity’s sterility.
During postmortems, JPL engineers com-
plained about the confusing and vague way
the office presented its requirements.
More recently, says John Rummel, a bio-
logist who was NASA’s planetary protection
officer before Conley, JPL has butted heads
with the office over the next big mission,
the Mars 2020 rover, which will gather
rock samples for later retrieval to Earth.
JPL is interested in having the rover target
areas with subsurface brines, an activity
that would not be allowed with its planned
level of cleanliness. Moreover, the plan-
etary protection office has not yet agreed
Fear of microbial taint curbs Mars explorers
Upheaval in NASA planetary protection office could put restricted areas back in play
In the 1970s, the
Mars Viking landers were
sterilized in ovens.
By Paul Voosen