118 TheEconomistDecember 21st 2019
1T
he idea, popular in science fiction,
that alien life will do bad things to life
on Earth if the two come into contact, is not
restricted to the activities of malevolent ex-
traterrestrial intelligences. In “The An-
dromeda Strain”, a novel by Michael Crich-
ton, the baddies are mysterious and deadly
(but completely unintelligent) microbes
that hitch a ride to Earth on board a military
satellite. They start by killing everyone in
the town of Piedmont, Arizona, and then
wreak havoc in a secret underground gov-
ernment laboratory, as scientists struggle
to understand and contain them.
Move one state north, to Utah, and at
least part of that fiction may, some hope,
soon become true. For Utah is the planned
landing place of the first samples to be col-
lected from the surface of Mars. Optimists
like to think that those samples might con-
tain traces, even if only fossil, of life on
Mars. And in case they do, the samples’ ul-
timate destination will be a purpose-built
receiving facility with level-four biosafety
controls—the highest category possible.
The Mars Sample Return (msr) mission
intended to achieve all this will requirethree launches from Earth over the course
of a decade, and five separate machines.
The organisations involved—America’s
National Aeronautics and Space Adminis-
tration, nasa, and the European Space
Agency, esa—are each responsible for spe-
cific craft in the chain of what David Parker,
esa’s head of human and robotic explora-
tion, calls “the most ambitious robotic
pass-the-parcel you can think of”.Delta force
On December 11th, at a meeting of the
American Geophysical Union in San Fran-
cisco, space scientists and astrobiologists
outlined the details of the msr. The project
will begin with the launch, next July, of
nasa’s Mars 2020 mission. This will carry
to the planet a successor to Curiosity, a
rover that has been crawling productively
over the Martian surface since 2012. TheMars 2020 rover, yet to be named, will land
in a 45km-wide crater called Jezero, in Feb-
ruary 2021. Its main purpose is to search for
signs of ancient microbial life. Around
3.5bn years ago, Jezero contained a lake.
Mars 2020 will drill for samples from the
clay and carbonate minerals now exposed
on the surface of what used to be a river del-
ta flowing into this lake (visible top right in
the picture).
When the rover finds something that its
masters want to bring back to Earth, it will
hermetically seal a few tens of grams of the
material in question into a 6cm-long tita-
nium test tube, and then drop the tube on
the ground. It can deal in this way with
around 30 samples as it travels to different
parts of the crater. Once it has dropped a
tube it will broadcast that tube’s location to
the Mars Reconnaissance Orbiter, a satel-
lite already on station that is armed with a
high-magnification camera. This camera
will take photographs of the tube and its
surroundings, so that the tube can be
found at a later date. The tubes are intend-
ed to be able to survive for more than 50
years on the surface of Mars, at tempera-
tures less than 20°C.
The next phase of the project will begin
in 2028, when a “fetch rover” designed and
built by esawill be sent to Mars to find and
collect the tubes. This rover will be small,
nimble and ten times faster than any of its
predecessors. It will also be semi-autono-
mous, which will permit it to spot, pick up
and manoeuvre the test tubes into the in-
terplanetary equivalent of a test-tube rackBringing rocks back from MarsA cosmic relay race
SAN FRANCISCO
The first stage of a Martian sample-return mission takes off next yearScience & technology
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