accident that there’s this whole mission queue in a
particular window,” says John Logsdon, emeritus
professor at George Washington University’s Space
Policy Institute.
For NASA, 2020 has always been the goal for its
next rover once the agency settled in late 2012 on the
idea of sending a Curiosity lookalike. (Curiosity itself
took roughly eight years from conception to launch.)
The UAE, noting that a 2021 arrival would coincide
with the country’s 50th birthday, has also eyed the
2020 window since announcing its mission in 2014.
For others, though, 2020 wasn’t the first choice:
ExoMars’ second installment was previously sched-
uled to launch in 2018, and SpaceX’s initial plan for
Red Dragon also called for a 2018 launch. The 2020
timing for China and India — both of which appear
to be developing their Mars missions on compressed
time lines, at least by NASA or ESA standards — may
partly reflect what some observers see as an emerging
space race in Asia.
Nonetheless, Logsdon says, the sizable group of
missions demonstrates the growing popularity of
Mars internationally, and reflects a combination of
factors: “that Mars has been a high-priority explor-
atory destination for the U.S., Europe and Russia;
and that new entrants into exploration, like the UAE
and India, find it more fascinating than going to the
moon.” China, meanwhile, “is building on its moon
program ... so Mars becomes the next logical place
to go,” he says.
“All space-faring nations regard Mars as both a
very interesting target and a sort of a badge of pres-
tige,” says Jorge Vago, ESA’s ExoMars 2020 project
scientist. Regardless of the various motivations for
each of the missions, “it’s a happy confluence of
interests in many places that so many missions are
slated to launch in 2020,” Vago says. “It’s going to
be busy times.”IEVGLMRKJSVMKRWSJ1MJI
Most of the 2020 missions are motivated, at least
partially, by the goal of improving our fundamental
physical understanding of Mars, especially about the
planet’s surface geology, internal workings, water,
climate and habitability. The spacecraft will arrive
armed with arrays of cameras, sensors and instru-
ments to image and analyze the planet above- and
belowground. NASA’s 2020 rover and ExoMars 2020
are also explicitly focused on searching for biosigna-
tures: chemical and mineralogical features in the rock
record that could represent residual bits of past life.
Searching out organic compounds is key to iden-
tifying potential biosignatures. But simply finding
organics, which are also formed abiotically and can
be transported through space via asteroids or comets,
doesn’t mean there was life. “You need something more
to tell you that it’s a biosignature,” says Ken Farley, a
geochemist at Caltech and the Mars 2020 rover proj-
ect scientist. “One of the important ways to do that is
looking at how [organic matter] is distributed within
a rock,” he says. Life tends to concentrate organic mat-
ter in characteristic ways, whereas material delivered
from space is apt to be more evenly distributed in rock
and soil. Life also tends to concentrate certain other
elements, like iron. Looking at rock samples on Mars,
Farley says, “a really compelling biosignature for us to
find would be concentrations of elements [important
for life] and concentrations of organics that are cor-
related with each other.”
The main tool aboard NASA’s 2020 rover that will
directly search for biosignatures is called SHERLOC
(Scanning Habitable Environments with Raman and
Luminescence for Organics and Chemicals). SHER-
LOC combines a camera, UV laser and spectrometer
to scan tiny patches of rock, simultaneously detecting
the types and distribution of organic matter present
as well as minerals and elements of interest. The.J WYGGIWWJYP XLI 9RMXIH &VEF
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