Tech Briefs Magazine - July 2023 - 30

Earthly Twin
Offers Test Bed for
NASA's Perseverance
Mars Rover
In addition to helping the rover avoid potential driving hazards on Mars,
its digital twin on Earth can also be used as a platform to figure out why
something went wrong and how to fix it.
O
PTIMISM, the full-scale engineering model of Perseverance,
is helping NASA assess the risk of potential
driving hazards on the surface of the Red Planet.
Short for Operational Perseverance Twin for Integration
of Mechanisms and Instruments Sent to Mars, OPTIMISM
is more generically known as a vehicle system test
bed. The twin of the Perseverance rover that is exploring
Jezero Crater on Mars is performing a crucial job: navigating
the Mars Yard's slopes and hazards, drilling sample cores
from boulders, and storing the samples in metal tubes - just
like Perseverance is doing in its hunt for signs of ancient microbial
life.
The rover has already begun testing out new equipment. The
tests help ensure that OPTIMISM's twin on Mars can safely execute
the commands sent by controllers on Earth. They also
could potentially reveal unexpected problems Perseverance
might encounter.
" The size and shape of rocks in the visual field - will they
turn into obstacles or not? " said Bryan Martin, the flight software
and test beds manager at JPL. " We test a lot of that, figure
out what kinds of things to avoid. What we have safely traversed
around here has informed rover drivers in planning their traverses
on Mars. We've done so much testing on the ground we
can be confident in it. It works. "
About as long as a doubles tennis court and twice as wide, the
Mars Yard has served as a testing ground for many a fully-engineered
rover twin - from the engineering model of the very
first, tiny Sojourner that landed on Mars in 1997 to the Spirit
and Opportunity missions that began in 2004 to the Curiosity
and Perseverance rovers exploring Mars today.
In each case, a rover double has scaled slopes, dodged obstacles,
or helped rover planners puzzle out new paths on the simulated
patch of Mars. OPTIMISM first rolled out into the Mars
Yard in September 2020, when it conducted mobility tests.
In 2022, it received some key updates to match features available
on Perseverance, including additional mobility software
and the bulk of the exquisitely complex sample caching system.
And while the team has already performed tests using the coring
drill at the end of OPTIMISM's robotic arm, they'll be testing
the newly installed Adaptive Caching Assembly for the first
time in the Mars Yard. The assembly on Perseverance is responsible
for storing rock and sediment samples. Some or all of
these initial samples could be among those returned to Earth
by a future mission.
" Now we can do it end-to-end in the test bed, " said the Vehicle
System Ted Bed systems engineering lead, Jose G. Trujillo-Rojas.
" Drill into the rock, collect the core sample, and now
we have the mechanism responsible to cache that sample in the
cylinder. "
And if problems arise on Perseverance on Mars, OPTIMISM
can be used as a platform to figure out what went wrong and
also how to fix it.
30
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Tech Briefs, July 2023
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Tech Briefs Magazine - July 2023

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