Set for launch later this month, NASA’s Mars 2020
mission features some of the most advanced
technology ever taken into space. Jon Excell reports planet return
Earlier this year (May 2020) space enthusiasts were granted
some temporary relief from their day to day terrestrial
concerns as NASA astronauts Robert Behnken and
Douglas Hurley blasted off to the International Space
Station (ISS) aboard a rocket and spacecraft developed by
Elon Musk’s SpaceX corporation.
The launch marked a symbolic moment. Not only
was it the fi rst time in almost a decade that US astronauts had
launched from American soil but it was also the fi rst NASA
mission of its kind to use a privately developed spacecraft, and
therefore represented a signifi cant landmark moment in the rise
of commercial space technology.
But whilst Bob and Doug’s trip to the ISS will no doubt grab
the biggest share of column inches, this month (July 2020) sees
the launch of a mission that is arguably far more technically
signifi cant, as the latest chapter of NASA’s robotic exploration of
Mars begins.
Scheduled to launch from the Kennedy space complex between
July 17 and August 5th, NASA’s Mars 2020 mission will see
Perseverance - an advanced rover bristling with an array of newly
developed scientifi c instruments - set off on a seven month long
trip to the red planet, where it will probe the surface for signs of
ancient life; collect and cache rock samples; and trial technologies
that will pave the way for a manned mission to the planet.
The mission will follow in the footsteps (or more accurately
tyre tracks) of the Curiosity rover which is still operational after
landing on Mars in August 2012 and will replicate many of the
aspects of that earlier mission.
This includes elements of Curiosity’s audaciously inventive
landing sequence which used thrusters, then a parachute, to slow
the descent of the rover-carrying spacecraft before deploying an
elegant “sky crane” manoeuvre in which the rover was lowered
gently to the surface on nylon tethers suspended from the
hovering spacecraft.
Described as “seven minutes of terror” by the engineers
involved this landing was famously seat-of-the pants fi rst time
round, but valuable lessons were learned from the mission, and
thanks to a number of innovations, NASA scientists hope that
Perseverance’s landing will be a slightly less nerve-jangling aff air.
A key development here is an
innovation known as range trigger
technology that will choose precisely
the right moment to deploy the
parachute in order to help the rover
land as close as possible to its prime
scientifi c target: Jezero Crater, an area
which scientists believe was once home
to an ancient river delta.
According to NASA this system,
which makes a calculation based on
the spacecraft’s position relative to the
landing target, enables scientists to
reduce the size of the landing elipse (the
oval shaped landing target) by as much
as 50 per cent and could save as much
as a year’s worth of “commuting” time
by placing the rover close to the areas of
most scientifi c interest.
With the parachute deployed, a
further system known as terrain relative
navigation will help to further optimise
the rover’s descent. This technology
will compare images taken by orbiters
with images of the fast-approaching
surface gathered by the rover, and adjust
the direction of the descent vehicle
accordingly. NASA says that this will be
critical to helping land the rover in the
challenging terrain that is considered
most interesting from a scientifi c point
of view.
As the rover descends, a new suite
of advanced sensors, cameras and
microphones will help engineers
understand more clearly what is
happening, as well as potentially give
viewers back on Earth a ringside seat
at one of space science’s most exciting
27 July 2020 / www.theengineer.co.uk
NASA’s Perserverence
Rover will probe the surface
of Mars for signs of ancient
life; collect and cache
rock samples; and trial
technologies that will be used
in future manned missions to
the planet.
/www.theengineer.co.uk