NASA testing
supersonic
parachute
By Brenden Clark
Force equals mass times acceleration – or in the case of
NASA and JPL planning for a landing on Mars – deceleration.
JPL is currently in the testing phase of the LDSD (Low-Density
Supersonic Decelerator) for future, larger load trips to the
Red Planet. The current limit of parachute and deceleration
technology has been reached with the most recent rover
programs, Curiosity being the largest at about the size of a
small SUV. For the future, we need to be able to land much
larger objects on Mars safely so that we can build habitats for
options is a small step, only increasing the payload from the
current 1.5 metric tons to 2-3 metric tons. But considering the
current deceleration system is the same one we’ve been using
since the Viking days forty years ago, it’s time for an upgrade.
The larger the mass, the greater the force needed to slow it
down. The engine of that force is friction or “atmospheric drag”.
While Mar’s atmosphere is much thinner than our own, it does
exist. And so JPL is working on much larger parachutes. The
larger the parachute, the more surface area to create more
friction and deceleration.
It seems like such a simple thing; just build a bigger parachute.
Well, sadly, it’s not. The parachutes JPL needs to build and
test are too big for wind tunnels and so they have to work out
inventive and complex ways to test the new chutes and make
over a kilometer above the ground via helicopter, releasing
the parachute where a rocket sled explodes to life, pulling the
parachute back down to ground at great speed and force.
But the parachute test is only half of the LDSD program.
aerodynamic decelerators. Basically a large ballon structure
a donut ring or inner-tube that increases the surface area of
to slow the payload down from Mach 3-4, down to Mach 2
when the parachute deploys, further slowing the vehicle down
to subsonic speeds.
The two stages together will be tested next month in Hawaii
and if every everything goes well, there are hopes that they
will be ready for missions starting in 2018. Click the link to watch
video of the test: www.youtube.com/watch?v=9h1NtQJ59kM.
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