But he’s not firing ordinary
shells: The
manager of Nasa’s Ballistic Range Complex is shooting tiny replicas of
meteors and spacecraft
from three guns to mimic how craters form and how vehicles may fare in space.
The
guns were built in 1964 to study re-entry to Earth’s atmosphere for the
Apollo missions;
now they’re simulating the space debris that might pummel a moon colony.
“We’ve come
full circle,” Cornelison says. “There’s always something new
to try.”
Light-gas gun
For each test, Cornelison loads the gun with a projectile and a nylon sabot,
which holds the tiny missile in place. Then it’s time to shoot: a gunpowder
charge initiates the fi ring, accelerating a piston that compresses hydrogen
to nearly 7 000 bar and a temperature as high as 3 225 degrees. The gas drives
the projectile out of the barrel - the only one in the world that can tilt up
to 90 degrees - and 5 m into a vacuum chamber.
High-pressure coupling
A coupling like this one helps make the transition from the larger diameter
pump tube to the smaller diameter gun barrel. It directs high-pressure hydrogen
into the barrel to propel the projectile.
Vacuum chamber
Cornelison fills this airtight container with blends of gases to mimic a planet’s
atmosphere, or removes the air to simulate the vacuum of space.
Impact bucket
The projectile is shot into a bucket filled with sand or pumice. To simulate
an ocean meteor impact, scientists once replaced the bucket with a kiddie pool.
Cameras
High-speed digital cameras and oscilloscopes record the projectile as it slams
into the bucket. Computers measure the velocity and the energy released on impact. |
Published by RamsayMedia (Pty) Ltd.: Digital Publishing.
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