NASA Performs Dangerous Vacuum Gun Test To Research Space Rock Impact Protection

nasa bullet test
In order to test for possible micrometeorites impacting a spacecraft, NASA is utilizing a 2-stage light gas gun to simulate potential hazards for future space missions. The test fires a bullet with a speed that is equal to 25 times the velocity of a 44 magnum, or like flying from New York to San Francisco in five minutes.

NASA is currently preparing for its Mars Sample Return mission. The mission is aimed at bringing samples collected by the Mars Perseverance rover back to Earth. The space agency is expected to launch its retrieval craft in 2027, and land on the Red Planet in 2028. But before a it is sent to retrieve any sample, NASA is performing tests to try and prevent any damage that might occur from micrometeorites.

bullet hitting target
Bullet fired by 2-stage light gas gun, traveling toward its target.

Micrometeorites can travel at a speed of 50 miles per second. Bruno Sarti, a NASA engineer at NASA's Goddard Space Flight Center, says at these speeds, "even dust could cause damage to a spacecraft."

Because of this potential danger, NASA is using a 2-stage light gas gun to simulate the kind of damage an impact of this nature could cause. The first stage of the gun uses gun powder as its propellant. The second stage differs from a traditional gun, by using highly compressed hydrogen gas that's forced into the smaller projectile tube. This increases the pressure within the gun, much like a car piston, according to NASA.

bullet exiting target
Bullet exiting its target after being fired from 2-stage light gas gun.

While a gun that builds pressure up so high that it could level a building sounds like a disaster waiting to happen, Sarti says, "That is why we hung out in the bunker during the test."

Tests of this nature requires extensive preparation, which is why engineers took three days preparing for the one-second experiment. While the gun used can propel its projectile at a speed of 5 miles per second, it is still six to seven times slower than a micrometeorite can travel in deep space. Because of this, the team uses computer simulations in order to effectively simulate a possible micrometeorite impact on a spacecraft's shield design at those speeds. In turn, the results will help the team to investigate a material's reaction to such energy.

The Mars Sample Return mission is said to be one of the "most ambitious endeavors in spaceflight history, involving multiple spacecraft, multiple launchers, and multiple government agencies." However, the reward will be high if the agency can return the samples collected by the Mars Perseverance rover back to Earth for scientists to study. If successful, NASA expects to bring those samples back to Earth by 2033.