Earth saver? Lasers manipulate spin of 'asteroid' in simulated experiment

©  UC Santa Barbara
Researchers have honed laser technology to be able to slow, stop, and reverse the rotation of an asteroid-like target in a simulated space environment. The findings could potentially help deflect Earth-bound asteroids in the event of a major-impact threat.

The DE-STAR (Directed Energy System for Targeting of Asteroids and exploRation) can, among other uses, stop the rotation of a spinning asteroid, according to small-scale, graphic demonstrations by the Experimental Cosmology Group, led by UC Santa Barbara physicist Philip Lubin and Gary B. Hughes, a researcher and professor at California Polytechnic State University-San Luis Obispo.  

In order to simulate the laser's deflection capabilities, researchers used basalt, which is composed of materials similar to those of an asteroid. The team directed a laser at the basalt until it began to turn from a mineral to a gas. As the "asteroid" lost mass, it became a propellant.

“What happens is a process called sublimation or vaporization, which turns a solid or liquid into a gas,” said Travis Brashears, a student at the University of California-Berkeley involved in the research. “That gas causes a plume cloud — mass ejection — which generates an opposite and equal reaction or thrust  — and that’s what we measure.”

Magnets were used to spin the basalt, simulating a rotating asteroid. The laser system was also used to slow the rotation of the target.

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“Our video shows the basalt sample slowing down, stopping and changing direction and then spinning up again,” said Brashears. “That’s how much force we’re getting. It’s a nice way to show this process and to demonstrate that de-spinning an asteroid is actually possible as predicted in our papers.”

Lubin said DE-STAR could also be employed for space exploration or mining.

“All asteroids rotate; it’s just a question of relative to whom and how fast. To mine an asteroid, it needs to be moving slowly enough so you can capture it,” Lubin said. “Our lab experiments show very graphically a practical way to de-spin or redirect an asteroid. It’s a vivid demonstration that the technique works very well.”

NASA's Sentry system monitors potential asteroid collisions with Earth. The system analyzes potential impacts over the next 100 years, continually updating the Sentry Risk Table to provide accurate information on objects recently and not recently observed.

In May, NASA announced that it would launch an asteroid capture mission within the next decade. The plan will involve capturing and redirecting an asteroid into Earth's orbit where it can be examined by astronauts.

“If we can do that and we get it into stable lunar orbit, we will have done something that is dramatically informative to humanity and may lead to the development of sustainable technologies that will then be able to save the planet,” said NASA Administrator Charles Bolden at the time.