Astronauts aboard the International Space Station released a tiny satellite last month as a test for a future "space surveillance network," according to Live Science.
The tiny sphere, SpinSat, is only 22 inches long and was released using a robotic arm. One goal of SpinSat is to test electronically controlled micro-thrusters, according to Live Science.
But the main goal is space surveillance. The military is testing orbit tracking and spacecraft spin.
"It's a good calibration object for them to say, 'OK, we know this thing's going by. Can we do a maneuver detection, can we do a change detection, how small of a rotation can we see, how small of a shift in the orbit can we see?'" primary project investigator Andy Nicholas said in a statement, according to Live Science.
SpinSat features retroreflectors (cubes with three flat mirrors). When the light hits the mirrors, it reflects creating a moving target for ground stations to zero in on with lasers. Satellite positions are then triangulated, according to Live Science.
"They know the laser light's moving at the speed of light," Nicholas said, according to Live Science. "They know where they were pointing the laser, and from that get very accurate orbit positions - down to the millimeter level."
SpinSat can also be used to gather information on atmospheric density. The sun is currently at its peak in its 11 year cycle and ultraviolet rays cause the Earth's atmosphere to swell, according to Live Science. Scientists can use the information to compare to results from 2006 and 2009 missions.
