Objects in space tend to spin in a way that's totally different from the way they spin on Earth. Understanding how objects are spinning, where their centers of mass are, and how their mass is distributed is crucial to any space mission. MIT researchers developed a new algorithm for gauging the rotation of objects in zero gravity using only visual information. They tested the algorithm aboard the International Space Station.

SPHERES satellites with goggles onboard ISS. (MIT Space Systems Laboratory)

There are thousands of pieces of broken satellites in space, and by sending a small spacecraft to collect them, and you try to dock to a small, tumbling thing, you also are going to start tumbling. So you need to observe the thing that you know nothing about so you can grab it and control it, according to the researchers.

The team tested the algorithm using two small satellites deployed to the space station through MIT's SPHERES project, which envisions that herds of coordinated satellites the size of volleyballs would assist human crews on future space missions. One SPHERES satellite spun in place while another photographed it with a stereo camera. The algorithm begins estimating all the dynamic characteristics of a spinning object at the same time, including position, orientation, linear and angular velocity, and inertial properties.

The work was funded by both NASA and the U.S. Defense Advanced Projects Research Agency (DARPA).