The discovery of gravitational waves was just the beginning of mankind’s sustained inquiry into these strange, faint signals. The European Space Agency was already thinking several steps ahead before the announcement by LIGO was made in February. That’s why it launched the LISA Pathfinder back in December — to detect and study gravitational waves directly out in space. What the ESA didn’t expect, however, was that LISA was going to exhibit data gathering capabilities not related to gravity wave research. Scientists are now proposing using the probe to tabulate micrometeoroids — space rocks virtually the size of a marble or smaller — that threaten our satellites and other spacecraft currently in orbit.
A single asteroid can be traveling up 22,000 miles per hour in the vacuum of space. At those speeds, it doesn’t matter if the rock is a size of a pea; it can still cause an immense amount of damage through our space hardware or even the spacesuits of astronauts conducting a spacewalk. But gravity waves and micrometeoroids are very different things. How exactly are scientists going to use LISA to study rocks?
The spacecraft is fitted with an instrument that floats weightlessly inside. It’s designed to pick up on very slight changes in spacetime — i.e. the very small ripples caused by gravitational waves, while accounting for and adjusting to other external stimuli. As reported by Space.com, NASA astrophysicist Ira Thorpe, part of the LISA Pathfinder team, wants to flip that last function on its head: instead of tossing out the noisy data the system throws out as just unwanted disturbance, collecting it, and using it to count micrometeoroids.
Spacecraft constantly threatened by small rocks zipping at high speeds. Bigger spacecraft like the ISS are fitted with more durable protection to resist tears from micrometeoroids — but that protection comes at a much bigger cost. Smaller satellites, especially ones that have no avoidance maneuver mechanisms, are virtually on their own.
This issue becomes an even bigger problem when we consider how scientists are looking to use more and more lightweight materials as a part of spacecraft structures. Case in point: Yuri Milner’s and Stephen Hawking’s Breakthrough Starshot initiative, which seeks to fit tiny sensors with meter-sized solar sails for propulsion. Those sails will be incredibly thin and lightweight, allowing the craft to move faster through space, but also putting them at risk for catastrophic failure from just a single tear or hit by a flying space rock.
Thorpe’s idea for LISA could be invaluable to space exploration down the road as we start to shift to thinner, lighter materials. If he can push his proposal from concept to reality, we’ll find out soon enough.