One of our first lab books was all about optics. We had won an Awesome Foundation grant to develop an edible optics curriculum and bring it into the schools. To make optics fun, we decided to give the kids a variety of challenges using lenses, lasers, and an asteroid of doom.
Basically, at the end of the lab kids are challenged with using the lenses to steer their lasers towards an asteroid with the idea that their lasers would be powerful enough to blow the asteroid up. We also looked at the importance of laser color as we passed red lasers through red, green and blue jello, discovering that the laser would actually only travel through the red jello.
While we can’t actually use lasers to blow things up in space (or really blow things up as large as an asteroid on Earth), we can use lasers to steer things. That’s right. We can use lasers to effectively push small objects around!
This is great news since right now there are millions, if not more, pieces of tiny broken down satellites in orbit around Earth. We call these whizzing objects space junk as they orbit around Earth and can’t really be cleaned up.
This poses a huge problem for spaceships and astronauts as many of the smaller pieces can’t be detected – these are called micrometeorites and some are traveling faster than bullets.
You can imagine that having your ship hit with one of these could be catastrophic. Right now the International Space Station has two major protections for space junk: they steer clear of larger objects, and they have a second skin to catch the smaller objects.
A second skin on the ISS? Really? Yes! The ISS has it’s main compartments surrounded by a baffled metal casing. This casing can get hit, and even punctured by the space junk without causing serious damage to the ISS itself. Then astronauts can go out and repair pieces to the casing to make sure the protection is always in tip-top shape.
However, with more and more satellites being deployed into space, and more and more of them turning into space junk, scientists are posed with a very real problem. How do we clean up the space junk around Earth?
Since 2015 some scientists have believed that the way to do this is by burning up space junk with lasers, but not directly in the way you’re probably imagining.
Scientists would use the lasers to move the space junk around. Yes, you read that, they would use the lasers to actually push the space junk closer to Earth. This would know the pieces out of their geosynchronous orbit and hurl them into our atmosphere where they would burn up and where we would make wishes upon them since they would look like shooting stars.
How can a laser move space junk? Well, a laser can push on anything, even you and me. We don’t see it in everyday life because we are very very heavy, and the laser can push only very lightly. But, if you took a piece of foil out into space and shined even your dollar store laser on it, it would begin to move.
This is because light has energy, and by shining light on a piece of foil, or on a piece of space junk, you are imparting that energy onto the object. That energy is in the form of kinetic energy. Think of it as throwing billions of really really really light and tiny ping pong balls at a piece of space junk. At some point, the energy of all those little balls will add up and cause the space junk to move in its orbit.
Scientists hope that by using this method we can clear Earth’s orbit and keep our functioning satellites, space stations, and astronauts safer. One of the biggest hurtles, however, will be international government cooperation – as right now I’m pretty sure no government wants another government to have high powered lasers in space.