Space debris is becoming more of an issue as time goes on with the number of objects doubling in the last 15 years. Part of that problem is inevitable as the stage based approach to rocketry, whilst being the most efficient way to transport mass to orbit, unfortunately leaves behind a considerable amount of mass. This, combined with the numerous defunct satellites and other bits of junk, means that our lower orbits are littered with objects hurtling through space with enough force to cause some rather significant damage to anything else we put up there. Solving this problem isn’t easy as just picking it up is far more complicated than it sounds. Thus researchers have long thought of ideas to tackle this issue and scientists working at the RIKEN institute may have come up with a workable solution for some of the most dangerous and hardest to remove debris out there.
The idea comes off the back of the Japanese Experiment Module – Extreme Universe Space Observatory (JEM-EUSO) telescope which is slated to be launched and installed on the International Space Station sometime in 2017. The telescope is designed to use the Earth’s atmosphere as a giant detector for energetic particles which will leave a trail of light behind them as they decay in the Earth’s atmosphere. The design of the telescope, which consists of three large lenses that direct the light to some 137 photodetector modules, means it has an extremely wide field of view. Whilst this is by design for its primary mission it also lends itself well to detecting space debris over a large area, something which is advantageous to the ISS which needs to do everything it can to avoid them.
However that’s only half the solution; the other half is a freaking laser.
Scientists at the RIKEN institute have posited that using something like the CAN laser, which is a fibre based laser that was originally designed for use in particle accelerators, could then be used to zap space junk and send it back down to Earth. This kind of approach only works for debris that are centimeters in size however they’re among some of the most devastating pieces of junk due to the difficulty in detecting them. With the JEM-EUSO however these bits of debris could be readily identified and, if they’re within the reach of the laser, heated up so their orbit begins to decay.
The current plan is to develop a proof of concept device that uses a 1/10th scale version of the current JEM-EUSO telescope combined with a 100 fiber laser. Whilst they haven’t provided any specifications beyond that going off their full scale design (10,000 fibers) the concept should be able to deorbit debris up to a kilometer away. The full scale version on the other hand would be able to zap space junk at a range of up to 100km, an incredible feat that would dramatically help in cleaning up Earth’s orbit. The final stage would be to develop a standalone satellite that could be put into a 800km polar orbit, one of the most cluttered orbits above Earth.
Our approach to tackling space debris is fast becoming a multi-faceted approach, one that will require many different methods to tackle the various types of junk that we have circling our Earth. Things like this are the kind of approach we’ll need going forward as one launch will be able to eliminate several times its own mass in debris before its useful life is over. It’s far from an unsolvable problem however whatever solutions we develop will need to be put to use soon lest our low orbits become a place that no man can ever venture through again.