Researchers in Japan are proposing an interesting way to get rid of space debris – mount laser in the International Space Station and zap it with a beam.
Land-based lasers have been proposed for such as task in the past but researchers at Japan’s largest research institution RIKEN want to combine a super-wide field-of-view telescope, developed by RIKEN which would detect objects and a recently developed high-efficiency laser system, known as CAN, that could track space debris and remove it from orbit.
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The RIKEN EUSO telescope, which will be used to find debris, was originally planned to detect ultraviolet light emitted from air showers produced by ultra-high energy cosmic rays entering the atmosphere at night. “We realized that we could put it to another use,” says Toshikazu Ebisuzaki, who coauthored a paper on the proposal. “During twilight, thanks to EUSO’s wide field of view and powerful optics, we could adapt it to the new mission of detecting high-velocity debris in orbit near the ISS.”
The CAN laser was originally developed to power particle accelerators. It consists of bundles of optical fibers that act in concert to efficiently produce powerful laser pulses. Combining these two instruments will be capable of tracking down and deorbiting the most dangerous space debris, around the size of one centimeter. The intense laser beam focused on the debris will produce high-velocity plasma ablation, and the reaction force will reduce its orbital velocity, leading to its reentry into the earth's atmosphere, the researchers stated.
The group plans to deploy a small proof-of-concept experiment on the ISS, with a small, 20-centimeter version of the EUSO telescope and a laser with 100 fibers. “If that goes well, we plan to install a full-scale version on the ISS, incorporating a three-meter telescope and a laser with 10,000 fibers, giving it the ability to deorbit debris with a range of approximately 100 kilometers. Looking further to the future, we could create a free-flyer mission and put it into a polar orbit at an altitude near 800 kilometers, where the greatest concentration of debris is found.” said Ebisuzaki in a statement.
According to Ebisuzaki, “Our proposal is radically different from the more conventional approach that is ground based, and we believe it is a more manageable approach that will be accurate, fast, and cheap. We may finally have a way to stop the headache of rapidly growing space debris that endangers space activities. We believe that this dedicated system could remove most of the centimeter-sized debris within five years of operation.”
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At the current density of debris, there will be an in-orbit collision about every five years, The research went on to say that about 10 to 15 large objects or about seven tons of debris need to be removed from space a year to reduce the risk of collisions and damage to other spacecraft, according to research presented at the 6th European Conference on Space Debris in 2014.
Space debris consists of human-made objects in Earth's orbit that no longer has a useful purpose, such as pieces of launched spacecraft. It is estimated that up to 600,000 objects larger than 1 centimeter and at least 16,000 larger than 10 cm orbit Earth. An object larger than 1 cm hitting a satellite would damage or destroy sub-systems or instruments on board and a collision with an object larger than 10 cm would destroy the satellite, according to Commission figures. The number of objects larger than 1 cm is expected to reach around 1 million in 2020.
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