The Yomiuri ShimbunCleaning up the massive volume of space junk that is floating high above the Earth has become a global problem.
Concerned parties in the industrial, government and academic sectors are working briskly to use Japanese technology to reduce this nuisance. We hope these efforts will steadily make progress.
Old satellites and fragments of rockets become space junk. When these pieces of junk collide, they scatter even more junk. An antisatellite missile test China pushed ahead with in 2007 created a surge in the amount of space junk.
There are said to be more than 20,000 pieces of space junk 10 centimeters or bigger. That this space junk can become a major impediment to space activities is a serious problem.
Space junk travels at the incredible speed of 7.5 kilometers per second at an altitude of about 400 kilometers, where the International Space Station is orbiting. If a piece of this junk collided with a satellite, it could render it inoperable.
There are no effective countermeasures for space junk. At a time when research by the leading spacefaring nations, such as the United States and countries in Europe, is lagging, expectations are rising for efforts being developed by Japan.
One plan is to make space junk slow down and then quickly fall to Earth. A basic experiment on this concept will soon be conducted using Kounotori, an unmanned Japanese cargo transporter that recently delivered supplies to the ISS.
After detaching from the station, Kounotori will extend a 700-meter cable through which an electric current flows. The experiment is described as aiming to confirm a slowdown effect caused by force generated on the cable in the opposite direction to which Kounotori is traveling, due to the Earth’s magnetic field.
If this method can be successfully applied to space junk, this debris could be eliminated without waiting decades for it to fall by itself. The tricky issue is how to attach the cable to the debris.
Strategy needed for sales
Astroscale Japan Inc., a start-up firm funded by the Innovation Network Corporation of Japan, is aiming to implement a different method.
Astroscale’s microsatellite has a receptacle that juts out and captures junk, then the engines fire and it falls to Earth. A demonstration model will be launched in 2018 or 2019. Astroscale also will put a satellite for tracking space junk into orbit this year.
These business activities are believed to be without precedent anywhere in the world. Astroscale expects its customers will be new space businesses aiming to construct a satellite network containing around 1,000 satellites.
A company under the SoftBank Group umbrella is among those planning to set up space telecommunications networks. If the number of satellites increases, there will also be more malfunctions. Removing dead satellites will become an increasingly important task.
We are also intrigued by the Japan Aerospace Exploration Agency’s space debris monitoring system. About ¥10 billion will be poured into this project, in which a radar monitoring installation and an optical telescope will be installed in Okayama Prefecture next fiscal year.
The special feature of this project is that the world’s most accurate defense radar technology has been adopted for civilian use. It will be able to detect — from the ground — 10-centimeter pieces of space junk. This technology has been honed over many years under the nation’s exclusively defensive security policy. It will begin operating in 2020.
The nation needs a strategy for promoting efforts by the private and public sectors to make Japanese technology become more widely used around the world.