Tag Archives: international space station

Space Junk Removal

RemoveDebris

The first experiment designed to demonstrate active space-debris removal in orbit reached the International Space Station on April 4, 2018 aboard SpaceX’s Dragon capsule.    The RemoveDebris experiment, designed by a team led by the University of Surrey in the U.K. as part of a 15.2 million euro ($18.7 million), European Union (EU)-funded project, is about the size of a washing machine and weighs 100 kilograms (220 lbs.).

It carries three types of technologies for space-debris capture and active deorbiting — a harpoon, a net and a drag sail. It will also test a lidar system for optical navigation that will help future chaser spacecraft better aim at their targets.

“For this mission, we are actually ejecting our own little cubesats,” Jason Forshaw, RemoveDebris project manager at the University of Surrey, said last year. “These little cubesats are maybe the size of a shoebox, very small. We eject them and capture them with the net.”

“We are testing these four technologies in this demonstration mission, and we want to see whether they work or not,” said Forshaw, referring to the harpoon, net, drag sail and lidar. “If they work, then that would be fantastic, and then these technologies could be used on future missions.”

Some 40,000 space objects — the vast majority of which are defunct satellites and fragments from collisions — are currently being tracked by the U.S.-based Space Surveillance Network. It is estimated that some 7,600 metric tons (8,378 tons) of junk hurtle around the Earth at speeds of up to 17,500 mph, threatening functioning spacecraft, according to a statement from the University of Surrey….

[T]hese same means of capturing debris could easily be used to destroy or otherwise interfere with functional orbital assets [i.e, a functional satellite], most of which are not equipped with a rapid means of evasion or any other form of defense. To a harpoon, net, or drag sail, there is little difference between an out of control hunk of Soviet era rocket and an operational communications or reconnaissance satellite.

Excerpts from BY ALEX HOLLINGS, SpaceX delivers prototype space junk collector to the ISS, but the experiment has serious defense implications, SOFREP.com, Apr. 6, 2018;This Space Junk Removal Experiment Will Harpoon & Net Debris in Orbit, Space.com, Apr. 6, 2018

The First to Shoot…from Space

image from NASA.

North Korea’s preparations to launch a more advanced reconnaissance satellite with a high-resolution scanning capability threaten to push Asia’s space race deeper into the military theater.  The Kwangmyongsong-5 Earth-exploration satellite, likely to be packaged with a separate communications satellite, will technically allow North Korea to transmit data down to the ground for the first time, thus offering real-time intelligence for potential ballistic-missile strikes.

This is well short of the technological capacity needed to deploy orbital weapon systems, but will cause some unease among Asian power-brokers China, Japan and India as they pour money into the last strategic frontier of outer space.  Space programs in Asia have largely been driven by competition for the US$300 billion global commercial transponders market, which is expected to double by 2030 if demand holds.

A shift toward miniature satellites of less than 20 kilograms, mostly used by governments and smaller companies, has drawn nations as diverse as Singapore, Pakistan, Vietnam and South Korea into a field led by Japan and China, with India a more recent player.

Japan placed two satellites in different orbits for the first time on December 2017, displaying a technical edge aimed at reducing launch costs for commercial clients. India announced this week that it had successfully tested a GSLV Mark III rocket that can lift a 4-ton satellite into orbit. In 2017, it managed to launch 104 satellites of varying sizes in just one operation. China has loftier ambitions, including a lunar landing some time in 2018, after sending a roving module down a steep crater on the moon in 2013. About 40 Chinese launches are likely in 2018, mainly to boost communications.  India and Japan are both locked in undeclared space races with China that go well beyond commercial rivalries and have muddied the debate over North Korea’s shadowy aims….

“Militarization” refers to any systems that enhance the capability of forces in a conventional setting, such as intelligence, communications and surveillance. “Weaponization” is the physical deployment of weapons in outer space or in a ground mode where they can be used to attack and destroy targets in orbit.  The United Nations Treaty on Outer Space prohibits the deployment of weapons of mass destruction in space, but the US has blocked efforts to ban space weapons outright. In 2007, Washington said it would “preserve its rights, capabilities, and freedom of action in space.”

Excerpts from  ALAN BOYD,  Asia’s Space Race Gathers Pace, Asia Times, Jan. 6, 2017

How to Wipe Out Space Junk

image frrom http://jemeuso.riken.jp/en/

Half a century of rocket launches has turned the space into a junkyard. Around 3,000 tonnes of empty rocket stages, defunct satellites, astronauts’ toothbrushes and flecks of paint are thought to be in orbit.

Besides being messy, such debris can be dangerous. Anything circling Earth is moving pretty quickly, so collisions between space junk and satellites can happen at closing velocities of 10km a second or more. Large bits of junk are routinely tracked by radar. The International Space Station (ISS), for instance, regularly tweaks its orbit to avoid a particularly menacing piece of litter. But at such high speeds, even a small, hard-to-follow object can do tremendous damage.

Rocket scientists have been pondering how to deal with this problem for years. But a paper just published in Acta Astronautica by Toshikazu Ebisuzaki and his colleagues at RIKEN, a big Japanese research institute, has gone further and proposed actually building a test device.

Dr Ebisuzaki’s plan involves zapping things with lasers. He proposes to point these lasers in the right direction using a telescope intended for a different job entirely. This is the Extreme Universe Space Observatory (EUSO). It is designed to be bolted on to the ISS. From that vantage point it will monitor Earth’s atmosphere, looking for showers of radiation caused by cosmic rays hitting air molecules. Dr Ebisuzaki, however, realised that the characteristics of a telescope designed for this job—namely a wide field of view and the ability to register even fleeting flashes of light—would also be well-suited for spotting small bits of debris as they whizz past the ISS.

Having identified something, the next step is to get it out of orbit—and that is where the zapping comes in… Fire a laser head-on at a piece of space debris for long enough, then, and you can slow it down to the point where its orbit will decay and it will burn up in Earth’s atmosphere.  This idea is not new. But putting lasers into orbit is tricky. Those powerful enough to do the job need lots of electricity and this is hard to deliver with the solar panels from which satellites typically draw their power. Dr Ebisuzaki proposes instead to employ a new, more efficient laser called a coherent-amplification network device, which was developed for use in high-energy physics.

He and his colleagues suggest a three-stage test. The first, with a smaller version of the EUSO and a fairly weedy laser, would serve as a proof of concept. The second would use the actual EUSO telescope and a much more potent laser. Finally, he says, the equipment could be mounted on a purpose-built satellite, from which it would be able to shoot down tens of thousands of bits of space junk every year, thus gradually sweeping the skies clean . 

Orbiting debris: Char wars, Economist Apr. 25, 2015, at 75