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Japan's space junk collection experiment ends in failure

Japan's space junk collection experiment ends in failure. Science & Technology World Website


Well that's disappointing. On January 27th, Japan's space agency (JAXA)successfully launched the Kounotori 6 spacecraft to the ISS. It was supposed to test a novel method of dragging space debris out of orbit however a technical issue prevented the spacecraft from carrying out that test before its fiery death in Earth's atmosphere on Monday morning.

The Kounotori 6 was an unmanned vessel designed to test whether attaching long, magnetized cables to dead satellites like those that now shroud the Earth, could effectively drag them out of orbit. It was outfitted with a 700 meter cable which, theoretically, would interact with the Earth's magnetic field and generate enough drag to pull the craft out of orbit. Unfortunately, a technical issue prevented that cable from unfurling and, despite a week of repair attempts, the Kounotori 6 itself fell out of orbit early this morning without having accomplished its primary goal.

"We could not extend the cable, but we think it is not because of the cable itself, but some other reasons," a spokesperson for JAXA told New Scientist. "A detailed analysis is underway."

This isn't the only space-junk removal scheme in the works, however. The UK plans to test a net and harpoon system next year while the ESA is working on a grabber-and-net setup with plans to launch in 2023.


Space junk accidents could trigger armed conflict, study finds

Space junk accidents could trigger armed conflict, study finds. Science & Technology World Website

 

The increasingly crowded space in Earth's low orbit could set the stage for an international armed conflict, says a new study.

Researchers from the Russian Academy of Sciences warn that accidents stemming from the steady rise in space junk floating around the planet could incite political rows and even warfare, with nations potentially mistaking debris-caused incidents as the results of intentional aggressive acts by others.

In a paper published in Acta Astronautica, the team suggests that space debris in the form of spent rocket parts and other fragments of hardware hurtling at high speed pose a "special political danger" that could dangerously escalate tensions between nations.

According to the study, destructive impacts caused by random space junk cannot easily be told apart from military attacks. "The owner of the impacted and destroyed satellite can hardly quickly determine the real cause of the accident," the authors write.

The risks of such an event occurring are compounded by the sheer volume of debris now orbiting Earth. Recent figures from NASA indicate that there are more than 500,000 pieces of space junk currently being tracked in orbit, travelling at speeds up to 28,160 km/h (17,500 mph).

The majority of those objects are small – around the size of a marble – but some 20,000 of them are bigger than a softball.

In addition to these 500,000 or so fragments – which are big enough for scientists to know about them – NASA estimates that there are millions of undetectable pieces of debris in orbit that are too small to be monitored.

But even extremely small fragments such as these pose a threat – in fact, they're considered a greater risk than trackable debris, as their invisible status means spacecraft and satellites can't do anything to avoid them until it's too late. As NASA observed in 2013:

"Even tiny paint flecks can damage a spacecraft when travelling at these velocities. In fact a number of space shuttle windows have been replaced because of damage caused by material that was analysed and shown to be paint flecks… With so much orbital debris, there have been surprisingly few disastrous collisions."

While we may have been lucky in the past, we can't rely on that to continue. The study by the Russian team cites the repeated sudden failures of defence satellites in past decades that were never explained. The researchers attribute two possible causes: either unrecorded collisions with space junk, or aggressive actions from adversaries. "This is a politically dangerous dilemma," the authors write.


Germany to tackle space junk with GESTRA project

Germany to tackle space junk with GESTRA project. Science & Technology World Website

 

Scientists estimate there are 20,000 particles of space junk measuring up at over 10 cm (4 in) in diameter currently hurtling around the earth at an average velocity of 25,000 km/h (15,500 mph), threatening to damage or destroy orbiting satellites. To combat the problem, the German Government has granted the German Aerospace Center (DLR) €25 million to create a system to track space junk as it orbits the earth and the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR) has been tasked with creating the new system's radar component.

The Institute will build on experience working with its existing Tracking and Imaging Radar Systems (TIRA) but Dr. Andreas Brenner, who is deputy director at FHR, says the new (German Experimental Space Surveillance and Tracking Radar (GESTRA) system is far more sophisticated.

"TIRA collects high-definition images of individual objects using a mechanically controlled, movable antenna," says Brenner. "The novel feature of the new GESTRA system is that its antenna is electronically controlled, and can therefore be reoriented even faster because it has no heavy moving parts. Unlike TIRA, it is capable of observing a very large number of objects simultaneously while still supplying data of high accuracy and sensitivity."

The GESTRA system will be made up of retractable transmitters and receivers consisting of phase array antennae, each of which is made up of multiple individual antenna elements, working at a frequency of 1.3 GHz. The array antennae are fitted with high-performance processors that pick up satellites and space debris in a number of different directions at once. This allows the system to cover a large portion of the sky, although GESTRA can also use a narrower beam to track individual objects. The transmitters and receivers are also fully retractable, allowing them to be easily transported inside their containers, which measure up at 4 x 4 x 16 meters (14 x 14 x 52 ft).

Researchers are hoping to use the system as an alarm, protecting satellites orbiting between 300 and 3000 km (186 to 1,861 mi) from earth, as well as watching for bits of debris that leave their orbit and enter our atmosphere.

Fraunhofer is aiming to have the project completed in 2018, at which point it will be operated by remote control from the German Space Situational Awareness Center in Uedem.

The GESTRA system is one of several potential solutions to the problem of space debris. In 2021, ESA is planning on using a harpoon to skewer large objects orbiting earth and prevent them from breaking into smaller clouds of debris, while DARPA's Space Surveillance Telescope is set to jump into action in 2016 – all in an attempt to ensure the orbits between 800 and 1000 km (497 and 621 miles) remain usable and passable for spacecraft and satellites alike.

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