By Earnest Wright  |  05-02-2017   News
Photo credit: Johannes Gerhardus Swanepoel | Dreamstime.com

Six decades of rocket launches have left behind a vast trash heap in orbit around Earth. Approximately 750,000 objects larger than a half-inch, are whipping around the planet at about 20,000 mph. Considering that speed, the impact of a small nut or bolt carries the wallop of a hand grenade. Even a pinhead-size chip of paint hits like a 22-caliber bullet.

This poses a serious problem to any satellite or astronaut working in space. Kessler, who is a former NASA astronaut keeps reminding people that the problems are overwhelming, in a now-famous 1978 paper, drawing on his research at NASA's Johnson Space Center, he and his colleague Burton Cour-Palais showed that collisions between pieces of debris in orbit could create more debris, leading to a potential chain reaction.

The multiplication of the amount of junk will effectively turn all of low-Earth orbit into a no-fly zone, which is a worst-case scenario known as Kessler Syndrome. The International Space Station (ISS) bears numerous scars from impacts with space debris.

Back in 2009, a dead Russian military satellite shattered a $50 million Iridium satellite, and near-misses are increasingly common.

Kessler arrived at the space-debris conference where revealed that there’s an awful lot of repetition going on, adding that it looks like there's not a lot of progress that's been made in the past 20 years.

Brigitte Zypries, Germany's minister for economic affairs, told those at the ESA conference that one of the practical solutions to the problem is the need to control how much junk we send up, adding that there’s need for a coordinated global solution to the global problem.

Some people also agree with the fact that releasing rocket stages at low altitudes so they quickly burn up would help a lot. Companies should also be forced to make sure that all fuel is vented from rockets or deactivated satellites that remain in orbit. Exploding fuel is a major source of space shrapnel.

Hugh Lewis of the University of Southampton pushed for a rule that would require new satellites to return to Earth within five years after deactivation. Even without intervention, objects orbiting fewer than 500 miles above the ground will come down within a few decades due to drag from the uppermost wisps of atmosphere.

There are computer models that show there's already enough junk in orbit to push us unnervingly close to the Kessler Syndrome. One of the space debris expert revealed that there are many different ways we could remove or remediate objects, adding that action needs to be taken immediately.

Mild-mannered space junk experts improbably morph into techno-visionaries as they seek out ways to take out the space trash.

Majority of the serious junk-removal concepts under consideration sound like something dreamed up by Tony Stark: electromagnetic lassos, gripping arms, solar sails, and laser cannons. That's no coincidence. The technologies needed to remove pieces of debris from Earth's orbit really are the same ones that inspired many science-fiction worlds.

The space tether or electromagnetic lasso saw the Japanese space agency, JAXA, attach a 2,300-foot-long spool of aluminum-and-steel cable to an uncrewed space station supply vehicle. Once unwound, the dangling cable would get enmeshed in Earth's magnetic field and get pulled slightly toward the ground. In the future, dedicated satellites could approach large pieces of debris, latch onto them, wind out a similar cable, and drag the offending piece of junk to a fiery burn up in the atmosphere.

This is a core technology needed to build a space elevator, a high-frontier concept for a 22,300-mile-high lift that would bring objects from Earth into space without a rocket. Arthur C. Clarke popularized the idea in his 1978 novel The Fountains of Paradise, in which he explained it as a tower, rising clear through the atmosphere, and far, far beyond. However, the JAXA's low-budget tether test failed but more experiments will follow, each providing a back-door test of that elevated idea.

The first space junk removal mission is set to be launched by the ESA in 2021, called e.Deorbit. It will hunt down a derelict satellite, grab it with a robot gripper or a net, and then steer it out of orbit. Being able to rendezvous with and capture a satellite is also just what you'd need to do if you wanted to lasso a small asteroid, clamp onto it, and start a space mining operation extracting its water for fuel or its metals for construction materials.

SOURCE: http://www.nbcnews.com/mach/space/scientists-have-some-pretty-wild-ideas-preventing-space-junk-armageddon-n752641

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