Thursday, April 10, 2008

Sign post up ahead: Beware of space junk

"NASA Announces That Space Junk Orbiting The Earth Will Confine Man To Earth Forever by 2010"


Scoop Dung

The New York Times

April 10th, 2008

A fake headline of course, but it is not that far from the truth and mankind might well consider what to do with all the junk in Earth's orbit.

As of the end of 2004...

There were 9,233 objects large enough to be tracked and catalogued by the USSTRATCOM Space Surveillance Network. Of this total there were 2,927 payloads, along with 6,306 object classed as rocket bodies and debris." That doesn't take into account the larger bodies breaking down into smaller objects. And the article mentioned the possibility of bringing the Hubble Space Telescope back..." At least two tons (2,055 kilograms) of the estimated 26,000 pounds (11,792 kilograms) of the observatory would survive the plummet from space. Such a fall would produce a debris track that stretches over 755 miles (1,220 kilometers) in length. The analysis suggests that the risk posed to the human population in the year 2020 is 1:250 -- a risk that exceeds NASA’s own safety standard." The Christian Science Monitor reported: "No one knows how much debris is up there. According to estimates from the second European conference on space debris at Darmstadt, Germany, last March, radar and optical telescopes now track more than 10,000 objects. There are also between 70,000 and 150,000 untrackable fragments 1 to 10 centimeters across. The number of dust-size particles probably runs to several tens of millions.

And Xinhua News Agency wrote:

China established the tracking station - which carries the weighty name of Space Target and Debris Observation and Research Center of the Chinese Academy of Sciences - at the Purple Mountain Observatory in Nanjing earlier this month. Space debris, trash cast off by humans and spacecraft while in Earth orbit, ranges from derelict satellites to expended stages and other components of launch vehicles. Chinese space officials expect the new tracking center to study the motions and affects of space debris in orbit in order to protect future manned spacecraft and unmanned satellites, Xinhua reported. Researchers at Purple Mountain Observatory told the Xinhua News Agency that if the current rate of space debris accumulation continues - about 2 percent to 5 percent each year - it could be unsafe to launch anything into orbit by the year 2300.

Some of the junk also causes hazards in Earth's orbit such as the collision [January 17th 2005] where a 31- year-old U.S. rocket body (1974-015B, U.S. Satellite Number 07219) and a fragment [1999-057CV, U.S. Satellite Number 26207] from the third stage of a Chinese CZ-4 launch vehicle, which exploded in March 2000 made a connection. What does fall from orbit usually disintegrates, gets shot down, or lands somewhere on Earth.

Entrepreneurs of the old Soviet Republic are conservationists in a way and gathering launch debris and recycling them for utilitarian and construction materials. As's Bill Christensen wrote:

In an unusual act of generosity, the Soviet space program has been showering valuable metal scraps on the villages surrounding the Plesetsk Cosmodrome for more than forty years. Over the years, more than 1500 launches have been performed with a success rate of over 98 percent. The cosmodrome includes 9 launch pads for Soyuz, Molniya, Cosmos-3M, Cyclone-3, Rockot launch vehicles, as well as a variety of assembly/testing facilities, telemetry and tracking stations.

Tons of "cosmic garbage" - mostly first stages jettisoned from Soyuz carrier rockets - have provided a vital economic boost to the impoverished villages surrounding the cosmodrome, including the main local town Mirny ("Peaceful"). As a suspected ICBM site, Plesetsk was a primary surveillance target on the flight plan for Gary Power's ill-fated reconnaissance flight on May, 1, 1960. Local adminstrators notify the citizenry several days prior to each launch; all "hunters, mushroom pickers, fishermen and reindeer breeders" are strongly advised to leave the dangerous area (yes, that's a quote). Within days, however, scores of local residents go looking for valuable spoils, including "little-damaged Soyuz first stages. Souyz carrier rockets are propelled by kerosene and oxygen, and their parts have a reputation for safety. Older Tsiklon and Rokot carriers propelled by poisonous heptyl leave scraps that people avoid for the time being.

'Self-cleaning', as locals put it, is just a matter of years for them, after which the metals are considered safe to extract.

Less damaged parts may be put to use in households; electric batteries are connected to lamps, sheets of stainless alloys are used to build basements, garages, and even long canoe-like boats.

NASA even had an idea but I don't believe anything was done:

Human-made orbital debris is a constant worry. Getting smacked by a bit of space junk can spoil the day of space travelers. Now under development is a unique orbital debris detector, built to be attached to the outside of the International Space Station (ISS). Once installed, the debris trap would be some 108 square feet (10 square meters) in size.

The detector is outfitted with a combination of debris-snagging aerogel and real-time event sensors. Aerogel is a lightweight material used in the Stardust spacecraft now en route back to Earth with its captured cargo of comet and interstellar particles. Given its large collection area, the orbital debris-snagging equipment for ISS offers two orders of magnitude greater surface area than most of the other detectors now stationed in space. "We’re looking to have it deployed in two years," said Nicholas Johnson, chief scientist and program manager for orbital debris at NASA’s Johnson Space Center in Houston, Texas. The detector is to be mounted on the ISS primarily by a space walker, with perhaps an assist from a robot arm. “It’s going to give us really good statistics on the small stuff,” Johnson said, “and collect data on larger debris,” he told The detector would be space exposed for a year, with its electronic sensors recording when and where the impacts occurred. Once back on the ground, scientists can also scrutinize in detail what specimens of orbital debris the aerogel has gathered.-- Leonard David,

Additional reading:

"Critical space junk threshold approaching"

"Fourth European Conference on Space Debris to address key issues"

"NASA Orbital Debris Program Office"

"Orbital Overload: Space Debris Crowds the Not-So-Friendly Skies"

"Space Debris a Growing Problem, NASA Report Says"

"Space debris mitigation: The case for a code of conduct"

"Space Junk: The Stuff Left Behind"

An audio presentation:

"Litter in Orbit"

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