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[Chicago Astronomer - Astro Joe]

LOST IN SPACE / Celestial dump : Space junk is fast becoming a major problem so scientists are trying to develop robots to clean up the mess and prevent disaster.

From the Chinese paper Asahi:

A space-age nightmare is unfolding in the heavens: It's called clutter.

Zooming around at speeds of between 28,800 and 36,000 kph, even the tiniest bits of space debris can spell disaster if they collide with a functioning satellite or spacecraft.

Scientists have catalogued more than 10,000 bits of space junk like out-of-commission satellites and rocket fragments that are stuck in perpetual orbit around Earth.

Each of these pieces has a diameter in excess of 10 centimeters, but millions of smaller objects go untracked. They, too, can have disastrous consequences if they collide with a man-made object.

``If nothing is done, space debris may become a major stumbling block to humanity's activities in space development,'' says Seishiro Kibe, who is working on a debris clean-up robot at the Japan Aerospace Exploration Agency (JAXA). ``First we need to get an accurate picture on the state of space pollution and the mechanism of how it occurs; and then we can think about getting adequate countermeasures in place.''

Cleaning up space of junk is now an international issue. Earlier this month, the U.N. Committee on the Peaceful Uses of Outer Space met in Vienna and agreed to develop international guidelines to regulate space debris. By 2007, the group plans to issue rules on space junk as well as what to do about decommissioned rockets and satellites. Though guidelines have been set up by 11 individual space agencies, including NASA and JAXA, the U.N. effort will produce the first international standards.


More here: www.asahi.com/english/Herald-asahi/TKY200503250186.html
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Humanity is quite messy.

[Maddad]

Chicago said:

Zooming around at speeds of between 28,800 and 36,000 kph, even the tiniest bits of space debris can spell disaster if they collide with a functioning satellite or spacecraft.

That is so misleading. At any one distance from Earth, the orbital speed of the junk is exactly the same as the orbital speed of anything else. Speed means movement as compared to something else. When you compare the speed of a spacecraft to the speed of the junk, the important number is the difference in their velocities.

[Centaur]

Maddad said:

That is so misleading. At any one distance from Earth, the orbital speed of the junk is exactly the same as the orbital speed of anything else. Speed means movement as compared to something else. When you compare the speed of a spacecraft to the speed of the junk, the important number is the difference in their velocities.

Colliding objects are not likely to be on similar paths. They could crash at many different angles from varying directions in 3-dimensional space. Even if two momentarily close together orbiting objects were at the same altitude and moving in an identical direction, they could be moving at significantly different speeds, e.g. one could be at its apogee and the other at its perigee. The trick is not to assume that all objects orbiting the Earth are in circular orbits spinning in the same direction over the equator.

[Chicago Astronomer - Astro Joe]

I agree that the speed stated is directly relative to a stationary object to the moving object. But also the acute and obtuse angles to a object is quite a factor to take into consideration.

One of the Hubble's solar panels has a micro metorite inpact in it, and a Shuttle window was impacted by orbiting debris during a mission.

It may not be 28,000 mph, but the differential of the two moving objects is still quite something.

[Chicago Astronomer - Astro Joe]

Living Off Space Junk

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.

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."

More here at Space.com: www.space.com/businesstechnology/technology/050523_technovelgy_junk.html

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Years ago in the '70's, there was a short lived tv show called "Salvage one", with Andy Griffith.

They would collect space junk for fun and profit...mostly profit.

[Al Degutis]

From ORBITAL DEBRIS QUARTERLY NEWS,
Volume 9 Issue 2, April 2005, NASA
Orbital Debris Program Office,
Johnson Space Center

Accidental Collisions of Cataloged Satellites Identified

Personnel of the U.S. Space Surveillance Network (SSN) have identified two new cases of accidental collisions between cataloged objects from different missions. One collision is recent, having occurred in January 2005, while the other is a much older event which occurred in late 1991 but has just now been recognized.

The subjects of the recent collision were 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. The event occurred on 17 January 2005 at an altitude of 885 km above the south polar region, a regime in low Earth orbit (LEO) with an above-average satellite population density. Both objects were in similar retrograde orbits at the time of the
collision.

Analysis indicates that the orbits of both objects were slightly perturbed at the same time that three debris (subsequently cataloged as U.S. Satellite Numbers 28591-28593) were released from the U.S. rocket body.
The rocket body was the relatively small (1 m2) upper portion of a Thor Burner 2A final stage. The fragment of the Chinese rocket body possessed a radar cross-section of only 0.06 m2.

The recently recognized collision of late December 1991 involved a Russian non-functional navigation satellite, Cosmos 1934 (1988-023A, U.S. Satellite Number 18985) and a piece of debris from a sister spacecraft, Cosmos 926. Both objects were in similar orbits with a mean altitude of 980 km and an inclination of 83 deg. Two pieces of debris (1988-023C, U.S. Satellite Number 21912 and 1988-023D, U.S. Satellite Number 22919) from
Cosmos 1934 were discovered by the SSN within a few weeks of the event, although they were not cataloged until later.

In this case the smaller impacting object apparently broke up into much smaller debris and was no longer trackable by the SSN, i.e., it could not be found after the collision. The event was only recognized recently when SSN specialists were examining historical tracking data.

The first recognized collision between cataloged objects from different missions involved an operational spacecraft and a fragment from a launch vehicle upper stage which had suffered a postmission breakup. In that event, which occurred on 24 July 1996, the French CERISE spacecraft
(1995-033B, U.S. Satellite Number 23606) collided with a fragment (1986-019RF, U.S. Satellite Number 18208) from the third stage of an Ariane 1 launch vehicle, which had exploded ten years earlier.

As the number of objects in Earth orbit increases, the likelihood of accidental collisions will also increase. Currently, hundreds of close approaches (i.e., passes within less than one kilometer) between cataloged
objects occur on a daily basis. If future spacecraft and rocket bodies are not removed from LEO within a moderate amount of time after the end of mission, e.g., within 25 years, the rate of accidental collisions will
increase markedly later in this century.

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