Mounting space junk threatens chain reaction

The New York Times ^ | 02/06/2007 | William J. Broad

[theBuckwheat]

Some important satellite systems, like GPS, Iridium, Milstar are actually set up in a constellation, with several evenly spaced satellites in the same orbit. The most important constellation of all are all the giant satellites (some weighing tons) in the Clarke belt, also known as the geostationary belt.

In any of these situations, a single load of sand slowly released along the right orbital path could bring all the satellites in the system down.

When the US tested its ASat, it took almost two decades for the debris to decay out of orbit.

[CFC__VRWC]

I know. I'm just so friggin' sick and tired of the constant hysterical, hyperventilating, apocalytic, wildly exaggerated drumbeat of gloom and doom and we're all gonna DIE!!!!! screeching that comes from the media without even the slightest pause for air.

[palmer]

All this junk will reflect sunlight back into space causing dangerous global cooling.

[kidd]

Assuming an average altitude of 1000 miles, the area covered by this space junk is about 255 million square miles. With 20,000 pieces of space junk, that works out to one piece of space junk for every 12,700 square miles. That's about one piece of junk for every area the size of the state of Maryland.

[Fitzcarraldo]

Since most (all?) of the junk is metallic, how about an orbiting supermagnet?

Depends on the composition of the material and the strength of the magnet ;^).

http://en.wikipedia.org/wiki/Space_junk

http://www.orbitaldebris.jsc.nasa.gov/

(before the Chinese event)

[Fitzcarraldo]

That's about one piece of junk for every area the size of the state of Maryland.

But the orbiting junk travels fast (5 miles/sec) so it sweeps out large volumes per unit time and would impact other satellites at high relative velocity in the miles/second range, creating more debris in a cascading effect / chain reaction.

[Fitzcarraldo]

http://en.wikipedia.org/wiki/Kessler_Syndrome

The Kessler Syndrome is a scenario, proposed by NASA consultant Donald J. Kessler, in which the volume of space debris in Low Earth Orbit is so high that objects in orbit are frequently struck by debris, creating even more debris and a greater risk of further impacts. The implication of this scenario is that the escalating amount of debris in orbit could eventually render space exploration, and even the use of satellites, too prone to loss to be feasible for many generations.

The Kessler Syndrome is especially insidious because of the "domino effect." Any impact between two objects of sizable mass will create additional shrapnel debris from the force of collision. Each piece of shrapnel now has the potential to cause further damage, creating even more space debris. With a large enough collision (such as one between a space station and a defunct satellite), the amount of cascading debris could be enough to render Low Earth Orbit essentially impassable.

Every satellite, space probe and manned mission has the potential to create space debris. As the number of satellites in orbit grow and old satellites become obsolete, the risk of a cascading Kessler Syndrome becomes greater.

The Kessler Syndrome presents a unique problem to human space travel. Space debris is very difficult to deal with directly, as the small size and high velocities of most debris would make retrieval and disposal impractically difficult. Given thousands of years, most debris in Low Earth Orbit would eventually succumb to air resistance in the rarefied atmosphere and plunge to the Earth. If magnetically susceptible, the debris could fall in a few decades due to the drag of the Earth's magnetic field.

To minimise the chances of damage to other vehicles, new vehicles and satellites are frequently required to demonstrate that it can be safely disposed of at the end of its life, for example by use of a controlled atmospheric reentry system.

Fortunately at the most commonly used Low Earth Orbit's residual air drag helps keep the zones clear. Altitudes under 300 miles will be swept clear in a matter of months.

[Right Wing Assault]

United Galactic Sanitation Patrol ship to the rescue.

I'd sign up to be a space garbageman. Sounds fun.

[Fitzcarraldo]

Since most (all?) of the junk is metallic, how about an orbiting supermagnet?

Here you go:

"...If magnetically susceptible, the debris could fall in a few decades due to the drag of the Earth's magnetic field..."

[Right Wing Assault]

Since most (all?) of the junk is metallic, how about an orbiting supermagnet?

My guess is a lot of that metal is aluminum and magnesium, which are minimally affected by magnets.

[Fitzcarraldo]

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V3S-479D818-9&_coverDate=12%2F31%2F1991&_alid=370611327&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5738&_sort=d&view=c&_acct=C000047944&_version=1&_urlVersion=0&_userid=918210&md5=6e09639c04a6e77b992efc3decabfc40

Collisional cascading: The limits of population growth in low earth orbit

Donald J. Kessler

NASA/Johnson Space Center, Houston, TX 77058, U.S.A.

Available online 25 November 2002.

Abstract

Predictions have been made by several authors that random collisions between made-made objects in Earth orbit will lead to a significant source of new orbital debris, possibly within the next century. The authors have also concluded that there are a number of uncertainties in these models, and additional analysis and data are required to fully characterize the future environment. However, the nature of these uncertainties are such that while the future environment is uncertain, the fact that collisions will control the future environment is less uncertain. The data that already exist is sufficient to show that cascading collisions will control the future debris environment with no, or very minor increases in the current low Earth orbit population. Two populations control this process: Explosion fragments and expended rocket bodies and payloads. Practices are already changing to limit explosions in low Earth orbit; it is now necessary to begin limiting the number of expended rocket bodies and payloads in orbit.

[Centurion2000]

Now, experts say, China's test Jan. 11 of an anti-satellite rocket that shattered an old satellite into hundreds of large fragments means the chain reaction will most likely start sooner.

Experts? Try idiots. Even LEO space is HUGE.

[sionnsar]

spreading chaos through the heavens.

What crappy writing. NYT subscribers get a bonus in my book for being able to read, but it ends just about there.

[dr_lew]

My idea is a huge ball of styrofoam that would sweep up objects then reenter after orbital decay, which would be rapid for a large low density object.

Not sure how that would work out!

Problems:

Low encounter rate.

Engineering a "capture density" for the styrofoam.

Getting it up there.

[rabidralph]

It's already happened.

[dr_lew]

That reminds me. Did everyone see the superbowl ad with the "moon mission" theme? They depicted zero-g effects on the lunar surface. To me, this sort of thing is a scary peek into the abyss of ignorance.

[sam_paine]

this sort of thing is a scary peek into the abyss of ignorance.

Well, doc....you were peeking into what has long been called a "boob tube."....... =P

[cavador]

I just saw a Doco on the Discovery channel about what happended to the Columbia and i really think it hit a piece of space junk in orbit, not a loose foam tile from the booster and I believe that's what damaged the wing tile that compromised the surface of the vehicle. Such a Tragedy .... May they rest in peace.
http://www.nasa.gov/columbia/home/index.html

[dr_lew]

I remember a show on "the boob tube" from the early sixties about lunar exploration. I think I must be remembering MEN INTO SPACE, from 1959-1960, based on the Wikipedia description, and the more I think about it, the more familiar the title seems to me. From Wikipedia:

Men Into Space, later syndicated as Space Challenge, used for its plots many technical and human problems anticipated by engineers and planners. For example, the show depicted attempts to refuel spacecraft by tanker in orbit, construction of a space telescope, an experiment to dispose of high level atomic waste by launching it into the sun, the search for life-sustaining frozen water on the moon, exploration and destruction of an asteroid whose orbit threatened Earth, and exo-fossil evidence of extraterrestrial life.

The episode that sticks in my mind was some kind of rescue during a lunar exploration that laboriously depicted the low-g lunar gravity.

1960

[arthurus]

It is all orbiting and in the same basic direction. It is not as if the stuff were all flying about randomly. I am sure that satellite defense systems are in development-some might be deployed on some satellites- systems that recognize pieces that are on collision course and can change orbit just a tad or even repel small bits. I know that many of the satellites are able to change orbit and can be repositioned to look at different parts of the earth.