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Posted on 02/26/2006 4:12:06 PM PST by Denver Ditdat
Sometime this year, an old Russian spacesuit — tossed overboard from the international space station this month — will make its final, fiery dive into the Earth's atmosphere.
Within seconds, Suit-Sat — alias Ivan Ivanovich, alias NORAD Object No. 28933 — will be toast and the U.S. Space Surveillance Network will have one less piece of space junk to surveil. Ditto for Object No. 28934, aka Ivan's glove, which broke off when the suit was shoved out the station's air lock.
At the moment, 9,233 pieces of space junk are being tracked in Earth orbit. But that tally only covers debris that's bigger than a bowling ball — enough to register as a radar blip on the space surveillance network.
As the Space Age approaches 50, the final frontier is awash in heavenly clutter. The litter from a half-century of heave-ho's by 20th-century pioneers includes exploded boosters, burned out rocket motors, radioactive coolant, paint flakes, an astronaut's camera and a toothbrush.
No one tracks — or even counts — the small stuff, but NASA estimates there are at least 100,000 pieces of debris the size of a dime or larger — and "tens of millions" of birdshot-sized fragments — hurtling around the globe many times faster than a speeding bullet.
Too small to worry about? Not when the closing speed between an errant wing nut and a billion-dollar spacecraft can be 30,000 mph. And not when the quantity of debris — 5,000 tons of it — is growing by the year.
Since Russia launched Sputnik in 1957, spacefaring nations and corporate entities of the world have put, or tried to put, more than 5,500 satellites in orbit. About 700 of them are working. Hundreds of others, now lifeless, are out there too, whizzing around the globe along with the rocket engines, upper stages and other hardware used to put them there.
Collisions make new debris
The European Space Agency estimates that 93 percent of all the man-made material in orbit is useless junk. Space, to be sure, is a big place. But not big enough to evade the hazards of cosmic clutter.
In 1996 a French military satellite, Cerise, was damaged when it was struck by a fragment of an Ariane booster rocket — also French — that had exploded in space 10 years earlier.
Last year the upper state of a U.S. Thor rocket, used to loft a satellite in 1974, collided with the remains of the third stage of a Chinese Long March rocket that exploded in space in 2000.
Each grinding collision, of course, generates new debris — smaller particles that form clouds of Space Age buckshot and add a new uncertainty to the hazard because they are too small to track.
In 2002, when U.S. shuttle astronauts changed out the solar panels on the Hubble Space Telescope and returned them to Earth for examination, engineers found them riddled with thousands of impact craters — including 174 punctures — none of them bigger than a BB. A speeding paint chip gouged a pit in one of the space shuttle's windows in 1983.
Gravity, of course, eventually brings most of the junk back to terra firma. But each new launch adds to the problem. And as things collide and proliferate, space junk is becoming a self-renewing nuisance.
"The current debris population in low Earth orbit has reached the point where collisions will become the dominant debris-generating mechanism in the future," said Nicholas Johnson, head of NASA's orbital debris program office.
"Even without new launches, collisions will continue to occur over the next 200 years and will force the debris population to increase," Johnson said. "In reality the situation will undoubtedly be worse, because spacecraft and their orbital stages will continue to be launched. "
NASA computer models predict at least 10 "catastrophic" collisions — capable of destroying spacecraft and crew — over the next two centuries.
Small collisions are already all too common. The crew of the international space station occasionally hear debris — man-made objects as well as meteoroids — strike their outpost. They reported one incident in 2003 that sounded like a "tin can being crushed against the hull."
None of the impacts has penetrated the armor of the station's crew quarters, which is built to withstand small hits. But engineers say an object the size of a grapefruit or larger could trigger a catastrophic depressurization of crew quarters or destroy other components needed to operate the station.
Litterbug crews
In its own small way, the space station has added to the problem. In 2004 the crew reported seeing a bolt and washer float off into space.
Since assembly of the station began in 1999, NASA says "about three dozen" objects have gone overboard. Suit-Sat was launched with a small transmitter for an experiment with amateur radio operators around the world.
"Sometimes when the crew is working outside, they will deliberately discard something," said Gene Stansbery of NASA's orbital debris program. "But usually it's an accident, like losing a tool or something."
Previous items reported lost in space include a camera dropped by Gemini 10 astronaut Michael Collins, a glove lost by Ed White on the first American spacewalk, assorted tools and garbage bags.
If the junk is one of the 9,000-plus objects big enough to be tracked, the U.S. Space Command alerts NASA in time to allow the station's orbit to be adjusted to avoid any chance of a collision.
57 known Earth hits
Evasive maneuvers are also routinely performed by the space shuttle, Department of Defense satellites and some government spacecraft.
Last October, NASA engineers maneuvered the 5-ton Terra spacecraft, flagship of the agency's Earth Observing System, to avoid a possible collision with debris from a U.S. Scout G-1 upper stage that had been launched in 1983. Two days later, the debris hurtled by at a safe distance of about two miles.
The Pentagon is considering a system that would make such alerts available to operators of commercial satellites too.
"Right now, if you have a commercial satellite in geo-stationary orbit, you are basically flying blind," said William Ailor of the Aerospace Corporation, a California-based engineering firm that studies orbital debris.
Eventually, objects in orbit will succumb to the inexorable tug of gravity — usually burning up harmlessly in the atmosphere or falling into the two-thirds of the Earth's surface that is covered by water.
But not always. Since Sputnik, an estimated 1,400 tons of debris has survived the fiery descent from space. An estimated 200 man-made objects re-enter the atmosphere every year. And at least 57 impacts on land have been thoroughly documented.
They include a titanium motor casing from a U.S. rocket that fell near Bangkok, Thailand, in January 2005; a plate-sized metal fragment from the fourth stage of a Russian Proton rocket that fell near Wichita, Kan., in 2000; and a piece of Russia's Sputnik IV, which fell on a street in Manitowoc, Wis., in 1962.
Rocket shard hits woman
So far no one has ever been hurt by incoming space junk — not even Lottie Williams of Turley, Okla., who was strolling in a park in 1997 when she was struck on the shoulder by a charred 6-inch fragment of a Delta rocket launched a year earlier. She was uninjured.
Five objects have re-entered the atmosphere just within the past month — the second stage of a U.S. Delta rocket, a small U.S. satellite, two Russian rocket motors and a Russian Molinya satellite. All burned up during re-entry or fell in the Atlantic or Pacific without incident.
Because bigger objects are less likely to be incinerated, large spacecraft pose a special problem. NASA's 85-ton Skylab, which broke up during its descent in 1979, rained debris across Australia. Russia's Mir space station was safely steered to a crash landing in the Pacific Ocean. And that's probably where the international space station — the largest structure ever assembled in space — will end up after it outlives its life in orbit.
NASA officials say measures to clean up the clutter — from laser "brooms" that would sweep debris into the atmosphere to robotic tugs acting as garbage trucks — are costly and impractical.
Instead, the United States and other nations have adopted policies that they hope will at least slow the growth of the problem. U.S. policy calls for all launches to include planning for the end of the spacecraft's useful life — usually a timely, controlled crash into the ocean.
But not everything that goes up will be coming down. Operators of satellites in geo-stationary orbits, the coveted 22,500-mile altitude used by hundreds of communications and weather satellites, frequently move obsolete satellites into a "disposal" orbit 150 miles farther out, where they won't collide with functional satellites — at least for a while.
"Our long-term prediction is that the disposal orbit shouldn't become a problem for a hundred years or longer, said NASA's Stansbery. "But then, who knows what we'll be doing in space 100 or 200 years from now."
Of course, dozens of interplanetary probes have made true one-way journeys — to the moon, the planets, and in the case of Voyager 1, eventually into the vast, still uncluttered, reaches of interstellar space.
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It would involve launching a relatively small package packed with a compressed blob of aerogel. Once exposed to vacuum, the aerogel would expand to a gigantic size, but still have very low mass. The gel could be shot through with loops of wire running every which-way, which in turn would be attached to a computer controlled switch that could feed small amounts of current through them. This would make the blob somewhat steerable, using the Earth's magnetic field to climb up and down.
Such a blob could be put in position to collide with the space junk, where it would become trapped. Now, the aerogels we have right now are pretty tough for their density, but they probably aren't tough enough to stop something tooling through at 18,000 mph. We might have to engineer something much tougher. But if the right pieces of junk are chosen, the relative velocity between the junk and the blob could be pretty small.
Now, here's the real trick: every piece of junk absorbed will kick the blob into a different orbit. If the objects are chosen in the right order, and with a little bit of orbital tweaking with the Helmholtz coils, each collision could put the blob in a good position for the next collision. The last few collisions, of course, would be chosen so as to cancel enough of the blob's momentum to drop it into the sea.
If you're on the Sea of Tranquility and you see a Big Mac wrapper blowing past, you have bigger problems than litter. What's making that damned thing move? Heavy boots, don't fail me now!
That's hardly a significant amount, considering the size of the objects and the area involved.
The Z Prize would offer $100 Million to the first space enterprize which develops a
Space Zamboni!
Much too complex.
How `bout a variation of Adopt A Highway -- Adopt An Orbit.
The solution is to put a bunch of garbage cans up there.
An interesting idea, the math would of course be unimagineably ludicrous and the materials are lacking, but I like the approach.
Of course. But there is no math so ludicrous that it won't be overtaken by Moore's Law in a calculably finite time.
It hasn't worked. In fact, the ISS has so far shed bits of junk.
To be stripped of at least blaming someone elses space junk for their failures has got to be depressing.
What would YOU pay for the astronaut's camera that was in space for the last how many years?
Somebody in Atlanta go take pictures of how much trash this paper produces a day (besides the actual newspaper).
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The first time I saw this mentioned was on a kid's show in 1965 called "The Big World of Little Adam." It talked specifically about obsolete objects that were in orbit, and suggested that at some point in time, there could be a problem with collisions with the objects. IIRC, it showed a space garbage truck going around to pick up the old rockets and satellites. Of course, it was a long time ago, and I was a kid, so my memory details are sketchy. |
Good idea. An aerogel film like a soap bubble within a ring orbiting retrograde would be better. The ring would be a superconductor about 5 km in diameter. That "magnetic sail" idea was expressed some years ago wherein the ring can, by tilting with or against the solar wind/magnetic field, move within the solar system. The tilting is done by shifting a cabin/weight near the center. The superconducting mag-field also keeps out solar flare-damage from the ring area. Thus the "dust pan" you need to clean up space junk....Also, with that much junk in orbit, one sees the impracticality of the space elevator concept with its cable running from 22,500 miles to grade; not to mention the possibity of shorting out the earth-ionosphere capacitor....Anyway, with so much GARBAGE orbiting around up there, this may be why UFO sightings have fallen off recently....
And I was hit on the head just last week from a chunk of insulating foam from the space shuttle!
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