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Russia's Mir space station is back dropped against the waters of Cook Strait near New Zealand's South Island. On its last day, Mir will fly over this same area as it plunges toward ocean waters.


U.S. Skylab fell from the sky in July 1979, with chunks of the outpost striking Australian outback.
Russian Ultranationalists Fight to Save Mir
Mir Space Station to Be Brought Down to Earth in February
Russia May Send Crew to Mir In January
Russian Space Chief: Government Must Make Sure Mir Doesn't Crash
Mir's Deorbit Will Rain Down Wreckage; But Where?
By Leonard David
Senior Science Writer
posted: 07:00 am ET
08 December 2000

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WASHINGTON -- Russia is on track to crash its history-making Mir space station into a huge, desolate zone of South Pacific waters in late February. The deliberate ditching of the Russian outpost will produce a sizeable shower of hardware that will reach Earth's surface.

Yuri Koptev, head of the Russian Aviation and Space Agency (Rosaviacosmos), stated last month that Mir's deorbit would take place in the February 26-28 time period.

Mir has been a long time fixture in space. The central core of the Russian station was hurled into orbit on February 20, 1986.

But now, just a little more than 15 years to the day, it will be lights out for the complex of large docked modules, sets of solar panels, antennas and various pieces of attached equipment.

[inset]

If all goes as planned, over 130 tons (132,080 kilograms) of space hardware will be carefully nudged out of orbit and sent screaming through Earth's atmosphere.

Space debris experts project that as much as 50 tons (50,800 kilograms) of Mir leftovers are likely to smack into the ocean after surviving the fiery fall from grace.

Goodbye salute

For NASA's chief, Daniel Goldin, it's goodbye to Mir, hello safety.

"As far as we are concerned, we salute the decision that the Russian government made. It's a very reasonable decision," Goldin told SPACE.com.

Goldin said that at NASA, safety is of the utmost priority. Protecting the general public first, then the astronauts, followed by workers on the ground and, finally, the assets.

"They are going right to the priorities we set. Protect the general public. That is more important than anything else -- I salute their decision," Goldin said.

Abandon in place

Congressman James Sensenbrenner (R-Wisconsin), chairman of the science committee in the House of Representatives, believes it's high time to lower the boom on keeping Mir alive.

"I had hoped the Mir would have been brought down a couple of years ago. That's when it was obviously used up. The Russian's actually abandoned it and its modules were slowly depressurizing. Then it became a political issue in Russia, and an issue of national pride," Sensenbrenner told SPACE.com.

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The U.S. lawmaker said one of the things hurrying the demise of Mir is the fact that two other technological marvels -- Russia's submarine, the Kursk, and the giant television tower in Moscow -- ended up having accidents within a few weeks of each other last summer.

"I think that if something like that happened to Mir, and a bunch of people were killed, that would be another blow to Russia's national pride, one that the Russian government and their president would not want to have to explain," Sensenbrenner said.

Real rocket science

Russia's disposal of Mir early next year will get an electronic helping hand courtesy of the U.S. military's global space surveillance tracking network. In addition, aircraft and mariner alert notices are to be issued via both U.S. and Russian channels.

Mir has housed numbers of space travelers over its 15-year stay in orbit.

But in some government circles, there is concern about too much American involvement. In the event that Mir's reentry goes awry, perhaps careening into a populated area, would the United States be held partly accountable for a botched job?

"Mir's health is pretty good. So I don't see any reason why they can't do it successfully," said Joseph Loftus, assistant director for engineering in space and life sciences at NASA's Johnson Space Center in Houston, Texas.

"Clearly, this is a Russian responsibility. They've acknowledged that it is their responsibility," Loftus said. "Keep in mind, these guys are good. They have been doing reentry exercises for years. This is not some arcane art. It is rocket science, but it's understandable," he said.

Loftus said that a formal and final government declaration to dump the Mir is forthcoming. "They treat these kinds of things like we treat base closings. So there's a commissionand going through their protocol," he said.

The fact that the Mir space base is being downed -- with its core segment having been in orbit around 15 years -- is of special meaning to Russian engineers, Loftus said. Those segment's longevity is the criteria by which engineers measure hardware for use on the International Space Station, he said.

Slam dunk

Tracking data shows that Mir can remain in orbit until at least the beginning of March.

The Russian plan as it is now sketched out is to loft in late January a Progress M1 craft, brimming with propellant. It will join a Progress 243 vehicle already docked to Mir.

Over several days, "phasing burns" of Progress engines will position the Mir for the final last blast.

On deorbit day, starting somewhere over Africa, Progress rocket motors are to ignite and burn for some 800 seconds. Mir ground controllers will be tracking the doomed station as it flies over Russia one last time.

As the critical firing ends off the east coast of Russia, Mir will be on a descending trajectory that will lob it well clear of Australia, New Zealand, the Marquesas Islands and other populated oceanic terra firma.

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The splashdown zone for Mir is huge -- about 3,726 miles (6,000 kilometers) long and 124 miles (200 kilometers) wide.

"By the time things start hitting the ocean, they'll be essentially south of everything. It's as good a place as you are going to find. There are no islands, no air or ship traffic," NASA's Loftus said.

Russian roulette

Odds are good that things will go smoothly for Mir's swan dive.

On the other hand, it might not be all smooth sailing. "I think the major uncertainty is how Mir itself is going to respond. It's an old system and [has] been up there a long time," said William Ailor, director of The Aerospace Corporation's Center for Orbital and Reentry Debris Studies in El Segundo, California.

Given the complicated structure of Mir, there is no telling how the orbiting lab might respond during its breakup, Ailor said.

Another uncertainty, Ailor said, is just how turbulent Earth's atmosphere might be on deorbiting day. Solar activity could mean larger aerodynamic forces acting on Mir, causing the station to become unstable.

If so, then Mir takes on a fate that mirrors the old adage: "What does a 500-pound gorilla do? Anything it wants to."

"If Mir goes unstable, then it's a random process after that. It will come down where ever it wants to," Ailor said.

But not too worry. No need to run out and buy anti-space debris hard hats.

"Even if the Russians can't control Mir, there's a lot of water down below. Three-quarters of the Earth is covered by water. So chances are it'll hit in the water, and [there's] one-chance-in-four Mir will hit land," Ailor said.

"There's plenty of open space," Ailor said. "That's why we've not had anybody actually get hurt, even though we have about 100 reentries a year of major items," he said.

 

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