Most of Mir will burn up upon reentering the Earth's atmosphere, but an estimated 20-25 tons will crash into an unihabited portion of the Pacific Ocean, somewhere between New Zealand and Chile.

According to a space engineer familiar with the project, precisely predicting the impact of Mir with the Earth is "like jumping off a very fast moving merry-go-round and trying to land on a handkerchief." The Russian-built space station currently weighs 137 tons.

Crown-Jewel of the Russian Space Agency

Mir, which is the Russian term for peace, was launched in February 1986, becoming the crown-jewel of the then Soviet Space Agency.

Mir has been part of a 30-year legacy of long-term Russian occupation in space, which began with the space station Salyut which was launched in 1971.

The most memorable and terrifying year for Mir came in 1997, when the aging space station—already six years beyond its planned mission-life—was hit by a remotely controlled supply ship that crashed into the Spektr science module, causing rapid depressurization of the station.

Onboard computers failed several times during that year, at times causing the station to gyrate out of control. A life-threatening fire onboard was quickly suppressed, but eroded confidence in the ailing craft.

Even with these glitches, Mir remained occupied until August 27, 1999, when two Russian cosmonuats and an French scientist closed the hatch for good.

The Russian Space Agency then turned control of the station over to MirCorp, which planned to turn Mir into a commercial space laboratory and an orbiting space hotel with a price tag of U.S. $20 million a trip. Other plans included sending winners of a game show to Mir.

Eventually, the money to keep Mir aloft was not enough to pay the bills. In late 2000, the Russian government finally raised enough money to give Mir an honorable burial at sea.

A Fiery Crash

Mir's altitude is slowly dropping. Now that it is below the critical 155-mile level that keeps it in permanent orbit scientists expect it will lose about one mile (1.4 kilometers) in altitude daily. Flight programmers plan to use rockets to keep the space station in orbit until March 19 or 20.

Once Mir drops to 137 miles (220 kilometers) above the Earth, it will be on a death trajectory. Russian ground controllers will then fire a series of braking thrusts at the peak of Mir's last two orbits. Mir will be tracked by U.S., European, and other ground stations for the next 45 minutes as it crashes through the atmosphere in a fiery ball.

As Mir falls to below 78 kilometers Nicholas Johnson, chief scientist and program manager for Orbital Debris at NASA, predicts that the "aerodynamic and thermal forces will become extreme and the spacecraft will rip apart."

Johnson says that "every time they [the Russians] have attempted a controlled deorbit over the Pacific they have been successful."

While the Russians do not expect Mir to hit any land mass, they have taken out an insurance policy of U.S. $200 million just in case something goes terribly wrong.

Spectators around the world will be able to watch the crash on the Internet.

Now the Russian Space Agency will concentrate solely on its contributions to the International Space Station. Their vast range of experiences with Mir have made the International Space Station a safer and better platform to continue human habitation of space.