The Tampa Tribune
March 12, 2001, Monday, Pg. 1
Return of Mir stirs questions about re-entry;
KURT LOFT, of The Tampa Tribune;TAMPA - When the Soviet Union collapsed in 1989, it left high in the sky one of its proudest symbols of technological prowess. Now it, too, comes crashing down, ending the longest-running human presence in space and a controversial era in the annals of exploration.
The Mir space station, an aging outpost begun 15 years ago, is soon expected to slip back into the atmosphere and break apart in a ball of fire. At more than 130 tons, it will be the largest man-made object to fall to Earth, and no one can say for sure when and where it will scatter any surviving debris.
Depending on atmospheric conditions, the massive hunk of metal could completely disintegrate March 20 - the expected date of re-entry. Or larger pieces could smack the ocean's surface along a plotted trajectory between New Zealand and South America.
Officials from the National Aeronautics and Space Administration and the Department of Defense call the re-entry "wholly a Russian plan" and have confidence the station will burn up over the ocean. The U.S. Space Command in Colorado, which tracks more than 8,300 orbiting objects, also expects a final descent over water.
Space Command tracks orbiting objects in accordance with the 1971 Nuclear Risk Reduction Treaty, which makes sure debris isn't misconstrued as an incoming missile.
"The trump-holders are the Russians because it's their spacecraft," said Army Maj. Barry Venable, a command spokesman. "We are expecting a controlled de-orbit over the South Pacific. It's just a matter of tracking it to see where it's going."
Any parts of Mir that survive re-entry would hit the ocean about 30 minutes after Mir encounters friction in the upper atmosphere.
Nobody can say if Mir will disintegrate, but one thing is certain: Skylab weighed 70 tons when it re-entered the atmosphere in 1979, and debris hit a remote area in western Australia. Mir is twice as heavy, and no data exist that can help officials predict what might happen with such a massive object.
"The problem is you only can control a craft to a certain point before natural forces take hold of it," Venable adds.
Yuri Koptev, general director of the Russian Space Agency, told the government newspaper Rossiskaya Gazeta that he expects a 98 percent chance that any remnants of Mir will land harmlessly in the ocean.
"However, if the station goes out of control, her wreckage could fall on practically any area of the planet," Koptev said. "The probability of pieces falling on a city would be 2 percent."
The Russians view Mir's demise as bittersweet. The station represented the former Soviet Union's dominance over the United States in the field of humans in space, but keeping Mir upgraded and safe for visiting cosmonauts and astronauts became too expensive.
Mir ate up nearly half of the 7.7 billion rubles ($ 2.7 million) set aside for Russia's entire space program this year.
Although many space experts argue that Mir outlasted its design life, others say the station won't fall to Earth in vain. It served as a major steppingstone to the human presence in space, and its contributions to science can't be underestimated, said retired Air Force Col. John E. Blaha, a former NASA astronaut who came home in January 1997 after four months on Mir.
"Mir is like the settlers heading west, the original exploration ground for long-duration science in space," he said. "It gave scientists an opportunity to try something new and to learn from their mistakes."
Jerry Linenger, an astronaut who was living aboard Mir when an oxygen canister explosion caused a near-fatal fire, said it makes no sense to keep Mir in orbit when we have a bigger and better replacement.
"It's sad to see Mir go down, but I'd like to see it go down in a blaze of glory," Linenger said. "It's time to retire it. You can't be too sentimental about technology. Mir is like a laptop computer that's getting old. It's time to get the next model, and we've the next model with the International Space Station."
Mir suffered more than 1,500 breakdowns over a 4,000-day period. The most serious happened in 1997, when an oxygen canister began burning uncontrollably and a cargo ship rammed the station, causing extensive damage.
But the majority of the problems were minor wear and tear, and the lessons learned in fixing them will be useful on the International Space Station now being constructed.
"So when scientists try things a second time on the International Space Station, they will do a much better job because of Mir," Blaha adds.
Mir's reputation as a dangerous rattletrap wasn't deserved, argues Louis Friedman, president of the Planetary Society in Pasadena, Calif.
"It contributed greatly to the development, capability and understanding of human space flight ..." he said. "It also helped preparations for the International Space Station. But, most of all, it helped demonstrate and create experience in mission operations, just as Apollo did with systems engineering in the 1960s."
Not everyone agrees. Experts are divided on the body of useful science that came from Mir.
"The history of Mir has been sort of like serving in the military - long periods of extreme boredom punctuated by brief episodes of terror," said John Pike, head of space policy with the Federation of American Scientists in Washington, D.C. "So one thing the Russians learned was that a space station is more useful as a political tool than as a scientific instrument."
Blaha believes the opposite.
"All the data the Russians learned about humans in space was critical: what goes on with bones and muscles, how to design the sleep protocols, all the health procedures, the type of food to eat on long missions. The Russians learned a lot about how to keep a person healthy and how to return them healthy to Earth. I salute them for that."
Copyright 2001 The Tribune Co.
