NASA LENDS HELPING HAND TO MIR DUMPING HOUSTON, Texas -- Timing is everything in a global effort to assure the safe disposal of the huge
Mir space station.A NASA team is ready here to help their Russian counterparts in the destructive dumping of Mir tonight. A communications link ties Mir deorbit specialists in Moscow with NASA Johnson Space Centers (JSC) trajectory and operations experts within the International Space Stations Mission Control Center.
With the orbiting outpost on its final flings around Earth, NASA will supply the Russians with up-to-the-minute Mir position reports. That information is to be gleaned from a worldwide network of radar and optical sensors operated by the militarys U.S. Space Command, based in Colorado Springs, Colorado.
In demonstrating what man can do in space, Mir has been phenomenal.
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European Space Agency (ESA) tracking post near Bonn, Germany is keeping a radar eye on Mirs final days in space, too.Also being relayed by NASA to Russian Mir handlers is solar activity data provided by the National Oceanic and Atmospheric Administrations (NOAA) Space Environment Center in Boulder, Colorado. The agency is monitoring the Suns output and its effect on Earths atmosphere, which is yet another dynamic affecting the precision bombing of Mir into ocean waters.
In NASAs lead hot seat for Mirs fireball finale is Scott Paul, a JSC trajectory operations officer. He is the space agencys designated driver for feeding U.S. Space Command tracking updates on Mir to Moscow.
Home of U.S. Space Command's Space Control Center that tracks Mir.
The
U.S. Space Commands global ability to watch Mir merges deep under Cheyenne Mountain in Colorado Springs. From there, the Mir tracking data is relayed to Paul at JSC."Primarily our role here is pretty much an interface between the mountain and Moscow," Paul told SPACE.com. "Coming back from Moscow are status reports on each deorbit burn," he said.
Paul has worked at NASA for seven years, assigned to Mir-shuttle flights, as well as the International Space Station during that time. Those Russians in charge of
bringing down Mir are good friends, companions he has met with in person during trips to Moscow, and when they visit Houston."I think there will be a lot of teary eyes over there in losing Mir. Theyve been flying it so long. They are at the point of no return now. Its coming in one way or the other," Paul said.
Paul and three JSC colleagues are on
Mir reentry duty. Several dry runs of deorbit day have been completed. The entire sequence of burns to dunk the Russian station into the ocean takes about six hours, he said."Its been busy, thats for sure. I think were in pretty good shape," Paul said. "The Russians are pretty experienced at what they do. Hopefully, Mirs systems will hold up and they dont have a
computer failure. I think thats their biggest worry right now," he said.Knockout punch
Splashdown of Mir within
a targeted zone of the south Pacific is now expected on March 23, around 1:00 a.m. EST (06:00 GMT), said Nicholas Johnson, NASAs chief scientist and program manager for orbital debris.Johnson said the Russians have a three-step plan for bringing down Mir. Using a fueled Progress M1-5, now docked to the complex, two separate firings of that crafts reaction-control thrusters will start to brake the 134-ton complex. Then, using a blast of the Progress main engine combined with control thrusters, a third and final maneuver will provide the knockout punch, putting Mir onto a fiery trajectory to Earth.
"All three burns will last about 20 minutes. The Russians plan to essentially use all the fuel on the Progress, with some margin in there," Johnson told SPACE.com. "This is the largest vehicle that has ever been maneuvered for the longest time," he said.
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High drama
Early in planning for the Mir reentry, the Russians had plotted out 48-hours worth of braking activity to dive the station into the south Pacific.
"The time scale is a little more compressed than it was before," Johnson said. All of Mir's maneuvers are now set to take place in just four and a half hours, he said. That means there will be less time available for U.S. tracking gear to firm up the exact orbit-to-orbit position of Mir.
"The [time] gap has pretty much evaporated, to be honest," Johnson said.
At present, there will be only one 90-minute revolution of Earth separating the first two braking maneuvers. Two hours later, the dramatic and final engine burn that will send Mir into the drink takes place.
"Its obviously not a typical reentry for the Russians by any stretch. But on the other hand, there are no new technical challenges. They have spent a great deal of time thinking about this," Johnson said. "In terms of executing the plan, this should not be a big deal. Clearly, they are making sure that all the "is" are dotted and all the "Ts" are crossedor whatever they have in Cyrillic," Johnson said.
Breaking up is hard to do
There is no telling just how much debris will actually make it to Earth.
Although computer models can number crunch and output guesses, there is far too much variability. Factors include: Mirs superstructure; the makeup of equipment and other items now onboard; the angle it hits the atmosphere; how the modular complex tears apart; and other unknowns.
The mechanical couplings that link Mirs various modules are sure to fail early, even before serious melting starts. Those modules are pressurized, so each will pop off and away from each other.
"What youll probably have is eight large objects coming through the atmosphere along the same path. If theres anybody down there, itll be a spectacular show," Johnson said.
The traveling light show will occur between 50 miles (80 kilometers) and 31 miles (50 kilometers) in altitude. Mir fireworks will be visible for just a few minutes.
Johnson said that Russian homework on the
reentry suggests that 20 percent of the 134 tons could strike Earth -- some 27 tons. Within that flaming wreckage, one item has already been identified as a sure survivor: a 1,540-pound (700-kilogram) film vault.
"In terms of the footprint, the vault will go the fastest and the very farthest," Johnson said, with lighter objects falling shorter and taking a slower tumble into the sea.
Mir: The history ship
In his pre-NASA post, Johnson did "threat analysis" of Russian capabilities, including Mir. "My reason for looking at Mir 15 years ago is not the same reason today. Its a whole different world," he said.
Looking back at the venerable,
good ship Mir, Johnson said that the Russian station has demonstrated many times over the role of humans in space. Being able to keep the station alive for 15 years; gaining biomedical knowledge regarding long-duration human stints in Earth orbit, along with numbers of spacewalking cosmonauts that tested construction techniques -- these are among some very significant achievements, Johnson said. "Plus, theyve been able to suffer through some pretty unexpected events, like collisions, fires and other less serious issues."
"In demonstrating what man can do in space, Mir has been phenomenal," Johnson said.
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