mir_plunge_010312 CHEYENNE MOUNTAIN, COLORADO SPRINGS, Colo. -- Here at the U.S. Space Commands Space Control Center, one blip on the screen currently attracting increased attention is simply tagged: 016609. This is Russias
Mir space station, the historic orbiting outpost that housed numerous space travelers.But soon it will be just that -- history. As Russia's Mission Control Center prepares the 130-ton Mir space station for its plummet to Earth; Space Command will be watching -- and helping.
Space Command Control Center resides deep within Cheyenne Mountain among carved out chambers and surrounded by a maze of twisting tunnels.
Also tucked inside the mountain are 15 buildings, 12 of which are three stories tall. The only way in or out is through one of a trio of gigantic doors, each weighing tons.
Home of U.S. Space Command's Space Control Center that tracks Mir.
Over 1,000 men and women daily live in this Cold War-era complex built for people on pins and needles but cushioned by over 1,300 huge steel springs. All the better to take the jarring bounce from a nuclear-bomb blast.
This is a circa 1960s home for Space Age cave dwellers of the 21st century.
Mirs number is up
In one section of this windowless world, five 11-person teams rely on a global network of electronic eyes to detect, track, identify and catalog all human-made objects circling Earth. Right now, that running catalog is comprised of more than 8,300 orbiting objects.
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It is now expected that between March 17 and 20, Russian space officials will power Mir down into Earths atmosphere. This controlled, but destructive swan dive of the station over south Pacific waters will mean a shower of debris pelting a target zone between Australia and Chile.
"The fact that Mir is the largest manmade object ever to reenter the Earths atmosphere makes it of high interest," said Canadian Naval Lt. Cmdr. H. Carl Sohn, a NASA Support Officer for the U.S. Space Command.
Canadian Naval Lt. Cmdr. H. Carl Sohn, a NASA Support Officer for the U.S. Space Command.
"We daily track Mir here in the Space Control Center, as we do reentering objects. So its business as usual here," Sohn told SPACE.com.
Spot-checking
The key message from Sohn and other Space Control Center officials is its not feasible to track all objects 24 hours a day, 7 days a week. What is being done is "predictive surveillance." That is a fancy term for spot-checking the whereabouts of spacecraft, as well as chunks of space debris, rather than tracking them continuously.
Tapped for this task is a far-flung ground-based space surveillance network of 14 radar and five optical-telescope sensors. Observations of high-flying space objects by the array of hardware are cranked into Cheyenne Mountain computers.
Serving as the nexus for incoming space surveillance data, crews at the Space Control Center number crunch the information to chart the present position of space objects and plot their anticipated orbital paths.
An output of this duty is predicting when and where an object with a decaying orbit -- like
Mir -- will reenter the Earths atmosphere. This type of space soothsaying supports the Nuclear Risk Reduction Treaty, which is designed to minimize the possibility that an incoming space object would fool a nation's defense radar into warning of an incoming missile attack, thereby triggering retaliation. That would be a bad day for everyone concerned."D-day" for Mir
The Space Control Centers tracking and trajectory data regarding
Mirs fiery finale will be fed to Russian space officials via NASAs Johnson Space Center in Houston, Texas. Late last month, Russian, NASA and U.S. military officers made a communications run-through of Mirs deorbit sequence. The simulation polished up a "space speak" network between U.S. and Russian teams committed to bring Mir down exactly as planned.
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"We are all in agreement that
safety is a key goal here," said Air Force Major, Perry Nouis, a spokesman for the U.S. Space Command.Obviously, the speed of calculations, churning out predictive reentry data and sharing information between all parties for Mirs deorbit day is critical. That "D-day" for Mir will entail hours of rapid-paced phone chat as the station makes its final swings around Earth.
"Were not talking fax machines here. This will be people-to-people contact," said Air Force Colonel Norman Black, chief, Space Exploitation and Force Enhancement Division within the U.S. Space Command Operations Directorate.
Col. Norman Black of U.S. Space Command
"Our whole intent [for this Mir deorbit] was to make sure that what occurs here in the Space Control Center is normal procedure," Black told SPACE.com. "We didnt want to add anything new to the equation, especially at the last moment. That usually causes problems in the long run," he said.
"Controlled reentries are nicer to deal with, of course, than uncontrolled," Black said.
What a drag
Air Force Colonel Black said there is a bottom line to reentry assessment. "Its an art as much as it is a science," he said.
For instance, there are variations in Earths tug of gravity on Mir, as well as solar radiation pressure and resultant atmospheric drag. These and other variables conspire to act on the station, orbit after orbit. Also, reentering objects can skip off Earths atmosphere. Just like a tossed stone skipping across a pond, busted up pieces of Mir could bounce across the atmosphere before reentering. That would land them far from the hoped-for splashdown zone.
U.S. Space Command officials stress that it is virtually impossible to accurately predict where and when space debris will impact. Predictably, therefore, they do not
give warning to civilian populations on point of impact for reentering objects.A silent hulk of its former self,
The Russian station's mass is over 130 tons (117 metric tons). At its heart is a central core module, now over 15 years old, that sprouts a cluster of newer modules, which have been attached to the original over the years. "Mir is comparable to seven school buses connected. Thats about the size were dealing with," Nouis said.
Taking the plunge
Because of the huge size of the Russian space complex, some space debris experts expect as much as 50 tons (45 metric tons) of the 130-ton Mir to survive the atmospheric plunge and strike the surface.
There are no guarantees that Mir fragments might not fall outside the predicted splashdown zone.
Russian space engineers will attempt to contain Mir leftovers within a remote south Pacific impact area that is 3,200 miles (5,150 kilometers) long by 120 miles (195 kilometers) wide, said Canadian Forces officer, Sohn.
"Heavier pieces will fall short. Lighter pieces will go long. Thats the way things happen," Sohn said.
Concerning any Mir debris possibly tumbling onto terra firma rather than splashing into ocean waters, Sohn said that if such hardware is found, it is the responsibility of Russia to recover those items. As the nation that launched Mir, Russia is liable for any damage caused by Mir debris hurtling down on a landmass, he said.
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