NASA Plans Emergency Spacewalks to Fix Space Station
2010 08 02

By Tariq Malik | Space.com


NASA is planning a pair of emergency spacewalks to repair the International Space Station after half of its cooling system shut down unexpectedly Saturday, forcing astronauts to power down several systems.

The two repair spacewalks will be performed by American astronauts Doug Wheelock and Tracy Caldwell Dyson and could begin Thursday to replace a pump module in one of the space stationís two cooling system loops. Engineers are assessing the spacewalk plans before making a final decision.

"The crew is being informed that replanning for alternate spacewalk activity is underway," NASA officials said in a statement. A spacewalk had already been planned for Thursday for the Wheelock and Caldwell Dyson to upgrade some station systems.

NASA has stressed that Wheelock, Caldwell Dyson and the rest of the six astronauts living aboard the International Space Station are in no danger from the cooling system problem. But it is something Mission Control would like to address quickly since initial troubleshooting efforts have failed.

"An attempt overnight Sunday to close the circuit breaker and restart the Pump Module was not successful," NASA officials said. The space agency will give an update on the space stationís status and spacewalk planning at 4 p.m. EDT (2000 GMT).

Cooling system problems

The space stationís cooling system troubles began late Saturday when a circuit breaker tripped and shut down the Loop A cooling system pump module, which is used to move super-cold liquid ammonia through the station to remove excess heat from its systems and laboratories.

The shutdown triggered alarms in the space station, awakening the outpostís six astronauts so they could begin turning off systems to reduce the heat load on the space stationís only remaining working cooling system string Loop B. The space stationís cooling system is critical to the outpostís operation since it prevents the station from overheating.

Station astronauts shut down two control moment gyroscopes (used to maintain the stationís orientation in space without thrusters), some station power converters and command-routing equipment, and backup systems for the stationís S-band communications antenna and Global Positioning System. So some station systems were running without backups in place if they fail.

Mission Control reactivated one of the two offline gyroscopes on Sunday and astronauts installed jumper cables between some station systems and the power system on the outpostís U.S. Destiny laboratory to preserve redundancy.

The space station is currently in stable shape with "most systems receiving cooling and many systems operating with redundancy following the installation of jumper cables from the Destiny Labís power system overnight," NASA officials said. "Temperatures on the Main Bus Switching Units, which route power to various systems, are a little higher than normal, but well within normal parameters and are stable."

Repair spacewalks ahead

The next step is a spacewalk repair. To prepare for the first spacewalk, Mission Control vented any remaining liquid ammonia from the Loop A system.

The space repair would likely call for two spacewalks by Wheelock and Caldwell Dyson, who would physically replace the afflicted pump module in the first excursion and hook up ammonia fluid and electrical connections in the second one.

There are two spare ammonia pump modules stored outside the space station on spare parts platforms attached to the orbiting laboratoryís backbone-like main truss.

The space station is currently home to three Americans (NASA astronaut Shannon Walker is the third) and three Russian cosmonauts representing Russiaís Federal Space Agency.

Wheelock and Caldwell Dyson had originally planned to perform a spacewalk Thursday to hook up a power extension cord for a future Russian laboratory and install equipment on part of the stationís Russian segment. That work will be rescheduled to a later date, NASA officials said.

Astronauts have been living aboard the $100 billion International Space Station, which is being built by five international space agencies representing 16 different countries, for nearly 10 years. Construction began on the orbiting laboratory in 1998.

NASA plans to fly two space shuttle missions (in November and February, respectively) to complete construction of the space station before retiring the shuttle fleet next year. Congress is discussing the possible addition of a third and final shuttle mission, which if approved would likely carry spare parts and other supplies to the space station in next summer.

Article from: space.com




Related Articles
International Space Station sex ban
Russian supply spacecraft misses Space Station for first time ever - spins out of reach (Video)
Aurora Australis Observed from the International Space Station
International Space Station Growth During 12 Years
Canadian circus billionaire heads to space station
US Astronauts May Have to Leave Space Station in 2012
NASA, USDA Sign Space Station Research Agreement
Space station deploys its new set of solar wings
International Space Station holed by meteorite


Latest News from our Front Page

The Aeon of Horus is Ending and the Elites are Nervous as their Icons are Dying
2014 04 18
I predict there is going to be a huge resurgence of interest in European indigenous spiritual traditions from Norse to Celtic/Gaelic to Slavic and so on. Millions of Europeans are going to realise that we are the victims of Christianity and New Age garbage. Their bastardised Kabbalah, the psychic force used by Crowley and the elites to cement his Aeon ...
Easter - Christian or Pagan?
2014 04 18
From: truthbeknown.com Contrary to popular belief, Easter does not represent the "historical" crucifixion and resurrection of Jesus Christ. In reality, the gospel tale reflects the annual "crossification" of the sun through the vernal equinox (Spring), at which time the sun is "resurrected," as the day begins to become longer than the night. Rather than being a "Christian" holiday, Easter celebrations date back ...
Man-Made Blood Might Be Used in Transfusions by 2016
2014 04 18
Researchers in the U.K. have created the first man-made red blood cells of high enough quality to be introduced into the human body The premise of the HBO show and book series True Blood revolves around a technological breakthrough: scientists figure out how to synthesize artificial human blood, which, as an ample new source of non-human food, allows vampires to "come ...
The Trials of the Cherokee Were Reflected In Their Skulls
2014 04 18
Researchers from North Carolina State University and the University of Tennessee have found that environmental stressors Ė from the Trail of Tears to the Civil War Ė led to significant changes in the shape of skulls in the eastern and western bands of the Cherokee people. The findings highlight the role of environmental factors in shaping our physical characteristics. ...
Our Fears May Be Shaped by Ancestral Trauma
2014 04 18
Last December, an unsettling Nature Neuroscience study found that mice who were taught to associate the smell of cherry blossoms with pain produced offspring who feared the smell of cherry blossoms, even if they had never been exposed to it before. We knew that the process was epigeneticóthat it was not hard-wired in the permanent genetic structure of the mouseóbut ...
More News Ľ