Space Station Suffers Troubling Coolant Leak
Liquid ammonia is used to cool the International Space Station's solar array that covers the approximate area of a football field.
Image: A view of the shuttle's payload bay wi
July 15, 2011 --
The final space shuttle mission (STS-135) to the International Space Station (ISS) continues. Supplies have been delivered by shuttle Atlantis and the final "shuttle era" spacewalk has been successfully completed. Here are a selection of photographs from the busy ISS since Atlantis docked with the orbital outpost on July 10.
While Atlantis was docked to the space station, a member of the STS-135 crew snapped this picture of some of the islands in the Bahamas, off the coast of the Florida peninsula (right). Miami can be seen toward the top right of the photograph. Cape Canaveral and Kennedy Space Center are located out of shot in the bottom right of the photo.
Welcomed... Fruit? Shortly after docking with the space station, the Atlantis crew (including STS-135 pilot Doug Hurley, left) gave the resident space station crew supplies of fresh food. With a smile, Expedition 28 flight engineer Mike Fossum (right) receives a bag of fruit.
While aboard the space station, the STS-135 crew are working on many tasks during their short stay. STS-135 commander Chris Ferguson (right) can be seen here working with Japanese astronaut and Expedition 28 flight engineer Satoshi Furukawa in the Quest airlock inspecting space suits assigned to NASA astronauts Mike Fossum and Ron Garan prior to the July 12 spacewalk.
Say "Cheese"! During the six and a half hour spacewalk to retrieve a failed ammonia pump module from an external storage platform and install a robotic refueling demonstration apparatus, NASA astronaut Mike Fossum takes a picture while Atlantis is docked behind him. Fossum can be seen restrained on the end of the space station remote manipulator system (Canadarm2).
Mike Fossum points at the camera as he waits at an International Space Station pressurized mating adapter (PMA-2) docked to the space shuttle Atlantis, as the station's robotic system moves the failed ammonia pump module (out of frame) over to the spacewalking astronaut and the shuttle's cargo bay.
Robotic Assistance Mike Fossum, while attached to Canadarm2, holds the Robotics Refueling Mission payload -- one of the main tasks to be carried out during the spacewalk. The failed pump module can be seen with the two-armed robot, Dextre, on left side of the photo.
Shuttle Stowage With his feet secured to Canadarm2, NASA astronaut Ron Garan carries the failed ammonia pump module toward shuttle Atlantis' open payload bay. When Atlantis returns to Earth on July 21, engineers will study the module to see how it failed and how the problem can be avoided in the future.
In addition to installing/removing space station hardware, STS-135 delivered up to a years-worth of supplies. STS-135 mission specialist Sandy Magnus can be seen here floating inside the Raffaello multi-purpose logistics module that Atlantis carried to the space station. Magnus is surrounded by the supplies for consumption of the space station residents for the months ahead.
A Picnic, Shuttle Style Seven astronauts -- six from NASA and one from the Japan Aerospace Exploration Agency (JAXA) -- and three Russian cosmonauts participate in a special meal on the Space Shuttle Atlantis' middeck on July 14. The STS-135 crew consists of NASA astronauts Chris Ferguson, Doug Hurley, Sandy Magnus and Rex Walheim; the Expedition 28 or station crew members are JAXA astronaut Satoshi Furukawa, NASA astronauts Ron Garan and Mike Fossum, and Russian cosmonauts Andrey Borisenko, Alexander Samokutyaev and Sergei Volkov. All photographs can be found in NASA's Human Spaceflight Gallery.
Astronauts on the International Space Station have discovered a leak of ammonia coolant on their orbiting habitat, and NASA is looking into the problem, though it poses no immediate danger to the crew, officials said today (May 9).
The space station uses chilled liquid ammonia to cool down the power systems on its eight giant solar array panels. A minor leak of this ammonia was first noticed in 2007, and NASA has been studying the issue ever since.
In November 2012 two astronauts took a spacewalk to fix the problem, rewiring some coolant lines and installing a spare radiator due to fears the original radiator was damaged by a micrometeorite impact.
At the time, those measures appeared to fix the problem, but today astronauts on the football field-size space station noticed a steady stream of frozen ammonia flakes leaking from the area of the suspect coolant loop in the Photovoltaic Thermal Control System (PVTCS).
"It is in the same area, but we don't know whether it's the same leak," NASA spokesman Kelly Humphries of the Johnson Space Center in Houston told SPACE.com. Humphries said the agency was taking the leak seriously because it affects an important system — if they lose the ability to cool that particular solar array, it won't be able to generate power for the station. In fact, the leak has worsened to the point that Mission Control expects that particular loop to shut down within the next 24 hours.
However, "the crew is in no danger," Humphries stressed. It's too soon to speculate on a possible spacewalk or other measure to deal with the issue, he added.
Mission Control has been discussing the problem with the astronauts on the station throughout the afternoon.
"What you guys have provided in the way of imagery and video has been just like gold to us on the ground," astronaut Doug Wheelock from Mission Control radioed to space station commander Chris Hadfield, a Canadian Space Agency astronaut. "We are fairly confident that it's coming from the vicinity of the TCS." However, flight controllers noted they were still unable to pinpoint the leak's exact location.
NASA engineers are reviewing plans to potentially move the station's robotic arm over to the area of the port truss, the scaffolding-like backbone of the station (the original leak was traced to the Port 6 truss).
"Tomorrow we'll plan to get the arm in the game to see if we can better pinpoint the location of the leak," Wheelock said.
Hadfield said he and his crewmates had noticed the rate of the leak varied depending on the orientation of the station with the sun, suggesting particular angles allowed the ammonia coolant to leak more quickly.
Hadfield is in charge of the station's Expedition 35 crew, which also includes NASA astronauts Tom Marshburn and Chris Cassidy, and Russian cosmonauts Roman Romanenko, Pavel Vinogradov, and Alexander Misurkin. He asked Mission Control to send the crew a summary of what they know about the problem, and the possible courses to take to address it, before their bedtime.
"It would just be good for the six of us to know," Hadfield said.
Today had otherwise been a relatively light day for the crew of the International Space Station, which had taken some time off to celebrate the Russian holiday Victory Day. Hadfield, Marshburn and Romanenko are due to depart the space station on Monday (May 13) to return to Earth after a roughly five-month stay. Three new crewmembers plan to launch on May 28 from Kazakhstan on a Russian spacecraft to take up residence on the orbiting outpost.
Hadfield asked Wheelock if the leak, and resulting power loss from that solar array, could delay his planned undocking.
"We don't see anything technically that we can't overcome with the undocking but we are still getting our arms fully around that issue," Wheelock responded, adding that they should have more information for the astronauts in the morning.
More from SPACE.com:
Space Station's Expedition 35 Mission in Photos
The International Space Station: Inside and Out (Infographic)
Cosmic Quiz: Do You Know the International Space Station?
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