Coolant Glitch Forces Space Station Shutdown
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.
A coolant system glitch on the International Space Station has forced several of the orbital outpost’s modules offline as astronauts and ground control manage the problem. The crew are not in danger and ground control teams are currently working to see how best to troubleshoot.
The issue, that occurred early on Wednesday, focuses on one of the space station’s two external ammonia cooling loops, along which the station’s electrical systems use to regulate their temperatures. The loop “automatically shut down when it reached pre-set temperature limits,” said NASA in a statement. It is thought that a flow control valve in the ammonia pump itself may have malfunctioned.
The shutdown has affected Loop A, prompting station managers to move some electrical systems over to Loop B while prioritizing life support systems, electrical systems and experiments. All other non-essential systems have been shut down in the U.S. Harmony node, Japanese Kibo laboratory and the European Columbus laboratory.
According to Alan Boyle over at NBC News, should extra-vehicular activity (EVA) be deemed necessary, it could take up to two weeks to plan for the spacewalk operation to fix the faulty pump. This breakdown, known as a “Big 14″ maintenance issue, crops up intermittently during normal operations of the space station. Boyle points out that other maintenance issues like this have cropped up in 2012, 2011, 2010, 2009 and 2007.
In May, the crew of Expedition 35, commanded by Canadian astronaut Chris Hadfield, were confronted with an ammonia leak from the exterior of the space station. In that case, the repair operation was planned and executed in two days. The leaky Pump and Flow Control System (PFCS) box located on the space station’s Port 6 truss was replaced.
On this occasion however, it may take some time for the space station’s Expedition 38 crew and ground control to troubleshoot the problem and to decide whether a spacewalk is needed or whether a software fix can be found.
The Expedition 38 crew include NASA astronauts Rick Mastracchio and Mike Hopkins, Russian cosmonauts Sergey Ryazanskiy, Oleg Kotov and Mikhail Tyurin, and the Japanese Space Agency's Koichi Wakata.
Underlining the quasi-routine nature of this partial shutdown, the NASA statement concluded: “The crew is safe and preparing to begin a normal sleep shift while experts on the ground collect more data and consider what troubleshooting activities may be necessary.”
Image: This picture of the International Space Station was photographed from the space shuttle Atlantis as the orbiting complex and the shuttle performed their relative separation in the early hours of July 19, 2011. Credit NASA