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Astronauts To Repair Cooling System On ISS
GWMAW writes "NASA Astronauts will conduct a spacewalk on Thursday to repair part of the cooling system of the International Space Station. The cooling system is essential for maintaining the temperature inside the station. There are two 'loops' in the system, one that uses water and draws heat from the inside of the station, and one uses ammonia and dumps the heat into space. Ammonia is used because it freezes at a much lower temperature than water. On Saturday the pump that controls the flow of ammonia through the system shut down."
Typical Slashdot, a bit behind. This is the press release they sent out on Tuesday.
Aug. 03, 2010
Stephanie Schierholz
Headquarters, Washington
James Hartsfield
Johnson Space Center, Houston
MEDIA ADVISORY: M10-107
NASA MOVES SPACE STATION REPAIR SPACEWALK TO FRIDAY, SETS BRIEFINGS
HOUSTON -- The first of two spacewalks by NASA astronauts to replace a
failed ammonia pump on the International Space Station has been
delayed by 24 hours to Friday, Aug. 6. A second spacewalk is planned
for Monday, Aug. 9, to complete the repairs.
Flight controllers and station managers made the decision Monday night
after reviewing proposed timelines, final procedures for the repair
work, and the results from a spacewalk dress rehearsal conducted in
the Neutral Buoyancy Laboratory near NASA's Johnson Space Center in
Houston.
Expedition 24 Flight Engineers Doug Wheelock and Tracy Caldwell Dyson
are scheduled to perform the spacewalks. The two NASA astronauts will
replace an ammonia coolant pump that failed July 31.
NASA Television coverage of both spacewalks will begin at 5 a.m. CDT.
Wheelock and Caldwell Dyson are expected to begin the spacewalks from
the Quest airlock at 5:55 a.m. Friday's spacewalk will be the fourth
for Wheelock and Caldwell Dyson's first.
Approximately two hours after the conclusion of each spacewalk, NASA
TV will broadcast a briefing from Johnson. The briefing participants
will be Mike Suffredini, International Space Station program manager;
Courtenay McMillan, Expedition 24 spacewalk flight director; and
David Beaver, Expedition 24 spacewalk officer.
Reporters may ask questions from participating NASA locations, and
should contact their preferred NASA center to confirm participation.
Johnson will operate a telephone bridge for reporters with valid
media credentials issued by a NASA center. Journalists planning to
use the service must contact the Johnson newsroom at 281-483-5111 no
later than 15 minutes prior to the start of a briefing. Phone bridge
capacity is limited and will be available on a first-come,
first-serve basis.
Engineers and flight controllers continue to review data on the
failure, which resulted in the loss of one of two cooling loops
aboard the station. This caused a significant power down and required
adjustments to provide the maximum redundancy possible for station
systems. The systems are stable, and the six crew members aboard are
not in any danger.
Wheelock and Caldwell Dyson originally were scheduled to perform a
spacewalk to outfit the Russian Zarya module for future robotics work
and prepare the station for the installation of a new U.S. permanent
multipurpose module. However, because of the importance of restoring
redundancy to the station's cooling and power systems, the two new
spacewalks will be dedicated to the pump module replacement.
For NASA TV streaming video, schedules and downlink information,
visit:
http://www.nasa.gov/ntv
For more information about the station and the Expedition 24 crew,
visit:
http://www.nasa.gov/station
-end-
Serious? Seriousness is well above my pay grade.
From the article: "[...] the Russian module of the system could take control for a period of time until repairs could be made."
Take control?... Open the pod bay doors!!!
Couldn't they just stick a cat up in the ammonia part of the cooling system? Those fuckers produce tons of the stuff and they seem to want to distribute it around as much as possible.
Monstar L
...given the current geomagnetic storms, isn't this thursday a bad time to be outside in orbit?..
From NASA article Staying Cool on the ISS:
Without thermal controls, the temperature of the orbiting Space Station's Sun-facing side would soar to 250 degrees F (121 C), while thermometers on the dark side would plunge to minus 250 degrees F (-157 C). There might be a comfortable spot somewhere in the middle of the Station, but searching for it wouldn't be much fun!
visit my pal the xkcd explainer!
I think its great that mundane repairs are being done on a real, fair dinkum space station, and there is nothing interesting to say about it.
http://michaelsmith.id.au
Dear troller troll...
You cannot loose heat in the vacuum. So all your heat is stored inside the space suit and not going anywhere. So yes, you can only overheat.
In a mostly metallic structure, the hot side will irradiate the heat to all its body. So if not isolated, ALL ISS will be at +/- 121C.
The space is cold, but you cannot feel it, because there are (almost) no heat transference.
But if you touch, for example, an asteroid, all you heat will be quickly absorbed, and you will freeze to dead.
Why is loops in quotes? If the concept of a control loop is too complex/obscure for the slashdot crowd, just call it a sub-system a la Star Trek.
I mean everyone up there's drinking the recycled pee of their crewmates.
As are we all. Our water supply is finite too, you know.
http://michaelsmith.id.au
A vacuum has no temperature.
Dear troller troll...
Reads almost as 'Dear tololololo'. Scary.
You cannot loose heat in the vacuum.
Maybe you cannot lose hear through convection but, in space, you can certainly loose heat by radiation. Deep space background is around 3K and a deep space radiative cooler is a very good and efficient way to cool something in space.
You cannot do any thermal analysis of an object in space without taking the radiative part into account.
Without knowing the exact heat balances in play there, I'll take a stab at it. In a vacuum (assuming no out-gassing or other mass exchanges) there is only one way to change temperature -- absorb electromagnetic radiation (visible light, infrared, microwaves, etc.) to heat up and emit similar radiation to cool down. In the case of Apollo 13, the spacecraft absorbed solar radiation, although being painted white and bright aluminum it must not have been an efficient absorber. And it emitted radiation, peaking in the infrared due to its temperature, which would cool it down. So the equilibrium between absorption and radiation was trending toward an uncomfortably cold spacecraft.
An uninsulated space suit in a vacuum wouldn't feel very cold on the inside as long as the suit doesn't touch anything on the outside.
What were the physics involved in the Apollo 13 mission when they were getting very cold after turning off the heaters in the spacecraft, using the LEM as a lifeboat?
When it comes to using power, it is easier to heat something than to cool it. The apollo spacecraft was designed to be passively cool in the sense that it reflected enough of the sunlight striking it to need as small amount of heating from batteries to stay warm. If it had absorbed more heat from the sun it would have required active cooling which is very expensive in energy terms.
http://michaelsmith.id.au