Image above: Expedition 24 Flight Engineers Doug Wheelock (right) and Tracy Caldwell Dyson work to replace a failed ammonia pump module outside of the International Space Station. Credit: NASA TV
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Overcoming a disappointing spacewalk last weekend, today astronauts Doug Wheelock and Tracy Caldwell Dyson successfully removed the failed ammonia coolant pump module on the S1 truss of the International Space Station. But NASA managers said that at least two more EVAs will be required to complete all the repairs to the critical cooling system. Earlier, it was hoped that two spacewalks total would allow enough time, but it will take at least four. “There were a number of challenges in the first EVA that set us back, but as we looked closer at this, we were hedging our bets at how many EVAs we had ahead of us,” said Spacewalk officer David Beaver at a press briefing following the successful EVA today. “As we have done more and more work in laying this out in a stepwise fashion, it became clear to us early on that this was a much bigger set of EVAs than we originally made time for.”
He added that on orbit, the astronauts have stopped all research in order to save on the cooling system. The complex systems keeps the station from overheating and the six-member crew has relied on just one — instead of the usual two pumps –to handle the cooling ever since the one pump failed during a power surge on July 31.
“The system has been kind to us and we haven’t had any more failures,” Beaver said.
The spare pump will be installed on the S1 truss during a spacewalk that is now scheduled for Monday – originally it was set for Sunday, but NASA managers decided an extra day would help both the astronauts and the teams on the ground preparing for the EVAs.
Wheelock and Caldwell Dyson were able to close the quick disconnect valve for the final fluid connector for the failed ammonia pump module, and then detach the final fluid line from the failed ammonia pump module – which was the problem that couldn’t be overcome on the first spacewalk.
The two astronauts then extracted the pump module and stowed on another location on the truss, and Caldwell Dyson prepared the spare pump for installation on the next spacewalk on Monday.
The spacewalk lasted 7 1/2 hours, slightly shorter than Saturday’s eight-hour marathon, the longest EVA at the ISS without a space shuttle present. Wheelock and Dyson had to use decontamination procedures after the spacewalk just in case some ammonia leaked on their suits.
In response to the power-saving reconfiguration that has had to be done, the science team worked quickly to establish a plan to preserve experiment samples in the Japanese Experiment Module freezer. The on-orbit crew was able to transfer all the samples from the freezer in the Kibo laboratory to an operating freezer. No sciences samples were lost due to the pump module anomaly.
While the crew schedule has been interrupted to support the newly added spacewalks, the payload ground teams have been working closely with mission controllers to preserve and re-plan high priority activities. Other activities that can be rescheduled with little or no impact are being postponed to a later date.
The International Space Station in 2010. Credit: NASA
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One of the International Space Station’s external cool system pumps quit working late Saturday, likely due to mechanical failure. This triggered subsequent shutdowns in other systems. Teams on the ground are working with the six astronauts on board the station to troubleshoot the issue, but it appears at least two spacewalks will be required to remove and replace the pump. NASA officials said the problem will have to be resolved quickly, as the cooling system is extremely important for all the station’s systems. This is a redundant system, so the backup loop is now cooling the station and the crew is in no danger, but NASA does not like to work any systems “single string,” i.e., with no backup.
NASA tried restarting the pump Sunday morning, but it did not work. There are two spare pumps on orbit. ISS astronauts Doug Wheelock and Tracy Caldwell Dyson had been already scheduled to make a spacewalk on August 5 to install part of a robotic crane and to do preparation work get ready for a new module (the Permanent Logistics Module) that is due to arrive in November aboard space shuttle Discovery.
EVA teams are now looking at using the August 5 space walk for the first half of the repairs, followed by the second EVA on August 7 (Saturday). The spacewalks need special planning since the system is in a reduced power configuration. One of the radiators which allow for cooling on board the ISS. Credit: NASA
The space station features two independent coolant loops that use ammonia circulating through huge radiators to dissipate the heat generated by the station’s electronic systems, primarily from the labs. Each loop is fed by a large tank of ammonia that includes an internal bellows pressurized by nitrogen. That pressurization system allows the loops to handle the periodic expansion and contraction of the ammonia coolant due to temperature changes when the station goes from sunlight to shadow while in orbit.
Back in April a valve failed on the coolant system, but the teams were able to troubleshoot and fix the problem without a spacewalk.
A status update from NASA listed several other systems that required powerdowns to as a result of the cooling loop shutdown in order to thermally protect them:
Redundant power to four CQs (Crew Quarters), three in Node-2, one in Kibo JPM, with both fans in each CQ remaining functional but zero fault-tolerant (crew is still Go for CQ use). Due to loss of heater power, MBS (Mobile Base System), SSRMS (Space Station Remote Manipulator System), and SPDM (Special Purpose Dexterous Manipulator) are currently zero fault-tolerant. Communications systems, but there could be some issues with possible overheating. No video will be available fromNode-2, Node-3, the Columbus and Japanese modules.
NASA’s Robonaut 2 will be the first human-like robot to go to space, and teams from Johnson Space Center have been putting “R2” through a battery of tests to make sure this futuristic robot is ready for its first mission. R2 will become a permanent resident of the International Space Station, and will launch on space shuttle Discovery as part of the STS-133 mission, currently planned for November 1, 2010.
The 136 kg (300-pound) R2 consists of a head and a torso with two arms and two hands. R2 Once aboard the station, engineers will monitor how the robot operates in weightlessness. R2 is undergoing extensive testing in preparation for its flight, including vibration, vacuum and radiation testing. Watch the video for more information on how R2 operates. Continue reading “Robonaut Getting Ready for ISS Mission”
How long does it take you to walk from one end of your house to the other? The ISS is now so large that it takes astronauts about six minutes to go between the two farthest points inside the space station — and that is by ‘flying,’ not walking. Enjoy this very cool video tour of the interior of the ISS, filmed earlier this year.
Screenshot from NASA TV of the new Rassvet module attached to the space station. Credt: NASA TV
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A 8,550 kg (17,760-pound) Russian Mini-Research Module, known as Rassvet or “Dawn,” was attached to the International Space Station today. This is the first (and last) Russian-built module to be delivered by a space shuttle, and the 8 meter long (20 ft) 2.5 meter (8 ft) diamater module will serve an area for scientific research, as well as for stowage and a docking port extension for future visiting spacecraft such as the Soyuz and Progress resupply vehicles.
“The ISS has grown by one more module,” Moscow mission control radioed up the crew. “We are really very grateful to you. And our congratulations to all of you for this new step in space research and thanks for all your effort and all your work.”
The MRM is packed full of 1,400 kg (3,086 pounds) of NASA equipment and supplies, plus an experiment airlock and European robot arm equipment that will be attached to other modules later. Location of MRM-1 and other components on the Russian Orbital Segment of the ISS
MRM was docked to the Earth-facing port of the central Zarya module, and will provide needed clearance between the forward Russian docking port and a US storage module, the Permanent Logistics Module, scheduled to arrive at the station later this year.
Operations began early this morning to install the MRM, with Atlantis commander Ken Ham and pilot Dominic Antonelli, operating the shuttle’s robot arm to take the new module from the shuttle’s cargo bay. Then astronauts Garrett Reisman and Piers Sellers installed the MRM-1 on Zarya, — appropriately waiting until orbital sunrise to attach the module with great precision. Controllers said Reisman maneuvered the module so precisely, he made a “hole in one.” The MRM, or Rassvet, seen during processing at Cape Canaveral. Image credit: Alan Walters (awaltersphoto.com) for Universe Today.
Now that the MRM is attached, the ISS and shuttle astronauts now turn their attention to the second spacewalk of the mission scheduled for Wednesday, May 19 to be conducted by Steven Bowen and Michael Good. The primary tasks are the removal and replacement of P6 truss batteries that store solar energy. These batteries have outlived their expected lifespan of 6 years, so the batteries will be swapped out with new ones.
Behind the scenes work has also been ongoing to develop a task to clear a cable that is pinched out on the end of the Atlantis’ boom and sensor system that prevented an inspection of the shuttle’s thermal protection system. NASA TV commentator Kyle Herring said the procedure appears to be a fairly straightforward task to clear the cable out of the way and secure it with a wire-tie. Mission planners are seeing where the procedure fits in best with the rest of the spacewalks tasks.
The crew of the International Space Station sent down an image of an unscheduled spacewalk that allegedly took place earlier today. “We wanted to welcome you guys to April, and hopefully we brought you guys some smiles and not a lot of nervousness,” T.J. Creamer radioed down to Mission Control in Houston.
“Yes, you welcomed us to April, and you did it in a grand way!” replied veteran astronaut Shannon Lucid, serving as Capcom. “You have a real problem, but you know it’s outside our ability to help you.”
Creamer and crewmates Soichi Noguchi and Oleg Kotav assured Lucid they were wearing eye protection and Lucid wondered if they put sunscreen on. “Getting vitamin D is great, but don’t stay out too long,” she said.
“Oh, Mom can’t we stay out longer?” Creamer joked.
This image is reminiscent of a picture fellow journalist Rachel Hobson took of me while we were at Kennedy Space Center, below. There was a model of the newly installed Cupola in the KSC press room, and several journalists took turns taking pictures of each other, and the images ended up looking similar to what the ISS crew created today. The astronauts obviously have some digital image editing software on board. Nancy at KSC for the STS-130 launch. Image by Rachel Hobson.
ISS as seen by the departing Endeavour crew on STS-130. Credit: NASA
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How long can the International Space Station really operate – until 2020, or 2028 or beyond? I recently had the chance to talk with Mark Uhran, NASA’s Assistant Associate Administrator of the ISS. We were both attending a conference on water sustainability at Kennedy Space Center, but Uhran took the time to talk with me about the state of our space station, NASA’s new budget and how that might affect ISS operations, and — speaking of water — how is the urine recycling system working these days?
Universe Today: How are things going as far the extension of the ISS? I heard there was recently a meeting with the international partners where they said it could be extended to 2028 if need be. Mark Uhran. Credit: NASA
Mark Uhran: We’ve made the decision in the United States as part of the President’s budget proposal to Congress, so we’re over the hump here in the US. And then we began a series of meetings with the partners starting in Japan last week. Of course each of the partners has been working with us for the past 12-18 months, but they are fully prepared to approach their governments and ask for an extension. There are no technical obstacles to extending to at least 2020, and we’re also going to be doing an evaluation to what the ultimate lifetime of the ISS might be. That evaluation is in process. So we’re looking at whether we can go as long as 2028, but that remains to be seen.
Universe Today: Since we’re here talking about water, how are things going with the recycling system up there on the station. I know there have been some glitches here and there.
Uhran: The station has been a real testbed for developing regenerative water and air technologies. We knew at the time deploying these systems they would be in a testbed mode, and it would probably take about a year to shakedown all the systems and we are making steady progress towards doing just that. All the systems are working today – that’s not to say they will be working tomorrow. We certainly do expect them to go up and down throughout the course of the year as we fine tune them and work out the details. By the end of this year we hope to add a Sabatier (carbon dioxide reduction system) reactor that will allow us produce yet further water on orbit. NASA"s Water Recovery System for the ISS. Credit: NASA
Hauling water is a very expensive proposition for us. Once the Sabatier is up there later this year, we’ll have basically the entire designed system deployed and I’m confident by this time next year we’ll have worked out all the filtration issues, the film formation issues, and precipitant issues and we’ll have this tuned so that it is basically available 90% of the time, which is an outstanding availability rate. So, this has been very worthwhile from our point of view not just because of the cost of hauling water to the space station but for the implications for human exploration beyond low Earth orbit.
Universe Today: The new NASA budget, which eliminates Constellation, how do you see that affecting space station operations?
Uhran: Well, space station is relatively small factor in that new budget. We’ve been extended, which is a major achievement from our point of view. But in terms of financial constraints, we are pretty well prepared now to go ahead and operate until the end of the decade, as well as to ramp up our research program on the station. With the assembly process being completed, the crew time now becomes available for supporting research. So most of our activities this year are geared towards repositioning our utilization program so that when the shuttle stops flying and the commercial cargo resupply services begin we are ready to ramp up that program aggressively, and that’s going very well.
Universe Today: I’ve been here at Kennedy Space Center for about a month and a half and a lot of the people here are talking about a possible extension for the space shuttle program. What are your thoughts on that?
Uhran: Well, the shuttle was certainly required for the assembly phase because we were hauling 20 metric ton elements up to orbit. It literally is the equivalent of a six-wheeler truck. But for the utilization phase, we can continue to maintain and operate the space station at much lower supply rates; typically 3 metric tons on a half a dozen to a dozen times a year. So there are other vehicles both that our international partners bring to the table as well as we’re hoping that the commercial US industry will demonstrate in the next 12-24 months that really will meet our needs once those are available. So although we’d all like to see the shuttles continue to fly forever, we really don’t have a requirement on space station for that kind of relatively heavy lift capability. A close-up look at the Solar Alpha Rotary Joint. Credit: NASA
Universe Today: Another issue that has been sort of looming for the space station is the solar alpha rotary joints (SARJ). Any progress on understanding why they aren’t working as hoped?
Uhran: Well, they are working now. And the failure analysis has been completed. So we know the root causes of the problem. The most challenging mechanisms in any spacecraft system are rotating mechanisms. So the control moment gyros, the solar array rotary joints, the thermal radiator rotary joints – they are all rotating mechanisms. And we’re passing power through those mechanisms, which adds to the complexity. So we think that we have all these under control. It turned out with the SARJ that we have determined the cause of the failure, and we’re doing, really two things. We’re operating the system more gently – we ramp it up more slowly, we stop it more slowly. That doesn’t put as much load on the system. And we find that is applicable to all our systems. The more gently we can operate them the less loads they bear and the longer their lifetime. So we’ll be operating the system more gently and we’ll be lubricating them more regularly. So between those two approaches, we’re pretty confident we won’t have any more problems with the SARJ. We do have a couple of tricks in our pocket in the case that we do see further problems but we think we can get there with the two remedial actions we’ve got now.
Universe Today: To do the lubrication requires a spacewalk?
Uhran: It’s an EVA based activity, yes. It is relatively simple. And not even that time consuming. We were lubricating before, we’ll just increase the frequency.
Thanks to Mark Uhran for taking the time to talk with Universe Today. For more information on the International Space station, visit www.nasa.gov/station.
The storied history of the Mir space station includes collisions, a fire, and political change. But it also consists of unprecedented long-duration spaceflights and scientific studies – and without it, the International Space Station may never have been built. Nine ten years ago, the journey of the 15-year-old Russian space station ended. On March 23, 2001, Mir re-entered the Earth’s atmosphere near Nadi, Fiji, and fell into the South Pacific. The planned and controlled re-entry began when the engines of a cargo ship docked to Mir were fired causing the station’s orbit to brake, starting Mir’s descent. The video here shows both real and computer generated images of the breakup of the 143-ton station as it descended to Earth. Continue reading “Mir’s Fiery Re-entry, March 23, 2001”
Here are some space station pictures. We’ve already done photo galleries of the International Space Station, but let’s take a look at some different stations as well:
This is a picture of the Mir Space Station, launched by Russia. This photograph was taken by the crew of STS-89 on the space shuttle Endeavour.
Here is a recent image of the International Space Station captured by the crew of STS-129. It shows how much of the construction has now been completed.
This is a picture of Skylab, the United States’ first space station. It was in orbit from 1973 to 1979, and was visited by 3 crews of astronauts.
And maybe some day we’ll live in a futuristic space station like this. It’s called a Stanford Torus, and rotates to provide the people living inside an artificial gravity.
This is an artist’s impression of a future space hotel developed by Bigelow Aerospace. The various modules are inflated and connected together. Test versions of the modules have already been sent into orbit.
We’ve written many articles about the International Space Station for Universe Today. Here’s an article about how you can track the International Space Station, and here’s an article about a how a radio operator was able to communicate with the station.
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Now that it’s mostly complete, the International Space Station is the brightest human-built object in space. It’s easy to see with your own eyes, the trick is knowing when to step outside and look up to see the station go overhead. If you do get your timing right, you’ll see the station as a bright star moving quickly in the sky. It only take a couple of minutes to pass through the sky above your house. Want to see the station for yourself? Here are some resources for International Space Station viewing.
The best place to go is NASA’s Human Spaceflight tracking page. This shows you the current location of the International Space Station, the Hubble Space Telescope, and any space shuttles currently in orbit.
So that shows you where the space station and shuttles are right now, but how will you know when they’re going to be passing over your part of the Earth?
NASA has a page for sighting opportunities. You can either choose your location from a list of common locations around the world, or you download an application that lets you pick your specific spot on Earth. It will then tell you the exact times ISS will be passing overhead.
If you’ve got an iPhone, check out the ISS Visibility App. This tool will calculate the next times you’ll be able to see the ISS pass overhead.
You can also use a great service called Heavens Above. This will also show you the current location of satellites, as give you times when ISS will be passing overhead.
