Sceenshot of a satellite view from Google/Digital Globe of the destruction in Moore, Oklahoma after the May 20, 2013 tornado. Click image to have access to an interactive, zoomable version via NPR.
For all you Earth observation geeks out there, we have some good news — two Russian astronauts are going to install a camera on Friday (Dec. 27) that will beam live images of Earth back to your browser.
The UrtheCast camera is the headline task for Expedition 38 astronauts Oleg Kotov and Sergey Ryazanskiy to perform, on top of installing a foot restraint and doing some equipment swapouts. This spacewalk, by the way, is not related in any way to the two successful contingency ones earlier this week to replace a faulty pump on station.
The spacewalk is supposed to start at 8 a.m. EST (1 p.m. UTC) and will be carried live on NASA Television, which you can view in the media player above or at this alternate link. The spacewalk is scheduled for seven hours, but could be longer or shorter as events arise.
“Imagine you have a nearly live Google Earth, but it isn’t four-year-old data – you have data that is being refreshed all the time, with videos coming down over interesting areas where interesting events are going on, showing you what is changing, what is going on,” said George Tyc, the chief technology officer at UrtheCast, in an interview with Universe Today earlier this year.
“What we really hope to pull off is to change the paradigm, get the everyday person interacting and seeing the data coming down from space to see the Earth and how it is evolving over time in a way that isn’t available right now.”
NASA astronaut Mike Hopkins during his first spacewalk on Dec. 21, 2013 during Expedition 38. He tweeted the next day: “Wow . . . can’t believe that is me yesterday. Wish I could find the words to describe the experience, truly amazing.” Credit: NASA
It’s been a busy week for spacewalkers on station as Rick Mastracchio and Mike Hopkins successfully replaced a pump that shut down two weeks ago and crippled one of the station’s two cooling loops for regulating the temperature of systems on station. With that work completed Tuesday (Dec. 24), a NASA update today (Dec. 26) said systems are slowly coming back online.
“Early on Christmas Day, the heat exchangers for the Destiny laboratory, the Harmony and Tranquility nodes and the Japanese Kibo laboratory were reintegrated to enable experiments racks and other systems affected by the partial Cooling Loop A shutdown Dec. 11 to come back on line,” NASA stated.
“The Columbus laboratory heat exchanger will remain down until the European Space Agency, at its own request, conducts that module’s integration next week when personnel return from the holiday.”
NASA astronaut Mike Hopkins holds a spare ammonia pump module during a spacewalk Dec. 24, 2013. Hopkins and fellow Expedition 38 Rick Mastracchio (top) performed two spacewalks to replace a pump blamed for crippling one of the International Space Station's two cooling loops Dec. 11. Credit: NASA TV (screenshot)
Toxic snowflakes in space were just one obstacle astronauts faced down today (Dec. 24) as they successfully replaced an ammonia pump that will, if all goes to plan, put the space station back in full service in a few hours.
“They’re just completely surrounding us now,” radioed NASA astronaut Rick Mastracchio of the ammonia flakes as the astronauts clipped four fluid lines into place on to the spare pump. NASA said the ammonia was just residual fluid and not indicative of a leak. “Some little ones, some big ones,” he added.
Within a few minutes, however, the ammonia dissipated. Some flakes did strike the spacesuits of Mastracchio and fellow NASA spacewalker Mike Hopkins, causing NASA to do a modified decontamination procedure where the astronauts stayed in a vacuum for a few extra minutes inside the airlock. (The sun’s heat bakes off ammonia over time, and the crew was outside long enough for most ammonia to dissipate, NASA said.)
The spacewalk completed with no further drama at 7 hours and 30 minutes, earning high praise for the participating astronauts from Mission Control in Houston.
“It’s the best Christmas ever,” radioed CapCom and NASA astronaut Doug Wheelock from the ground as the spacewalkers entered the International Space Station’s Quest airlock at the end of the repair job. “We got it,” Mastracchio responded.
NASA astronaut Doug Wheelock (left) and Japanese astronaut Aki Hoshide served as CapComs during two tricky ammonia pump replacements in December 2013. Wheelock assisted Expedition 38 spacewalking astronauts Mike Hopkins and Rick Mastracchio, while Hoshide helped Japanese astronaut Koichi Wakata with robotic maneuvers. Credit: NASA TV (screenshot)
Preliminary tests show the spare pump is working perfectly. The pump is a welcome present for the six-person Expedition 38 crew, which saw a reduction in science and backup systems for two weeks after a valve in the last pump failed, causing one of the station’s two cooling loops to shut down automatically. The loops are needed to regulate the temperatures of electronics and systems on station.
The Expedition 38 crew was so quick with the repair that they finished the job in two spacewalks instead of the planned three. The astronauts fell behind the timeline today as they struggled with some of the fluid connections to the new pump, but the final steps — putting the electrical connections in place — took just minutes. The pump was brought from another location on station today, and installed into its permanent spot to help ammonia flow through the cooling system.
Anywhere between hundreds and thousands of people at NASA and international partners scrambled to put spacewalks together to fix the cooling problem after it happened. Wheelock, himself a veteran of a tricky ammonia pump repair in 2010, communicated with the spacewalkers. Japanese astronaut Aki Hoshide filled the other CapCom slot, helping Japanese astronaut Koichi Wakata who handled robotics in orbit.
Japanese astronaut Koichi Wakata controlled Canadarm2 during two spacewalks to replace a faulty ammonia pump in December 2013. Credit: NASA TV (screenshot)
Mastracchio marked his eighth spacewalk with today’s repair while Hopkins, who rode Canadarm2 for the first time in a last-minute decision, was on his second. As with a spacewalk on Saturday (Dec. 21), the astronauts reported no helmet water leaks — comforting words for agency officials who put in new procedures and parts after an incident in July. (Mastracchio experienced a water problem during repressurization Saturday that was unrelated to the first incident, and wore a backup suit today to let the primary one dry out.)
Should the ammonia pump work as planned, this clears the way for the Russians to do a spacewalk Dec. 27 to install the Urthecast high-resolution camera that will beam live views of Earth, among other tasks. Expedition 38 has the day off tomorrow (Dec. 25), NASA TV added.
The only other Christmas Eve spacewalk in NASA history took place Dec. 24, 1999 during Hubble Space Telescope servicing mission STS-103. Another Christmas Eve milestone for NASA took place 45 years ago today, when the Apollo 8 crew made a now-famous broadcast while orbiting above the moon.
NASA astronaut Mike Hopkins during his first spacewalk on Dec. 21, 2013 during Expedition 38. He tweeted the next day: "Wow . . . can't believe that is me yesterday. Wish I could find the words to describe the experience, truly amazing." Credit: NASA
Two astronauts are oh-so-close to fixing the International Space Station cooling system that shut down Dec. 11. NASA astronauts Mike Hopkins and Rick Mastracchio will head “outside” on a spacewalk around 7:10 a.m. EST (12:10 p.m. UTC) to replace a faulty pump that led to the problem.
The spacewalkers were so quick on their first outing (on Saturday, Dec. 21) that they accomplished many of the tasks planned for their second spacewalk. They unhooked the first pump module and stowed it safely, then elected to wait until their second to retrieve the replacement pump, swap it in and turn it on.
Below the jump, here are some things to watch for — including why Hopkins is getting a ride on the Canadarm2 robotic arm this time instead of Mastracchio.
The suits. NASA has new safety procedures and measures in place to protect against helmet water leaks, and everything worked perfectly the first time. In an unrelated incident, while the astronauts were in the airlock, an inadvertent switch-throw introduced some water into Mastracchio’s sublimator. The suit is airing out and Mastracchio is wearing a backup suit. While sublimators need water to function, this water could have ended up in the wrong spot. If he had used the one with the water in it, it could have frozen during the second spacewalk and caused problems, Judd Frieling, the Expedition 38 lead flight director, explained on NASA TV Monday.
The background personnel. While it’s easy to shine the spotlight on the two guys outside, also remember that Japanese astronaut Koichi Wakata will be piloting the robotic arm under direction from CapCom and fellow Japanese astronaut Aki Hoshide. Giving advice to the spacewalkers will be CapCom and NASA astronaut Doug Wheelock, who did a similar repair on the International Space Station in 2010. As Wheelock told Universe Today, there are literally hundreds (likely, thousands) of people working the procedures to get this done.
The timeline. NASA really, really wants to wrap this repair up soon, and it’s not because of the holidays. Dec. 27 marks a planned spacewalk for the Russian side of the station that is totally unrelated to what is going on right now. The Americans are hoping they won’t disrupt the schedule so that the Russians can proceed with their experiment swapouts and foot restraint installation as originally planned.
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
The robotic arm. Hopkins is a much more junior spacewalker than the experienced Mastracchio, who has seven spacewalks underneath his belt before today. Hopkins, who is on his first spaceflight, is in a situation where he can expect more flights in the future. So any training he can get in orbit would be fantastic as he would be a stronger asset on future missions. So, Mastracchio was supposed to ride the Canadarm2 on the second spacewalk, but at that time NASA anticipated it would take three to do the repair. Since the crew finished the work so swiftly, it’s likely only two will be needed. As such, giving Hopkins the slot would be the best practice, NASA and the crew determined.
The future pump move. NASA decided not to move the faulty pump from its temporary stowage location until later. Due to thermal conditions on station, it can stay in its temporary spot until June. This saves the spacewalkers extra work now, but someone will need to head outside by summer to move it to a more permanent location.
This broken ammonia pump is visible through the helmet camera of NASA astronaut Rick Mastracchio, who performed a spacewalk Dec. 21 to begin replacing the tank along with Mike Hopkins. Credit: NASA
The ghosts of spacewalks past did not haunt the quick-working pair of astronauts who began replacing a faulty ammonia pump on the International Space Station today (Dec. 21).
Unlike a difficult spacewalk to do a similar repair in 2010, NASA astronauts Rick Mastracchio and Mike Hopkins were so far ahead of schedule that they began doing tasks scheduled for the second in their expected trio of spacewalks.
In better news yet for the spacewalkers, a water leak in Hopkins’ spacesuit this past July — one that sent astronauts scrambling back to the airlock for safety — did not happen again, showing that the part replacement NASA directed had worked. An unrelated water issue in Mastracchio’s suit, however, made agency officials decide to delay the next spacewalk one day to Dec. 24.
The pump replacement is needed to put the space station at full fighting weight. Since Dec. 11, science experiments and other non-critical systems have been offline since a valve in the pump broke. While the astronauts are in no immediate danger, one of their two cooling loops is shut down and there is not a big margin of safety if the other loop fails.
Since this is NASA’s first spacewalk since the leaky suit was last used, the agency emphasized two new measures it has to protect the astronauts if another leak occurs. The first is a new helmet absorption pad (HAP) to soak up any water in the helmet. The second is a pipe — a snorkel — that would let astronauts breathe air from another part of the suit, if required.
But with every “HAP check” that CapCom and astronaut Doug Wheelock called up to the astronauts today, they reported that the suits were dry and everything was fine. The new water issue happened after the spacewalk, while the astronauts were repressurizing the airlock. In a statement, NASA said water could have entered Mastracchio’s suit sublimator and decided to switch him to a backup suit as a precaution.
The spacewalk tasks themselves, however, went far more swiftly than problems Wheelock experienced in 2010, such as when an ammonia line on the pump refused to unhook as required and caused a lengthy delay. NASA made some changes (such as lowering the pressure on the lines, as Wheelock told Universe Today), and this time, Mastracchio powered through the line and electrical removals. The astronauts quickly moved 1.5 hours of schedule and then beyond. A few stray ammonia flakes hit Mastracchio’s suit, but not enough to cause concerns about contamination since the traces of substance baked off in the sun as he worked.
“I don’t know if you believe in miracles, but I got it on the first try,” Mastracchio radioed early in the spacewalk as he got a tricky part of a Canadian robotic arm foot restraint threaded. Mastracchio rode the arm for much of the spacewalk while Hopkins was the “free floating” colleague hovering and doing other tasks nearby.
NASA astronaut Rick Mastracchio (right) pulls an 800-pound ammonia pump module out of its spot on the space station Dec. 21, 2013. At left is fellow NASA astronaut and Expedition 38 member Mike Hopkins. Credit: NASA TV
The most spectacular television shots occurred towards the end of the five-hour, 28-minute spacewalk when Mastracchio carefully wrestled the 800-pound ammonia pump module out of its spot on the space station while riding aboard Canadarm2. (Controlling the arm was Japanese astronaut Koichi Wakata, guided by CapCom and fellow Japanese astronaut Aki Hoshide on the ground.)
After he stowed the module, Mission Control gave the astronauts the go-ahead to put in the spare. Mastracchio, however, said he felt it was best for the astronauts to leave it for next time. While the pair have three spacewalks (including today’s) slated to finish the task, it’s possible they could wrap it up in two — but only if things go as smoothly as this time.
The next spacewalk will take place Dec. 24 at 7:10 a.m. EST (12:10 p.m. UTC), and will be available on NASA Television. We’ll keep you up to speed as the next spacewalk occurs. Today’s excursion was Mastracchio’s seventh and Hopkins’ first.
NASA astronauts Rick Mastracchio and Mike Hopkins of Expedition 38 worked outside for more than five hours Dec. 21, 2013 to begin replacing a faulty ammonia pump on the International Space Station. Credit: NASA TV
NASA astronaut Rick Mastracchio during a space station spacewalk on STS-131 in 2010. Credit: NASA
There’s a cooling problem on station, and two astronauts are ready to head outside to fix it. NASA astronauts Rick Mastracchio (a six-time spacewalker) and Mike Hopkins (a rookie) are expected to spend 6.5 hours “outside” starting at 7:10 a.m. EST (12:10 p.m. UTC) on Saturday. On robotics will be Japanese astronaut Koichi Wakata, who has operated every bit of robotics currently on station.
Click to watch Expedition 38’s crew action live above. (If for some reason the stream is not working, an alternate link is available here.) We’ll have full coverage of the spacewalk after it happens, too.
For a walkthrough of what’s going to happen, NASA handily provided a video that you can see below the jump. We also have links to all of our coverage so far.
However, the station is entering a time when there will be a lot of sun shining on it, making dockings and spacewalks difficult. To be prudent, NASA decided to do a spacewalk now and replace the pump. To keep the astronauts safe if another spacesuit leak happens again, the agency has introduced soaker pads and snorkels to the spacesuits.
Here’s what’s going to happen during the three spacewalks that are scheduled for Saturday, Monday (Dec. 23) and if necessary, Wednesday (Dec. 25), according to lead U.S. Spacewalk Officer Allison Bolinger:
NASA astronaut Doug Wheelock, who was commander of Expedition 25. This 2010 picture of him also shows the Sabatier system that extracts drinkable water from the International Space Station's atmosphere. Credit: NASA
When you learned to drive a car for the first time, remember how comforting it was to have an experienced driver beside you, able to anticipate the hazards and keep you on schedule?
That’s surely how the Expedition 38 crew feels about one of the voices “on the line” as two astronauts prepare to venture outside to replace a crippled ammonia pump. One of the “CapComs” or people communicating with the crew on Saturday, Monday and Wednesday will be astronaut Doug Wheelock — who just happens to be known for co-replacing a broken ammonia tank himself in 2010. (The other CapCom is Japanese astronaut Aki Hoshide, who will chat through robotic procedures with Koichi Wakata).
Wheelock is the visible edge of hundreds — likely thousands — of people working feverishly at NASA and its international partners this past week to get the spacewalks ready through pool simulations, a virtual reality lab and other means. Several backup and non-critical space station systems are offline because of that pump, which has to regulate temperatures properly for vital electronics to work.
“I am their choreographer,” Wheelock told Universe Today of his plan for the astronauts. While spacewalkers Mike Hopkins and Rick Mastracchio already know what they are supposed to do when, Wheelock said he will be “their eyes and ears on the timeline.” If something needs to be stopped or changed, he’ll help them figure out what to do next.
NASA astronaut Doug Wheelock anchored to Canadarm2 during an August 2010 spacewalk. He and Tracy Caldwell Dyson ventured outside three times during Expedition 24 to swap out and replace a broken ammonia pump. Credit: NASA
Wheelock and fellow astronaut Tracy Caldwell Dyson had to spring into action themselves in August 2010. A pump in the same location broke, forcing space station systems offline and requiring them to go outside a few days later. With astronaut Shannon Walker piloting Canadarm2, the astronauts accomplished their tasks in three spacewalks — but encountered obstacles along the way.
During the first spacewalk, as Wheelock disconnected lines from the broken pump, he not only faced a pipe that wouldn’t let go, but a shower of ammonia snowflakes. That was “what got me on the EVA [extra-vehicular activity],” he recalled. That’s why NASA plans to lower the line pressure on the cooling system before the astronauts head outside this time. Normally the lines are pressurized at 360 pounds per square inch, but they’ll be lowered to 120 psi through commands from the ground.
Other “lessons learned” are more recent. Italian astronaut Luca Parmitano was wearing a NASA spacesuit in July when he experienced a water leak in his helmet, putting him at risk and terminating the spacewalk early. This will be the first spacewalk since that time. NASA believes it has replaced the part of the suit that failed, but the agency has new backups in place. Hopkins and Mastracchio will have soaker pads in their helmets as well as a “snorkel”-like device, or tube that will let them breathe oxygen from a different part of the suit if water flows into the helmet again.
Allison Bolinger, NASA’s lead U.S. spacewalk officer, holds up a snorkel-like device that astronauts began using in spacesuits in December 2013. The pipe (modified from spacesuit parts) is supposed to be a backup if a helmet fills with water, as what occurred during a July 2013 spacewalk. Credit: NASA (YouTube/screenshot)
So what are some key parts of the spacewalks to look for? Wheelock identified a few spots.
‘HAP’ check. That soaker pad is called a “helmet absorption pad”, and as a matter of course the astronauts will be asked to verify that the pad is not wet at the same time that they also check their gloves for tears (another lesson learned from a past spacewalk.) So you will hear Wheelock calling “HAP check” from time to time to the crew.
Unlatching and latching the ammonia connectors on the pumps. Because this is when leaks are most likely to occur — posing a risk to Mastracchio, who is performing the work — Wheelock is going to do a “challenge and response” procedure. He will read up the step, the astronaut will verify it and will do the work. There will be “a lot more chatter on the [voice] loop” during those times, Wheelock said, with everyone on the ground watching through Mastracchio’s head camera feed (visible at the front of the room) to see what is happening. “There will be a lot of people standing in Mission Control at that point,” he joked, himself included.
Leak procedures. If ammonia does start to shower out, Mastracchio will quickly close the valve and wait a few minutes as it could be just residual ammonia in the line. If that doesn’t work out, Mastracchio is trained on a procedure to attach a device to the front end of the connector and move a lever that prevents a cavity in the line from filling with ammonia. Then he can open the valve again, bleed out the ammonia that’s left over and keep going.
NASA astronaut Rick Mastracchio inspects two spacesuits to be used during spacewalks in December 2013. The spacewalks were to remove and replace a faulty ammonia pump. Credit: NASA TV
Decontamination procedures. The ammonia makes a distinctive “ping” when it hits the helmet, says Wheelock (who yes, heard that happen himself.) You can also see ammonia on the suit, he said, as it looks a bit like candle wax and obscures the stitching. All of which to say, NASA has procedures in place if the agency suspects or can confirm large amounts of ammonia got on Mastracchio’s suit. (Small amounts would essentially fleck off in the sun.) Hopkins, who will be out of the line of fire, can do a thorough inspection of Mastracchio and scrape off any ammonia with a warm metal tool — without hurting the suit underneath. The astronauts could also do a “bakeout” in the airlock — 30 minutes if suspected, an hour if confirmed — where they will sit with the hatch open and wait for any ammonia to sublimate off the suit. Once they close the hatch, the astronauts can verify if the ammonia is gone using Drager tubes, which have gold crystals inside that turn “purpleish blue” in the presence of ammonia, Wheelock said.
Margin calls. Because NASA needs to make sure the astronauts have 30 to 60 minutes to decontaminate at the end of their spacewalks, officials will preserve a margin of oxygen available for the astronauts to walk through that work. So it’s possible the agency may terminate a spacewalk before all tasks are completed just because they need that bit of margin at the end.
To learn more, Wheelock has been answering questions occasionally on his Twitter account from followers, and you can read through what he posts when he finds the time. Universe Today will also cover the spacewalks (currently planned for Saturday, Monday and Wednesday) as they occur.
NASA astronaut Rick Mastracchio during a spacewalk on STS-118. Credit: NASA
When NASA astronaut Mike Hopkins steps into space for the first time this week, he will wear a spacesuit that previously sprung a water leak and forced Italian astronaut Luca Parmitano back to station in July, NASA officials said Wednesday (Dec. 18).
While at first glance this sounds like an extra bit of drama as Hopkins and Rick Mastracchio make contingency spacewalks Dec. 21, 23 and 25 to kickstart a shut-down cooling loop, NASA officials say the suit is ready to go for another trip outside because astronauts (under NASA’s direction) have made a bunch of changes to the unit.
Repurposing spacesuit parts, a new pad will be added to the back of all NASA spacesuit helmets to soak up water, should one leak again. Astronauts also velcroed a pipe into each suit — a sort of snorkel — that in the worst case, would give an astronaut with a water leak an alternate route for drawing in air.
Also, the Expedition 38 crew swapped out a fan pump separator that likely malfunctioned and caused the spacesuit leak. The cause is still under investigation, but NASA believes that a problem in the water chemistry caused contamination that plugged a tiny hole inside the water separation part of the unit. This allowed the water to escape, enter the air loop and get into the helmet.
Finally, there are new procedures in place for the astronauts themselves. They will monitor the helmet pad for fluid. NASA additionally plotted out its spacewalk procedures — which include the use of a Canadian robotic arm on station — to make sure the astronauts are always within reasonable reach of an airlock.
NASA astronauts Rick Mastracchio and Mike Hopkins will do spacewalks in December 2013 to swap out a cooling pump on the International Space Station. Credit: NASA
So here’s why the spacewalks are happening: a week ago (Dec. 11), a flow control valve inside of a pump — the pump is located outside of the station — stopped regulating ammonia temperatures inside of an external cooling loop. The loop is required to, as the name implies, cool down space station electronics. The loop got too cold, it shut down automatically, and NASA took science experiments and redundant systems offline to deal with the problem. (The main problem is NASA can’t run a heat exchanger on Node 2, which affects experiments in the U.S. Columbus laboratory and Japanese Experiment Module. No completed research has been lost to date, however.)
After figuring out that it couldn’t control the valve again, NASA shifted its attention to an isolation valve upstream. That valve is only designed to be in two positions — opened or closed — but the hardware vendor said it could be used at spots in between to regulate the ammonia flow. So software engineers created a patch to make this happen, and uploaded it to station.
Throw in another element, however: the station is about to enter what’s called an annual “high beta” period, when orbital dynamics mean the sun will be shining on it for longer periods of time than usual. (Read more technical details here.) When the angle exceeds 60 degrees, for safety reasons NASA suspends all cargo flights to station as well as spacewalks. This year, it will happen between about Dec. 30, 2013 and Jan. 9, 2014.
The International Space Station in 2010. Credit: NASA
So if NASA spent time playing with the valve and found out it couldn’t work in the long run, a couple of problems could happen. First, it would be harder to do a spacewalk to fix it.
Here’s a diagram of the pump that Mastracchio and Hopkins plan to replace:
A view of a pump module aboard the International Space Station that is used to maintain ammonia at the correct temperature in an external cooling loop. Credit: NASA
The “nominal” plan is for three spacewalks, but it could range anywhere from two to four depending on how things go. To put things simply, here’s how the spacewalks would go:
EVA 1: The pump with the broken valve would be disconnected and a spare pump (which is some distance away, but reachable using Canadarm2) would be prepped for the swap.
EVA 2: The pump with the broken valve would be removed and set aside while the spare pump is partially installed (meaning, only the bolts and electrical connections would be put in.)
EVA 3: The spare pump’s installation would be finished, and the pump with the broken valve would be stowed more permanently outside. NASA thinks that eventually, it could use that first pump again if astronauts installed a new valve on it, but that isn’t a need for the time being.
Flying Canadarm2 would be Japanese astronaut Koichi Wakata, who has operated every type of robotics currently in orbit. Mastracchio has six spacewalks under his belt already, while Hopkins will be on his first go.
If all goes to plan, NASA will not only swap out the pump, but also preserve the option for the Russians to proceed with a planned Dec. 27 spacewalk that is less urgent. In that case, the cosmonauts plan to swap out experiments, put in a foot restraint and install some cameras.
We’ll cover the spacewalks as they happen. They’re scheduled for Dec. 21, 23 and 25 at 7:10 a.m. EST (12:10 p.m. UTC) and should run about 6.5 hours each. Broadcasts will run live on NASA Television.
By the way, the pump with the problem is just three years old — astronauts had to make three spacewalks in 2010 to install it after a more severe failure. NASA characterized this situation as a more unusual failure and said this is not a symptom of an aging station at all.
Overview of the tasks that Rick Mastracchio and Mike Hopkins will perform during three spacewalks in December 2013 to remove and replace a pump with a faulty valve inside of it. The pump is required to maintain the external cooling system at the right temperature. Credit: NASA
The Expedition 38 crew tests spacesuits in preparation for December spacewalks to replace a pump for the International Space Station's cooling system. In the spacesuits are NASA astronauts Mike Hopkins (left) and Rick Mastracchio. Japanese astronaut Koichi Wakata is in the foreground, with Russian commander Oleg Kotov behind. Credit: NASA TV
The week before Christmas will be full of spacewalk preparations for Expedition 38 as they get ready to remove and replace a malfunctioning pump aboard the International Space Station.
NASA astronauts Rick Mastracchio and Mike Hopkins will participate in the spacewalks, NASA said today (Dec. 17), with Japanese astronaut Koichi Wakata handling robotic operations during the Dec. 21, Dec. 23 and Dec. 25 activities.
A new pump is needed to regulate temperatures in an external ammonia cooling loop that shut down automatically Wednesday (Dec. 11) when it got too cold. The loop keeps equipment at the right temperature on station. While the astronauts have been fine for the past week, several redundant systems and some experiments are offline. Luckily for the crew, other astronauts previously installed three spare pumps on station, which you can see in the graphic below.
Locations of spare pumps on the International Space Station as of December 2013. Credit: NASA
Spacewalks are always a risky proposition, and NASA has not conducted any since Italian astronaut Luca Parmitano experienced a leak in an American spacesuit in July. As such, the agency spent several days trying to fix the cooling loop by other means.
A faulty control valve made the pump malfunction on Wednesday. The valve normally mixes warm ammonia that flows past external radiators on station with cooler ammonia that was put through those radiators. NASA first tried to control the valve from the ground, then focused its attention on an isolation control valve upstream from the pump that the agency hoped could serve as a backup. The isolation valve, however, was only designed to be closed or opened fully — not positioned in between.
As of 11 a.m. EST (4 p.m. UTC) today, NASA was working on a software patch to try to freeze the valve in different positions to manually regulate the flow of ammonia.
“The fidelity that we have here on the ground to precisely control when that valve starts moving and stops is on the order of about 0.2 seconds, 0.3 seconds, somewhere in that range. We really need the fidelity to be much higher than that,” said Judd Frieling, the Expedition 38 lead flight director, in an update on NASA Television.
“We need it to be on the order of 0.1 seconds. So the way we can reliably produce that is by putting some software on the computers on board that basically allows us to get that finer control. So engineers and coders, overnight, have been working on a software — we call it a patch — software fix, to one of the computers that controls that valve.”
NASA planned to upload the patch to the station this afternoon (EST) to see if it was possible to control the isolation valve by telling it to move, then cutting the power when it got to a certain spot. The agency did not say how successful that fix was, but will likely address that in a media briefing tomorrow at 3 p.m. EST (8 p.m. UTC).
Cooling problems have occurred on station before. The most recent failure was a leak in May, which the Expedition 35 crew fixed just days before some of the astronauts went home. A more prominent failure on the same cooling loop occurred in 2010, when Expedition 24 astronauts performed three spacewalks to replace a faulty pump.
Each of the three emergency spacewalks this month (Dec. 21, 23 and 25) will start at 7:10 a.m. EST (12:10 p.m. UTC) and take about 6.5 hours to perform, NASA added. The activities will be carried live on NASA Television, with coverage starting about an hour before each spacewalk is expected to begin.
NASA Television graphic of where spare cooling pumps are located on station as of Dec. 13, 2013. On that day, NASA was weighing whether spacewalks were necessary to deal with a cooling problem caused by a malfunctioning flow control valve inside of a pump. Credit: NASA TV
NASA may allow its first spacewalk since summer to deal with a malfunction that crippled a cooling loop on the International Space Station.
If extravehicular activity is deemed necessary for a fix, it would be the first time NASA spacesuits were used “outside” since Luca Parmitano, an Italian astronaut, experienced a water leak in one that cut short a spacewalk in July. NASA suspended all spacewalks as a precaution while the cause was investigated.
Since then, the agency has put in place procedures to protect astronauts from it happening again, opening up a spacewalk or spacewalks as an option to deal with a balky control valve inside a pump on the station.
The valve is an essential part of an S1 (starboard) truss pump that helps maintain the correct temperature for space station electronics. Ammonia circulates through two external cooling loops and is put through radiators to bleed off heat. The valve is required to mix the cool and warm parts of liquid in the ammonia loop.
Expedition 35 Flight Engineers Chris Cassidy (left) and Tom Marshburn completed a the 5-hour, 30-minute spacewalk on May 11 to inspect and replace a pump controller box on the International Space Station’s far port truss (P6) leaking ammonia coolant. Credit: NASA
A pump automatically shut down on Wednesday (Dec. 11) when the loop got too cold. As NASA began troubleshooting the issue, it powered down non-critical systems (including experiments and redundant systems) in the Columbus laboratory, Harmony node and Japanese Kibo laboratory. Primary systems are still online.
The astronauts are safe, NASA said today (Dec. 13), with the biggest impact to their activities being the science they perform. Expedition 38 astronaut Rick Mastracchio did a live media interview this morning (EST) where he similarly assured reporters that everyone on board is fine.
Cooling problems have happened on station before, most recently in May when an emergency spacewalk was needed to replace a pump controller box on the P6 (far port) truss. This particular cooling system experienced an issue in 2010, which required three contingency spacewalks to remove and replace a failed pump on the S1 truss.
Expedition 24 astronaut Douglas Wheelock exits the Quest airlock at the beginning of a spacewalk Aug. 11, 2010 to replace a failed ammonia pump on the International Space Station’s S1 truss. Credit: NASA
If a spacewalk is needed this time around, NASA has three spare pumps available on station for astronauts to use. NASA, however, is looking at all options before making a decision — including ways of controlling the errant valve from the ground. The agency is holding multiple meetings to decide what to do next after turning on and off the cooling loop yesterday and seeing the same malfunction.
On Monday, NASA will decide whether to move forward with a launch of a cargo spacecraft expected to head to the station on Dec. 18. The window for Orbital Sciences’ Cygnus spacecraft extends to Dec. 21 or 22, but as of Thursday (Dec. 12), the agency said the lack of redundant systems on station violates certain “commit criteria” for the launch to move forward.
While NASA spacewalks were suspended, activity using the Russian Orlan spacesuits has continued as usual. A spacewalk took place in November with the Olympic torch, amid other duties. Another spacewalk is planned Dec. 27 to install high- and medium-resolution cameras, put in a foot restraint, and remove and replace several external experiment packages.
NASA astronaut Rick Mastracchio inspects a spacesuit during repairs in the Quest airlock aboard the International Space Station. Taken during Expedition 38 in November 2013. Credit: NASA
Judging from the way those food packets are floating around, looks like the folks on the International Space Station will have to catch their turkey! NASA astronauts Rick Mastracchio and Mike Hopkins, two of the six people working on Expedition 38, recently shared their plans for U.S. Thanksgiving on Thursday.
“Though we miss our families, it’s great to be in space. As astronauts, this is what we train for and this is where we want to be. Opportunities to fly in space are rare, so we have to take advantage of them whenever they occur,” Hopkins said in the message.
The best part of this missive? Watching the astronauts casually toss the microphone back and forth in between their statements. That’s the fun of recording in microgravity.
Thanksgiving will be a full workday on station as the astronauts continue to work on their experiments. A recent status report indicated that Mastracchio (the crew medical officer) was examining Hopkins’ eyes as part of ongoing work looking at how microgravity affects ocular health. Flight controllers also moved one of the solar arrays for Mastracchio to take pictures and monitor how the mast is doing “for future inspections”, NASA stated.
