Steve Swanson, commander of Expedition 40, during a spacewalk on 2007 shuttle mission STS-117. Credit: NASA
Remember those snorkels and pads astronauts used during the ammonia pump replacement on station this past December? The new measures went a long way to helping astronauts stay safe if another helmet water leak happens, but at the same time, NASA is eager to find the cause so they know how it happened and how to prevent it.
Two maintenance spacewalks are planned for Expedition 40, but they’re not necessarily going forward yet. NASA has traced the issue to a fan pump separator, but there’s another issue, explained expedition commander Steve Swanson: where the particulates in the water came from. Perhaps they were from a filter, or perhaps from the water system itself. So NASA is reserving spacewalks on a need-only basis until more is known.
“That was the problem. Now, we’ve got to find out where that came from,” Swanson said in a phone interview with Universe Today from Houston to preview Expedition 39/40’s mission, which launches in late March. Joining the two-time shuttle astronaut will be two other people, including Alexander Skvortsov. The Russian cosmonaut commanded Expedition 24 in 2010, which experienced a similar ammonia leak to the one that was just repaired a few months ago.
Expedition 39/40 cosmonaut Alexander Skvortsov during a 2010 mission to the International Space Station, when he served as commander of Expedition 24. In the background is NASA astronaut NASA astronaut Tracy Caldwell Dyson. Credit: NASA
While leaks and spacewalks are the items that grab headlines when it comes to spaceflight, one of the major goals of the International Space Station is more subtle. Researchers hope to understand how spaceflight affects the human body during long-duration missions. (This will be a major focus of a one-year mission to station in 2015.) Through a translator, Skvortsov explained that the recent decision to extend station’s operations to at least 2024 will be a help for research of this kind.
“It is great that they have expanded the station until 2024 at least, and it will be very beneficial to the science programs and projects we have on board,” he said in Russian. “I hope that it will be extended even further. It will depend on the condition of the station.”
Expedition 39 is expected to launch March 26, 2014 from the Baikonour Cosmodrome in Kazakhstan. The crew will join orbiting spacefarers Koichi Wakata (who will command Expedition 39, a first for Japan), Rick Mastracchio (who participated in the ammonia pump swap-out) and Mikhail Tyurin.
The Expedition 39/40 crew at a NASA press conference in January 2014. From left, Oleg Artemyev, Alexander Skvortsov and Steve Swanson. Credit: NASA
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 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.
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.
The International Space Station as seen by the departing STS-134 crew aboard space shuttle Endeavour in May 2011. Credit: NASA
While Expedition 38 astronauts Rick Mastracchio and Michael Hopkins get their spacesuits and the Quest airlock ready in case they need to do a spacewalk to fix a cooling problem on board the station, NASA engineers have come up with an alternate proposal that could allow an interim fix from the ground.
A faulty flow control valve inside an external pump caused one of the station’s two main cooling loops to shut down automatically on Wednesday when the loop became too cold. This forced NASA to power down noncritical systems and some experiments as they moved the most needed systems on to a single loop.
After playing with the balky valve for several days, controllers determined it can’t be worked normally. Yet there is another valve nearby that possibly can.
Just “upstream” of the control valve is an isolation valve that possibly can be manipulated to control the temperature, said Kenny Todd, the ISS mission operations integration manager. While the valve is usually either open or closed to do its work, it is possible that it could be positioned at positions in between to warm up the coolant.
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
“Can we use it as a regulator, if you will, to restrict the flow coming from the radiator and by doing that, that would help to put the temperature in the loop a little warmer,” Todd said in an update broadcast on NASA Television today (Dec. 16) that you can watch in full below.
He added, “We’re taking a valve and using it for a different purpose than we’d originally intended.” This means that software must be adapted to control the valve from the ground, among other things. The hardware vendor (which Todd did not name) has said that theoretically this finer control would be possible.
It’s too early to say if this fix could work in the short term, let alone the long term, which is why Mastracchio and Hopkins are standing by ready to do a spacewalk if need be. NASA has experience with this kind of repair before, most notably in 2010 when astronauts aboard Expedition 24 performed three spacewalks to deal with a broken pump in the same cooling loop. There are three spare pumps aboard station that could swap out the crippled one.
NASA and Mastracchio have both said that the crew is doing fine. The largest scheduling changes are reportedly related to science experiments being suspended, as well as adding in some spacewalk preparation activities. Also, the Cygnus cargo spacecraft’s planned launch has been pushed back at least one day to Dec. 19; last week, NASA said the station’s cooling problem means it is violating certain “commit criteria” for the launch to move forward.
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.
