Astronauts take Christmas Eve spacewalk, make critical repair

Astronaut Mike Hopkins, anchored to the end of the world area Station’s robot arm, inspects a brand new pump module after ammonia coolant strains and electrical cables were connected.

Two astronauts efficiently put in a substitute coolant pump aboard the global space Station Tuesday, wrapping up a excessive-stakes two-spacewalk repair job and clearing the way in which for flight controllers to re-activate a crucial coolant system.

“we’d similar to claim because of the entire great other folks doing all this difficult work to get this area station back up and running,” spacewalker Rick Mustachio radioed as he returned to the search airlock module.

“No, thank you guys,” astronaut Doug Wheelock spoke back from mission control in Houston. “It can be the very best Christmas ever. Thanks, guys.”

“Yeah, I would similar to so as to add to that,” Mike Hopkins stated from the airlock. “Improbable work, Merry Christmas to every person. It took a few licks to get her completed, but we acquired it.”

the one problem of any importance throughout the seven-hour 30-minute spacewalk used to be hassle getting one in every of 4 ammonia strains disconnected from a so-known as jumper field where it used to be quickly plugged in all the way through a spacewalk Saturday.

Hopkins and Mustachio finally freed a snappy-disconnect fitting preserving the 1/2-inch line in position, and were sprayed with ammonia ice crystals trapped in the connector. The poisonous chemical posed no possibility to the astronauts however they spent just a few further minutes in vacuum to make sure any ice caught to their fits had time to dissipate before they re-entered the station.

The ammonia infection barely slowed the astronauts down. After releasing the stuck line, Hopkins and Mustachio finished hooking up all four ammonia lines to the alternative pump module and plugged in 5 electrical cables. Flight controllers then conducted a so-referred to as “bump” test, briefly spinning up the pump and verifying the operation of interior valves.

“Just right news! The thermal keep an eye on officer reviews a good bump start check on the newly put in pump module,” NASA’s mission keep an eye on commentator, Rob Navies, stated. “We’ve a pump that is alive and smartly.”

 

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Later nowadays, flight controllers planned to begin re-activating coolant loop a, clearing how one can restart scientific experiments and different hardware that was shut down when the coolant loop suffered a malfunction December 11.

The a hit spacewalk additionally clears the best way for expedition 38 commander Oleg Kato and Russian flight engineer Sergey Ryazanskiy to carry out a spacewalk of their own on Friday. They plan to challenge outdoor to mount cameras on the hull of the Zelda command module as part of an industrial venture to beam down high-definition Earth views to subscribers worldwide.

nowadays’s spacewalk was the 258th via U.S. astronauts, the 176th dedicated to station meeting and repairs given that construction began in 1998, the tenth so far this yr, the eighth for Mustachio and the 2d for Hopkins.

100 and 14 astronauts and cosmonauts have now spent 1,107 hours and 37 minutes of spacewalk time building and sustaining the world house Station due to the fact building began in 1998. Mustachios complete thru eight spacewalks now stands at 51 hours and 28 minutes, transferring him up to sixth on the record of most skilled spacewalkers. Hopkins complete EVA (extravehicular task) time through two spacewalks stands at 12 hours and fifty eight minutes.

The goal of as of latte’s trip was to put in a replacement ammonia pump module in coolant loop A, one in every of two cooling systems used to dissipate the heat generated via the station’s electrical techniques. A valve in the loop a pump meeting malfunctioned December eleven, partially disabling the machine and forcing flight controllers to energy down non-essential methods.

Extra important, the malfunction left the station one failure away from a much more drastic energy-down must the lone operational coolant loop damage down.

during a five-hour 28-minute spacewalk Saturday, Mustachio and Hopkins disconnected the suspect ammonia pump module on the best aspect of the station’s main energy truss, pulled it from its slide-in rack in the S1 section of the truss and established it on a nearby storage fixture to complete segment one of the most coolant system restore job.

On account of an unintended change throw throughout the airlock at the end of the spacewalk, a small amount of water acquired into the plumbing of Mustachio’s backpack, elevating the likelihood that doubtlessly destructive ice may kind all over the 2d EVA.

consequently, Mustachio assembled a special go well with for the 2d spacewalk whereas Hopkins used the one he wore Saturday, the same go well with that developed a doubtlessly dangerous leak all through a July spacewalk.

After exhaustive troubleshooting, engineers concluded the leak was once resulting from contamination that clogged a filter. While the basis cause of the infection has no longer yet been determined, the astronauts changed suspect elements and both fits performed in most cases right through both coolant restore spacewalks.

Right through their 2d spacewalk Tuesday, Mustachio and Hopkins desirous about putting in the alternative pump module.

In magnificent video down linked from the station, Mustachio and Hopkins, anchored to the top of the station’s robotic arm, might be seen unbolting the spare pump module from its storage pallet and pulling it from its insulated enclosure.

“Looks like you are virtually there,” Mustachio radioed as arm-operator Koichi Waikato, working inside the future lab module, slowly pulled Hopkins and the pump meeting away. “you might be out of the groove there, Mike, I think you are in cost now of the pump module…it’s secure, Mike, it seems excellent, you might be doing an ideal job, it looks gorgeous.”

Hopkins held the tethered pump module in his gloved arms as Waikato slowly moved him inboard from the storage pallet on the S3 truss segment to the pump’s set up region in the S1 segment.

This view from astronaut Mike Hopkins’ helmet camera presentations two ammonia strains linked to a substitute coolant pump to the left side of the frame. However the astronauts had drawback disconnecting two different ammonia lines, visible to the proper, that had been hooked up to a so-called jumper field during a spacewalk Saturday.

The astronauts then guided the large module into position and drove residence bolts to lock it down. That they had no trouble hooking up the primary two ammonia strains, often called M1 and M2. Any other two traces, M3 and M4, were attached to a jumper field Saturday to allow the ammonia within the coolant loop to expand and contract as needed when the station flew into and out of daylight.

The astronauts at first were unable to disconnect the 1/2-inch-wide M4 line from the jumper field. Mustachio retrieved a tool designed to apply extra force to the fast-disconnect bale holding the mechanism collectively. The idea was to push the lever far enough over to allow the astronauts to depress a locking button, permitting them to separate the 2 sides of the precise.

However the stubborn fitting refused to cooperate.

“One thing we never expected,” Mustachio muttered at one level.

After positioning the short-disconnect software with varying degrees of power, flight controllers decided to lower the drive within the line. Proper round that time, the astronauts successfully demoted the cussed fitting, however said “we do have snow coming out.”

A number of moments later, astronaut Douglas Wheelock in mission keep an eye on requested the spacewalkers if ammonia was nonetheless leaking out “or has it dissipated.”

“Sure. It’s about one each 2d, one little snowflake a 2nd,” Mustachio replied.

Asked if their spacesuits had been hit with the aid of any ice, Mustachio said “absolutely,” adding a couple of moments later “they’re simply totally drowning us now.”

“Copy, Rick,” Wheelock stated. “And we have no video, Rick, so we’ll just take your persevered description.”

“Good enough. They’re pretty just right measurement particles, so much greater than anything now we have ever viewed. See that giant one going by way of you, Mike?”

“I do,” Hopkins said.

“It seems like they’re coming inboard of the pump module, all around the pump module, looks as if,” Mustachio said. “I can’t see it far and wide, where the sunshine is, however they are hitting the wrist cluster of the SSRMS (robotic arm), they’re enveloping Mike, almost definitely enveloping me, also.”

“Sure there,” Hopkins said. “Giant chunks, giant chunks.”

The ammonia possibly used to be trapped in the line and expelled when flight controllers sent instructions to vent the jumper field. The leak charge diminished just a few moments later and the astronauts pressed in advance with work to attach M4 after which M3 to the alternative pump module.

The ammonia posed no threat to the spacewalkers, but they had to spend a number of further minutes in vacuum to present any ice crystals that can have caught to their fits time to dissipate. Decontamination strategies have been required all over past spacewalks involving the ammonia coolant device to verify returning spacewalkers don’t introduce any toxic subject material into the station’s air supply.

NASA initially held open the possibility of a 3rd spacewalk to finish the coolant machine restore work, but with the a success pump set up and activation Tuesday, the station crew now can sit up for a quiet Christmas in orbit prior to making preparations for the Russian spacewalk Friday.

 

Author: Rohit Shetty

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