NASA Postpones First Two of Three Spacewalks

NASA decided to postpone by one day each the first two of a set of three spacewalks from the International Space Station (ISS) planned over the next week and a half.  The first was scheduled for tomorrow, February 20, but will wait until February 21.  The second will slip from February 24 to February 25.  The third remains on track for March 1.

NASA astronauts Barry “Butch” Wilmore and Terry Virts will use the spacewalks to begin the process of outfitting ISS docking ports so they can accommodate new commercial crew vehicles when they start ferrying astronauts to the ISS in 2017.  All three involve running cables and moving equipment on the exterior of the space station.

Experts are still troubleshooting an issue with the fan pump separators on the astronauts’ spacesuits, however.   NASA’s ISS Operations and Integration Manager Kenny Todd revealed the problem at a press briefing yesterday.  He said a decision on the schedule for the spacewalks would be made today after a special ISS Mission Management Team (IMMT) meeting.  That meeting at Johnson Space Center (JSC) concluded about 2:30 pm Central Time (3:30 pm Eastern) with the decision to wait one more day for the first two.  

NASA would like to get all three spacewalks completed before Wilmore returns to Earth on March 12.  The third of the three is still scheduled for March 1.  All three spacewalks will begin at about 7:10 am Eastern Time, with NASA TV coverage beginning at 6:00 am ET.

Todd explained that corrosion was discovered in the fan pump separators probably due to water intrusion.  The corrosion creates mechanical binding on the bearings, preventing the fans from spinning up.  The problem was discovered on orbit first on one suit and then on another.  Those fan pump separators were replaced and returned to Earth on the recent SpaceX cargo mission to the ISS (SpX-5) giving engineers an opportunity to study them more closely.

He stressed that this is not the same problem that led to the “water in the helmet” episode in 2013.  That was caused by a filter being clogged by particles in the water that allowed the water to enter European Space Agency (ESA) astronaut Luca Parmitano’s helmet.  “That is not an issue here,” he emphasized.   “Fan pump separators can fail for a variety of reasons” and crews “train for that,” he said.  Nevertheless, NASA wants to be as certain as possible that there will be no problems at all during the spacewalks.  Todd said the decision on when to conduct the spacewalks will be “data driven” and they will take place only when “we have high confidence” the suits will work properly.