Changing a flat battery trickier than it looks for space crew

Spacewalking astronauts completed battery and cable work outside the International Space Station yesterday.

US astronaut Anne McClain, left, and Canadian counterpart David Saint-Jacques change batteries on the International Space Station. Picture: NASA.

Spacewalking astronauts completed battery and cable work outside the International Space Station yesterday despite communication troubles that made it hard for them to hear.

During the spacewalk, Canadia­n astronaut David Saint-­Jacques reported that US astronaut Anne McClain’s voice was faint at times. The problem worsened as their 6½-hour excursion drew to a close.

“We know that it’s a lot of hard work and a lot of big sighs of relief as soon as this hatch gets closed,” Lieutenant Colonel McClain said once the pair were inside the airlock. Within moments, the spacewalkers could barely hear their colleagues over the radio loop. They had to shout and repeat words at times, as did the astronauts on the other side of the hatch.

Colonel McClain, meanwhile, reported having a thin layer of moisture inside her helmet. The change to her visor was noticeable in the last 15 minutes of the spacewalk, she noted.

NASA is wary about moisture inside helmets ever since an Italian­ astronaut almost drowned during a spacewalk nearly six years ago because of a water leak in his suit. Colonel McClain insisted she wasn’t wet, and that the moisture was minimal. A crewmate later noted perspiration.

Earlier, Colonel McClain and Dr Saint-Jacques hustled through their part in battery swaps that began last month. It was the third spacewalk in just 2½ weeks for the space station crew.

The cable routing took more time, providing a back-up power circuit for the station’s Canadian-made robot arm and expanding wireless communications. At one point, the spacewalkers had to use a bar to loosen a stuck fastener and get behind a protective panel.

The ongoing battery work involve­d reinstalling two old batteries. One of six new lithium-ion batteries did not work, so Colonel McClain had to remove an ­adapter plate she put in.

Last week, flight controllers used the space station’s robot arm to remove the failed battery, along with an associated charging ­device. Working remotely, the controllers also installed a spare charging device and one of the old batteries made of nickel hydrogen. The second outdated battery will go in — robotically — later this week.

NASA said it would send up another new battery, although it is uncertain when. Until then, this combination of old and new batterie­s is expected to work fine, ­according to managers.

Because of trouble with a trunnion­ pin, Dr Saint-Jacques could not complete prep work for a ­future payload platform.

Colonel McClain has now logged two spacewalks and Dr Saint-Jacques one. Their six-month mission began in December. The next spacewalk will be next month, by the two Russians on board. Two more Americans round out the six-person crew.

AP