Next week, March 29, McClain will join Christina Koch in space. This will be the first outing in the entirely female space, a historic event.
Koch and Hague joined the space station last week. For The Hague, it was a delay compared to the unsuccessful launch of Soyuz in October. McClain joined the station in December.
The International Space Station has been in use for almost two decades. While it draws most of its energy from the massive solar panels that make up its distinctive shape, it also needs to store this energy in rechargeable batteries when the station turns around at night. The resort experiences sunset and sunrise every 90 minutes, spinning over the surface of the Earth.
Most of the station's current batteries are nickel-hydrogen and should be replaced every six years or so, like any other rechargeable battery. Since 2017, NASA has replaced them with new lithium-ion batteries, which are twice as charged as the old ones, even at their best efficiency. Some of the replacement maneuvers can be done with the robotic arm of the space station, but some parts of the rewiring require human contact.
Hague and McClain will begin their spacewalk Friday at 8:05 am EST, and will spend about six and a half hours outside the International Space Station.
McClain and Koch will continue their work on March 29 by exchanging more old batteries for new ones and connecting them to the station's electrical system. In total, NASA plans to exchange 12 old batteries for six new ones. Both space releases will be broadcast live on NASA's website.
Each of the new batteries weighs about 300 pounds on Earth, although in space they do not weigh at all. They are always bulky and difficult to maneuver. The astronauts have practiced their movements in the underwater laboratory that NASA uses to imitate the low-gravity environment of space.
A third spacewalk is scheduled for April 8, during which Hague and David Saint-Jacques of the Canadian Space Agency will install preliminary materials for a future science platform.