Two NASA astronauts completed the first spacewalk of 2017. The oldest female astronaut to reach space, Peggy Whitson, and International Space Station (ISS) commander Shane Kimbrough replaced batteries near the solar array of the ISS.

The spacewalk conducted last Jan. 6 was done to upgrade some of the power systems of the space station. The whole process took six hours and 32 minutes to complete.

The Expedition 50 astronauts installed adapter plates and connected the electrical system of the new lithium-ion batteries. The spacewalk was seen live by everyone through NASA TV. A huge amount of time outside the space station was spent tightening the new latches and connecting the power systems, which are conducted by Whitson while being assisted by Kimbrough.

According to NASA, the nickel-hydrogen batteries were replaced by lithium-ion. The batteries store the energy collected by the space station's solar array. The two astronauts, however, did not do all the dirty work as robots did the initial stage of the process since the start of the year.

Another spacewalk will be conducted this month in order to finalize the power upgrade. The second one will take place on Jan. 13 with the European Space Agency (ESA) astronaut Thomas Pesquet and Roscosmos cosmonaut Oleg Novitskiy.

NASA revealed other details of the mission. "Once again, Kimbrough will be designated extravehicular crew member 1 (EV 1), wearing a suit bearing red stripes for the fourth spacewalk of his career," an agency official said in a press release.

ESA's Thomas Pesquet, however, will perform his first spacewalk this weekend. Pesquet will be the 11th ESA astronaut to walk outside the space station.

"We have started well in advance to prepare for the spacewalks of January," Thomas Pesquet said in a statement. "It is a lot of work to service the suits and get them ready, get familiar with the choreography and prepare the tools and equipment. Not even mentioning the thousands of hours of work for all the personnel on the ground."

In total, there were 196 spacewalks completed; that's 1,224 hours and six minutes outside the science lab in space.