Two NASA astronauts finished the pair of spacewalks on February 1. They just built a European science platform and wrapping off a lengthy sequence of battery replacements from outside the International Space Station.

The spacewalk started at 7:56 am EST and was livestreamed on this website.

According to NASA, the said event is the 234th spacewalk, or extra-vehicular activity (EVA), to support the assembly, repair, and improvement of space stations. Only a couple of days ago, on January 27, the 233rd spacewalk took place.

In Focus: Scott Kelly's Year In Space
(Photo : NASA via Getty Images)
IN SPACE - DECEMBER 21: In this handout photo provided by NASA, NASA astronaut Scott Kelly is seen floating during a spacewalk on December 21, 2015 in space. NASA astronauts Scott Kelly and Tim Kopra released brake handles on crew equipment carts on either side of the space stations mobile transporter rail car so it could be latched in place ahead of Wednesdays docking of a Russian cargo resupply spacecraft. Kelly and Kopra also tackled several get-ahead tasks during their three hour, 16 minute spacewalk.

NASA cosmonauts Victor Glover and NASA astronaut Mike Hopkins worked out this spacewalk. This was the second spacewalk by Glover and the fourth spacewalk by Hopkin.

NASA astronaut Kate Rubins and Japan Aerospace Exploration Agency (JAXA) astronaut Soichi Noguchi, and NASA astronaut Bob Hines, supported the two guys and relayed the next moves from the field to the spacewalkers.

What's So Special With The Spacewalk?

The cosmonauts equipped the space station is with 24 lithium-ion batteries to hold the electricity the solar panels produce.

The massive, boxy batteries, each exceeding 180 kilograms, supply the orbital lab with electricity while it's on Earth's night side.

They are so strong that they require just half the amount of existing nickel-hydrogen batteries they have replaced.

After one of the latest batteries died, the replacement lasted longer than planned since it was mounted two years earlier and had to be fixed.

In total, to complete the battery work, 14 spacewalks were needed.

NASA hopes that these batteries will last for the remainder of the operational existence of the space station.

In addition to battery function, Mr. Hopkins and Mr. Glover mounted a new camera outside the station's Japanese lab, called Kibo, or Hope in English, in the US Destiny lab and removed parts of the camera device.

During a spacewalk last Wednesday, the two cosmonauts made upgrades to the European lab, Columbus.

NASA will perform two further in around a month to prepare for more solar panels scheduled for launch later this year.

ALSO READ: NASA To Upgrade ISS This Year as Solar Arrays Continue to Degrade

Why Change The Battery When It's Solar-Powered?

Currently, the latest spacewalk is a wrap-up of some prior testing outside the space station that was being performed. The long-term aim is to substitute specific aging and unreliable battery packs with modern ones that carry more capacity and are more effective overall. That might sound straightforward, but these battery packs are very big, and the process of removal and installation is certainly a challenge.

Battery work started several months ago, with several spacewalks scheduled to eventually upgrade the latest, more powerful versions with lithium-ion batteries.

According to BGR, any journeys beyond the space station culminated in more work being completed than was expected, which is always the case for spacewalks. Others were often short, eventually forcing subsequent spacewalks to make up for the missed time.

As long as NASA and other space agencies see the benefit in any event, the battery replacement work would eventually help the space station keep up and working.

You might be asking yourself why, because it is solar-driven, the space station requires batteries at all. That's a fair point, and you're right. Whenever it's in direct sunshine, the ISS absorbs a lot of strength from the Sun.

However, since the space station orbits the Earth several times a day, it frequently slips into the shadow of the Earth, and the ISS will essentially shut down without a steady supply of electricity from the Sun if it had no batteries to hold excess power for usage when the solar panels fell into the shadow.

ALSO READ: International Space Station Deals With Busted Toilet as Astronauts Head Home

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