ISS crew members
Crew members of the International Space Station (ISS) expedition 50/51 Peggy Whitson (L) of the US, Oleg Novitsky of Russia (C) and Thomas Pesquet of France pose for a picture behind a glass wall during a news conference before their launch to the ISS scheduled on November 17, at the Baikonur cosmodrome in Kazakhstan, November 16, 2016. Reuters/Shamil Zhumatov

NASA astronauts are bracing to carry out the remaining two of three scheduled spacewalks outside the International Space Station (ISS) before end of March and early April. Since the start of the year, they have been busy upgrading station hardware and preparing for the arrival of the US commercial crew spacecraft’s arrival.

To date, only Russia’s Soyuz spacecraft can dock to transport people to the ISS. Commercial aircrafts including SpaceX’s Dragon must be grabbed by a robotic arm and berthed to offload cargo.

The space station is regarded as an international human experiment consisting of the collaboration of 15 nations aiming to create a world-class, state-of-the-art orbiting research facility. ISS activities have held the attention of space tech-savvy individuals since the NASA astronauts set out on the preliminary phase of their mission.

Spacewalkers Thomas Pesquet and Shane Kimbrough (who is also Expedition 50 commander) ventured out in space to conduct inspections, upgraded the space station's computing capabilities, and prepared for the installation of the new docking port. Pesquet and Kimbrough recently wrapped up their first successful spacewalk.

Time-lapse videos continue to be shown in leading social media sites. Many people witnessed the robotic removal of the Pressurized Mating Adapter-3 from the Tranquility module and its attachment to the Harmony module. Some netizens exclaimed that it was a cool opportunity to witness such historic events online. Some wrote on Facebook that it was exciting to view the unfolding events real-time.

The first conducted spacewalk prepared the Pressurized Mating Adapter-3 (PMA-3) for installation of the second International Docking Adapter to accommodate commercial crew vehicle dockings, NASA said in its media advisory.

The next spacewalk will have NASA Flight Engineer Peggy Whitson Kimbrough undertaking the reconnection of cables and electrical connections on PMA-3 at its new home on top Harmony. They will also handle the installation of the second of the two upgraded computer relay boxes on the station’s truss, among other key tasks.

The final spacewalk will have Whitson and Pesquet handling the replacement of an avionics box on the starboard truss called an ExPRESS Logistics Carrier. It is a storage platform that contains electrical and command as well as data routing equipment for the science experiments and replacement hardware in storage outside of the station.

Numerous spacewalks have been carried out before. The three slated this year marks the 198th, 199th and 200th spacewalks necessary for space station assembly and maintenance. An enthralled public is seeing how meticulous NASA astronauts work can be.