NASA Astronauts will perform a 6.5-hour spacewalk outside the International Space Station (ISS) today, to install a new docking mechanism for greater visitor access.

The International Docking Adapter, or IDA, will end NASA’s reliance on the Russian Soyuz spacecraft to ferry astronauts to and from the ISS, and will receive future manned missions from Boeing and SpaceX in 2017 and 2018.

Launched to the ISS back in July by one of SpaceX’s Falcon 9 rockets, the IDA is a large metal ring with a 160 cm diameter (63 inches).

It's being 'unboxed' by the station’s Canadarm2 robot, and will then be connected to the port on the ISS’s Harmony model by NASA astronauts Jeff Williams and Kate Rubins from around 8:05am ET (10pm AEST) today.

You can see them checking out their spacesuits in the picture at the top of the page.

"[W]e’re very excited to get that milestone checked and get to the point where we can have crews launch from different places around Earth and servicing the station," Kenny Todd, NASA space station operations manager at the Johnson Space Centre in Houston, told CBS News.

As Loren Grush reports for The Verge, this is not the first IDA to have been launched to the ISS, but it’s the only one that's actually made it.

"This is the second IDA to be sent to space, though the first one never actually made it to orbit; it was destroyed when the SpaceX Falcon 9 rocket carrying it to the ISS disintegrated during launch in June 2015," she reports.

Installing new IDAs on the ISS is a crucial part of NASA’s Commercial Crew Program - recently initiated by the space agency to ensure that private companies, like SpaceX and Boeing, can easily taxi cargo and crew to and from the ISS in the future.

And that’s super exciting, because if anything can establish once and for all that we’ve truly entered a new era of space exploration, it’s the fact that private companies are willing to fork over millions of dollars to get humans beyond the bounds of Earth’s orbit, and NASA is taking real steps to help them do it.

One of the most immediate benefits of having this new IDA installed is that it will allow more astronauts to be ferried to the ISS than ever before - something that will be a huge help to those conducting research and experiments onboard the facility.

"Along with giving NASA and partner astronauts independent access to the space station, the new commercial ferry ships will carry four crew members to the station per flight compared to the three-seat Soyuz," William Harwood reports for CBC News.

"That will allow NASA to boost the station’s crew from six to seven, greatly expanding the time available for research," he adds.

"If you look today at the way the increments play out, a lot of times we’ll be running a little short on crew time," Todd told him. "That tends to be our pinch point sometimes, relative to some of the research we’re doing. So having an extra ... crew member is going to be very important for us."

Today's spacewalk will be Jeff Williams’ fourth, and Kate Rubins’ first, and they will be assisted by Japanese astronaut Takuya Onishi, who will help from inside the ISS, and Tom Marshburn, a veteran spacewalker who will be communicating with them from mission control in Houston.

We wish the team the best of luck, and hope you guys enjoy watching it live below: