Two astronauts are heading into space today: When and where to watch the ISS spacewalk live

Two astronauts are set to step outside the International Space Station (ISS) today, August 18, for a challenging spacewalk to replace a key communications antenna. NASA astronaut Anil Menon and European Space Agency (ESA) astronaut Sophie Adenot will spend around six-and-a-half hours working in the vacuum of space.

The spacewalk will be streamed live for free, giving viewers a chance to watch the astronauts carry out the delicate repair work outside the orbital outpost.

When and where to watch the ISS spacewalk live

The live stream will begin at 6:05 PM Indian Standard Time (IST), corresponding to 8:35 AM EDT.

The spacewalk can be watched for free on NASA TV through NASA's official website and on NASA's official YouTube channel. The live event link is embedded below.

What will Anil Menon and Sophie Adenot do outside the ISS?

The main task is to replace the Space-to-Ground Antenna (SGANT) mounted on the station's Z1 truss segment.

SGANT is a high-speed data and communications antenna used by NASA to support communication between the ISS crew and mission control on the ground in Houston. The astronauts will disconnect the existing antenna and replace it with a spare stored on an external stowage platform.

The job will then involve making the required electrical and data connections so the replacement antenna can be activated.

The work is expected to be particularly delicate because the astronauts will be handling the equipment while outside the space station, exposed to the vacuum of space.

How will the astronauts carry out the spacewalk?

The two astronauts will have different roles during the operation.

Anil Menon will ride the Canadarm2 robotic arm, which will be operated from inside the ISS. ESA astronaut Sophie Adenot will remain tethered to the space station as she works outside.

Inside the station, NASA astronauts Jessica Meir, the station commander, and Jack Hathaway, the flight engineer, will operate Canadarm2 and monitor the spacewalkers.

The planned activity is expected to last approximately six-and-a-half hours and will become the 97th American spacewalk in history.

What is a spacewalk?

A spacewalk is when an astronaut leaves a spacecraft or space station to work outside while in space. NASA also refers to it as an extravehicular activity, or EVA.

Astronauts wear specially designed spacesuits during EVAs. The suits provide the oxygen astronauts need to breathe and the water they need to drink while they work outside the spacecraft.

Spacewalks can be used for a range of tasks, including repairing spacecraft, testing equipment and conducting experiments. Experiments can also be placed outside spacecraft to study how different materials and systems respond to the space environment.

Spacewalks allow astronauts to repair equipment in orbit rather than bringing it back to Earth.

From the first spacewalk to today's ISS missions

The first human spacewalk was carried out by Alexei Leonov on March 18, 1965. His historic spacewalk lasted about 10 minutes.

Spacewalks today are far longer. At the International Space Station, they typically last between five and eight hours, depending on the work astronauts need to complete.

The record for the most spacewalks is held by Russian astronaut Anatoly Solovyev, who has completed 16 spacewalks, spending more than 82 hours outside in space, as reported by NASA.

For Menon and Adenot, today's mission will mean spending hours outside the ISS as they work on a communications system that plays an important role in keeping the station connected with mission control.