Nasa astronauts make all-women spacewalk

Two Nasa astronauts are making the first all-female spacewalk.

After suiting up, Christina Koch and Jessica Meir exited the International Space Station's Quest airlock to replace a failed power control unit.

The astronauts will have to venture to one end of the ISS. Once there, they will then spend five and a half hours replacing the power regulator with a spare, BBC News reports.

There have been 13 female spacewalkers, including Koch.

She has already carried out two extra-vehicular activities (EVAs) at the space station this year. Jessica Meir is set to become the 14th.

Koch and Meir stepped outside in their Nasa spacesuits at 11:38 GMT (07:38 EDT).

They are making their way to a location called the Port 6 truss structure. Once here, they will have to replace the device, known as a battery charge-discharge unit (BCDU).

Once this task is complete, Koch and Meir will return to the airlock with the failed BCDU. The device will subsequently be loaded on to the next SpaceX Dragon resupply ship for inspection on Earth.

In March this year, Nasa announced that Koch would take part in the first all-female EVA with colleague Anne McClain.