Expedition 73 Flight Engineers Anne McClain and Nichole Ayers are scheduled to leave the ISS at 8 a.m. EDT, according to NASA. NASA will begin live coverage at 6:30 a.m. on NASA+.

They would be the fifth all-female walk in NASA history and the first this year. The 275th spacewalk is "in support of space station assembly, maintenance and upgrades," according to NASA.

It will be the third spacewalk for McClain, 45, and the first for Ayers, 36.

They plan to install a mounting bracket before additional panels are put in place later this year when a SpaceX Dragon performs a resupply mission.

The panels are lightweight power sources that provide more energy than traditional solar arrays and weigh a lot less.

They will increase by 30% total available power from 160 kilowatts to up to 215 kilowatts.

The antenna will be moved a foot and a half to "clear one of the antennas from structural blockage," Diana Trujillo, spacewalk flight director, said at a news conference last week.

The antenna allows ISS to communicate with arriving spacecraft.

There are seven aboard the ISS.

Commander Takuya Onishi of the Japan Aerospace Exploration Agency and NASA Flight Engineer Jonny Kim will assist them getting in and out of their spacesuits. Kim is a trained medical doctor.

Also aboard the ISS are three cosmonauts from Russia: flight engineers Sergey Ryzhikov, Alexey Zubritsky, Kirill Peskov.

For several hours, the spacealkers will breathe pure oxygen for several hours to get rid of nitrogen in their bodies. They will be tethered to the ISS.

Kim also photographed tomato plants growing for a space agriculture experiment. They are studying if crops can grow without photosynthesis in microgravity, possibly increasing plant cultivation on Earth and in space.

On Tuesday, the Expedition 73 crew learned how to manufacture nanomaterials, which can possibly lead to new therapeutics, vaccines and regenerative medicine.

McClain and Kim were inside the Kibo laboratory module mixing solutions to create DNA-like nanomaterials. The samples will be analyzed using an electromagnetic light tool and will be returned to Earth for further examination.

Kim later partnered with Ryzhikov and Zubritsky for vein scans inside the Columbus laboratory module. Onishi operated the Ultrasound 2 device so doctors on the ground could look at the crew's neck, shoulder and leg veins.

In November, the ISS will mark 25 years of astronauts onboard. The ISS since Nov. 2, 2000, has never been unmanned.

Related Links
Space Tourism, Space Transport and Space Exploration News