Ahead of SpaceX spacewalk, Polaris Dawn astronauts venture the furthest since Apollo 17

The SpaceX Polaris Dawn crew made it further from Earth than any astronauts have been in 52 years.

Blasting off early Tuesday on a mission that is a first of its kind, the crew's Dragon spacecraft traveled higher than any human-rated spacecraft since the NASA Apollo 17 mission in 1972.

By the end of the first day in space, the spacecraft's 16 Draco thrusters boosted the spacecraft to a height of 1,400.7 km or 870.35 miles. According to NASA , the International Space Station orbits at approximately 250 miles above the Earth, and the furthest humans have ventured since Apollo 17 had been to the Hubble Space Telescope, which orbits at approximately 320 miles.

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When is the Polaris Dawn spacewalk?

The mission is not stopping there. The next record the Polaris Dawn crew hopes to break: the first spacewalk by private astronauts. That spacewalk is set to begin at 2:23 a.m. Thursday morning. Go to floridatoday.com/space for the latest.

The FLORIDA TODAY Space Team will provide live updates beginning 90 minutes prior to the spacewalk. Live video coverage by SpaceX will be streamed one hour prior to the spacewalk.

On Wednesday, the spacecraft was lowering back down in altitude to prepare for the spacewalk

What is planned for the SpaceX Polaris Dawn spacewalk?

Historically, the only humans who have suited up and ventured outside the safety of their spacecraft have been NASA astronauts and Russia's cosmonauts. And it's always been a spacesuit regulated by a government space agency. This time it is all being done by SpaceX: they created and tested the spacesuits and are overseeing the spacewalk, which will be unusual itself.

When it nears time, the entire four-person crew will suit up and open the Dragon spacecraft's hatch. Unlike the space station or space shuttle, Dragon is not equipped with an airlock. Once the Dragon is unpressurized, all four crew members will be relying solely on their SpaceX EVA (extravehicular activity) suits to keep them alive in the vacuum of space.

Just after launching Tuesday morning, the crew began preparations for the spacewalk with a two-day pre-breathe protocol. What is happening is the air pressure in the Dragon will slowly decrease while the oxygen levels increase. The increase in oxygen will assist in removing nitrogen from the crew's bloodstream. This is because the pressure difference when they suit up and open the hatch puts them at risk for decompression sickness.

Once safely underway, mission commander Jared Isaacman will venture out of the Dragon while holding onto the skywalker structure attached to the spacecraft. While the exact timing has not yet been released, at some point fellow crew member Sarah Gillis will follow. Gillis works as an astronaut trainer at SpaceX, and will be gathering valuable experience to train future astronauts, SpaceX officials have said. Astronauts Anna Menon and Scott Poteet will remain inside the Dragon spacecraft.

SpaceX launch of AT&T Bluebird satellites

This is not the only SpaceX activity planned for Thursday morning. Early risers may catch the launch of the first five direct to cell satellites for AST, in collaboration with AT&T, known as Bluebirds. The Bluebird satellites will be launched atop of a SpaceX Falcon 9 from Cape Canaveral Space Launch Complex 40 no earlier than 4:52 a.m. Thursday morning. Check floridatoday.com/space for updates.

FLORIDA TODAY live updates will begin 90 minutes prior to launch.

Brooke Edwards is a Space Reporter for Florida Today. Contact her at bedwards@floridatoday.com or on X: @brookeofstars .

This article originally appeared on Florida Today: Ahead of SpaceX spacewalk, Polaris Dawn astronauts venture the furthest since Apollo 17