Astronauts to journey farther from Earth than any mission since Apollo 17

Four people are about to blast off on a private SpaceX mission, called Polaris Dawn, and travel more than three times farther away from the Earth than the International Space Station.

Four people are about to embark on a journey that will take them farther from Earth than anyone has traveled since 1972 when Apollo 17 astronauts landed on the moon.

Polaris Dawn, a private SpaceX mission, will send a crew of four on a high-flying journey around the Earth, much different from any mission launched in the past 50 years. Liftoff is set for between 3:38 a.m. EDT and 7:09 a.m. EDT on Tuesday.

Groundbreaking mission to include a spacewalk

When NASA sends astronauts to the International Space Station, they orbit the Earth approximately 250 miles above the planet's surface. In contrast, the Polaris Dawn mission will travel more than three times that distance, reaching an altitude of 870 miles from the planet's surface.

The crew will also conduct a spacewalk, the first time civilian astronauts have traveled outside of a spacecraft in the history of human spaceflight.

"This will be the first human spaceflight for Mission Pilot Kidd Poteet, Mission Specialist Sarah Gillis, and Mission Specialist and Medical Officer Anna Menon. Mission Commander Jared Isaacman previously flew to space as commander of Inspiration4," SpaceX said on its website.

During the five-day mission, the four will conduct dozens of experiments focused on human health, long-duration spaceflight and communication with Starlink satellites, which are operated by SpaceX.

"This will also be the first time two SpaceX employees will be part of a human spaceflight crew, providing valuable insight to future missions on the road to making life multiplanetary," SpaceX said.