SpaceX launches Polaris Dawn, which will take astronauts further than any human in more than 50 years

A SpaceX Falcon 9 launched in the early hours of Tuesday morning with a crew on board that will attempt the first commercial spacewalk and fly higher than any manned mission in 50 years.

The Polaris Dawn mission launched from NASA's Kennedy Space Center at 5:23 a.m. EST after several weather-related delays. Near the end of the first day of the mission, the orbit of the SpaceX Crew Dragon capsule will reach an apogee of 1,400 kilometers (870 miles). This will be the highest altitude humans have reached since the Apollo 17 mission to the moon in 1972, and three times higher than the International Space Station.

The four-person crew will fly through the high-energy Van Allen Belt, where radiation levels are much higher than at lower altitudes. During this phase of the mission, they will conduct research to better understand the effects of radiation on the human body.

“We can learn a lot from [that environment] in terms of human health science and research,” mission leader Jared Isaacman said at a press conference last month. “If we get to Mars one day, we would like to come back healthy enough to tell people about it. So I think it's worth having some presence in that environment.”

The crew includes billionaire entrepreneur Isaacman, founder of Shift4 Payments, mission pilot Scott “Kidd” Poteet, a retired U.S. Air Force lieutenant colonel, and two SpaceX employees: mission specialist Sarah Gillis, an engineer and astronaut trainer, and mission specialist Anna Menon, a medical director who also runs mission control during SpaceX flights.

On the third day of the five-day mission, the crew will lower the Dragon's altitude to about 430 miles (700 kilometers). They will then attempt the first spacewalk without government astronauts. All four will don spacesuits and open the spacecraft's hatch, although only two crew members, Isaacman and Gillis, will exit the Dragon. They will take turns diving into the vacuum of space for about 15 to 20 minutes while tethered to the capsule by umbilical cords.

The crew will don new SpaceX spacesuits that will be tested for the first time. SpaceX has also made a number of modifications to Dragon, such as handholds around the hatch to facilitate mobility during the spacewalk. These handholds are crucial because Isaacman and Gillis do not plan to float freely, but will hold on to Dragon throughout the walk. The entire operation, from venting to depressurization, will take about two hours.

Given SpaceX's long-term ambitions to establish a human colony on Mars, the suits are particularly exciting because hundreds or thousands of people could wear similar suits in the future.

This mission is a partnership between Isaacman and SpaceX. Neither party has ever disclosed the cost of the flight or how much Isaacman is paying for the flight, but it provides SpaceX a welcome opportunity to test its technology in orbit. In addition to the suits, the crew will also test communications between the Dragon and SpaceX's Starlink constellation, which would enable Wi-Fi in the capsule, an important technology that could enable reliable crew communications on future missions to the Moon or Mars.

This will be the first of three missions in Isaacman's Polaris program, with the third scheduled to be the first manned launch of SpaceX's spacecraft. He first traveled to space three years ago on the private astronaut mission Inspiration4, which also launched with SpaceX.

Shortly after the launch, Isaacman thanked the company: “Without all 14,000 of you at SpaceX, we would not be embarking on this journey,” he said.

After five days in orbit, the crew will return to Earth and splash down off the coast of Florida.