All four astronauts in the Polaris Dawn spacecraft will be in the vacuum of space during the spacewalk.

Talk about a daring, privately funded space mission. Polaris Dawn The crew members will don newly designed spacesuits 435 miles above Earth, then open the hatch of their SpaceX Dragon capsule — which has no air chamber, leaving them all exposed to the vacuum of space during the pioneering spacewalk.

Or as mission commander Jared Isaacman put it, you give up the safety of your spacecraft — and “your suit becomes your spaceship.”

“They had never experienced these suits in space before. The exposure of everyone to the space environment was reminiscent of the early days of the Gemini missions,” said Don Platt, director of Harvard University’s space program. Florida Institute of Technology Spaceport Learning Center In Titusville.

“When they did the spacewalk, they opened the hatch of the Gemini capsule. One crew member stayed seated and was probably strapped in, so he wouldn’t float away — you don’t want both of them in space. Then the other one would stick his head out and try to move around a little bit in space,” Platt said.

Cape Canaveral: Is there a launch today? SpaceX and NASA’s upcoming launch schedule from Florida

“It happened so early on, nobody even realized that you needed things like handrails to hold on to. Otherwise you have no leverage at all in a zero-gravity environment,” he said.

The unique Polaris Dawn mission is scheduled to lift off at 3:38 a.m. EST Tuesday aboard a SpaceX Falcon 9 rocket from Pad 39A at NASA’s Kennedy Space Center. Backup launches are available at 5:23 a.m. and 7:09 a.m. Tuesday, if needed. FLORIDA TODAY’s space team will provide live coverage beginning about four hours before liftoff at floridatoday.com/space.

“The Polaris launch has been delayed for over a year already because of all the complexities of the incredible technological issues that had to be resolved to get to this point where we are fully ready to go — at the mercy of the weather, as always,” said Emmanuel Urquieta, vice chair of the Department of Aerospace Medicine at the University of Central Florida.

“But I think it will be a very historic mission,” Urquita said.

First spacewalk attempt from Dragon capsule

The nearly five-day Polaris Dawn orbital flight promises to “usher in a new era of commercial space exploration,” and will include the world’s first all-civilian spacewalk using SpaceX’s first-generation spacesuits. The crew will be the first to spacewalk from a Dragon capsule — and the spacewalk will be livestreamed.

The Polaris Dawn crew consists of Isaacman; pilot Scott “Kid” Poteet, a retired U.S. Air Force lieutenant colonel who flew F-16 Fighting Falcons; and two SpaceX senior space operations engineers: mission specialist/medical officer Anna Menon and mission specialist Sarah Gillis.

The spacewalk is scheduled to take about two hours from venting the Dragon to re-pressurizing the capsule, Isaacman said. Two astronauts are scheduled to spend 15 to 20 minutes each outside the spacecraft.

“We’re going to completely de-air the vehicle. There’s no air chamber on Dragon. That means all four crew members are exposed to the vacuum of space,” Isaacman told media during a Monday briefing at NASA’s Kennedy Space Center.

“Two will stay inside the vehicle,” Isaacman said. “And two will emerge, in turn, from the vehicle. And when we’re there, we’ll use different mobility aids that the SpaceX team has designed — it’ll be like we’re doing a little dance. That means we’re going through a series of array tests on the suit.”

“The idea is to learn as much as we can about this suit and feed it back to the engineers to inform future suit design developments,” he added.

Why the late-night launch? Isaacman said the SpaceX crew chose the time to help mitigate the risks posed by micrometeoroids and orbital debris. Even paint flecks just 1 centimeter in size can hit with tremendous force at orbital speeds averaging 22,000 mph, NASA reports.

“For the spacewalk itself, we will orient the vehicle in a way that protects the crew,” Gillis told media during Monday’s briefing.

He described spacewalking as a “risky adventure.”

Crew members expressed confidence in the groundbreaking spacewalk during Monday’s media event, pointing to their training and the work of SpaceX engineers. Isaacman said engineers conducted a series of “crazy reviews” and risk briefings across a range of mission parameters.

“It’s a risky venture to go outside,” said Bill Gerstenmaier, SpaceX’s vice president of construction and flight reliability. “But again, we did all the preparation. We did the capsule testing. We did the suit testing. We did the hyperbaric chambers. We did all the work to really prepare for this.” Gerstenmaier was previously NASA’s assistant administrator for human exploration and operations.

“You know, we built on the legacy of NASA,” Gerstenmaier said. “But I think we also extended the legacy of NASA a little bit further.”

SpaceX crews have upgraded Dragon’s life support system to provide oxygen to all four astronauts during spacewalks, Gillis said. Before the spacewalk, she said the capsule will slowly depressurize to pull nitrogen from the astronauts’ bodies and reduce the risk of decompression sickness. Crew members practiced wearing oxygen masks during a two-day simulation inside a vacuum chamber in NASA Johnson Space Center.

“It’s an interesting mission. I think it’s cool that we’re doing these things and trying to push the boundaries here. There’s been talk about SpaceX and the Polaris program trying to convince NASA to let them repair the Hubble Space Telescope, which would be a really interesting event for a future mission,” Platt said.

“I don’t know if NASA would agree with that. But they’re really looking beyond the everyday stuff — they’re not just going into space to take some pictures and say, ‘Hey, I’m in space.’ They’re actually trying to do something useful. So I applaud them for doing that.”

Polaris Dawn Orbiter Flight Schedule

Day 1: Launch, then pass through the interior of Van Allen radiation belt on Earth To an altitude of 1,400 kilometers above the Earth’s surface. This is the highest altitude astronauts have reached since Apollo 17, the last mission to the moon, in December 1972.
Day 2: Preparing for a spacewalk during the appropriate “motion demonstration”; descending to a cruising orbit at an altitude of 700 km.
Day 3: Put on spacesuits, perform leak checks and spacewalk.
Day 4: Test A Starlink Laser based communication system.
Day 5: Preparing to re-enter the atmosphere.
Day 6: Re-enter Earth’s atmosphere and land at one of seven locations off the coast of Florida in the Gulf of Mexico or the Atlantic Ocean.