'A risky adventure': All 4 Polaris Dawn astronauts will be in vacuum during spacewalk

Update: SpaceX has postponed the Polaris Dawn launch target time 24 hours — to 3:38 a.m. Wednesday — while crews work on a groundside helium leak.

Original story: Talk about a daring privately funded space mission. All four Polaris Dawn crew members will put on newly designed spacesuits 435 miles above Earth, then open the hatch of their SpaceX Dragon capsule — which doesn't have an airlock, making them all vulnerable to the vacuum of space during a pioneering spacewalk.

Or as mission commander Jared Isaacman described it, you're throwing away the safety of your vehicle — and "your suit becomes your spaceship."

"They've never really tested these suits in space before. And having everybody exposed to the space environment is kind of reminiscent of the early days, the Gemini missions," said Don Platt, director of the Florida Institute of Technology's Spaceport Education Center in Titusville.

"When they did their spacewalks, they just basically opened the door of the Gemini capsule. One crew member remained seated and probably seat-belted, so he wouldn't float away — you don't want both of them out there. And then the other one would stick his head out and try to move around a little bit out there," Platt said.

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"That was very early on, and nobody even realized that you needed things like handrails to hold onto. Otherwise, you're not going to really have any leverage at all out there in the microgravity environment," he said.

The unique Polaris Dawn mission is scheduled to launch at 3:38 a.m. EDT Tuesday aboard a SpaceX Falcon 9 rocket from pad 39A at NASA's Kennedy Space Center. If needed, backup launch opportunities are available at 5:23 a.m. and 7:09 a.m. Tuesday as well. FLORIDA TODAY's Space Team will provide live coverage starting about four hours before liftoff at floridatoday.com/space.

"Polaris has already been delayed more than a year because of all the complexities of really incredible technological issues that had to be solved to bring us to this point, where we're pretty much ready to go — at the mercy of the weather, like always," said Emanuel Urquieta, vice chair of aerospace medicine at the University of Central Florida.

"But i think it's going to be a very historical mission," Urquieta said.

First spacewalk attempt from a Dragon capsule

Promising to "usher in a new era of commercial space exploration," the roughly five-day Polaris Dawn orbital flight will feature the world's first all-civilian spacewalk using SpaceX-designed, first-generation EVA (Extravehicular Activity) spacesuits. This crew will become the first to perform a spacewalk from a Dragon capsule — and the spacewalk will be livestreamed.

Polaris Dawn crew members are Isaacman; pilot Scott "Kidd" Poteet, a retired U.S. Air Force lieutenant colonel who flew F-16 Fighting Falcons; and two SpaceX lead space operations engineers: mission specialist/medical officer Anna Menon and mission specialist Sarah Gillis.

The spacewalk operation should take about two hours from venting the Dragon to re-pressurizing the capsule, Isaacman said. Two spacewalkers would each spend 15 to 20 minutes outside the spacecraft.

"We are going to vent the vehicle entirely down to vacuum. There is no airlock 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 remain inside the vehicle. And two, in sequence, will go outside the vehicle. When we are out there, we're going to make use of various mobility aids the SpaceX team has engineered — and it'll look like we're doing a little bit of a dance. And what that is is, we're going through a series of test matrix on the suit," Isaacman said.

"And the idea is to learn as much as we possibly can about this suit and get it back to the engineers to inform future suit design evolutions," he said.

Why launch so late at night? Isaacman said SpaceX crews selected the window to help mitigate risks posed by micrometeoroids and orbital debris. Even paint flecks measuring just 1 cm can strike with tremendous force at orbiting speeds averaging 22,000 mph, NASA reports.

"For the spacewalk itself, we'll be orienting the vehicle in a way that shields the crew members," Gillis told media during Monday's briefing.

Spacewalk labeled 'a risky adventure'

Crew members expressed confidence about the groundbreaking spacewalk during Monday's media event, citing their training and the work of SpaceX engineers. Isaacman said the latter conducted a series of "paranoia reviews" and risk briefings across an array of mission parameters.

"EVA is a risky adventure. But again, we've done 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 get ready for this," said Bill Gerstenmaier, SpaceX vice president of build and flight reliability. He was formerly NASA's associate administrator for Human Exploration and Operations.

"You know, we kind of built off of what NASA's heritage was. But I think we've also extended NASA's heritage a little bit further," Gerstenmaier said.

Gillis said SpaceX crews upgraded the Dragon life-support system to supply oxygen to all four astronauts during the spacewalk. Prior to 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 trained by wearing oxygen masks during a two-day simulation inside a vacuum chamber at NASA's Johnson Space Center.

"Interesting mission. I think it's great that we're doing these things and kind of pushing the envelope here. There's been talk about SpaceX and this Polaris Program trying to convince NASA to allow them to go repair the Hubble space telescope, which would be really quite an intriguing event, for a future mission," Platt said.

"I don't know if NASA's going to buy into that one. But they're really looking outside the bounds of everyday activities — they're not just going up to take a few pictures and say, 'Hey, I'm in space.' They're actually trying to do something that's productive. So, kudos to them for doing that," he said.

Polaris Dawn on-orbit schedule

• Day 1: Launch, then pass through the inner regions of Earth's Van Allen radiation belt to 1,400 km above the surface. That represents the highest altitude astronauts have reached since Apollo 17, the final moon mission, back in December 1972.

• Day 2: Prepare for spacewalk during a suited "mobility demo;" descend to a 700-km cruising orbit.

• Day 3: Don spacesuits, perform leak checks and conduct spacewalk.

• Day 4: Test a Starlink laser-based communication system.

• Day 5: Prepare for atmospheric reentry.

• Day 6: Reenter Earth's atmosphere and splash down at one of seven sites off the Florida coast in the Gulf of Mexico or Atlantic Ocean.

For the latest news and launch schedule from Cape Canaveral Space Force Station and NASA's Kennedy Space Center, visit floridatoday.com/space.

Rick Neale is a Space Reporter at FLORIDA TODAY. Contact Neale at [email protected]. Twitter/X: @RickNeale1

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This article originally appeared on Florida Today: All 4 Polaris Dawn astronauts to be in vacuum of space during spacewalk