In the early-morning hours of August 27, the four-person crew of the Polaris Dawn mission is set to launch into an ultrahigh orbit—and into history books—from NASA’s Kennedy Space Center.
Despite the U.S. space agency playing host, none of the crew are from its astronaut corps. And the private aerospace company SpaceX is providing the mission’s Falcon 9 rocket and Crew Dragon spacecraft—as well as new spacesuits, operational protocols and upgraded life-support systems. All of these innovations will be put to the test in a daring bout of extravehicular activity (EVA), more commonly called a space walk, that will be the first ever for a commercial mission. During the five-day flight, the spacecraft will reach altitudes as high as 1,400 kilometers—surpassed only by moon-bound Apollo astronauts in the 1960s and 1970s—and the crew will conduct nearly 40 science experiments, as well as laser communications tests with SpaceX Starlink satellites.
Bankrolled and led by its mission commander, billionaire Jared Isaacman, Polaris Dawn is by far the most ambitious commercial spaceflight mission yet attempted. If it succeeds, it’s likely to prove to be just a preview of greater feats to come.
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Polaris Dawn is only the first of three crewed flights Isaacman has purchased from SpaceX for an undisclosed sum as part of his Polaris program. He has made no secret of his hopes that the second, also slated for a Falcon 9 and a Dragon, could visit NASA’s Hubble Space Telescope to boost the observatory into a higher orbit and refurbish some of its aging components during another space walk (though the agency has not taken him up on the offer). A third Polaris flight would eventually take place on SpaceX’s Starship vehicle but only after that in-development spacecraft has been demonstrated as safe via a large number of test and cargo flights.
Starship “could very well be the [Boeing] 737 for human spaceflight someday,” said Isaacman in a briefing at Kennedy Space Center a week before the planned launch. “But it’ll certainly be the vehicle that will return humans to the moon and then on to Mars and beyond.” One key driver of the Polaris program, Isaacman said, is the need to prepare for that possible future by advancing the state of the art in EVA spacesuits and protocols. “You know, there’s going to be an armada of Starships arriving on Mars at some point in the future,” he said, “and those people are going to have to be able to get out of it and walk around and do important things.”
The Polaris Dawn mission will not be Isaacman’s first foray into space—he previously paid for and flew with three other civilians on another SpaceX mission, Inspiration4, which, in the run-up to its 2021 launch, helped raise more than $250 million for St. Jude Children’s Research Hospital. (Polaris Dawn is raising money for the same cause, Isaacman says.) His Polaris Dawn crewmates are former Air Force fighter jet jockey Scott “Kidd” Poteet (the mission’s pilot), as well as two SpaceX engineers, Sarah Gillis (mission specialist) and Anna Menon (mission specialist and medical officer). Together, they’ve invested some two and a half years training for this fateful, high-frontier foray—from taking part in endurance-building scuba dives, mountain climbs and zero-g jet flights to spending thousands of hours in simulators sweating the details of the mission’s operations and possible emergencies (most of them related to the planned space walk).
“I can tell you, without a doubt, this has been some of the most challenging training that I’ve ever experienced,” Poteet said during the briefing. “It’s been an awesome journey preparing for this mission, and it also took … an entire organization—14,000 [SpaceX] employees—and some of the brightest and smartest engineers I’ve ever met have been a part of this.”
“We are truly ready to go fly,” said Bill Gerstenmaier, vice president of build and flight reliability at SpaceX and former head of NASA’s human spaceflight program, during the briefing. “SpaceX and the teams and the crew … are continuing to push the envelope of what it takes to go the moon and Mars…. EVA is a risky adventure, but again, we’ve done all the preparation.”
Five Days of Firsts
Polaris Dawn’s liftoff is set to occur in one of three launch windows between 3:30 and 7 A.M. EDT. Each window was chosen by SpaceX to minimize the risks of the Dragon craft hitting space debris on its way to an ultrahigh orbit.
The mission’s technical high point will come early: On its first day the Falcon 9 rocket will deliver the Dragon into an initial orbit with an apogee located 1,200 km above Earth’s surface. Shortly thereafter, the Dragon will fire its engines to raise this apogee to 1,400 km. At such heights, the spacecraft will be within the inner part of our planet’s hazardous Van Allen radiation belt, and the vehicle will orient itself to act as a shield, minimizing the crew’s exposure. This will be the farthest from Earth anyone has ventured since the all-male crew of Apollo 17 in 1972, and it will set a record for the highest flight of any woman in history.
Around 10 hours after reaching its initial orbit, the Dragon will fire its engines again, lowering its apogee to 700 km—the vicinity in which its spacewalk will occur on the mission’s third day. Day two will mostly be spent in preparation for that space walk, although one of the most essential and experimental preliminary steps will have begun just an hour after launch. This step, which Gillis and others have called a “prebreathe protocol,” will involve gradually lowering the air pressure and increasing the concentration of oxygen inside the crew cabin. It’s intended to help the crew adapt for the nerve-racking feats to come.
Because Dragon has no airlock, performing day three’s spacewalk will require the crew to don SpaceX’s new spacesuits, which include an oxygen-supplying umbilical—and then to purge all the air from the cabin for the EVA’s duration. The prebreathe protocol will purge nitrogen from the astronauts’ bodies, too. Otherwise, when the cabin transitions to hard vacuum, excess nitrogen could bubble up in their blood—giving them debilitating and dangerous decompression sickness. “Just like when you open a can of soda, bubbles are released” in nitrogen-saturated blood when it is exposed to a sudden reduction in ambient pressure, Menon explained during the briefing. The crew will use an ultrasonic device to monitor each of their bodies for this potentially lethal effect. But if it arises, they’ll probably know in other ways: scuba divers sometimes call decompression sickness “the bends” for its penchant to make those stricken double over in severe pain.
Assuming all goes well, about two hours will pass from opening the hatch to closing it and repressurizing Dragon. In that time, two of the crew—reportedly Isaacman and Gillis—will take turns clambering on tethers to exit the spacecraft and enter the void. They’ll be testing the suits’ mobility, as well as a handhold-and-foothold structure that is mounted outside the hatch (and aptly called “Skywalker”). The entire space walk will be livestreamed to Earth via cameras on the helmets of the spacesuits, as well as on Skywalker and the Dragon’s nose and within the cabin, where the two other crew members will wait.
Day four will be devoted to testing a laser-based communications system for Starlink and other satellites and spacecraft. “We will have some checkouts and then perform a series of demonstrations as a part of that test,” Menon said at the briefing. “You’ll want to stay tuned for this.” On day five the Dragon vehicle will lower its orbit in advance of reentry as the crew finishes their remaining science experiments, which are mostly focused on monitoring their physiological reactions to space. On the morning of day six the crew will don their spacesuits once more before Dragon plunges through Earth’s atmosphere and splashes down at one of SpaceX’s seven preselected recovery sites off the coast of Florida.
At the conclusion of the prelaunch briefing, Gerstenmaier reflected on Polaris Dawn’s unorthodox path to space. Although the mission’s schedule has repeatedly slipped from an initial launch target of late 2022, it has still arrived at this moment with astonishing speed—especially compared with NASA’s typical timescales. “This pace of development that we get to do at SpaceX is very much like the pace of development that was required back in the early Apollo days,” Gerstenmaier said. “We’re getting a chance to do that again, where we’re really starting to push frontiers with the private sector and learning new things that we would not be able to learn by staying in the risk-free environment of here on Earth. It’s time to go out; it’s time to explore. It’s time to do these big things and move forward.”
