SpaceX Polaris Dawn crew completes historic private spacewalk

Commander Jared Isaacman and mission specialist Sarah Gillis each spent a few minutes outside the Dragon capsule, performing tests on their spacesuits.
By | Published: September 12, 2024

The four-person crew of SpaceX’s Polaris Dawn mission made history on Thursday morning by completing the first spacewalk with private astronauts.

Commander Jared Isaacman, the billionaire CEO of Shift4 Payments who purchased the five-day orbital flight from SpaceX, and mission specialist Sarah Gillis, one of the crew’s two SpaceX engineers, who are the company’s first employees to fly to space, exited SpaceX’s Dragon capsule one at a time, each spending about 12 minutes outside. The astronauts were traveling at 17,500 mph at an altitude more than 450 miles above Earth, higher than the International Space Station.

Because Dragon does not have an airlock, all four crewmembers were exposed to the vacuum of space. The mission profile added risk compared to a typical spacewalk, where astronauts enter and exit through a vacuum-sealed chamber.

“Today’s EVA was the first time four humans were exposed to the vacuum of space while completing the first-ever commercial astronaut spacewalk from a commercially-produced spacecraft in commercially-produced extravehicular activity [EVA] suits,” said Stu Keech, vice president of Dragon engineering at SpaceX.

SpaceX provided live stream coverage of the full, approximately two-hour process, which can be rewatched here.

The Falcon 9 rocket carrying Dragon and the Polaris Dawn crew lifted off from Launch Complex 39A at NASA’s Kennedy Space Center in Florida early Tuesday morning. Almost immediately, the astronauts began preparing for the spacewalk.

The first step was a “prebreathe” to remove nitrogen bubbles that can form within body tissues, causing decompression sickness. During the approximately two-day process, the cabin’s pressure was lowered and oxygen levels were raised gradually to help the crew acclimate.

After that, the astronauts donned their EVA spacesuits, which are designed to be worn both inside and outside the spacecraft. Developed by SpaceX with help from Isaacman’s Polaris team, the suits have endured hundreds of hours of testing and feature greater mobility, durability, and even a high-tech heads-up display (HUD).

“Building a base on the Moon and a city on Mars will require thousands of spacesuits,” SpaceX said in a post on X. “The development of this suit, and the EVA performed on this mission, will be important steps toward a scalable design for spacesuits on future long-duration missions.”

After completing suit leak checks and venting Dragon down to vacuum, Isaacman opened the hatch and was first to egress. Remaining attached to the spacecraft, he used a specially designed structure called Skywalker to move around and perform tests on the suit’s thermal and mobility systems. Skywalker is equipped with several cameras that were used to capture the moment in real time.

“SpaceX, back at home we all have a lot of work to do,” Isaacman said as he looked down on the planet below, “but from here, Earth sure looks like a perfect world.”

After Isaacman returned, it was Gillis’ turn. The SpaceX engineer stepped out and performed the same series of tests, while mission pilot Scott “Kidd” Poteet and mission specialist and medical officer Anna Menon monitored her support systems.

Finally, the hatch was closed, Dragon was repressurized, and the astronauts removed their suits.

“Dragon uses pure nitrogen during ‘repress,’ which mixes with the pure oxygen being released into the cabin via the open loop system that keeps the EVA suits pressurized,” SpaceX said. “This process is unique to Dragon which acts as its own airlock.”

From venting to repressurization, the entire process took about one hour and 45 minutes.

SpaceX CEO Elon Musk was quick to praise the crew for its historic achievement, as was NASA administrator Bill Nelson.

“Congratulations @PolarisProgram and @SpaceX on the first commercial spacewalk in history!” Nelson posted on X. “Today’s success represents a giant leap forward for the commercial space industry and @NASA’s long-term goal to build a vibrant U.S. space economy.”

Polaris Dawn, the first of three missions Isaacman purchased for SpaceX under the Polaris program, has so far lived up to its lofty expectations. In addition to the spacewalk, the astronauts on day two of the mission ascended to an orbital height not reached by humans since the Apollo 17 astronauts in 1972, passing through hazardous radiation belts. 

Menon also read a children’s book she authored, Kisses from Space, for her family and patients of St. Jude Children’s Research Hospital, live from orbit. While the Polaris missions are scientific—Polaris Dawn alone will conduct nearly 40 experiments—they are also billed as charitable endeavors to raise money for St. Jude.

Ultimately, the Polaris program may have a ripple effect on NASA’s efforts to return Americans to the Moon via the Artemis program.

Polaris Mission 3 is expected to be the debut crewed flight of SpaceX’s Starship, the largest and most powerful rocket ever built. The space agency has asked the company to develop a lunar lander variant of Starship to land astronauts on the Moon’s south pole, which will be used during Artemis 3 scheduled for September 2026.


This article was first published on flyingmag.com.