Polaris Program Aims High with First Commercial Spacewalk

On September 10, 2024, one of the farthest-reaching civilian missions in human history lifted off from Launch Complex 39A at the Kennedy Space Center in Florida, aiming to smash records and push boundaries in support of human spaceflight objectives. The Polaris Dawn mission, launching atop a SpaceX Falcon 9, also completed the first commercial spacewalk, with Commander Jared Isaacman and Mission Specialist Sarah Gillis exiting the spacecraft for an extravehicular activity (EVA) lasting just under two hours. The mission will remain in orbit for several more days, conducting biomedical research and various other experiments, before returning to splash down in the ocean off the coast of Florida.  

The Polaris Dawn mission is commanded by private spaceflight veteran and entrepreneur Jared Isaacman. An avid fighter pilot, Isaacman sought to push even further with more ambitious missions to advance human spaceflight knowledge, funding three additional missions in conjunction with SpaceX. Piloting the mission is Scott “Kidd” Poteet, a US Air Force veteran and mission director for the Inspiration4 mission, which was commanded by Isaacman. Completing the crew are SpaceX employees Sarah Gillis and Anna Mennon as Mission Specialists. Gillis, the company’s senior space operations engineer who also leads training of private spaceflight missions, will join Issacman on the spacewalk. Menon, a lead space operations engineer and mission director for the company, will act as onboard medical officer for the mission, tapping into her six years of experience as a biomedical flight controller at NASA, where she oversaw International Space Station operations. The mission is unique as it represents one of the first direct human research missions conducted entirely outside of government. 

During the leadup to launch, the mission was delayed repeatedly by tight constraints for both launch and landing. Unlike International Space Station missions, which rendezvous with the orbital outpost, the mission is limited by supplies and other consumables, and must splash down after 5 days in orbit. The mission launched on September 10th, 2024 from Launch Complex 39A at Kennedy Space Center, heading for a 51.7º 190×1200 km orbit. The booster, 1083.4, previously supported NASA’s SpaceX Crew-8 mission and two Starlink flights. The capsule, C207 Resilience, is making its third spaceflight, having previously supported the NASA SpaceX Crew-1 mission and Inspiration4, also commanded by Isaacman. The booster, having completed first stage flight, landed on the droneship A Shortfall of Gravitas, stationed in the Atlantic. This is unusual for crew missions, but the performance required to insert Resilience into its elliptical orbit necessitated a downrange landing. Following successful separation of Dragon, the crew immediately began prebreathing procedures for their spacewalk, which  required a full depressurization of the vehicle’s cabin. After performing several passes through the Van Allen belts during the first few days of flight, the Polaris Dawn crew reduced their orbital height to 192×730 km for their upcoming spacewalk, in order to mitigate radiation and debris concerns.  

One of the highlights of the Polaris Dawn mission was the spacewalk, the first time a non-government agency has performed such a feat. The crew began prebreathing for their spacewalk as soon as they entered orbit, lowering the pressure inside Dragon to ensure that the crew did not experience decompression sickness – nitrogen coming out of solution in the bloodstream due to change in atmospheric pressure. On flight day 3, Thursday September 12, the crew began final preparations for their voyage outside their spacecraft. The final step in preparation for the EVA saw the crew don their suits which transitioned to 100% oxygen for the final stage of pre-breathing. 100% oxygen atmospheres in the suits prove useful to ensure a survivable atmosphere while permitting workable suit pressures for mobility. With this final step complete, Resilience was fully depressurized, with Poteet and Menon moving to the outermost seats to help manage the umbilical cables Isaacman and Gillis were tethered to. Following depressurization, Isaacman, with callsign EV1, opened the capsule’s forward hatch to space. A new structure, which SpaceX has named Skywalker, was affixed on the forward bulkhead to provide hand and foot holds to aid in mobility.

Although two astronauts performed this EVA, only one was outside of the spacecraft at any given time. Issacman exited the spacecraft and performed a series of three planned tests on the spacesuit, focusing on mobility. The first test, according to SpaceX, focused on using a single hand to control body movement. The spacewalkers evaluated their ability to move in all directions, hold a single position for 10-15 seconds, and hold position while the other arm is simulating tool use. The second test assessed the utility of Skywalker using a variety of hand and footholds, enabling the spacewalkers to move to different vantage points. The third test evaluates using a foot restraint. Isaacman and Gillis gauged the difficulty of getting in and out of the restraint, how easily they could move their body, the ease with which they could maintain position while hands free or using tools, and recover from a single foot disengaging from the structure. Ultimately, these tests will provide useful data to help SpaceX assess the suits’ performance and refine the design for future missions. The second spacewalker, Mission Specialist Sarah Gillis with callsign EV2, exited the spacecraft after Isaacman had returned to his seat, and performed the same series of tests. Following the completion of her test, she was responsible for closing the hatch after re-entering the spacecraft, and Resilience was then repressurized. The total EVA time for both astronauts was roughly 30 minutes outside the spacecraft, with total depressurization time sitting just under 2 hours. 

Testing spacesuit capability was a central component for the Polaris Dawn mission, with SpaceX seemingly vying to compete in the new commercial suit market alongside companies like Axiom and Collins Aerospace. SpaceX designed the EVA suits for this mission based on the intravehicular activity (IVA) suits typically worn during launch and landing. These suits, which are designed to help protect the crew in the event of emergency, are rated for depressurization while still inside the spacecraft. In order to conduct a fully fledged EVA, modifications needed to be made. The EVA suits are designed to keep astronauts safe in the vacuum of space while also being comfortable and flexible enough for launch and landing, eliminating the need for separate IVA suits which would take up space on a free-flying mission. Much like the Gemini suits of the 1960s, fabric and soft joints provide mobility, while the boots are made from the same thermal material used on Falcon 9’s interstage and Dragon’s trunk, according to SpaceX. Compared to the IVA suits, thermal management has been improved and the helmet received thermal insulation coatings and an anti-fog treatment. During the spacewalk, a heads-up display provided information on suit metrics. The suit, however, does not have its own backpack, and relies on an umbilical connection to the spacecraft for power and breathing gas. 

Polaris Dawn represents a fundamental shift in the way commercial human spaceflight missions are conducted, with SpaceX transitioning from largely tourism focused missions to pre-existing destinations to developing independent capabilities akin to a space agency. This comes at a time where human health and performance data is at a premium in the LEO space economy, with companies such as SpaceX, Axiom, and Vast aiming to capitalize on this lack of “everyman” data for broader spaceflight access. The mission is the first of three flights that make up the Polaris Program, which was announced two years ago following the widely followed Inspiration4 mission, of which Isaacman was also the commander. The parameters of the second mission have not yet been fleshed out publicly, but Isaacman has claimed from the beginning that the third mission will be the first crewed flight of a SpaceX Starship rocket – a vital step for potential certification of the vehicle to carry crew. Starship development, much like the Human Landing System for NASA’s Artemis program, will remain a crucial schedule driver of readiness for the third Polaris program mission. 

The new age of spaceflight is one marked by bold ambition and daring feats, but all of this comes with the understanding that there is a long way to go before space is applicable or even safe for the masses. Missions like Polaris Dawn are part of that push, with companies eager to dabble in human health and performance – a scientific field that has long been constrained to government research institutions. At the Commercial LEO Development forum at the Space Policy Institute on September 6, several key players in the aerospace industry stressed that commercial human health data would become a vital currency in the future of sustainable human presence in space, something the Polaris Dawn crew hopes to build on. Early missions such as Polaris Dawn or Vast’s upcoming Haven-1 space station may be part of a crucial revolution in exchange of knowledge for the burgeoning space economy, should they prove to be a component of sustainable industry outside of government support. 

With the Polaris Dawn mission drawing to a close, it is possible now to imagine a world where not just government astronauts can float free outside of their spacecraft – potentially constructing new facilities in Low Earth Orbit or beyond, or servicing spacecraft. While not as flashy as an ISS spacewalk, the Polaris program seeks to shift knowledge towards the general public in favor of a proliferated future for want-to-be spacewalkers. Now all that needs to fall into place is a market that supports it.

Edited by Beverly Casillas