SpaceX’s Polaris Dawn mission made history with its launch early Tuesday, sending a four-person crew of civilian astronauts into orbit. Hours later, the crew had already achieved a significant milestone: reaching the highest orbit around Earth ever recorded, surpassing a record set by NASA’s Gemini 11 mission in 1966.
The SpaceX Crew Dragon spacecraft carrying the Polaris Dawn crew reached a peak altitude of 1,400.7 kilometers (870 miles) at 9:19 p.m. ET on Tuesday, exceeding the Gemini 11’s record of 853 miles (1,373 kilometers). While NASA’s Apollo missions traveled further, they were destined for the moon and did not orbit Earth. The Polaris Dawn mission also marks the farthest any human has traveled since the last Apollo mission in 1972, and the farthest into space a woman has ever journeyed.
In an update posted on social media, the Polaris Dawn program reported that the crew enjoyed their first on-orbit meals and began the mission’s initial science and research tasks, including testing SpaceX’s Starlink network. Starlink, which currently provides internet services on Earth, is being tested for potential in-space connectivity, a capability crucial for future deep-space missions.
Despite these achievements, the most challenging aspects of the five-day mission are yet to come. The Polaris Dawn crew, which includes Shift4 Payments CEO Jared Isaacman, former US Air Force pilot Scott “Kidd” Poteet, and SpaceX engineers Anna Menon and Sarah Gillis, is preparing for the first commercial spacewalk, set to begin early on their third day in space. This spacewalk will occur approximately 435 miles (700 kilometers) above Earth.
During the spacewalk, the Crew Dragon capsule will be depressurized, and a circular hatch will be opened. Two crew members, Gillis and Isaacman, will exit the spacecraft for about two hours, exposed only to the vacuum of space and protected by SpaceX’s new Extravehicular Activity (EVA) suits. These suits, developed in just two and a half years, contrast sharply with NASA’s aging spacesuits, which have been in use for over 40 years.
To prepare for the spacewalk, the Crew Dragon capsule is conducting a lengthy “pre-breathe” process to adjust the astronauts’ bodies to the changing pressure. This process involves slowly purging nitrogen from the crew members’ blood to prevent decompression sickness, similar to the precautions scuba divers take to avoid rapid ascent.
The pre-breathe routine for Polaris Dawn will last about 45 hours, significantly longer than the rapid pre-breathing process used on the International Space Station, which takes only a couple of hours. This extended preparation is designed to mitigate the risk of nitrogen bubbles forming in the blood as pressure changes.
