On September 12, two people on a SpaceX flight, entrepreneur Jared Isaacman and engineer Sarah Gillis, performed the first commercial spacewalk in history at an altitude of more than 700 kilometers.
SpaceX's private mission Polaris Dawn, which began orbiting Earth on September 10, has already set multiple records.
Shortly after launch, the Crew Dragon spacecraft on the Polaris Dawn mission reached an altitude of 1,400 kilometers (870 miles). This is the highest orbit ever achieved by a manned spacecraft and the greatest distance humans have flown from Earth since Agency's Apollo missions in the late 1960s and early 1970s.
On September 12, two people on a SpaceX flight, entrepreneur Jared Isaacman and engineer Sarah Gillis, performed the first commercial spacewalk in history at an altitude of more than 700 kilometers.
“There’s a lot of work waiting for us back home, but from up here, Earth really does look like a perfect place,” Isaacman said as he peered out of the spacecraft’s hatch, preparing for his spacewalk.
While these achievements are notable, what is even more interesting to the researchers who spoke to Nature is how this mission could impact the future of space science.
As more private citizens travel to space, there will be more opportunities to conduct experiments in microgravity and explore the limits of human space travel.
“We're probably living in the most exciting time in space travel since the 1960s,” says Christopher Mason, a geneticist at Weill Cornell Medical College in New York City. Mason directs the Space Medical and Omics Atlas (SOMA), a key collection of health data on astronauts.
“We now have spacesuits, spacecraft and a mission, all under the leadership of a private company, SpaceX. This is the first time we've seen this kind of independent organization in spaceflight,” he said.
The ability for civilians to conduct spacewalks could provide more opportunities to repair scientific equipment in space.
In 2022, Isaacman suggested that Agency should use a SpaceX crewed mission to boost the Hubble Space Telescope into a higher orbit, which would help it last longer.
The telescope has been in space for 34 years and will slowly descend until it eventually burns up in Earth's atmosphere.
Agency has so far rejected the proposal, citing the serious risks it could pose to both the Hubble telescope and the crew.
However, with the success of the current spacewalk, also called extravehicular activity (EVA), it seems more likely that a private company could handle these challenging space tasks.
“If Polaris Dawn successfully completes its commercial spacewalk, it will be a huge step forward and could persuade Agency,” Laura Forczyk, CEO of space consulting firm Astralytical in Atlanta, Georgia, tells Nature.com.
Polaris Dawn, meanwhile, will provide science results after it lands in the Gulf of Mexico or the Atlantic Ocean in the coming days.
The Crew Dragon spacecraft, named Resilience, carries 36 experiments from 31 different organizations in Canada, Saudi Arabia and the United States. Many of these experiments focus on the health of space travelers.
More crews, more data
Polaris Dawn is the first of three missions planned, funded and led by Isaacman, who is CEO of Center Valley, Pennsylvania-based payments processing company Shift4.
One goal of the Polaris program is to support the human spaceflight goals of SpaceX, a company based in Hawthorne, California.
The third Polaris mission will be the first crewed flight of SpaceX's Starship, a fully reusable mega-rocket. Agency plans to use the rocket to send astronauts to the surface of the Moon in the coming years as part of its ambitious Artemis program.
Before moving on to those missions, Polaris Dawn is testing a few key aspects. For starters, it debuted SpaceX’s EVA suit, which is the company’s first suit designed to keep people safe in the vacuum of space.
Gillis and Isaacman wore the suits during their spacewalk. “We know,” Isaacman said at the Aug. 19 press conference, “that someday someone might wear a version of this suit while walking on Mars.”
Another goal of the mission is to monitor the health of the crew members on board. “Spaceflight puts a lot of stress on the body,” says Jimmy Wu, deputy director of the Translational Research Institute for Space Health (TRISH) at Baylor College of Medicine in Houston, Texas. The institute collects medical data on commercial space travelers, including the Polaris Dawn crew.
How does the body adapt to space?
Gabel's team plans to take high-resolution X-rays of the Polaris Dawn crew's wrists and ankles after they return to Earth. This will help them study how a few days of microgravity may have affected their bone structure.
His previous research on astronauts who have spent time on the International Space Station revealed that spending months in microgravity can weaken the internal structure of weight-bearing bones, such as those in the legs. This damage does not fully heal, even after a year back on Earth.
Several researchers are also studying Polaris Dawn to learn more about spaceflight-associated neuroocular syndrome (SANS), a condition in which astronauts suffer permanent vision changes or even vision damage.
Scientists believe that spaceflight-associated neuroocular syndrome (SNAS) is caused by fluid buildup in the eye. On Earth, gravity helps this fluid drain away, but in space, this is not the case.
The Polaris Dawn crew is working with ophthalmologist Prem Subramanian and space health researcher Allie Hayman of the University of Colorado at Boulder. Each crew member is wearing a “smart” contact lens that measures the pressure of fluid in their eyes.
Other researchers will study how space radiation, composed of high-energy charged particles, affects the body by analyzing DNA, RNA and other biological samples collected from the crew of the Polaris Dawn spacecraft.
Importantly, Polaris Dawn is the first mission where many of these tests will be conducted on the same space traveler during two different missions. Isaacman was also involved in the SOMA and TRISH research when he led Inspiration4, an all-civilian orbital mission led by SpaceX in 2021.
Mason says Isaacman is “one of the most studied people in history.” He adds: “He gives us the best opportunity to learn about what happens to the body before we go into space and what happens every time someone goes into space.”