Polaris Dawn, the private SpaceX mission currently orbiting Earth, has already set several records since its launch on September 10th. Just hours after launch, the mission's Crew Dragon spacecraft reached an altitude of 1,400 kilometers, the highest orbit above Earth ever reached by a crewed spacecraft. This is the furthest humans have traveled from Earth since NASA's Apollo missions in the late 1960s and early 1970s. Today, two crew members, US entrepreneur Jared Isaacman and SpaceX engineer Sarah Gillis, completed the first commercial spacewalk at an altitude of over 700 kilometers.

“There's a lot to do at home, but Earth really looks like a perfect world from here,” Isaacman said as he poked his head and torso out of the spacecraft's hatch, preparing for his spacewalk maneuvers.

Although these milestones are impressive, for scientists whoNatureWhat the mission could mean for the future of space exploration is even more fascinating. With private citizens and flights that are increasingly flying into space, there will be more opportunities to conduct experiments in microgravity and explore the limits of human space travel.

“It's probably the most exciting time in space travel since the 1960s,” says Christopher Mason, a geneticist at Weill Cornell Medical College in New York City who directs the Space Omics and Medical Atlas (SOMA), an important archive of astronaut biomedical data. “Now we have spacesuits, spaceships and a mission all coming from a private company, SpaceX, which is really the first time we have all of this independent of any organization in spaceflight.”

Space mechanics

The ability of civilians to complete a spacewalk could even mean more options for repairing scientific equipment in space. In 2022, Isaacman suggested that NASA use a manned SpaceX mission to launch the agency's Hubble Space Telescope into a higher orbit to extend its lifespan. The telescope has been in space for 34 years and will gradually descend until it burns up in Earth's atmosphere. NASA has temporarily rejected the proposal, citing the potentially catastrophic risks to both Hubble and the crew.

But with the success of today's spacewalk - also known as extravehicular activity (EVA) - the idea of ​​a private company carrying out such difficult space operations has become much more plausible. “If Polaris Dawn is completely successful with its commercial EVA, it will be a step forward, and it may be enough to convince NASA,” said Laura Forczyk, managing director of space consulting firm Astralytical in Atlanta, Georgia.

Die vier Mitglieder der Polaris Dawn Crew am Kennedy Space Center.

Meanwhile, Polaris Dawn will deliver science results after it lands in the Gulf of Mexico or the Atlantic Ocean in the coming days. The mission's Crew Dragon spacecraft, theResiliencecarries 36 experiments contributed by 31 different institutions from Canada, Saudi Arabia and the United States, many of which focus on the health of astronauts. “We can learn a lot,” Isaacman said at an Aug. 19 news conference. “If we get to Mars one day, we would like to be able to go back and be healthy enough to report on it.”

More crews, more data

Polaris Dawn is the first of three planned Polaris missions funded and led by Isaacman, chief executive of payment processing firm Shift4 based in Center Valley, Pennsylvania. One goal of the Polaris program is to advance the human spaceflight ambitions of Hawthorne, California-based SpaceX. The third Polaris mission will be the first manned flight of SpaceX's Starship be, a fully reusable mega rocket that NASA will use in the coming years to transport astronauts to the lunar surface as part of their ambitious Artemis program has planned.

Before all of this, Polaris Dawn is testing some fundamental aspects. For one thing, it introduced SpaceX's EVA suit, the company's first suit designed to protect people from the vacuum of space. Gillis and Isaacman wore the suits during their spacewalk. "It's not lost on us," Isaacman said at the Aug. 19 press conference, that "at some point someone might wear a version" of the suit during a Mars walk.

In addition, the mission examines the health of the crew members on board. “Spaceflight is just a huge stressor,” says Jimmy Wu, deputy director of the Translational Research Institute for Space Health (TRISH) at Baylor College of Medicine in Houston, Texas, which collects medical data from commercial space travelers, including the Polaris Dawn crew.

Researchers believe private manned spaceflights will provide answers about how space travel affects health more quickly than government-led missions with trained astronauts because they take off more frequently. "It's really hard to study astronauts because it takes so long to get even 10 or 12 of them through six-month missions," says Leigh Gabel, a kinesiologist at the University of Calgary in Canada who studies the effects of microgravity on bone health. “Private space travel could give us a real edge.”

How the body copes with space

Gabe's team will take high-resolution X-rays of the Polaris Dawn crew's wrists and ankles once they return to Earth to measure the effects of several days of microgravity on bone structure. Her previous work with astronauts who spent time on the International Space Station has shown that months in microgravity can weaken the internal structure of supporting bones, such as those in the legs, preventing them from fully recovering even a year after returning to Earth. 1

Several researchers are using Polaris Dawn to better understand what is happening with space-associated neuro-ocular syndrome (SANS), a condition in which astronauts experience permanent changes - and even damage - to their vision. Scientists suspect that SANS comes from accumulated fluid in the eye that would normally drain away in Earth's gravity. Working with ophthalmologist Prem Subramanian and space health researcher Allie Hayman of the University of Colorado Boulder, the Polaris Dawn crew members each wear a "smart" contact lens that can record fluid pressure in the eye.

Other researchers will study the effects of exposure to space radiation - high-energy charged particles - on the body by analyzing DNA, RNA and other biosamples from the Polaris Dawn crew. Importantly, Polaris Dawn represents the first time that many of these analyzes will be performed on the same spacecraft across two different missions: Isaacman also participated in SOMA and TRISH research when he commanded Inspiration4, an all-civilian orbital mission operated by SpaceX in 2021.

Isaacman is “one of the most well-characterized people who ever existed,” Mason says. "It's the best chance we have to understand what happens to the body before you go into space, and then what happens to the body every time you go into space."