Four civilian astronauts launched into space from Cape Canaveral, Florida, on Tuesday, September 10. They hope to go deeper into the cosmos (870 miles, to be exact) than anyone since Gemini 11 started in 1966.

Early Thursday, September 12, the crew of the SpaceX Polaris Dawn mission will attempt the first purely civilian spacewalk. (Observers can watch online.)

In addition, they plan to conduct dozens of studies and experiments in orbit over the next five days to better understand the effects of space travel and radiation on humans.

“This is a milestone,” Anna Menon, a SpaceX mission specialist and medical staffer, told PEOPLE earlier this year as she and the other astronauts prepared for launch. “It helps develop technologies that will bring humanity closer to Mars and beyond.”

Menon will be joined by Commander Jared Isaacman, a billionaire technology entrepreneur who is funding the flight, as well as pilot Scott “Kidd” Poteet and Sarah Gillis, another mission specialist.

Isaacman previously led SpaceX’s Inspiration4 in 2021. He told PEOPLE that the flights are “small steps toward opening that final frontier. There is so much we can learn.”

Both he and Gillis plan to exit their capsule during the spacewalk, although technically all four will participate since they will be exposed to the emptiness of space.

“We hope to inspire future generations,” Gillis previously told PEOPLE.

Poteet, a retired Air Force lieutenant colonel, said his discipline in stressful situations and his commitment to the team will serve him well.

The Polaris Dawn The start of the expedition was delayed for several years as the team worked to refine the dizzying array of technologies they would need, including suits for the crew to wear outside their capsule as it traveled at 17,000 mph in temperatures between 230 and 240 degrees Fahrenheit (110 and 110 degrees Celsius). (You won’t feel the speed in the same way you would on Earth.)

Astronauts from the past have reported a strange detail about their travels: they claimed that space sometimes smells like gunpowder or burnt food. What does this mean? Polaris Dawn Crew expected?

“I’ll let you know,” Menon told PEOPLE, “when we get back.”

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Once the group is floating among the stars, there is another goal: “I will read a children’s book that I wrote, Kisses from spaceboth my children and some of the brave children at St. Jude Children’s Research Hospital,” Menon said on a live broadcast to raise funds for the Tennessee-based health facility that focuses on childhood cancer and other childhood diseases.

The Inspiration4 has raised more than $250 million and Menon said they want to contribute even more: “We can make great strides for our common future, but also address the problems here on Earth today.”