KENNEDY SPACE CENTER, Florida — SpaceX is set to make history as Elon Musk’s space company prepares to launch four civilians to orbit. They will become the first full crew of non-professional astronauts to fly to space.

Known as Inspiration4, the mission is the creation of SpaceX and billionaire entrepreneur Jared Isaacman, the founder and CEO of Shift4 Payments. Isaacman purchased the multi-day flight from SpaceX for an undisclosed fee, with the goal of raising awareness and funding for St. Jude Children’s hospital.

The mission is scheduled to liftoff Wednesday night, with a five-hour window that opens at 8:02 p.m. EDT.

“This is significant and historic because it’s going to be the highest that any humans have gone into orbit since the Hubble [Space Telescope] servicing missions,” SpaceX senior director of human spaceflight Benji Reed told reporters on Tuesday. “Another historic part for SpaceX is that this will be the first time that we have three [Dragon capsules] in orbit.”

Isaacman and the Inspiration4 team have worked with SpaceX to train since announcing the flight in February. He noted that the crew on Tuesday met with company leadership — including Elon Musk, who “gave us his assurances again that the entire leadership team is solely focused on this mission.”

Asked how he felt with less than 24 hours to liftoff, Isaacman said he had “no jitters, excited to get going.”

SpaceX’s Crew Dragon capsule was notably developed with heavy investment from NASA, which has flown 10 of its professional astronauts on the spacecraft to date. While the U.S. space agency has comparatively minimal involvement in the Inspiration4 launch, NASA director of commercial spaceflight Phil McAlister told CNBC that private missions were one of the goals set when contributing government funds to SpaceX’s vehicle.

“We are seeing a sort of renaissance in commercial orbital human space transportation,” McAlister said. “For the first time in human history, you can go to a private company and purchase a ticket to orbit. You’ve never been able to do that; historically, you had to go to a government agency.”

One of the key factors for launching on Wednesday night remains the temperamental Florida weather, which will affect the timing of both liftoff and the capsule’s splashdown a few days later.

“We look at not only the launch weather but we have to look at the return weather,” Reed said.

The U.S. Space Force’s 45th Space Wing forecast that the weather has a 80% probability of being clear to launch during Wednesday’s five-hour window. If SpaceX decides to postpone the launch, the next available opportunity would be Thursday.

SpaceX will broadcast steady live coverage of the launch, from four hours before liftoff to until the spacecraft reaches orbit.

Isaacman gathered a unique group of individuals for the mission through three ways: From St. Jude’s staff, through an entrepreneurial competition, and via a charity lottery.

Isaacman, the Inspiration4 commander, founded his payment processing company in 1999 when he was 16 years old. He’s also an avid pilot, with a variety of ratings in commercial and military jets. He has flown in more than 100 airshows, and he is the co-founder of Draken International, a private air force that helps train pilots for the U.S. military.

Hayley Arceneaux, a cancer survivor and now a physician assistant at St. Jude, is the mission’s medical officer.

She survived osteosarcoma, a type of bone cancer, at 10 years old and will be the first person to fly in space with a prosthetic body part — as a significant portion of her leg is metal. At 29, Arceneaux will also become the youngest American to fly in space.

“From a medical officer perspective, I’m so excited about the medical research that we’re going to be doing — we’re going to be collecting a lot of swabs to learn about the microbiome, how that changes in flight; we’re going to be performing ultrasounds to evaluate for fluid shifts; as well as performance and cognitive tests and studying radiation effects of going to our high altitude,” Arceneaux told reporters before the launch.

Sian Proctor is the Inspiration4 pilot, and the joined the crew after winning an online business competition through Isaacman’s company.

She is a geoscientist and science communication specialist, with a passion for space exploration that extends back to her childhood, as she was born in Guam while her father worked for a NASA ground station during the Apollo missions. Proctor is an analog astronaut, having completed multiple Earth-based missions that simulate the isolation of living in space. In 2009, Proctor was a finalist for NASA’s 2009 astronaut selection.

“It’s really special for me to hold that title [of pilot] because I’m going to be the first Black female pilot of a spacecraft,” Proctor told reporters. “There have been three Black female astronauts that have made it to space, and knowing that I’m going to be the fourth means that I have this opportunity to not only accomplish my dream, but also inspire the next generation of women of color and girls of color and really get them to think about reaching for the stars.”

The fourth member of the crew is Chris Sembroski, who serves as the flight’s mission specialist. He donated to the St. Jude fundraising campaign and was selected from among nearly 72,000 entries.

Sembroski is a U.S. veteran, having served in the U.S. Air Force and deploying in Iraq.

“I’ve been just thinking about how lucky I am to be a part of this crew, to be a part of this mission. From watching a Super Bowl commercial and making a donation, to not winning that and then having my friend win it, and then through his generosity give that spot to me, I think that just really puts me in a very special spot,” Sembroski said. “Not only do I feel very lucky to be here, but I have a huge responsibility to pay that forward and show that generosity toward others.”

The four members of the crew have spent much of the last six months training with SpaceX to prepare for the mission. Reed noted that the Inspiration4 members studied over 90 different training guides and manuals, took a multitude of lessons to learn how to fly the spacecraft, and did numerous simulation flights — including 12-hour and 30-hour simulations.

Isaacman also said the crew has “been tearing up the skies in some fighter jets” during training and prep, “which I put at relatively higher risk than this mission, so that we’re nice and comfortable as we get strapped into Falcon.”

Proctor praised SpaceX’s training process.

“Since the announcement, when we were here [at Kennedy Space Center] last, every day has been the best day of my life and it’s only getting better,” Proctor said.

The primary goal of Inspiration4 is to raise funds and awareness for St. Jude. The Inspiration4 team aims to raise $200 million for the research hospital. Just over $30 million has been donated to date, with another $100 million coming from Isaacman.

SpaceX’s Crew Dragon capsule will fly to an orbital altitude of about 575 kilometers, where the Inspiration4 crew will float for about three days before reentering the atmosphere and splashing down on either the Gulf Coast or the Atlantic Coast of Florida.

Four hours before liftoff, the astronauts will suit up. About a half an hour later, the crew will walk out to their Tesla Model X rides, which will drive from the NASA astronaut quarters to the launchpad.

With 2½ hours to go, the astronauts will strap into their seats in Crew Dragon and begin checking that all systems are good to go. Then, with just under two hours until launch, the hatch to the spacecraft will be closed. 

SpaceX will begin loading the rocket with fuel 35 minutes before launch, which will initiate a final series of processes and checks.

A few minutes after liftoff, the Falcon 9′s booster stage will return and attempt to land on the company’s barge stationed in the Atlantic Ocean.

If anything were to go wrong in the last half hour before the launch or during the launch, Crew Dragon will abort and fire its emergency escape system. The company performed a full test of that system in January 2020 with no one inside the spacecraft. That test saw SpaceX trigger the system during the most intense part of the launch to show that it could be done at any time.

While NASA’s role in the Inspiration4 mission is minimal compared to astronaut launches to the ISS, the agency is still involved. NASA is supporting Inspiration4 on a fully reimbursable basis under agreements with SpaceX, with the services in total worth about $1 million.

“We are providing some services and some equipment, that just make more sense for NASA to provide,” McAlister said.

Reed thanked NASA for its partnership with SpaceX, as the agency was heavily involved in the development of the company’s Crew Dragon capsule.

SpaceX developed its Crew Dragon spacecraft and fine-tuned its Falcon 9 rocket under NASA’s Commercial Crew program, which provided the company with $3.1 billion to develop the system and launch six operational missions. Commercial Crew is a competitive program, as NASA also awarded Boeing with $4.8 billion in contracts to develop its Starliner spacecraft — but that competing capsule remains in development due to an uncrewed flight test that experienced significant challenges nearly two years ago.

Crew Dragon is the SpaceX capsule that will transport the passengers, with this specific spacecraft being dubbed “Resilience” by prior NASA astronauts. It is an evolved version of the company’s Cargo Dragon spacecraft, which has launched to the space station more than 20 times. Just as Cargo Dragon was the first privately developed spacecraft to bring supplies to the ISS, so Crew Dragon is the first privately developed spacecraft to transport people. 

NASA is now benefiting from the investment it made in Crew Dragon’s development, which the agency certified for operational use last November.

“This is the culmination of what we envisioned for the Commercial Crew Program 10 years ago,” McAlister said. “It’s actually in the original charter for the program, that the objective of what we were trying to accomplish was to achieve a system capable of crew transportation to the International Space Station, but also to enable a commercial capability for other customers.”

“The program wouldn’t be fully successful, unless we had these kinds of missions [like Inspiration4],” McAlister said.

Crew Dragon with its trunk stands just under 27 feet tall and 13 feet around. The spacecraft includes its own system of small rocket engines for directional control in space and a launch abort system in the event of an emergency. Its trunk is the large lower half that’s covered in solar panels, which can carry cargo.

The spacecraft is designed to carry as many as seven people. It has a system of controls that is focused around touch screens, although NASA notes that Crew Dragon has a “robust fault tolerance built into the system.” As the astronauts will be wearing custom SpaceX spacesuits, the touch screens work whether or not the astronauts are wearing gloves. The spacesuits are largely designed to protect the astronauts in the event that the spacecraft loses pressurization, with life support and power systems connected through a point on the spacesuit’s leg.

SpaceX made one major change to Resilience, which was to add a “cupola” window in place of the spacecraft’s docking adapter in the nosecone.

Reed noted that SpaceX’s manifest of Crew Dragon missions “is getting busier by the minute,” with a growing backlog of private trips planned. He said that SpaceX is “gearing up to be able to fly” three to six times a year least.

Musk’s company has announced several private missions already, including a deal with Japanese billionaire Yusaku Maezawa to fly on the company’s Starship rocket on a trip around the moon in 2023. SpaceX also has space tourism deals with Axiom Space, which aims to fly four people to the International Space Station on a 10-day trip early next year, and Space Adventures, which plans to fly four tourists on a five-day “free-flyer” trip to orbit by 2022.

SpaceX’s Falcon 9 is the workhorse of the company’s growing fleet of rockets. It stands at nearly 230 feet tall and is capable of launching as much as 25 tons to low Earth orbit. 

A few days before the Inspiration4 launch SpaceX performed a static fire test of the full Falcon 9 rocket on the launchpad.

Crew Dragon sits in place of the rocket’s nose cone at the top. After launching the spacecraft on its way, the large lower portion of Falcon 9, known as the “booster,” will reenter the Earth’s atmosphere and attempt to land on the company’s drone ship in the ocean. SpaceX has landed its Falcon 9 rocket boosters 84 times.