SpaceX's all-civilian Inspiration4 mission launches today. Here's what to expect.

Editor's note: SpaceX's Inspiration4 crew successfully launched into orbit at 8:02 pm ET from NASA's Pad 39A at the Kennedy Space Center. You can see a launch replay above and the full webcast below. Read our launch wrap here.

CAPE CANAVERAL, Fla. — SpaceX will launch its first all-civilian crew on a three-day journey around the Earth in what will be a historic step for private space travel. 

The private spaceflight company will launch the Inspiration4 crew,  a team of four private citizens, on a veteran Falcon 9 rocket it calls B1062. The previously flown rocket is scheduled to blast off from Pad 39A and Kennedy Space Center here in Florida tonight (Sept. 15) during a five-hour window that opens at 8:02 p.m. EDT (0002 Sept. 16 GMT). 

You can watch the launch live here and on the homepage starting at 3:45 p.m. EDT (1945 GMT), courtesy of SpaceX. Netflix will also stream a live webcast of the launch countdown on YouTube beginning one hour before liftoff, and you can watch that live here.

Related: Inspiration4: When to watch and what to know
Live updates: SpaceX's Inspiration4 private all-civilian orbital mission

Officials at the 45th Weather Squadron have said that the weather here at the Cape will likely be good on launch day, with an 80% chance of favorable conditions for liftoff. If the mission is unable to get off the ground on Wednesday night, the next attempt will be Thursday (Sept. 16) at 8:05 p.m. EDT (0005 Sept. 17 GMT).

Today's flight will mark the 23rd Falcon 9 mission for SpaceX so far in 2021, and it's the second launch within a week. (The company sent 51 of its own Starlink internet satellites into space atop a different Falcon 9 rocket from its West Coast facilities on Monday, Sept. 13.) 

In addition, the flight marks the fourth crewed mission for SpaceX, but the first to carry private citizens as opposed to professionally trained astronauts. The Inspiration4 mission is part of a massive fundraising effort to raise $200 million for St. Jude Children's Research Hospital.

To that end, billionaire and founder of Shift4 Payments, Jared Isaacman, purchased the flight on one of SpaceX's Crew Dragon spacecraft, donating two of the seats to St. Jude and awarding the fourth seat as the top prize in a "shark tank-like" competition to one entrepreneur to raise money for the charity. 

The Inspiration4 crew, from left: Chris Sembroski, Sian Proctor, Jared Isaacman and Hayley Arceneaux. (Image credit: John Kraus/Inspiration4)

"I can't express enough how appreciative we are of this amazing opportunity, we know that the four of us are about to have an experience and only about 600 or so had before us," Isaacman told reporters Tuesday. "And we're very focused on making sure that we give back every bit of that time that we get on orbit for the people in the causes that matter most to us."

Joining him on the flight are medical officer Hayley Arceneaux, a cancer survivor and physician's assistant at St. Jude; pilot Sian Proctor, a geoscientist and science communicator; and mission specialist Chris Sembroski, a data engineer. 

"Today, we had our launch readiness review," SpaceX's Benji Reed said during a media event with the crew on Tuesday (Sept. 14). "It's our final big review to make sure we've closed out all of the items, and addressed any concerns and issues and risks on this mission as we get ready to go." 

"We're happy to say that this crew and our operations team at SpaceX is certified and ready to fly," he said. 

Related: Inspiration4: When to watch and what to know

Both the crew's ride to space and their spacecraft have flown before. The Falcon 9 rocket responsible for ferrying them to orbit previously launched two different next-generation GPS satellites for the U.S. Space Force. Their Dragon, named Resilience, first carried a crew of four astronauts to the International Space Station (ISS) as part of NASA's first long-duration astronaut mission to launch from U.S. soil since the end of the shuttle program in 2011. 

To ensure that B1062 is in top working order ahead of Wednesday's flight, SpaceX rolled the rocket out to the pad on Sept. 12 and fired up the Falcon's nine Merlin 1D engines as part of a pre-launch test. The rocket was held down on the pad while its engines briefly fired up, allowing engineers to ensure the booster was working properly. 

All the data collected from that test indicates that Falcon 9 is ready for launch. According to Reed, the team will continue to monitor systems on both the Falcon 9 and the Crew Dragon spacecraft to ensure everything is in order prior to liftoff. 

The SpaceX Falcon 9 rocket and Crew Dragon that will launch the private orbital spaceflight dubbed Inspiration4, as seen during launch preparations. (Image credit: SpaceX)

As of right now, the weather is looking promising, but weather forecasters will keep a close eye on the skies as the final hours before launch countdown. The team not only has to monitor the weather at the launch site, but also along the spacecraft's flight path in case an emergency crops up during ascent. 

SpaceX equipped its Dragon capsules with a special launch escape system that will be able to push Dragon away from the rocket in case of an inflight anomaly. This type of abort feature can be activated at any time from liftoff to orbit — a feature that the space shuttle did not have. 

Related: From Etsy to Earth orbit: Inspiration4 crew packs mementos for space (and sale)

Flight milestones

Wednesday's launch will be the 128th overall flight for SpaceX's 229-foot-tall (70 meters) Falcon 9 booster, and if all goes as planned, it will also be the 92nd recovery of a Falcon 9 first stage booster since the company landed its first one in December 2015. 

It will also mark the first time that there will be three Dragon spacecraft in orbit. Two of those (another Crew vehicle and a cargo version) are currently attached to the ISS after they delivered astronauts and supplies to the orbital outpost. 

The Crew Dragon Resilience will not visit the space station, but will instead free-fly around the Earth for approximately three days. It's orbit will reach 357 miles (575 kilometers) above the Earth, which means it will fly higher than the ISS and higher than the current orbit of the Hubble Space Telescope — an altitude that humans haven't reached since the Hubble servicing missions during the space shuttle program. 

Following a successful liftoff, SpaceX plans to land the rocket's first stage on the deck of one of its massive drone ships, named "Just Read the Instructions". It will be assisted by one of SpaceX's newest ships, "Doug", which is named after retired NASA astronaut Doug Hurley, who was one of the first two humans to fly inside a Crew Dragon spacecraft as part of the Demo-2 mission in May 2020.

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Amy Thompson
Contributing Writer

Amy Thompson is a Florida-based space and science journalist, who joined as a contributing writer in 2015. She's passionate about all things space and is a huge science and science-fiction geek. Star Wars is her favorite fandom, with that sassy little droid, R2D2 being her favorite. She studied science at the University of Florida, earning a degree in microbiology. Her work has also been published in Newsweek, VICE, Smithsonian, and many more. Now she chases rockets, writing about launches, commercial space, space station science, and everything in between.