SpaceX is launching another crew to space this evening, sending four astronauts to the International Space Station for a six-monthlong stay in orbit. Traveling inside SpaceX’s Crew Dragon spacecraft, the crew will get a late start on their mission, with liftoff scheduled for 9:03PM ET on November 10th out of Cape Canaveral, Florida.

The mission is called Crew-3, and it will carry NASA astronauts Thomas Marshburn, Raja Chari, and Kayla Barron, as well as European Space Agency astronaut Matthias Maurer. This will be the first trip to space for Maurer, Barron, and Chari — the mission’s commander. For Marshburn, this will be his third flight to space, and for each of his missions, he’s flown on a different vehicle. His first flight was on the Space Shuttle and his second flight was on Russia’s Soyuz spacecraft. Now he’ll get to experience the Crew Dragon, which the astronauts have nicknamed “Endurance.”

Crew-3 is SpaceX’s third operational crewed flight for NASA as part of the space agency’s Commercial Crew Program — an initiative to use private vehicles to ferry NASA astronauts to and from the International Space Station. As part of its initial contract with NASA, SpaceX is slated to perform up to six crewed flights for the agency, with two flights tentatively scheduled for next year. However, NASA recently indicated it is already thinking of how to transport astronauts beyond those initial missions.

While this is SpaceX’s third operational mission, it’s actually the company’s fifth time launching people to orbit on its Crew Dragon spacecraft. In order to prove the Crew Dragon’s safety for NASA, SpaceX launched two NASA astronauts to the ISS in May 2020. That first successful test flight paved the way for SpaceX to start doing routine flights with Crew Dragon.

And in September, SpaceX launched a crewed flight called Inspiration4 that carried four non-NASA astronauts to orbit. Touted as an all-civilian crew, the passengers included a tech billionaire — who paid for the trip — a childhood cancer survivor, a professor, and an engineer. The foursome, who stayed in orbit for just three days, used the launch as a way to raise charity for St. Jude’s Children’s Hospital. It was SpaceX’s first truly private human spaceflight mission.

WHAT TIME IS SPACEX’S CREW-3 LAUNCH?

SpaceX’s Falcon 9 rocket is scheduled to take off on Wednesday November 10th, from NASA’s Kennedy Space Center in Cape Canaveral, Florida at 9:03PM ET.

Scheduled launch time: New York: 9:03PM / San Francisco: 6:03PM / London: 2:03AM / Berlin: 3:03AM / Moscow: 5:03AM / New Delhi: 7:33AM / Beijing: 10:03AM / Tokyo: 11:03AM / Melbourne: 1:03PM

HOW TO WATCH SPACEX’S CREW DRAGON LAUNCH LIVE:

Livestream: NASA’s livestream coverage can be found on YouTube and on the agency’s website. Coverage will begin at 4:45PM ET.

A NUMBER ONE PROBLEM

Though Inspiration4 wasn’t a NASA mission, SpaceX learned a few things from that flight that will help with the upcoming Crew-3 trip. The Crew Dragon that flew the Inspiration4 flight operated pretty smoothly, except for one key element inside the spacecraft: the toilet. SpaceX revealed that a tube in the toilet that transports urine into a storage tank came unglued. This caused urine to spray into the toilet’s fan system instead and pool under the floor. It wasn’t really a problem during the flight itself.

“We didn’t really even notice it; the crew didn’t notice it until we got back,” William Gerstenmaier, vice president of build and flight reliability at SpaceX, said during a press conference ahead of flight. “We got the vehicle back, we looked under the floor, and we saw the fact that there was contamination underneath the floor.”

After seeing this, SpaceX worried that the same problem might be happening on the Crew Dragon used for Crew-2, which was docked with the International Space Station until Monday. Sure enough, the astronauts on the space station went inside that Crew Dragon and found similar urine contamination under the floor of the toilet.

The main concern with this pooling is that it’s not just urine collecting under the floor; SpaceX adds a compound to the urine called Oxone, which removes the ammonia from the liquid to help get rid of odor and prevent bacteria from growing. But SpaceX became worried that the mixture of Oxone and urine in the floor could actually corrode the spacecraft itself. The company did tests that involved combining the urine and Oxone mixture with aluminum — the primary metal used to make Crew Dragon — inside a chamber that simulated the same temperature and humidity on board the spacecraft.

The toilet issue was more of a problem on Inspiration4, since the crew spent their entire mission inside Crew Dragon, using the bathroom for multiple days, leading to more potential corrosion. Most of SpaceX’s other Crew Dragon missions send people straight to the International Space Station, so astronauts are typically only using the toilet before docking. Also, SpaceX claims that the aluminum alloy it uses on Crew Dragon is “very insensitive” to corrosion.

SpaceX opted to fix the toilet issue anyway by making the toilet an “all-welded structure” so that there are no longer any parts or tubes that can come unglued. That way no unwanted liquids will cause any trouble again.

GETTING TO THE PAD

Crew-3 is set to take off from SpaceX’s launch site LC-39A at Kennedy Space Center. The crew will then spend a little less than a full day in orbit before rendezvousing with the International Space Station. Crew Dragon is designed to dock autonomously with the ISS, but the astronauts can jump in during the process if necessary.

Once Crew-3 arrives, they will join three crew members already on board the ISS: NASA astronaut Mark Vande Hei and Russian cosmonauts Anton Shkaplerov and Pyotr Dubrov. Originally, the incoming crew was supposed to be greeted by a much larger welcoming committee. Four additional astronauts, part of SpaceX’s Crew-2 mission that launched to the space station in April, were meant to be on board when Crew-3 arrived to help pass the baton.

However, the Crew-3 launch has dealt with a number of delays. Originally scheduled for October 31st, the launch was pushed a few days due to bad weather forecasts. Then one of the crew members on Crew-3 developed a minor medical issue, prompting another delay. When that happened, NASA opted to bring the Crew-2 crew home first, worried that waiting any longer would mean landing the astronauts in choppy winter weather off the Gulf Coast. The Crew-2 astronauts safely splashed down off the coast of Pensacola, Florida in their own Crew Dragon on Monday night at 10:33PM ET, in what NASA called a “flawless” undocking.

The splashdown of Crew-2, however, didn’t appear to be flawless at first. Just before hitting the water, only three of the capsule’s four parachutes — critical for slowing down the vehicle — appeared to inflate normally. The fourth eventually did inflate, but took about 75 seconds longer than the others. SpaceX claims it removed that parachute right after landing and brought it back to NASA’s Kennedy Space Center in Florida for closer inspection with NASA.

“It performed essentially the way it was designed to perform,” Gerstenmaier said during another press conference last night. “We can land with three parachutes if we have to. This is potentially a known condition that can occur with the four parachutes — one of the four parachutes can be a little slow to deploy.”

Ultimately, NASA cleared the way for SpaceX to launch last night, but there is still one last item on the agency’s to-do list. Six hours before takeoff, NASA plans to fire up the International Space Station’s thrusters to move it out of the way of a piece of space debris — a precaution to make sure the vehicle doesn’t suffer any damage. The debris is a leftover fragment from 2007, when China destroyed one of its own satellites in space to prove that it could take out spacecraft in orbit. The test created thousands of pieces of debris, which still seem to be causing a nuisance in orbit.

However, the avoidance maneuver should not have an impact on today’s launch, which NASA says SpaceX can accommodate. After that, it’ll be time for the Crew-3 astronauts to fly, starting a six-month stay on board the ISS. They’re scheduled to return to Earth sometime in the spring of next year.

Update November 10th, 11:00AM ET: This post has been updated multiple times to indicate the various launch delays. New information was added about the Crew-2 landing and space debris avoidance maneuver.