SpaceX will launch its next mission to the International Space Station (ISS) on April 23. A crew of four astronauts will join Expedition 67 aboard the space station. Of the four, Italian ESA astronaut Samantha Cristoforetti will join the three American NASA astronauts on their journey. Among those astronauts is Jessica Watkins, who will become the first African-American woman to make a long-duration stay on the ISS.

These astronauts will ride aboard the Crew Dragon capsule Freedom, boosted by the much-tested Falcon 9 rocket. Once at the ISS, Expedition 67 will a few months aboard the space station before returning in the fall of 2022.

The Crew-4 astronauts named their Crew Dragon spacecraft Freedom. According to NASA, this is “to celebrate a fundamental human right, and the industry and innovation that emanate from the unencumbered human spirit.” This will be Freedom’s first flight.

Conversely, SpaceX is well-known for reusing its Falcon 9 rockets, and this mission is no exception. Crew-4 marks the fourth reuse of booster B1067. The rocket had previously powered the last NASA mission to the ISS, Crew-3.

What will Crew-4 do on the International Space Station?

Once on the International Space Station, the astronauts will conduct various research experiments, as well as general upkeep. NASA says that the Crew-4 astronauts will gather data for fields such as materials science, health technologies, and plant science in preparation for human expansion into the Solar System. In total, the astronauts will complete more than 200 science experiments over the course of their stay on the International Space Station.

SpaceX Crew-4 launch date, time, and schedule

The Crew-4 mission will launch no earlier than 5:26 a.m. Eastern time on Saturday, April 23. The Crew-4 launch vehicle will consist of a Crew Dragon capsule stuck atop a SpaceX Falcon 9 rocket. The Falcon 9 will lift off from pad LC-39A at the Kennedy Space Center in Florida. NASA is also naming Sunday, April 24 and Monday, April 25 as backup launch dates. You can watch the launch on either NASA TV or SpaceX’s website.

Originally slated to launch on April 20, NASA has already delayed the launch twice “to complete final prelaunch processing,” according to the agency. NASA said that the delay would give them time to “complete final prelaunch processing for the Crew-4 mission following the April 8 launch of Axiom Mission 1 (Ax-1) to the space station.”

Axiom 1, also launched by SpaceX, was the first-ever privately funded and operated trip to the International Space Station. NASA expects the Ax-1 crew to splashdown in the Atlantic ocean on April 20, just 3 days before Crew-4 launches.

SpaceX Crew-4 astronauts: Who’s on the ship?

The mission will contain four astronauts, with three Americans, and one Italian astronaut.

The astronauts aboard Crew-4 are:

1. NASA astronaut Kjell N. Lindgren as spacecraft commander
2. NASA astronaut Robert Hines as pilot
3. ESA astronaut Samantha Cristoforetti as mission specialist
4. NASA astronaut Jessica Watkins as mission specialist

As the mission’s spacecraft commander, Kjell Lindgren is responsible for overall mission success. He has to ensure that the astronauts aboard Crew-4 are safe, and that the capsule is in secure condition. Lindgren also bears responsibility for guiding the spacecraft during all stages of flight. On his projected 144 days aboard the Space Station, Lindgren will be a flight engineer. This is a broadly defined position that ESA astronaut Luca Parmitano described as “The plumbers, the engineers, the cooks, the scientists, the commanders” of the space station. This will mark Lindgren’s second spaceflight and trip to the space station since his 141-day visit back in 2015 aboard the Soyuz TMA-17M Soyuz flight.

Robert Hines will serve as Crew-4’s mission’s pilot. He will make sure that spacecraft systems are operational, as well as overall spacecraft performance. Pilot the spacecraft, alongside Lindgren. Contrary to popular belief, the spacecraft pilot is neither exclusively responsible for maneuvering the spacecraft, nor is that the only duty they are tasked with. This is Hines’ first mission as an astronaut, and he will also be a flight engineer on the ISS.

As the only ESA astronaut aboard Crew-4, Samantha Cristoforetti is one of the two mission specialists. At a whopping 199 days, the Italian astronaut currently holds the record for longest time in space of any European. As mission specialist, Cristoforetti will “monitor the spacecraft during the dynamic launch and re-entry phases of flight,” according to a NASA press release. This will mark her second trip to the International Space Station, where she will also serve as another flight engineer on the ISS.

Lastly, Jessica Watkins is the second mission specialist aboard Crew-4. Like Hines, this is Watkins’ first mission to space. It will be an important one though, as she is the first black woman to complete a long-term mission to the International Space Station. Watkins has worked on NASA’s Mars rover, Curiosity, at JPL. She will join the rest of the crew as a flight engineer on the ISS.