SpaceX and NASA launched the Crew-4 mission early Wednesday morning, Florida time. The Crew Dragon docked with the International Space Station several hours later. This is the fifth crewed mission of NASA’s Commercial Crew program and SpaceX’s seventh crewed mission overall.
The crew includes NASA astronauts Kjell Lindgren, Jessica Watkins and Robert Hines and ESA astronaut Samantha Cristoforetti. Lindgren and Cristoforetti have visited the International Space Station before. This is the first flight for Watkins and Hines.
This is the first flight of their Crew Dragon, which they named “Freedom.” The name is a reference of the United States’ first crewed spaceflight, in which Alan Shepard spent 15 minute on a suborbital mission on the Mercury spacecraft Freedom 7.
Freedom 7 currently resides at the Smithsonian Air and Space Museum in Washington, D.C. The Freedom Crew Dragon is reusable with a little refurbishment and may not end up in a museum anytime soon.
The Crew Dragon Freedom is much more spacious than the cramped Mercury spacecraft and can carry up to seven passengers. So far, the Crew Dragons have only carried up to four passengers.
NASA and SpaceX initially pushed back the launch of Crew-4 to accommodate the Axiom-1 (AX-1) mission. AX-1 journeyed to the International Space Station on another of SpaceX’s four Crew Dragons to make initial preparations for the arrival of Axiom Space’s inflatable modules. Its return to Earth had been delayed due to bad weather in its target landing zone. AX-1 finally returned to Earth on April 25, 2022, after 15 days in space.
This made room for Crew-4, which will spend the next six months on the International Space Station as part of Expedition 67. According to NASA, they will spend their time conducting valuable research, especially in the medical sciences.
Planned experiments include the manufacture of artificial retinas in microgravity, which could be valuable for astronauts on long-duration missions. Astronauts frequently suffer degradation to their vision during missions that could last six months or even longer. The research may also lead to practical applications that help people on Earth that suffer vision issues related to their retinas.
Expedition 67 will also test aging of the immune system in microgravity. The immune system seems to “age” faster in microgravity. This experiment will study the role that stem cells and a form of white blood cell known as T cells play in this process.
These are just two of the more than 200 experiments that Expedition 67 will conduct during their six months on the International Space Station.
NASA’s Commercial Crew Program is part of its efforts to develop partnerships with private aerospace companies like SpaceX. Its efforts help incubate development of technologies that will be owned by the companies that create them.
NASA can effectively “rent” these technologies on an as-needed basis and the companies can use them for private applications. SpaceX has used the same Crew Dragons for its Commercial Crew contract and private missions like Axiom-1 and Inspiration4, for instance.
SpaceX has said that it won’t manufacture any more of the current generation of Crew Dragons, though it will still make parts to enable maintaining its current fleet. This does not rule out the possibility that it could manufacture more Crew Dragons if it needs to. However, it believed that four operational and reusable Crew Dragons will be enough to meet current demand now that Crew-4 and the “Freedom” Crew Dragon have launched and docked with the International Space Station.