A few hours ago, SpaceX’s Crew Dragon Freedom spacecraft docked to the International Space Station’s Harmony module completing the first part of its Crew-4 or SpaceX Crew-4 mission that began almost 16 hours earlier with its launch. After checking that the pressure is correctly balanced, the hatch will be opened to allow Robert Hines, Samantha Cristoforetti, Jessica Watkins, and Kjell Lindgren to enter the Station.
The Crew Dragon spacecraft is equipped with an automated docking system to the International Docking Adapter (IDA). The approach procedure, with safety as the top priority, has been extensively tested during the Crew Dragon spacecraft’s previous missions.
The position of the International Space Station in its orbit matters a lot in calculating the time it takes to reach it. In the previous Crew Dragon spacecraft’s missions, the journey took about one day but a favorable position of the Station already allowed the Ax-1 mission to reduce the time to about 16 hours. The Freedom reached the Station almost 40 minutes earlier than the original schedule, so it took less than 16 hours of travel.
The Crew-4 mission’s crew met the Crew-3 mission’s crew, which is scheduled to come back to Earth in early May. Already the Ax-1 mission ended a few days late due to bad weather in the splashdown area and the problem could happen again. There’s more traffic than usual with various Crew Dragon spacecraft arriving and leaving the Station within a few days. This offers an idea of the possible situation in the future with an increase in SpaceX missions and the beginning of Boeing missions to the International Space Station and later to commercial space stations.
The Crew-4 mission will last until September 2022 as part of Expedition 67. Originally, it was scheduled to have a longer duration and Samantha Cristoforetti was supposed to take on the role of Station Commander in the first part of Expedition 68 but this plan changed with the shortening of the Crew-4 mission.
Actually, there may be further changes in a crew rotation schedule, which is becoming quite fluid. When the Russian Soyuz spacecraft were the only ones carrying astronauts and cosmonauts, the rotation was determined by their journeys but now that SpaceX’s missions have become normal, the rotation is more frequent and the schedule can change following the combinations of the launch programs of the different space agencies.