A little while ago, SpaceX’s Crew Dragon spacecraft docked with the International Space Station’s Harmony module by completing the first leg of its SpX-DM1 (SpaceX Demonstration Mission 1) or SpaceX Demo-1 mission that started yesterday with its launch. The opening of the hatch is scheduled for 13.45 UTC and all the tasks concerning the Crew Dragon will be completed rather quickly, since its departure is scheduled for March 8.
Unlike the Dragon space cargo ship, which gets captured by the Canadarm2 robotic arm and driven to one of the International Space Station modules, the Crew Dragon is equipped with an automated docking system that drives it to the International Docking Adapter (IDA). The approach to the Station instead follows a substantially identical procedure. The Station’s safety is the top priority so every little step of the Dragon is checked up. Only if everything goes well in the spacecraft’s position and speed they proceed with the next step and in case of problems they can have an abort at every step. In this test mission the verification that these systems work properly and of the Crew Dragon’s maneuvering possibilities are crucial so the procedure was a bit longer than normal.
The Crew Dragon spacecraft was also used to transport some cargoes for a total of about 180 kg (about 400 lbs). In the next few days they will be unloaded and some cargoes will be brought back to Earth on the return journey. This possibility, which limits the number of people that can be trasnported, was decided because many biological experiments are carried out on the International Space Station and in some of them the astronauts themselves are the guinea pigs with the consequence that various samples are taken to be sent to Earth as soon as possible to be analyzed. For years the Dragon cargo spacecraft has been the only one that could bring cargoes back to Earth but between a mission several months can pass so it’s useful to use manned spacecraft to bring biological samples as well.
According to the schedule, at 7:30 UTC on March 8 the Crew Dragon spacecraft will depart the International Space Station to return to Earth. SpaceX developed a landing system on the mainland but at least for now NASA opted for a splash down like its old manned spacecraft and the Dragon space cargo ship. The return journey is scheduled last a little over six hours and after splashing down the Crew Dragon will be recovered and returned to the mainland where it will be physically examined and the data collected by the on board sensors will be analyzed, including the ones connected to the Anthropomorphic Test Device (ATD) nicknamed Ripley. It’s already a historical moment.