If its design is changed by the US, JEM's design also has to be changed. This affects our task schedules, and we face difficulties in international technical negotiation. MHI produces aircraft and rockets. Producing JEM requires high level technology. Rocket missions are short, so there is no need to maintain them after they are launched.
Aircraft can receive maintenance after the flight, on the ground.
After Space Station is launched, however, only astronauts are available, so it has to be designed considering maintenance and operations activities performed by astronauts only. Also, if a space suit is damaged during extravehicular activities, it is very dangerous, so it is very important to design the equipment with no sharp edges. To avoid air leaks, primary structure is produced by welding a large aluminum sheet. Welding an aluminum structure that is four meters in diameter requires extremely high-level technology, which MHI is proud of. Welded parts are checked by X-ray testing.