The reason for this postponement is the time required to transport the completed spacecraft to the spaceport in French Guiana and mount it on a rocket.
The James Webb Space Telescope will be launched with the large rocket Ariane 5, but due to the shipping status of the telescope and the progress of preparations for Ariane 5 and the spaceport side, it is expected that a few weeks will be required from this date.
NASA plans to ship the telescope to the spaceport, but the shipping schedule has not been clarified due to concerns about pirate infestation on that route. However, it is said that the loading work on the ship will be around the end of August, and there is not much time left for transportation.
Even after the ship arrives safely, it will take 55 days to prepare for the launch, and considering that, it is currently predicted that the launch will be carried out after mid-November at the earliest.
The preparation of the Ariane 5 rocket is not without delay. This has never been launched since August 2020, when a defect in the fairing covering the payload was discovered.
It is said that the problem has already been resolved, but for confirmation, two launches are scheduled for July to August before the actual launch. If these appointments are delayed, the space telescope can also be stalled.
On the other hand, there are signs that preparations on the spaceport side will be delayed. This is because French Guiana has not yet received a new corona vaccine, and the possibility that the schedule will be delayed depending on the infection situation has not yet been eliminated.
The James Webb Space Telescope must unlock 178 locations after launch and then deploy approximately 50 locations. NASA is doing things very carefully because all of this needs to be completed successfully.