研制: development and construction.Could someone help me understand the underlined sentence? It mentions a training simulator for manned lunar landing. Does the sentence say/imply that the simulator is operational, or is it still under construction?
随即: hereon, thereupon, immediately after.
It means that the training immediately started after construction, it is operational now.
Unlike inducstrial product, there is only one simulator. Once the development is finished, it is constructed, there is no need to wait, just use it.