The sending of commands to spacecraft in the present time. This may be necessary to add an activity to a mission, or to correct mistakes discovered in the on-board command sequences. Real-time commanding, however, is a high-risk operation because of the possibility that an incorrect command file may be uplinked or that typographical errors may occur. In contrast, the planned command sequences already stored on the vehicle have been carefully devised and tested.
Subjects: Astronomy and Astrophysics.