Complex sentence: The 1.54-tonne satellite was orbiting with a period of 23 hours two minutes, instead of the planned 24-hour geosynchronous orbit, only permitting a limited series of experiments to be conducted, including digital audio broadcasting and compressed digital TV signal transmission.
Split into simpler sentences: The 1.54-tonne satellite was orbiting with a period of 23 hours two minutes, instead of the planned 24-hour geosynchronous orbit. The satellite was to be used for a variety of experiments such as digital audio broadcasting and compressed digital TV signal transmission.