The Starliner launch didn't go as planned today
After being released by the rocket, Starliner was supposed to use its Orbital Maneuvering and Attitude Control engines to provide the thrust needed to reach a stable orbit and begin the process of catching up to the International Space Station. But that did not happen.
What intrigued me was this part
When ground-based controllers realized the problem, they immediately sent a command to begin the orbital insertion burn, but due to a communications problem—which could have been a gap in coverage of NASA's Tracking and Data Relay Satellite System or some spacecraft error—those commands were not received right away by Starliner. So it continued to expend fuel to maintain a precise attitude.
What do they mean by a gap in coverage? Is there some part of orbit that cannot be reached by a satellite or a ground station?