Low-earth-orbit satellites move across the sky, casting much smaller beams, so that large fleets of them are required to cover the entire planet simultaneously.

But they spotted it before then and afterward, as the satellite moved into sunlight.

The satellite can now move from one orbit to another with the help of the engine, which discharges no reaction mass.

They watched the television picture shift away from a flat in Brighton as the satellite moved.

Both the shuttle and the satellite were moving around Earth at 17,500 miles an hour.

This may be simplest with geostationary satellites because other satellites move too fast.

So from the ground it will look as though the satellite isn't moving.

Even as she watched, another one winked out, and this time the satellites did not move to compensate.

"The satellites are moving into position," continued the resident.

The plume observations were delayed for nine hours because the satellite moved into the wrong position.