A. Satellites are little instruments in relation to the vast expanse of outer space. So in theory, there will always be room for new satellites.

But in certain cases, spacing can be a concern, said astronomer James Lattis, director of the UW-Madison Space Place in Villager Mall.

For example, "geosynchronous" satellites - which have revolutionized weather forecasts and global communications - circle the planet once every day, with each satellite beaming its signal in a wide arc over the Earth.

To ensure those signals don't overlap, scientists must carefully launch geosynchronous satellites into specific locations in orbit, he said.

Space "junk" is another factor that can influence where a satellite can be placed, Lattis added. The debris - thousands of leftover nuts, bolts, rocket fragments and other bric-a-brac from past space missions - can hurtle around the Earth at speeds of up to 17,500 mph.

Moving at such speeds, space junk presents a serious hazard to satellites, astronauts and spacecraft, so scientists take care to place satellites out of harm's way.

Produced in cooperation with University Communications

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