The Navy has been in space since the end of World War II, when it began bouncing radio waves off the atmosphere to reach ships out at sea. The Navy realized that "communication could be a huge advantage for ships," said Pete Wilhelm, director of the Naval Center for Space Technology, a branch of NRL.

When satellites began getting more complex, with transistors and solar cells, messages could be sent to ships very easily. Navigation satellites came next, because "if you want to shoot from a submarine, you need to know where you are," Wilhelm said.

The first navigation satellites could not help the covert action of submarines because they had to come to the surface for 15 minutes to calculate positions. But by the time the sixties rolled around, Wilhelm said, the Navy had developed the technology to synchronize the satellites and the devices on the submarines so that they did not have to come to the surface.

One of the more unusual satellites the Navy has in orbit is called a tethered satellite. The satellite is made of two masses separated by a distance, which makes the whole thing align vertically to the earth, Wilhelm said. The satellite stays vertical because the two masses are moving at different speeds on the end of the tether. The higher mass pulls up while the slower-moving lower mass tends to fall toward earth.

The tether is about four kilometers long, and when fitted with a conductive wire and an electron gun, the satellite can move up or down in orbit. This is especially valuable to dead satellites, he said.

Wilhelm said that if a dead satellite needed to be moved out of orbit, it simply could deploy a tether and something as small as a two pound weight. After completing the electrical circuit, the space junk can be moved out of orbit.

According to NASA, the tether system "has the potential to provide a near-propellantless propulsive capability to upper stages." Using the earths magnetic field, the charged particles in the tether can move the satellite.

"It's cheaper and simpler," Wilhelm said. "A satellite could be totally dead and could still do it."

He added that some people didn't think the tether would survive for very long with the danger of space debris breaking it.

"Some people said it wouldn't last a week," Wilhelm said. The Tether Physics and Survivability Experiment (TiPS) satellite has now been in orbit for three years.

But the Navy space program also delves into space science. The two major subjects of the Space Sciences Division are ionosphere and solar research, said Dr. Herbert Gursky, the superintendent of the division.

"The sun is a driver for a lot of the phenomena that takes place in space," Gursky said. His division develops instruments for many of the satellites that study space, like NASA's Solar and Heliospheric Observatory (SOHO).

SOHO uses a lens developed by the Space Sciences Division that spies on the solar atmosphere and tries to spot solar eruptions. The eruptions can cause magnetic storms that travel to earth and not only disrupt communications vital to the Navy fleet, but also wreak havoc with power transformers around the globe. The transformers can burn out and cities can lose power. With the Navy's lens, scientists have about three days before the storm arrives, so they can prepare for the power outage.

Gursky's division also studies the atmosphere he said. His division is just beginning research on the weather and its patterns above the troposphere, he said, which could yield understanding of long term climate changes.