PHILADELPHIA -- A clearing in the weather, which allowed American spy satellites to firmly locate Iraqi military targets, helped set the timing of the war, experts say.
Until Tuesday, clouds had obscured the view of the region, blinding the watching satellites. And clouds were predicted to roll in again tomorrow.
The United States has at least five reconnaissance satellites taking pictures of military operations in Iraq and Kuwait. With the recent opening in the cloud cover, the commanders of Operation Desert Shield received a detailed picture of the position of Iraqi troops, aircraft, and tanks. Stationary bombing targets, such as Iraqi radar stations, were already well-known.
"In this war, satellites are one of the major advantages that the U.S. has over the Iraqi forces," said John Pike, a space programs expert with the Federation of American Scientists. "We have a God's-eye view of the battlefield. We can watch them -- and they can't watch us."
Pike and others said U.S. satellites have been one of the key elements in planning for war in the Middle East since the Aug. 2 invasion of Kuwait. It was American satellites that discovered Iraqi troops massing along the borders of Saudi Arabia.
In addition to the imaging satellites, there are two satellites that listen in on Iraqi communications; several orbiting infrared detectors, designed to pick up the hot exhaust of a missile launch and give warning; navigation satellites; communication satellites; and military weather satellites.
"This conflict will be the first real test of how well the U.S. has exploited space technology," said Paul Stares, a senior fellow in foreign policy at the Brookings Institution in Washington. "There's no doubt that satellites are intended to play a major, vital role in this conflict. Their military uses have already been proven in peace. Now, we'll learn how well they work in a high-intensity war."
The centerpiece of the reconnaissance satellite program is the "Keyhole" satellites -- the KH-11s and KH-12s -- which reportedly cost more than $1 billion each. The Keyhole series uses advanced telescope technology to spy on the planet.
The program is so secret, specialists say, that the Defense Department refused to make available its state-of-the-art equipment to test NASA's flawed Hubble Space Telescope.
These satellites circle in a low-Earth orbit, about 150 miles high. They can see details on the ground to a resolution of 6 inches or less, meaning they could not make out Saddam Hussein's face, but can easily find human targets.
Jeffrey Richelson, the author of the 1990 book, "America's Secret Eyes in Space," said there are between four and six Keyhole satellites now monitoring Iraq. Half are thought to have infrared sensors -- which detect heat -- giving them night vision as well.
"But none of them can penetrate cloud cover," Richelson said.