KENNEDY SPACE CENTER, Florida (CNN) -- The Air Force launched a top-secret satellite Tuesday for the National Reconnaissance Office, which operates the United States' fleet of spy spacecraft.

A Titan IV-B rocket was used to launch the large spacecraft, believed to be an electronics listening satellite, into a position 22,300 miles above the Earth's equator.

The National Reconnaissance Office would not reveal any details about the satellite, including its cost, purpose or which contractor built it.

"I cannot discuss what the payload is other than to tell you that it will provide additional capabilities for our nation's leadership and military," said Art Haubold, a spokesman for the NRO.

This particular satellite was delayed for more than three years due to technical problems and had been scheduled for launch as recently as several months ago.

The NRO's electronics listening satellites use baseball diamond-size antennas which fold up like an umbrella for launch.

The large antennas permit the satellite to monitor extremely faint signals, even individual cell phone conversations.

It's believed that similar satellites have been used to monitor and track terrorists.

Astronomer and satellite observer Ted Molczan said: "These satellites are so large they can be seen in high quality backyard telescopes. Some amateur satellite observers have photographed these satellites in their operational locations."

The new heavy-duty spy satellite for the National Reconnaissance Office (NRO) arrived in Earth orbit Tuesday following a successful ride into space atop the United States' most powerful unmanned rocket -- we think.

Following a stricter policy than seen before, launch commentary was concluded about 19 minutes into flight and NRO officials said they would not confirm anything more, including spacecraft separation, which is the point where a launch is declared a success or failure.

What is known is that the nearly six-hour satellite delivery mission began at 12:29 a.m. EDT Tuesday (0429 GMT) with the launch of an Air Force Titan 4B rocket from Cape Canaveral Air Force Station.

Equipped for the final time in history with a Centaur upper stage, the Lockheed Martin Titan 4B (B-36) rocket worked flawlessly as it carried the NRO spacecraft toward geosynchronous orbit.

The flight began with the ignition of the rocket's twin solid rocket boosters and a quick climb through a low cloud deck that created a spectacular display of light and shadows over Florida's Space Coast.

Two minutes and 11 seconds later the twin-engines of the Titan's core first stage fired up, allowing the spent boosters to be jettisoned about 15 seconds later. Three brilliant points of light could be followed as the boosters fell and the Titan continued on its way.

A burn of the Titan 4B's second stage, followed by the first of three planned burns of the high-energy Centaur upper stage were confirmed before officials stopped providing updates.

If all went well from there, the Centaur upper stage would have placed the NRO spacecraft into a geosynchronous transfer orbit about 27 minutes after launch.

Then a long 5.5-hour coast period followed as the Centaur upper stage and its still-attached spacecraft climbed 22,300 miles above the planet. A third Centaur burn was to circularize the orbit and set up conditions for spacecraft separation.

Just about 6:15 a.m. EDT (1015 GMT) the NRO platform was to be successfully delivered into its proper orbit and launch officials could then declare a success.

Officials won't release any details as to the exact nature of the NRO satellite, which industry observers believe is a signals intelligence spacecraft, capable of eavesdropping on electronic communications of all types.

That conclusion is based on known facts such as the flight path of the Titan 4B at launch, the inclusion of a Centaur upper stage on the vehicle as well as the size of the rocket's nose cone, which in this case is 86 feet (26 meters) long.

It is expected the spacecraft will provide the nation's top military leaders and policy makers with information needed to execute the war against terrorism, as well as keep tabs on other hot spots around the world.

Unspecified problems with the spacecraft last year and the desire to launch a MILSTAR communications platform earlier this year delayed the launch to late this summer.

An attempt to launch in August was delayed because of a propellant leak at complex 40. After that spill was taken care of, a battery problem on the rocket and another issue with the spacecraft delayed the shot to Monday night.

A planned 11:12 p.m. EDT Monday (0312 GMT Tuesday) blast off was delayed at the last minute by concerns raised about a temperature reading on the Centaur upper stage.

Engineers determined the indication would not be a problem and, after waiting about 30 minutes for some new weather balloon data to be processed, re-set the launch time and picked up the countdown again.

Although Centaur hardware will continue to fly on other rockets, Tuesday's shot marked the last time the Titan-Centaur combination would fly as there are just three more Titan 4's left to fly and none of those missions requires the extra lifting power of the Centaur.

Titan-Centaur combinations have carried some of the most important missions in space program history, including both Viking probes to Mars and both Voyager probes to the outer planets.

Two more Titan 4's are scheduled for launch from the Cape through 2004, and the final Titan 4 is to fly from Vandenberg Air Force Base in California during 2005.