One scenario in which NOSS satellites could play a vital role: monitoring the position of the Chinese navy in any potential conflict with Taiwan.

Originally scheduled for launch in the late 1990s, the newest generation of more capable spacecraft are built by Lockheed Martin reportedly to operate against both land- and ocean-based targets.

Previously launched on the larger and more expensive Titan 4, these newly designed satellites are apparently small enough and light enough to take their ride into space atop the less powerful Atlas 2AS rocket, and in the future the Delta 4.

Saturday's mission is expected to take about 73 minutes from launch to spacecraft separation.

Titan 4 up next

If all goes well this weekend, the NRO will have little time to celebrate their success before gathering back at Vandenberg for another launch, this one targeted to fly on Oct. 1 using America's biggest unmanned booster, the Titan 4B.

Another secret satellite will ride atop the Lockheed Martin-built rocket, and as yet there are few firm indications as to the identity of this particular classified cargo.

The Air Force has yet to publicly disclose the length of the Titan's payload fairing -- an important clue that often helps to identify the spacecraft and its mission. Nevertheless, industry experts and outside observers believe the payload will be some sort of imaging satellite.

A likely candidate may be an improved version of a radar imaging satellite nicknamed Onyx and previously called Lacrosse, said analyst Jeffrey Richelson -- author of a new book The Wizards of Langley: Inside the CIA's Directorate of Science and Technology -- who is an independent expert on intelligence collection systems and has written about the Onyx program.

"A radar-imagery satellite, rather than a visible light or infrared sensing satellite, can obtain imagery both at night and in the presence of cloud cover. In that sense, Onyx gives you additional opportunities to cover a target because you have satellites that can obtain imagery in conditions other than visible light," Richelson said.

Richelson is among those who believe that an advanced radar-imaging spacecraft is likely to be deployed.

"It is a reasonable assumption that we still have that program. The current focus on 'continuity of coverage' would seem to indicate a need for this. Without it, denial and deception would be much easier [for potential adversaries]. Right now, you can have five different spacecraft at five different places at the same time. I don't see any reason why Onyx would be canceled," suggests Richelson.

Canadian space analyst Ted Molczan, an international expert in tracking classified U.S. space assets, speculates that the Titan 4B "will be the second launch of a mystery satellite" similar to one launched in 1999.

This mystery 1999 spacecraft, known as USA-144, was launched from Vandenberg on May 22, 1999 into a very unusual 1,677 by 1,944 miles-high (2,700 by 3,130 kilometers-high) orbit -- much higher in altitude than a conventional imaging spacecraft.

Published accounts have speculated that USA-144 was the first launch of a new reconnaissance spacecraft known officially as the Enhanced Imaging System (EIS).

The system is designed to take images over a broader area coverage, has the ability to "hang" or dwell for a longer period over an area of interest and includes the capability to transmit its collected data more rapidly. These advancements hint at the requirement for a higher orbit, such as that of USA-144.

In March 1998, NRO Director Keith Hall testified before Congress and said, "In the area of imagery intelligence, we are completing the development of the Enhanced Imaging System in response to growing customer demands and large area imagery collection shortfalls."

Richelson concedes that the EIS is a possibility for the Titan's secret payload.

"By now, EIS is a candidate. There is no evidence that imagery spacecraft are getting smaller. All imagery payloads are still being launched on Titan 4 or [subsequent] large launch vehicles," he said.

An Atlas from the Cape

A final NRO payload for 2001 is scheduled to be lofted into orbit atop an Atlas 2AS rocket, this time from Cape Canaveral Air Force Station. Designated MLV-12, the mission is set to fly on Oct. 11, according to the Eastern Range schedule.

Military space analysts believe that this spacecraft may be a new, smaller variation of either a classified Satellite Data System (SDS) spacecraft or a signals intelligence satellite -- downsized to fit on the smaller, cheaper Atlas 2AS rocket instead of the behemoth Titan 4B heavy-lift launcher.

Another Atlas 2AS was launched from Cape Canaveral to geosynchronous orbit late last year and military space observers are not sure what it was, although a new signals intelligence satellite remains the most likely possibility.

The key to this MLV-12 mission will be the orbit that the satellite is launched into. Nine of the last ten classified launches to geosynchronous orbit have been signals intelligence satellites. A satellite launched into a highly elliptical orbit would likely be an SDS satellite.

Such spacecraft provide both a communications capability with nuclear bombers flying over the polar regions as well as a relay for imagery from imaging reconnaissance satellites when operating out of range of the ground-based receiving stations. They may also carry an extremely high frequency transponder to communicate covertly with nuclear submarines running "silent and deep."