Late last year, Space Imaging Corporation launched Ikonos, a satellite able to image objects as small as 1 meter (3 feet) long, anywhere on the planet. Early this year, we at the Federation of American Scientists ordered an image of the secret military base known as Area 51. We sought to test the capabilities and accessibility of this new technology.

Some 10 weeks later, with the Area 51 image on our website, we now have a clearer picture of not only the secret military base at Groom Lake, but of the limits of "near-real-time" imagery acquisition.

Historically, Area 51 is where the U 2, A 12, SR 71, D 21 Drone and F 117 Stealth Fighter were flight-tested in secret. Area 51 is an advanced-technology flight-test center -- a "black" version of Edwards Air Force Base. Speculation aside, the 1-meter Ikonos image we purchased shows buildings and facilities consistent with those at Edwards AFB.

A new 11,900-foot (3,625-meter) runway was built after the F 117 Stealth Fighter program became public knowledge. In 1995 the Department of the Interior withdrew over 3,900 acres (1,578 hectares) of public land that curiosity-seekers used to observe activity at Area 51. These facts taken together point to ongoing flight-test activity or at least a desire on the Air Force's part to maintain such a capability at Area 51 for the foreseeable future.

The other thing we learned from our experience purchasing the Area 51 image was the limits that weather and tasking constraints place on the ability to acquire "near-real-time" imagery. Almost from the beginning of the availability of commercial satellite imagery, defense officials and the public-policy community have voiced concerns over the possible national security implications of commercial remote sensing.

Some analysts have asserted that terrorists, rogue nations or adversaries might be able to use high -resolution imagery to plan attacks on U.S. troops or thwart U.S. military operations. Some have argued that "shutter control" might have to be imposed -- that U.S.-government officials would have to limit access to imagery during times when national security or international treaties might be affected.

Our experience with the Area 51 image shows "near-real-time" can be a concept denominated in weeks, not days. When conditions are ideal, an image can be tasked, collected and processed in hours, as in the case of the Ikonos image showing tornado damage in Fort Worth, Texas. But ideal conditions are the exception, not the norm. Over 60 percent of the world is covered by clouds. Given the three-day revisit time between satellite passes, it could take from several to dozens of passes to get a cloud-free image.

Imagery acquired by government intelligence agencies as reference material for their target folders is not time-sensitive. For this application, waiting months is acceptable. But the operational or tactical user, such as a battlefield commander, cannot wait months, or even days, for imagery of the battlefield to be collected. Such pictures have an extremely short shelf-life.

Uncertainty of acquisition will be another problem for anyone seeking to gain military advantage from commercial imagery. Will the next image arrive on a battlefield commander's desk in a week, a month or longer? Those who are entrusted to fight their nation's wars simply cannot count on maybe.

Ideal conditions are the exception, not the norm. Over 60 percent of theworld is covered by clouds.
     

Our experience with the Area 51 image demonstrates the uncertainty and unreliability inherent in acquiring commercial imagery. Such factors limit its potential utility in any future conflict. Certainly, nations can, and already have started to, order imagery sets of their rivals' military installations.

But should a war start, cloud cover and tasking problems could render such imagery a curiosity. Add the mere possibility of U.S.-imposed shutter control, and commercial high-resolution satellite imagery will be virtually useless to foreign battlefield commanders. For the foreseeable future, belligerent nations will not be able to rely on U.S. commercial high-resolution satellite imagery for use in warfare.

Weather and tasking issues pose sufficient limits on foreign military use that U.S.-imposed shutter control will not be necessary for some time to come. Any foreign intelligence official who promises the local dictator a military advantage from commercial, high-resolution imagery is taking a big, personal risk.