New spy satellites and communication switchboards in the sky -- already planned for launch in 2002 well before the events of Sept. 11, 2001-- have been put on hold, in one case to give engineers time to improve the satellite so it can better track terrorist movements.

In the aftermath of the destruction of the World Trade Center, the damage to the Pentagon and the loss of life in Pennsylvania, U.S. officials are in the midst of a major reappraisal of how space can help thwart future attacks at home, as well as fight the enemy on distant battlefields.

Be it using robot drones, orbital bombers, and super-snooping satellites or carrying out down-and-dirty, hand-to-hand combat -- the utilization of space technology is now more vital than ever to assuring national and global security.

Unpiloted aerial vehicles, like this Predator craft, can be navigated via Global Positioning System (GPS) satellites. This class of vehicle can deliver bombs, carry out surveillance of the enemy, and serve a variety of behind-enemy-line duties - all without endangering human pilot. Credit: U.S. Air Force

Artist's rendering of a Lockheed Martin Defense Satellite Communication System (DSCS) spacecraft, which connects military bases to field operations from 22,300 miles up.

Air Force operates Milstar spacecraft that provide strategic tactical relay. These satellites are beefed up to withstand nuclear blasts in space.

The network of Global Positioning System (GPS) satellites are critical to military operations in the air, on the ground, and in Earth orbit.

During President George W. Bush's address to the nation in June, he highlighted the role of science and technology. "In the war against terrorism, America's vast science and technology base provides us with a key advantage."

Underscoring that view is White House science advisor, John Marburger.

"Our terrorist enemies are technically savvy, and continued technological progress is required to better defend the homeland and 'stay one step ahead' of their technical capabilities," Marburger remarked in a recent report to the White House. "American science and technology leadership can and will help the nation counter and respond to the terrorist threats we are confronting," he said.

Central to staying that one step ahead is growing cooperation and collaboration between the military, civil and industrial sectors. A search is on to find "crosscutting technologies".

For NASA's part, the agency has funded a treasure-trove of technologies, such as in biosensors. Built to spot extreme forms of life on other worlds, detectors also are needed to sense lethal biological agents spread by terrorists.

Work on robots that motor around on Mars can be applied to "androids" that serve homeland-defense missions. That includes surveillance and protection of population centers, facilities and assets, as well as rescue or cleanup in response to an attack.

Space suits replete with cooling tubes, climate-control systems and sensor technology could prove useful in designing the future military battle uniform.

Data management techniques needed to handle the outpouring of satellite information can help keep track of varying degrees of terrorist actions. In addition, systems analysis and systems engineering -- critical to the success of the Apollo, space shuttle and International Space Station efforts -- could be tapped to help counter terrorism.

Lastly, information security is a major element in the nation's vulnerabilities. NASA has made important contributions to computer-network technology over the years.

There are several unique uses of space technology that became especially evident post 9/11, said Joan Johnson-Freese, chair of the National Security Decision Making Department at the Naval War College in Newport, Rhode Island.

For one, Global Positioning System (GPS) satellites were used to record with great accuracy where debris was pulled from at ground zero in New York City. That sped up clean up and removal by a huge time factor, she said.

In another instance, Johnson-Freese added, the military's Defense Support Program (DSP) satellites found a new task early in the campaign to strike back at terrorists.

U.S. Air Force Space Command DSP spacecraft are equipped with infrared sensors to detect heat from missile and booster plumes against the Earth's background. Those same sensors picked up heat signatures from explosions in Afghanistan tunnels, Johnson-Freese said, permitting the U.S. military to identify what kind of ordinance was stored there.

"Increasingly, use of space assets is becoming an accepted tool, by civilians and the military, not an oddity," Johnson-Freese noted. "The technology has been integrated into mainstream use, rather than one thought-of, let alone used, by only a select handful. Whereas the Gulf War has often been referred to as the first Space War, in retrospect it was a trial run so that we could get it right with the War on Terrorism."

The United States has come a long way in integrating space and ground structure, particularly since Desert Storm when some of the first applications of the GPS were used.

"We still have a long way to go," said John Parsons of The Aerospace Corporation, speaking at a recent gathering of experts on national security and satellites. "There are a lot of new technologies and architectures that will enhance the role of space in military applications."

Space technology has been integral to the war on terrorism in at least two principal ways -- intelligence and communications support, suggests Steven Aftergood, director of the Project on Government Secrecy for the Federation of American Scientists in Washington, D.C.

"Of course, both of these functions are nearly as old as the space age. But the war on terrorism has given them a new focus: acquisition of imagery, signals intelligence, and other intelligence data to combat terrorism in many corners of the globe together with the means to rapidly share and disseminate such data," Aftergood said.

The post-9/11 environment also has had a "negative" impact on a variety of programs, Aftergood said, by imposing new priorities and weeding out some of the lower priority programs.

One high-tech commercial impact stemming from the terrorist attack on America last year involved private-sector Earth remote sensing satellites.

The events of 9/11 validated and accelerated the government's interest in high-resolution commercial imaging, said Mark Brender, Executive Director of Space Imaging's Government Affairs & Corporate Communications in Arlington, Va. Space Imaging, based in Thornton, Colo., operates the super-powerful, but privately controlled Ikonos satellite.

"During Operation Enduring Freedom last fall, Space Imaging provided assured access and exclusive rights to imagery taken over Afghanistan and Pakistan. Ikonos collected some 470,000 square kilometers of high-quality, map accurate imagery. We were able to meet all of their requirements on short notice," Brender said.

Since 9/11 there has been a shift in the government's attitudes regarding commercial imaging, Brender said.

The Pentagon is buying more products and services to support the military mapping mission. Since June when the Director of Central Intelligence directed that commercial imagery be used for the military mapping mission, Space Imaging has witnessed an increase in orders, Brender said.

Murray Felsher, Editor of the Washington Remote Sensing Letter, sees a blossoming of the commercial satellite imaging community in the post-9/11 world.

"The fact is that since 9/11 the global remote sensing community -- government and industry, both here and abroad -- has been drawn much closer together."

Felsher said there is a unified, but still largely uncoordinated, willingness by all involved parties to provide the U.S. political leadership with the geospatial intelligence and technological means to prevent, forestall, evaluate, predict, measure, and assess all manner of threats to national security.

"Rest assured that remote sensing -- all-platform remote sensing -- will play a major role in these efforts, and we will see greater and greater emphasis placed on imagery derived via commercial sources.

While using "show and tell" satellite imagery is increasingly in vogue -- such as building up the case against Iraqi President Saddam Hussein -- some experts see too great a reliance on spaceborne sensors.

Plowing loads of money into space-based spying is a concern of Robert David Steele, 25-year veteran of the national security community. He is author of On Intelligence: Spies and Secrecy in an Open World.

"Space-based intelligence right now is the Achilles' heel of the U.S. intelligence community. It is grossly over-funded and terribly mismanaged," argues Steele. "It's waste robs the American taxpayer of the funds needed to restore the capabilities of our human intelligence assets--our clandestine cadre, our all-source analysts, our non-existent counterintelligence and covert action branches," he said.

Military, government and industry experts largely agree: space has changed the paradigm of warfare.

That view is shared by Brigadier General Simon Worden, Deputy Director of Operations for the U.S. Space Command in Colorado Springs, Colorado. He painted a high-tech picture of the current war on terrorism for SPACE.com.

Upgraded and well-integrated satellite systems, making use of emerging technologies, are leading to more instantaneous communication and data transfer in military missions.

Worden said that U.S. military forces fighting al-Qaeda and the Taliban are less in number than soldiers once engaged in the Persian Gulf war. Yet war fighters now deployed have access to an order of magnitude more bandwidth to carry out operations.

"The reason for that is the explosive growth in using unmanned aerial vehicles (UAVs)," Worden said.

Increased proliferation of UAVs, geared for reconnaissance and other duties, demand more and more bandwidth. That is being made possible via satellite links. "We have been able to move some satellites around. We have looked very carefully at launch schedules, and we've accelerated some of those schedules…to provide greatly expanded bandwidth," Worden said. "There is huge attention to increasing bandwidth."

Another satellite success story, Worden said, is the performance of Global Positioning System satellites. "They have proven phenomenal. In this conflict, more than anything, accuracy is essential," he said.

Afghanistan is a special operations war, consisting of uniquely trained soldiers, some even riding horses through the mountains of that country.

"In the past, we didn't talk to those guys. We didn't know what 'snake eaters' did. And they didn't know what Space Command was. But these special forces are effective because they have got direct connection to spacebased capabilities across the board," Worden said. "This is probably the major story coming out. In this current war on terrorism, what gives special operations the edge is access to high-technology."

In looking to the future, Worden foresees needed organizational change. Doing so will further beef up U.S. military prowess by assimilating space technology. Next generation communications architectures are in the offing. So too is global, real-time, all-weather battlefield surveillance. Then there's "force application", "to apply force precisely, globally, and as quickly as you can," Worden said. "That's the essence of both a strategic deterrent and a strategic force capability."

Worden said that some of that force can be applied through cyberspace, rather than populating the heavens with laser battle stations. "For the foreseeable future, placing weapons in space is probably not a very cost-effective, or maybe even an effective way to do things," he said.

Still a work in progress is the issue of access to space, the need for new generations of boosters. Many studies have tried to tackle the topic in the past. "This is the ultimate cat herding," Worden said.

"Access to space underlies everything. It is essential that we get an answer to that, get moving on it, and that it's the right answer. That probably tells me that it is not cheap. Also, it probably isn't a one-approach-fixes-everything kind of thing," Worden concluded.

Now on track for this October, Worden said, is an initiative to help transform the U.S. military into a 21st century fighting force. Two unified commands whose missions include control of America's nuclear forces, military space operations, computer network operations, strategic warning and global planning are to be merged. That fusion brings together the U.S. Space Command with the U.S. Strategic Command. The intent of this will improve combat effectiveness and speed up information collection and assessment needed for strategic decision-making.

"We are seeing intent to do modernization, and space is part of it," Worden said.