A typical scene from the conflict in Afghanistan, where for the first time space-specifically, more than one hundred orbiting military satellites-has been a centerpiece of the war machine: A soldier on the ground spots a Taliban target. With a lightweight, handheld Global Positioning System (GPS) receiver known as a "plugger," he uses the constellation of GPS satellites to calculate the longitude and latitude of his mark and phones in the coordinates, via satellite, to an air base in Florida. From there, an alert is sent to commanders in Saudi Arabia, who direct a Predator drone to fly over the Taliban site and relay real-time video of the scene-again, via satellite. The target is approved for bombing, and a B-52 pilot, cruising more than 20,000 feet overhead, safely out of range of antiaircraft missiles, punches the GPS coordinates into the computer of a Joint Direct Attack Munitions (JDAM) bomb before releasing it. The bomb uses its own GPS receiver to careen Earthward toward the target, exploding within a few feet of it. The whole process takes only minutes, not days as in previous wars. And the $20,000 JDAM bomb is a bargain compared with already old-fashioned $100,000 laser-guided bombs, which have difficulty finding their targets through dust, clouds, and smoke.
But there were regrettable incidents as well. In December, after an Air Force spotter calculated the position of a Taliban target with his plugger, the device's battery went dead. The spotter changed the battery and relayed the GPS coordinates to a B-52 approaching the target. What the spotter didn't realize was that his plugger was programmed to display the coordinates of its own location upon rebooting. A 2,000-pound JDAM bomb landed with devastating precision, killing three Special Forces soldiers and five Afghan allies.
Even without human error, space military technology can be unreliable. GPS signals are easily jammed; the sharpest-eyed spy satellites have trouble seeing through clouds; and communications among myriad military forces and systems frequently clog the airwaves. Meanwhile, military satellites are completely undefended and vulnerable to attack.
The solution, if space is going to play a bigger role in future warfare, say Secretary of Defense Donald Rumsfeld and others within the administration, is "space control." Defense strategists aren't just concerned about repairing deficiencies; they see space as a new and largely unexploited frontier. In other words, they want to seize the high ground in space-not just to watch the globe for enemy activities or to launch strikes from space, but also to deny adversaries access to space as a military vantage point. It's a risky approach, with its share of critics, because it invites countermeasures from potential adversaries and terrorists-and possibly all-out war in space.
Still, riding this doctrine, U.S. military planners are pursuing dozens of space-based technology efforts. New assets in the works include satellites that can see through camouflage, space-based radar that can monitor the movements of troops and vehicles, more powerful communications satellites to give soldiers cellphone-like connections, and orbiting sensors that can track ballistic missiles. The hardware on the Pentagon's wish list includes items that have offensive as well as defensive potential-such as a military spaceplane, a space-based laser, and a reentry vehicle that could drop bombs of virtually any size. Here's a preview of what may be in orbit in the coming years.
The National Reconnaissance Office and the Pentagon are planning to replace virtually their entire inventory of imaging satellites during the next decade or so at a cost of more than $60 billion. The plan is to buy a fleet of birds with much keener eyes than today's optical imaging satellites and eventually to purchase equipment that can, unlike current satellites, provide continuous visual data about a target.
One technology under consideration: hyperspectral satellites that take images in hundreds of different infrared and visible bands of light. Such satellites could be useful, for instance, in uncovering a tank hidden by a camouflage net, because infrared imaging would detect the heat coming from the engine (see "Nowhere to Hide," Aug. '01).
Another technology under review is a space-based radar network that will continuously bounce signals off Earth's surface and under all conditions-even low clouds, storms, or darkness-detect moving targets such as trucks and missile launchers. "If you're a bad guy and you move, we'll see you move," says Robert Dickman, deputy for military space in the Office of the Undersecretary of the Air Force.
The military already uses airplane-mounted radar to spot moving ground targets-such as during surveillance of the "Highway of Death," the main road between Kuwait and Iraq during the Persian Gulf War. And in 1994 and 2000, NASA successfully orbited radar systems on the space shuttle. But for the global, around-the-clock radar coverage that the Pentagon wants-a system that would not risk pilots' lives or intrude in foreign airspace-a constellation of two dozen or more high-powered satellites in low Earth orbit would be needed. "We would like to be able to fly around the end of the decade," says Dickman, "but space-based radar is a tough challenge technologically and it's also a challenge financially."
The key obstacles: Not only must the system provide a penetrating view of "denied" territory from a great distance, well above where an airplane can fly, but it must also be integrated with existing communications equipment so that information can be instantly relayed to forces on the ground and in the air. And even if these problems are overcome, using existing satellite technology it may not be possible to place enough of these devices in space to achieve full coverage because of the billions of dollars it takes to build and launch them. Congress has already killed one proposed satellite radar network, known as Discoverer II, because it didn't meet cost expectations, and the Air Force and MIT's Lincoln Laboratory are currently conducting an analysis of alternatives expected to be completed in November of next year.
One possibility is the Technology Satellite of the 21st Century, or TechSat 21, a concept being studied by the Air Force Research Laboratory (see One System, Many Eyes," left). Instead of large satellites the size and weight of cars, TechSat 21 would use "virtual satellites"-clusters of microsatellites weighing about 300 pounds apiece. Each microsatellite would have a bistatic receiver that would not only detect radar signals bouncing off Earth from its own transmitter, but also the signals sent by its neighbors, improving the resolution of the images collected.
Researchers are convinced that mass-produced micro-satellites, working in groups, will eventually make today's bulky and more costly devices obsolete. Among the advantages: If one microsatellite fails, the entire system doesn't have to be replaced. And they'll be much more flexible, because by simply reconfiguring clusters, operators will be able to conduct different missions. For example, the same group of microsatellites could be initially widely spaced to provide worldwide radar coverage, and then within hours moved closer together to conduct fine-toothed searches of smaller areas.
Much work remains to be done before TechSat 21 will be ready. For example, researchers must figure out how to keep the microsatellites in their tight pattern of slightly different orbits without burning too much fuel. The first real demonstration of the TechSat 21 concept will occur in 2005, when the Air Force plans to launch a cluster of three identical microsatellites to see whether they can fly in a precise formation.
The marked difference between the next generation of location-finding GPS satellites, known as GPS III (see "Jam-Proof Signals"), and current models-which, besides military applications, are used for everything from crop surveys to creating digital maps in cars-is that they will have separate signals for military and civilian use. This will make it more difficult for enemies to jam military output. The importance of this capability was underscored two years ago when engineers from the Air Force Research Laboratory used instructions downloaded from the Internet to build a $7,500 homemade device that easily drowned out GPS signals in a flood of electronic noise. That demonstration stoked the fear that any enemy with little more than access to the Web could sidetrack a smart- bomb attack. To avoid this, GPS III, scheduled to be ready by the end of the decade, will transmit a higher-powered and more concentrated signal than what is provided by existing equipment. These so-called spot beams will be virtually impossible to jam without expensive and sophisticated devices.
GPS III satellites will also have improved clocks. The more precise the temporal information sent from the satellites to receivers on the ground, the better the receivers can calculate the distance traveled by the signals and then "triangulate" a position using measurements from at least three satellites. With better GPS location data, satellite-guided weapons will be able to find their targets more accurately-to within a meter, as compared to about 6 meters today.
Approximately half of the roughly 700 operational satellites in orbit today are U.S. spacecraft and of those, 110 are military satellites used for navigation, communications, weather forecasting, imaging, surveillance, and early warning of missile launches. The problem is that each of the different branches of the military and intelligence agencies links to these satellites with proprietary systems, which experts call "stovepipes" because they send information between a station on the ground and space but are ill-equipped to disseminate data throughout a broad network. "What you don't want is what we have today, independent databases all over the place," says Hugo Poza, senior vice president for homeland security at Raytheon. "The not sharing of information is what caused September 11. It was not a failure of technology; it was a failure of networking."
The Pentagon hopes to overcome these shortcomings with what it calls a transformational communications system, a giant web capable of managing and distributing all military information. With this network, for instance, if an unmanned surveillance plane snaps a picture of al Qaeda operatives on the move, the photo will be immediately relayed to Special Forces units on the ground in time for them to intercept the enemy.
One of the significant deficiencies to be tackled by this new communications system is the shortage of bandwidth in many of the newest far-flung and undeveloped regions of conflict. Detailed pictures from unmanned Predator and Global Hawk airplanes can easily overload military networks, especially in places like Afghanistan where there is very little existing telecom infrastructure. In 2004, the military plans to debut the first of its Wideband Gapfiller Satellites, which will have "active" antennas with multiple communications beams that can be focused anywhere that extra bandwidth is needed. Each of these satellites will be able to provide more bandwidth than 10 of today's wideband communications spacecraft.
In a further effort to increase bandwidth, as early as 2005, the military hopes to begin replacing traditional radio signal technologies on future satellites with advanced laser beam optical systems. The Pentagon has requested $200 million in next year's budget to jump-start laser communications, which the agency believes would be able to handle even the heaviest communications traffic loads as well as move information around the globe more quickly by relaying it instantly from satellite to satellite.
Work is also under way on new narrowband systems, which are used for voice or low-data-rate communications by soldiers who are able to carry only a limited amount of gear into the field. The multi-satellite Mobile User Objective System, which is scheduled to be launched in 2008, will provide cellphone-type voice and data services via handheld terminals.
Today's satellites are big and cOMPLEX, which makes them costly to launch. And once in orbit, there's no inexpensive and simple way to service them. That's why the idea of upgradable satellites is so compelling to the defense industry, whose engineers are borrowing ideas from computer science to design a "plug-and-play" satellite that could be reprogrammed with new software as well as inspected, refueled, and repaired while in orbit.
The first step is a joint effort between the Defense Advanced Research Projects Agency, NASA, Boeing, and Ball Aerospace and Technologies Corp. to build a mock-up of a repairable satellite called NextSat in a couple of years. Then, by 2006, this team hopes to launch a smaller satellite, called ASTRO (short for Autonomous Space Transport Robotic Operations), to rendezvous with NextSat in orbit and prove that the two satellites can dock (see "In-Flight Upgrades"). If this demonstration is successful, next would be full-scale development of a fleet of actual upgradable satellites.
NASA is also funding a program called DART, or Demonstration of Autonomous Rendezvous Technology. The spacecraft in this test, being built by Orbital Sciences Corp., will have onboard video sensors for eyes as it attempts to approach a communications satellite, park some 15 meters away, run through a series of collision-avoidance maneuvers, then fly to another orbit-all without human intervention.
These new technologies have a dangerous side, though. A spacecraft that can examine, refuel, or reprogram a satellite might also be capable of disabling, destroying, or deprogramming it. An enemy microsatellite would be difficult to detect, and could even be contained inside a larger, harmless-looking satellite. In a disturbing hint of just such a possibility, in 2000 a Hong Kong newspaper quoted Chinese sources as saying that China has already ground-tested a "parasitic" satellite that could attach itself to an enemy satellite and destroy it later if necessary, but the report has not been confirmed.
Among the most coveted items on the military's wish list is a spaceplane-a reusable, unmanned vehicle that could be launched on short notice. It could release or refuel satellites, move them to new orbits, or replace their hardware and software. It might also act as a temporary satellite itself for surveillance or communications missions. And, says Gen. Ed Eberhart, commander in chief of the North American Aerospace Defense Command and U.S. Space Command, a spaceplane could also be useful for "putting steel on target."
The idea for a spaceplane has been around for 40 years. The National Aerospace Plane program, created to design a supersonic jet that could fly payloads into space like the shuttle and also be used as a bomber to reach destinations around the world in a couple of hours, was scrapped in 1994. Engineers realized that the plane would never be able to reach orbital velocity on its own. More recently, NASA abandoned hope for the X-33, a proposed replacement for the space shuttle that was supposed to fly from the ground to orbit in a single stage, rather than using a booster rocket, because the technology never quite panned out. Now, NASA has earmarked $4.8 billion for a Space Launch Initiative to develop a replacement for the shuttle that will be another two-stage reusable launch vehicle but cost much less to maintain and operate. The Defense Department has piggybacked on that program. The first demonstration of the Pentagon's version of this spaceplane is expected to occur around the end of the decade, and by 2014 the military hopes to have an operational, unmanned vehicle.
That spaceplane, known as the Space Operations Vehicle (SOV), will be a cargo carrier that can lift a variety of payloads and probably won't be any bigger than the space shuttle. In a separate program, the Pentagon is designing a smaller unmanned spaceplane, called the Space Maneuver Vehicle (SMV), that could be launched by the SOV, a rocket, or even a high-flying airplane. The SMV could remain in orbit for up to a year before landing autonomously on a runway. Boeing has already built a scale version and dropped it from a helicopter to demonstrate its landing capability. Among the payloads the SMV might carry is the Common Aero Vehicle, a reentry craft intended to deliver weapons from space (see "Bombs Away").
Missile defense is the single largest R&D category in the Defense Department's budget. The Bush administration has requested more than $7 billion in fiscal 2003 to build a system capable of shooting down ballistic missiles. But before that occurs, the Pentagon will have to design better infrared satellites than the nation's existing Defense Support Program (DSP) birds. Existing DSP satellites can tell whether a missile has been fired at the United States, but intercepting it requires being able to distinguish between warheads and decoys, track multiple objects released by a single booster, and hand off trajectory information to an interceptor vehicle-none of which DSP can do.
The Pentagon is developing a two-part replacement technology known as the Space-Based Infrared System (SBIRS) High and Low. High satellites, which will operate in geosynchronous and highly elliptical orbits, will supplant the early-warning DSP spacecraft and give a clearer picture of where a missile is headed upon launch. Satellites in low Earth orbit will provide a closer view for precision tracking of individual warheads.
SBIRS High was supposed to be launched within the next few years but it is $2.2 billion over budget and may never be completed. "We redid the costs, redid the schedule," Undersecretary of Defense Edward Aldridge said at a May 2 press conference, "and the message to the prime contractors, Lockheed Martin and Northrop Grumman, is that they're in a spotlight. If we find that six months from now, the program is going south, I have no hesitation to pull the plug." The SBIRS Low program has also been restructured, and the first of its satellites won't be launched until 2006 at the earliest.
Meanwhile, the Pentagon is studying two types of weapons that might someday be used to intercept enemy missiles: kinetic energy weapons, including "kill vehicles" that would destroy missiles by colliding with them; and directed-energy weapons, such as space-based lasers that could also attack targets on the ground. These research activities are raising the hackles of critics who view them as aggressive behavior that will backfire on the United States. "Putting weapons in space is going to open the door for other nations to do the same," warns retired Army Col. Daniel Smith, chief of research at the Center for Defense Information, a military policy research organization in Washington.
That's a possibility that the military is preparing for. In January 2001, at Schriever Air Force Base in Colorado, the U.S. Air Force staged its first-ever space war game. Set in 2017, the mock conflict pitted a large, "near space-peer" nation, "Red," against "Brown," a small neighboring country. "Blue," a superpower, takes up the fight for "Brown" and a battle in space ensues-waged by spaceplanes, missile defenses, anti-satellite lasers, microsatellites, ground-based lasers, and advanced surveillance and communication satellites. As could have been predicted, military officials concluded that the United States would have to spend lots more money on space weaponry in the future to fend off the "Reds." "It opened a lot of people's eyes to the importance of space," says Maj. John Wagner, deputy chief of the Space Warfare Center's Wargaming and Simulation Branch at Schriever.
In an expanded simulation planned for February 2003, the players will be battling with even more ambitious equipment from the military's wish list, devices that may not be ready for 15 to 18 years-such as space-based radar, missile interceptors, and reusable launch systems that have yet to be designed. One goal for that weeklong game is to learn more about how all of the armed services can integrate space systems into their battle plans. "Our Cold War forces are evolving into leaner, faster, and more lethal forces," says Wagner. "Space is integral to all of those things."