Network-Centric Warfare: Space Style
In mid-February an SM-3 missile from the cruiser USS Lake Erie (CG-70) hit a large U.S. reconnaissance satellite that was falling out of control and would have re-entered the atmosphere within a few weeks. The missile took three minutes to hit the satellite, which was at an altitude of about 130 miles. That is twice the altitude at which SM-3s are designed to intercept ballistic missiles, but it is far lower than the satellite the Chinese destroyed last year, and far lower than the orbit of reconnaissance satellites. The U.S. satellite had already decayed well out of its intended orbit. Even so, hostile commentators in Russia described the shot as a covert test of an anti-satellite system. The Chinese saw hypocrisy: Americans condemned the Chinese test, but then conducted their own. They carefully avoided marked differences. Quite aside from any strategic or political implications, the Chinese test created debris at an altitude through which many satellites, particularly military ones, pass. The debris from the much lower-altitude U.S. test will almost certainly re-enter the atmosphere and simply burn up. It is unlikely to threaten anyone else's satellites.
The shot was an impressive example of network-centric warfare. Although descriptions of the Aegis system typically emphasize the associated SPY-1 phased-array radar, the key to Aegis is the tactical picture the system creates and maintains. The system uses the picture to guide the missile into an interception "basket" within reach of the target. It homes the rest of the way. In the case of SM-3, terminal homing uses infra-red sensors mounted on the kinetic-energy (hit-to-kill) warhead. In the original anti-aircraft version of Aegis, the picture came from the radar on board the ship. That radar cannot possibly suffice for a target as distant as a missile or a satellite. Instead, the ship must exploit a wide range—a network—of other sensors, including satellites and remote long-range radars. What remains from the original anti-aircraft system is the picture-keeping computer directly linked to a fire-control system that commands the missile in flight through its autopilot.
The term "network-centric" is unfortunate. It is certainly true that the cruiser's shot required a network of remote sensors, all working together, with sufficient communication links to bring their data to where it was needed. However, the key was the picture maintained on board the cruiser. Everything had to come together properly in that picture. For example, the cruiser and the sensors all had to know their relative positions, something probably impossible before the advent of the Global Positioning System (GPS). Position includes timing. The precision of the picture also depends on knowing the timing of the data and GPS provides accurate timing signals.
Missile Defense
Even more than a satellite shoot-down, missile defense is obviously a network-centric enterprise. The system is often cued by sensors that look down on the territory from which the missile is fired. In theory, surface over-the-horizon radars could provide the same sort of information, but at a horrific cost and with limited precision. Moreover, a combination of different sensors may well be the best way to filter out decoys and avoid errors.
The satellite shoot-down was, in effect, a test of the combination of sensors the United States deploys. Because the satellite target was out of control and already tumbling at fairly low altitude, its precise path was slightly unpredictable. It really mattered that the SM-3 could home on it. Moreover, the missile only succeeds if it actually hits the target. Many other anti-satellite weapons, probably including the one fired by the Chinese, produce fragments over a wide area likely to include the target. In this case the kinetic-kill SM-3 vehicle offered the important advantage of not creating further space debris.
The missiles on the cruiser were modified for the satellite shot, and it took a few days to return them to their usual anti-missile configuration. Presumably that meant a different seeker, using a somewhat different target signature. A missile warhead at an altitude of about 60 miles is already being heated by even the thin atmosphere through which it is passing. That heating makes it much easier to distinguish against the cold of space. The satellite, though far larger than a warhead, was less subject to atmospheric heating, so the key signature was probably reflected light.
Both the Chinese test last year and February's shoot-down dramatized for many the possible vulnerability of satellites, particularly those in low earth orbits such as reconnaissance satellites. This year's official report on Chinese military power, for example, mentions the apparent determination of the Chinese to deny satellite reconnaissance over their country in a time of tension. Since each shoot-down involves a massive missile system (at least for the Chinese), it may be argued that the most effective counter would be to multiply the number of U.S. satellites, and to build a capability to replace them quickly.
This year's defense appropriations bill includes money for satellite defense. That probably means arming a new generation of large reconnaissance satellites with weapons capable of neutralizing approaching anti-satellite weapons. It is not clear just how such weapons would be recognized. Much would depend on how the anti-satellite systems worked. They could be orbited, then maneuvered to intercept, or they could be fired directly from the earth's surface (as in the Lake Erie shot). If orbited, they could be destroyed just like other satellites, assuming that the U.S. system acted promptly enough, directly from the surface.
It is more difficult to imagine a counter to a direct surface shot. It may be that the best defense is simply to multiply the number of satellites by making them individually cheaper and more easily replaceable. It may also be possible to develop countermeasures, ranging from stealth (already reported for satellites) to deception of enemy satellite-tracking radars. A satellite with sufficient maneuvering fuel could also be commanded to maneuver itself out of trouble, if the trouble were recognized early enough.
Ultimately, satellites are vulnerable because they have predictable orbits. Anti-satellite measures may thus favor long-endurance UAVs.
Indian Missile Test Successful
Late in February, India announced a successful test of its Sagarika (K-15) undersea-launched ballistic missile, whose range is given as 700 kilometers (about 350 nautical miles). Sagarika has long been associated with the Indian project for a nuclear-powered submarine, the Advanced Technology Vehicle (ATV). The test was made from a submerged barge, a technique also used by the United States and the former Soviet Union. According to the Indian media, Chief Controller of Defence Research and Development S. Prahlada had already stated that only one more test was needed to "ratify the missile system and the parameters which would form the main armament of the country's indigenous nuclear submarine expected to enter sea trials late next year."
A sketch in an Indian newspaper showed a 7-meter-long missile carrying a one tonne nuclear warhead, using a booster to carry it out of the water and then a main propulsion stage (U.S. missiles are blown out of the tube by a gas generator, and the Russians use either a gas generator or they float the missile out). Some commentators suggested that a future version of K-15 would carry a 500-kilogram warhead to a range of about 1,800 kilometers, nearly a thousand miles. Another Indian source gave a missile length of 11 meters and a diameter of 50 centimeters; the difference may be the first-stage booster. Yet another gave a length of 6.5 meters and a weight of 7 tonnes. The sketch showed four quad-packs of missiles mounted abaft the submarine's sail. Length was given as 104 meters, and the sketch showed a big Russian-style fin pod for a towed array. The same sketch carried a supposed timeline for the ATV project. It claimed that the ATV was laid down in 1998, and that the reactor was installed in 2007, with sea trials scheduled for 2009 and full entry into service for 2010. Note that the Indian press has often reported the imminent completion of the ATV project in the past.
A later Indian press report, referring to an interview with Mr. Prahlada, called this the final test of K-15 before it could be integrated into its "mother ship." The report said that referred to three 6,000-ton ATVs, each designed to carry 12 missiles. According to this account, it will take two or three years after the first ATV is at sea to integrate the missiles with it. This report described the ATV as a 25-year project, i.e., begun about 1982. Reportedly U.S. Defense Secretary Robert Gates, who was in India at the time, congratulated the Indians on the K-15 test.
Indian media stated that K-15 had been tested secretly six times before the most recent shot, which was announced in advance, indicating confidence that it would succeed. Some previous tests may have been announced as Prithvi (land-based ballistic-missile) shots. Reportedly, Sagarika was first secretly tested to full range in April 2007. The missile may also be used from fixed and mobile ground launchers.
Building Cooperative Security
Gunner's Mate 2nd Class Benjamin Martin motions to his Bulgarian partner to get ready to move forward during visit, board, search, and seizure (VBSS) drills on board the guided-missile cruiser USS San Jacinto (CG-56) in February. Bulgarian sailors are training with the crew of the San Jacinto in VBSS and damage control techniques and procedures. The ship is operating in the Black Sea as part of a larger international team effort to improve maritime safety and security in the region using existing political-military relationships.