In the past decade, navies have been roundly criticized for extensively testing active sonar due to its potentially detrimental affect on marine life. Military-grade active sonar sends out a powerfully loud low-frequency signal with a range anywhere from tens to hundreds of miles under water. The effect on whales has been well documented—it’s akin to you or I standing next to a jet engine without ear protection.

By now you've probably heard the strange story of USA 193, the out-of-control military satellite slated to be shot out of the sky this evening. Amidst controversy over the safety and necessity of the mission, the U.S. Navy is planning to launch a $10-million missile from the USS Lake Erie somewhere west of Hawaii as early as 9:30pm EST and take the school-bus-sized sat down.

Launched in December 2006 by the ultra hush-hush National Reconnaissance Organization, the rogue satellite sported a powerful imaging sensor and a central computer that failed almost immediately. Its orbit began to decay, gradually and then suddenly. And when it became clear that the satellite would plummet to Earth this week, the government grew concerned that its 1,000 pounds of onboard fuel would survive the plunge and pose a health risk to anyone who came in contact with the hydrazine gas. That's their side, anyway—and their explanation for preparing three SM3 anti-ballistic missile interceptors to shoot the bugger down from an Aegis destroyer.

It’s hard to tell what kind of wars the future will bring, but one thing is certain: Robots will be doing much of the fighting. In fact, they already are. Last year, aerial drones flew 258,502 hours of missions—up from 27,201 in 2002. Spending on unmanned aircraft systems by the U.S. military is expected to hit $3.76 billion by 2010. Robotic warfare, long the stuff of science fiction, is now a reality.

Um, wow. This video comes from a test firing of the Navy’s Elecromagnetic Railgun (EMRG), which was carried out yesterday at the Naval Surface Warfare Center in Dahlgren, Virginia. The gun—which generates a powerful electromagnetic field to hurl projectiles at extremely high speeds—is rated at 32 megajoules, but the railgun engineers have to work up to that number slowly: this test was designed to reach a record-setting muzzle energy rating of 10 MJ. (The actual number turned out to be 10.64 MJ, according to Collin Babb with the Office of Naval Research.)

One big question this video begs is, what causes the giant fireball?

For a closer look, click 'View Photos' at left to launch the photo gallery

It will be almost silent, nearly invisible to enemy radar—and capable of dropping six powerful missiles simultaneously on a single target up to 95 miles away. But the most important feature of the DDG1000 Zumwalt, the Navy's first new destroyer in 30¿years, could be its versatility. The 600-foot-long ship will be just as comfortable in the deep ocean as in the mine-infested shallows of the Persian Gulf.

Lockheed Martin's Skunk Works, famed for the U-2 and Blackbird spy planes that flew higher than anything else in the world in their day, is trying for a different altitude record: an airplane that starts and ends its mission 150 feet underwater. The Cormorant, a stealthy, jet-powered, autonomous aircraft that could be outfitted with either short-range weapons or surveillance equipment, is designed to launch out of the Trident missile tubes in some of the U.S. Navy's gigantic Cold Warâ€era Ohio-class submarines.