Atom bombs are just the beginning. In the last half-century, the greatest military minds on Earth have developed an arsenal of weapons to make mutually assured destruction seem tame.

Whether these masterpieces of destruction come from miles above Earth or millimeters below the skin, they have one thing in common: they're spooky as hell.

Afghanistan. A hidden bunker. Four men with rifles guard a thick, rusted steel door. Bam! A huge fist pounds against it—from inside. Bam! More blows dent the steel. The hinges strain. The guards cower, inching backward. Whatever's trying to break out is big. And angry.

The American soldier may soon have a personal combat-ready sidekick that will fetch him essentials such as water, ammo and medicine and provide extra firepower when he’s under attack. It’s a robotic servant dubbed BirdDog that’s in the works by the U.S. Navy and the private research firm Science Applications International Corporation. BirdDog is designed to complement the military’s future fleet of unmanned vehicles, which are expected to account for one third of all ground combat vehicles by 2015.

We told you about a new ultra-black material back in January and guess who was the first group to come knocking on the researchers' door?

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.

For a look at a prototypical Space Marine mission, launch the photo gallery.

Sounds too futuristic to be true? See below for a video of the Skyguard system taking out mortar rounds, artillery shells and rockets