Remote robots: Human-free by land, sea and air

The recent downing of an uncrewed surveillance airplane in Iran offers a rare peek at some of the US government's most advanced military hardware. But the drone is only one of the remotely operated vehicles in the US military arsenal. Here is a look at some of the other independent interlopers being deployed on land, at sea and in the air. Phil McKenna

Autonomous Platform Demonstrator
Nicknamed "The Crusher", this 9-tonne robotic vehicle can power over metre-high obstacles and cruise at 80 kilometres per hour, and is now under test by the US army. It is the only hybrid electric drone known to sport LADAR – a laser-radar surveillance system that detects moving objects.

Boeing SolarEagle

What goes up doesn't necessarily have to come down – at least, not any time soon. The SolarEagle aims to stay airborne for at least five years at a time. Circling at a height of 17,000 metres, the solar-powered surveillance drone in effect blurs the line between spy plane and space satellite. Boeing beat all challengers last year to continue developing the 120-metre-long craft for the US Department of Defense. Under the terms of the agreement, SolarEagle will begin test flights in 2014.

 T-Hawk Micro Air Vehicle

The Sentinel isn't the military's only eye in the sky. Honeywell's T-Hawk Micro Air Vehicle has logged more than 17,000 hours over Iraq and Afghanistan during recent conflicts. The flying robot streams video and still images to soldiers on the ground in real time on flights that can last up to 40 minutes.

The drone also flew over Japan's Fukushima-Daiichi nuclear plant after last spring's tsunami to help emergency-response personnel assess the damage using its radiation sensors

RQ-170 Sentinel

Despite making headlines around the globe after falling on Iranian soil, little is known about the specifications or capabilities of the RQ-170 Sentinel, other than its use of special coatings and unusual shape to help it evade enemy radar. The Sentinel can intercept communications and take photographs, and is believed to fly at 800 to 950 kilometres per hour.

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