On a far-off world, one that's an average distance of 140 million miles (225 million kilometers) away from our own, there's an SUV-sized, nuclear-powered vehicle with its own Twitter account. Ladies and gentlemen, let's talk about the Curiosity Rover.
In 1997, NASA's Mars Pathfinder became the first spacecraft to land on another planet (you can guess which one) without first orbiting it. One of the Pathfinder's most ambitious successors is the Mars Science Laboratory, a $2.5 billion probe whose main attraction is a six-wheeled rover named "Curiosity." Earlier rovers were powered by solar panels, which left them at the mercy of Martian dust storms and low-light periods. Curiosity sidesteps those problems by using plutonium to generate electricity [source: Belanger].
For a Martian rover, Curiosity is huge. Weighing 1,982 pounds (899 kilograms), it's 10 feet (3.04 meters) long by nine feet (2.74 meters) wide and seven feet (2.13 meters) tall. That makes the vehicle four times heavier — and twice as long — as two of the rovers that preceded it to Mars, namely the Spirit and the Opportunity. Oh yeah, and Curiosity totally dwarfs the Pathfinder rover, which had the rough dimensions of a microwave oven [source: Webster].
The craft's bulk forced NASA to execute a complex landing process involving a breakaway parachute and disposable rockets. On Aug. 6, 2012, the Martian Science Laboratory successfully touched down on the Red Planet's surface. It's spent the past six years examining the geology and climate of our closest planetary neighbor. Among other things, Curiosity has found compelling evidence to indicate that both liquid water and organic molecules could have once existed on Mars [source: Freeman].
Plus, the 'bot is an internet celebrity. A Twitter account in Curiosity's name that's run by the NASA social media team has 3.94 million followers [source: Meredith].
Curiosity and the other Mars rovers have given us crucial information about the Red Planet. Millions of Americans hope to see NASA put a human being up there someday. But that shared dream wouldn't exist if it weren't for the next accomplishment on our list.