The principal goal of Curiosity is to run a chemical analysis of a small area on the surface of Mars to search for organic life in the present, or traces indicating that life forms (microbes) were there. This mission is about discovery, and has captured the imagination of the people of Earth.
To add to the drama, the scientists would only know whether or not the landing sequence was successful about fourteen minutes after it took place. That is because all electromagnetic waves, including those emitted by the Curiosity rover back to Earth, travel through the vacuum of space at the speed of light (300,000 km/s). This long time delay for information transfer is a constant reminder of how far away this probe journeyed. Consider the reasonable 1.3 second time delay that ensues on any Earth/Moon conversation as a point of comparison. Can you imagine a fourteen minute time delay? A hundred years from now, the dialogue between Earth and Mars civilizations will require some serious patience. Amazingly, there is no technology that will reduce this lengthy delay, as it is governed by a universal speed limit.
Fortunately, the landing sequence was a great success. The Curiosity rover arrived just as planned, and a roomful of scientists and engineers erupted into cheer and danced long into the night - OK, maybe there was no dancing.
Currently, the rover is undergoing initializing sequences to prepare for its two year investigation of the Martian surface. And what a glorified science experiment this will be; the nuclear-powered Curiosity makes most previous Martian probes seem like rejects from a science fair. For starters, the nuclear battery allows it to shed those cumbersome solar panels, and enables it to work during the Martian night-time.
The rover was originally named MSL (Mars Science Laboratory) and it certainly does come equipped. It will use a robotic arm to collect surface samples for chemical assessment. An in-depth mineral analysis of the soil and rocks will be performed by an X-ray diffraction and fluorescence instrument called 'CheMin'. An on-board camera will take high-resolution images (pixels as small as the thickness of a human hair) that can be transmitted back to Earth.
However, I think my favourite 'toy' is the laser, which helps Curiosity determine where to probe next. Rather than do an in-depth analysis everywhere (there isn't time), it does a quick chemical check in an innovative way. It first shoots its laser onto a rock some distance away thereby heating it up. It then uses a telescope to zoom in on the light emitted by the rock and assesses the chemical composition of the rock by way of spectrometry. Such rough checks will save the rover much roving and probing, allowing it to make optimal use of its time.
And if all of that were not enough, the rover is cute too. The camera fastened to the mast looks like a little head on neck. If you ignore the gadgetry, the robot looks like a scaled up version of WALL-E.
There have been a couple of bumps on the Martian surface though. Some of the environmental sensors (wind, temperature) have not been functioning perfectly. Engineers are trying to correct the problem as I write.