The Mars rovers Spirit and Opportunity left Earth for the red planet in July of 2003. An incredible achievement, these robots scoured the surface of our neighboring planet and sent back to us amazing images and data about the martian surface.
Now, little more than eight years later and NASA has sent a new, more high tech rover to once again change our understanding of the planet that has captured the imagination of our civilization for hundreds of years.
Bigger, Heavier and Lots More Tech
Looking at an image of NASA's new rover, dubbed Curiosity, it looks of similar design to the now defunct Spirit and Opportunity twins. But looks can be deceiving.
While its predecessors were no lightweights, standing some 4.5 feet high, with similar proportions of length and width, Curiosity is must larger.
Closer in size to a large pick-up truck, the new rover is roughly twice as long and five times as heavy.
The reason for the added bulk is all the new instruments that have been added to the new explorer. There are ten scientific instruments aboard this behemoth; with a mass 15 times greater than the previous missions all told.
And it is these new instruments that will not only allow Curiosity to operate more efficiently, but also begin to search and analyze the surface (and what's beneath it) in ways that we've never been able to before.
According to NASA, Curiosity "will use a drill and scoop at the end of its robotic arm to gather soil and powdered samples of rock interiors, then sieve and parcel out these samples into analytical laboratory instruments inside the rover."
Among the new instruments is a laser-firing instrument with the capability to determine the composition of rocks and other solid objects, even from a distance.
What We Hope to Learn
The primary scientific goal of Curiosity is to attempt to establish whether the red planet is, or ever was, habitable.
The new instruments that Curiosity will carry along with it will allow scientists to characterize the environment and atmosphere (what little there is) of Mars.
NASA's long term goal is to send a human expedition to Mars, but they can not take that step until they know more about the surface of the planet, as well as what lies beneath.
There is significant concern that the dust that is kicked up from the surface would be toxic to humans. While astronauts would not be walking around on the surface without the protection of space suites, it is till possible that different instruments and the suits themselves can become contaminated by the dust.
Then when the astronauts return to their habitat they would carry along with them the dust, possibly then contaminating the entire living area, threatening the mission.
Related to this problem is the massive dust storms that can reek havoc on the surface. It is unclear how damaging these dusty winds can be to the integrity to hardware that astronauts would need to establish living quarters on the surface.
There is also the issue of radiation. Because of the thin atmosphere of the planet and relatively weak magnetic field, there is little protection from the harmful effects of the Sun's solar-wind. This is one of the major stumbling blocks for any long term mission beyond Earth's magnetosphere.
But to get a better understanding of the environment on Mars, Curiosity will be taking radiation measurements on the surface be gauge any potential radiation threats to life.
Curiosity was designed to execute a two year scientific mission, but like previous mission to Mars will likely survive long after this and will continue to provide scientific understanding for many years to come.
Because of the immense size, especially compared to its predecessors, of Curiosity, a new insertion method was developed for safely landing the rover on the surface of Mars.
Launched aboard a Atlas V rocket, Curiosity was sent on a one way, 352-million mile journey to Mars on November 26, 2011.
In the past a series of airbags were used to cushion the landing of the rover as it descended upon the surface of the planet. But because of the 1 ton mass and large volume, this type of landing was prohibited.
Instead, part of the vehicle bringing the rover to the surface employs a rocket-powered descent stage. The rover will be lowered on tethers while the rocket engines control the descent speed.