Mars Rovers are the new explorers of modern time. They are sent where no humans can reach yet to discover and conquer new territories.
I just love them as you can see: I think the duo Spirit Opportunity are two of the greatest robots ever! Each robot that has been sent there successfully has delivered a lot more than what was expected. They found water on Mars, analyzed the sediments and rocks of the planet and are still working sometimes even years after the end of their official mission. These space robots demonstrate the possibilities of autonomous robots in unknown environments. So let's enter the realm of Mars exploration.
Let's keep it simple. The definition of a rover is an exploration vehicle designed to move across unknown environment. So Mars Rovers are just a mobile robot that can explore the Red Planet. Did I say "just a mobile robot"? Let's see their common features, and what they can do before judging.
Mars rovers and the Phoenix Mars Lander
Since they operate on Mars, these robots need to be autonomous. They cannot get a battery change, and cannot be teleoperated like robots or RC cars on Earth: the delay of communication with the Earth varies between 3 to 22 minutes due to the speed of light. That's why all the space rovers on Mars have solar panels to gather energy, and have to find their way by themselves. They still receive orders and special movement sequences from Earth daily, but they execute them alone.
The new Curiosity Rover is not using solar panels. Instead, it uses a nuclear battery that provide more energy night and day. Check out this Curiosity Rover nuclear battery here.
They also need to drive on rocky, desert like grounds. That's why they all have these wheels (usually 6) with a complex system of suspension. This system, called Rocker-bogie, enables the wheels to go up and down on rocks without losing the balance of the rover.
They also have a communication system that allows them to transmit information to the Earth, either directly or via some relay station (usually an orbiter). That means they must be able to locate the Earth or the relay satellite from anywhere, at anytime.
And like other space robots, all this must be done with minimum computing power. The computer and electronics hardware has to be radiation proof, vibration proof and anything-can-happen proof. As a result, they run all their software with computers that are equivalent to 10 year old computers on Earth!
All Mars rovers have science tools to analyze Mars rocks or take realistic pictures. That's why they called the future Mars exploration robot the "Mars Science Laboratory". The space rover is a complete mobile science laboratory in itself!
To finish with the list of common features, this may be the most important one: they need a lander! Landing on Mars is actually the hardest obstacle that took years to overcome by both Americans and Russians. And as the rovers grow bigger, the challenge is always renewed.
To send exploration rovers to Mars, we need to launch them via a rocket like any other satellites. Next, the satellite will reach Mars in approximately 6 months. There is a so-called "launching window" to send satellites to Mars when the Earth and its neighbor are at their nearest. The Martian year is about twice the length of the year on Earth, which cool since the planets tend to meet every two years. Approaching Mars is clearly mastered by the main space agencies. China and India plan to go there soon but are more focused on the Moon right now (2011).
Next is the orbit phase. The orbiter will slow down to take its position around Mars and spend years there analyzing the atmosphere and take high-resolution pictures of the planet. It will also release the Mars lander to let him do his job. The lander will then softly crash on the planet. If it survived (which only few landers did), it will open and release the rover inside. The lander itself is usually a robot too, that will analyze its surroundings while the Mars rover wander around to find...
To find what? That's the next question! Why do we send these robots out there and what do we want to find on this desolated planet?
For me, I just think it's cool to have these robots travel across the Space Ocean to reach new lands. But then, my boys' dream may not be enough to justify the hundreds of millions of dollars that are spent for Mars Exploration.
Mars rovers are there for 4 main reasons:
These important questions will be discussed further in another article.
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