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Saturday, April 04, 2009

Robot of the Day: Mars Pathfinder and the Sojourner Rover

On July 4th, 1997, which also happened to be the Independence Day of the United States, the Mars Pathfinder successfully landed on Mars. It made history because it was:
  • The third lander (since the two Vikings) successfully landing on Mars.
  • The first time a bouncing air bag landing mechanism was used for a lander.
  • The first time a robot rover was successfully deployed.
  • The first time a space mission was broadcasted on the Internet live.
After the successful landing, images of the mysterious red planet from the planet surface was broadcasted "live" on the Internet. This event had profound and extraordinary impacts on the public interests in space exploration, robotics technology, and web technologies, and inspired a generation of potential roboticists.

The Mars Pathfinder consisted of a lander and lightweight wheeled robotic rover named Sojourner (named after a a nineteenth-century black feminist and campaigner for the abolition of slavery). It was wrapped in large airbags. After entering the Martian atmosphere, a parachute was first deployed to slow down the falling of the capsule. Then a self-inflating airbag system in the shape of a tetrahedral was released, which "soft" landed on the terrain surface of Mars and rolled and bounced up and down all over the place. After the tetrahedral finally stopped rolling, the airbags were deflated and the lander unfolded itself, letting lose of the robotic rover. It is simply mind-boggling to see how the lander and the rover survived such vigorous movements, especially when one would have expected the scientific equipments on board to be very delicate devices. The video below shows some animations and footage of the landing process.

The main objective of the mission was to demonstrate it is possible to perform extraterrestrial exploration with low cost. As added benefit, the Mars Pathfinder also conducted some scientific experiments with a cameras, atmospheric structure instruments, and a spectrometer on the rover. The rover had six independently-controlled wheels and performed rock analysis as it roved about not far from the lander. The video below shows some footage of the rover moving about.

Roughly three months later, the mission control lost contact with the Pathfinder, but the mission had exceeded its goals just during the first month. Although still visible from Mars Reconnaissance Orbiter up high in the Martian sky, the robot (system) had become fully autonomous and just wondered about like a lonely ghost. Just like its name suggests, it had finally broken free from its human masters and became a free, uh, robot!

When I interned at NASA Ames in California in 2009, I was very fortunate to spot a prototype of the Sojourner Rover at the Intelligent Robotics Group (see pic on the left). I am strong believer in space colonization because we must "spread the seeds of human civilization" before we totally destroy our planet earth. And to make space colonization possible, we totally need robots that can build habitats for us. I wish the government would spend more on robotics and space exploration instead of sending troops to other countries to torture their citizens under the name of spreading "democracy" and "freedom".

Anyway, if you want to find out more about the Mars Pathfinder, you can watch "The Pathfinders" Documentary on YouTube.

Picture of the Day:

Photo of a meteor taken by astronaut from the International Space Station.