Saw the latest XKCD, about the sticking of Spirit.
I was wondering, how are those machines driven?
It can’t be someone on earth with a joystick, the delay would be too long (I would imagine), so they must have fairly good AI.
In fact, the more I think on it, the AI would have to be very, very good to operate on an alien planet successfully.
Am I right? Is it AI, or is there someone on Earth right now piloting it?
Alessan
February 2, 2010, 12:24pm
2
Who cares how long the delay is? It’s a static environment. It’s not as if the rocks will have moved in the hour or so it takes for the transmission to get there.
Move a few cm - transmit - receive - repeat.
From the rover website :
The rover has a top speed on flat hard ground of 5 centimeters (2 inches) per second. However, in order to ensure a safe drive, the rover is equipped with hazard avoidance software that causes the rover to stop and reassess its location every few seconds. So, over time, the vehicle achieves an average speed of 1 centimeter per second. The rover is programmed to drive for roughly 10 seconds, then stop to observe and understand the terrain it has driven into for 20 seconds, before moving safely onward for another 10 seconds.
http://marsrovers.jpl.nasa.gov/mission/tl_surface_nav.html
Moving safely from rock to rock or location to location is a major challenge because of the communication time delay between Earth and Mars, which is about 20 minutes on average. Unlike a remote controlled car, the drivers of rovers on Mars cannot instantly see what is happening to a rover at any given moment and they cannot send quick commands to prevent the rover from running into a rock or falling off of a cliff.
MarcusF
February 2, 2010, 12:33pm
4
They are semi autonomous. The people at mission control tell them where they have to get to and the general path to follow then the onboard systems pick the best path and avoid obstacles and hazards - sometimes not entirely sucessfully! See this NASA page .
What Fear Itself said!
The time unit of sol., used in the quote, what does that mean?
Specifically, a Martian solar day