Video Transcript: Building Curiosity: Rover Rocks Rocker-Bogie
Hello, my name is Sean Haggart and I'm a mobility engineer on the Mars Science
Laboratory. As you can see down there, we just recently completed testing the wheels
and suspension system on the flight rover. Now, the mobility system might look familiar.
It's a classic rocker-bogie suspension system we've used for the last two generations of
Mars rovers and it does a lot of things actually, the mobility system hasn't done in the past.
So for this mission, the mobility system not only drives the rover around, it's also
the landing gear. The wheels are actually the first thing that make contact
to the surface of Mars. Now just about everything you see on the mobility system
looks black, but that doesn't mean it's all the same material. The tubes,
the suspension arms coming down to the wheels; those are all titanium.
The tires themselves; those are aluminum. The shell on those tires is actually a piece
of machined aluminum that's about 30-thousandths of an inch thick.
It's about the thickness of seven pieces of paper, and when they're that thin,
it makes them actually soft, so they behave in much the way a rubber tire would behave
--give you that springy load for landing, for driving over rocks. This test was sort
of an obstacle course for the rover because we have to drive over obstacles at certain
heights and those correspond to rocks at certain heights that we expect to see at the surface
of Mars. So those ramps are mimicking those rocks to make sure that we can actually
drive over them and get to the science. Now you'll notice that it's six-wheel drive
and all four-corner wheels steer. Now, those wheels can steer plus or minus 90 degrees.
What that allows you to do is actually position the wheels, kind of toe-in and turn the
rover in place, and it makes it a very maneuverable platform to position itself for science.
What you saw in that test was actually top speed of the rover, about four centimeters
per second. Or put it another way, it takes about 40 minutes to go the length of a
football field. We want to go slow because when you're 50-million miles away from the
nearest service station. It's okay to go a little slow and be a little careful.
My name is Sean Haggart. This has been the Building Curiosity update.
NASA, Jet Propulsion Laboratory, California Institute of Technology