NASA wants to go to an asteroid. Great! And once NASA gets there, then what? Exploration, of course, since that's what NASA does. But the microgravity (or minigravity?) environment is a challenging one to get around in. There's likely not enough gravity to use wheels or treads to drive across an asteroid, and moving from place to place using thrusters would be complicated and dangerous and suck up a lot of fuel. If you've taken the time to glance at the picture at the top of this article, you know one potential solution: robotic tumbling cubes that can move by themselves, as if by magic. That's because their motion is driven entirely from the inside.
Essentially, NASA is funding a microgravity version of these:
Or maybe more accurately, this:
So yes, this has all been done before. Or at least, it's been done before on Earth, which may be harder in some ways because of that whole gravity thing. Space telescopes (and other space-y things) use reaction wheels to orient themselves, so it's been done (sort of) in microgravity, too. What's new about these cubes is the application to asteroids, and it makes a lot of sense. You don't get the fine level of control with this sort of jumping, tumbling motion that you'd get with a wheeled rover, but you can get generally where you need to go.
There are lots of other advantages to this design, too. It's sealed up with no external moving parts, which ought to improve reliability. It doesn't depend on expendable propellant, so with some solar panels on it, you'd be good to tumble around indefinitely. Putting different instruments on different sides of the cube gives you plenty of options for surface contact measurements. You'd deploy a bunch of these things from a mothership, which takes care of all of the control and communications and localization and navigation stuff, allowing the tumbling robots to be (relatively) cheap and simple.
The funding that this project is getting from NASA isn't for a deployable, space-ready system: it'll be enough to get the concept from TRL 2 to TRL 3.5. TRLs are Technology Readiness Levels, an actual government term that describes how improbably crazy some experimental new technology is. TRL 2 is "technology concept and/or application formulated," TRL 3 is "analytical and experimental critical function and/or characteristic proof of concept," and TRL 4 is "component and/or breadboard validation in laboratory environment."
For something to make it into space on a mission, it probably has to hit TRL 8, which is "actual system completed and qualified through test and demonstration." So don't hold your breath on this one, but by the time NASA figures out how to successfully wrangle asteroids, these little robots will probably be good to go.
Via [ NASA ]