NASA show off new 'Star Wars' type PDA

urk writes " NASA's got some prototypes of a new 'personal satellite assistant' that could be joining astronauts in 3 yrs time, from telling them about warnings of gas levels, checking on payloads to reading them bed time stories or teaching them russian. It's a little red sphere that floats around the shuttle / space station by itself. It should be able to talk, relay information and have conversations. Star wars comes to life! " The inspiration for this came from the Practice Ball in the Falcon in A New Hope.

Comments

Re:My Friend the Red Ball

[tgd]

Okay, not to throw a light of doubt on this, but I'm not so sure an A/C claiming to work at NASA throwing around some ideas should really be trusted.

Couple reasons:

1) The fans spinning wouldn't be an issue with a simple fixed-axis gyroscopic system like they use in airplanes for the horizon control.

2) You can't use one of those with six fans, that's the biggest proof that this guy doesn't know what he's talking about. To move around in a 2-d surface, you'd need fans to push it in each of the directions in 3-d space (6, unless you're reversing the fans, but that'd mean having air passages through the device, which uses up a lot of the interior space), PLUS you need fans to control orientation in space. Sure, you could use actuators on a system like the one I mentioned above to force it to turn against the interia of the gyroscopes, but if they were doing that, then the stability wouldn't be an issue would it?

There's pleanty of other ways to counteract the tendancy of the device to spin when the fans turn -- like doubling up on the fans, on axis, and spinning them in opposite directions. But that's twelve fans, and still doesn't solve the problem how how to adjuct yaw, pitch, and roll.

I dunno, I just don't find this post that likely to be real.

I also can't imagine that carrying compressed air really would be an issue. Weight isn't an issue, only mass. And anyone whose ever had the luck to see someone knock a valve off a scuba tank can tell you that mass to thrust, you can get a lot of oomph out of compressed gas, especially in a microgravity environment.

You'd think an engineer working on this would know the distinction.

Don't believe the AC? Do the physics.

[Tau Zero]

If there's anything I hate, it's ignorance of something so basic as elementary physics.

Okay, not to throw a light of doubt on this, but I'm not so sure an A/C claiming to work at NASA throwing around some ideas should really be trusted.

The AC comment appears well-informed, unlike your criticism. Taking yours apart point by point:

1) The fans spinning wouldn't be an issue with a simple fixed-axis gyroscopic system like they use in airplanes for the horizon control.

Aircraft attitude-control systems use aerodynamic forces, not gyroscopic, to aim the nose in the desired direction. The gyros are for reference, not reaction.

2) You can't use one of those with six fans, that's the biggest proof that this guy doesn't know what he's talking about.

'Fraid he's right and you're not. You have exactly three perpendicular axes, so three thrust lines will do. To balance torque around each one, you have two fans per axis. Each fan pair can pull as well as push, so you do not need two fans per face. Three axes * 2 fans/axis = 6 fans.

I also can't imagine that carrying compressed air really would be an issue.

Look up Froude efficiency, and compare that of an air jet to a fan 4 cm across. Then compute the energy capacity of a volume of compressed air at 1000 PSI, and the same volume of NiMH battery. How long can each deliver 0.01 Newton of thrust? Show your work.

Confucius say: Is better to be silent and be thought a fool, than to speak and remove all doubt. I believe the AC; I can't take you seriously.

My Friend the Red Ball

[Anonymous Coward]

I figure I may as well chime in here. I'm one of the research scientists at NASA working on the PSA (though it's been renamed SMR, Spacecraft MicroRobot, nobody seems to want to call it that). Right now, we have a version that floats on an air hockey table in two dimensions (actually, a fifteen ton granite slab is the table, and the PSA has an air pump so that it floats like a hovercraft), just as a proof of concept and to test control algorithms. We are currently designing the gimbal to test the three dimensional (though larger, since it will still be a prototype) version, which we are also designing right now.

As for a few of the things posted by other people: the speech technology is pretty far along. If you look at the NYT this morning, there is an article about a car computer that accepts speech commands. There are still many issues that we need to work on, but it's not that far off.

The current plan for propulsion are a bank of six fans (not pictured on the model). We have four fans on the 2D version, so 6 will give us enough to move in 3D. Compressed air is a nice idea, but the question becomes how to direct it, how to generate it (assumming that you don't want to have to carry a canister, which is very heavy), and how much force you can actually get from it.

I like the image of a PSA avatar (the dancing paperclip).

We can test it in microgravity in two ways: First, we are building the gimbal that I mentioned above, which allows us to test it in a limited range here in the lab. Second, we will use the "Vomit Comet", the plane that goes into a long dive, providing low-gravity for about thirty seconds at a time.

And yes, the fans spinning up in micro-g cause all kinds of control problems. From where I'm sitting, I can see two people that are using up all of our writing pads trying to solve them.