Participate in the Google Lunar X Price

[Fredrik Andersson]

I came across this team that participates in the Google Lunar X Price competition. It's completely open-source so they're openly welcoming new team members (seems so at least, I'm not a member myself yet).

Maybe it could be something? Even though they may not work it out would be an incredible experience.

http://xprize.frednet.com/

The whole competition really seem to encourage people to participate, even amateurs and students.

[hgordon]

The FredNet project was featured on CNBC in this broadcast using one of our robots -
    http://www.cnbc.com/id/22421401

[bukowski]

My money's on Carnegie Mellon. They had a profile of the rover in winter's Robot mag. They already had a working prototype but that seems like the easy part. Getting it up there is the hard part.

[Admin]

Anyone know of a good article/tutorial on what it takes to get a robot and/or electronics to be space certified? I've always wanted to know . . . I couldn't find anything with a quickie google search.

[JonHylands]

The search term you want is:

radiation hardened

http://en.wikipedia.org/wiki/Radiation_hardening

- Jon

[paulstreats]

You have to remember that things like accelerometers that rely on earths gravity to operate just wont work aswell

[JonHylands]

accelerometers work fine in space, they just don't measure acceleration due to Earth's gravity, so you can't use them as tilt meters. But if you apply an acceleration to one in out space (from say a thruster), it measures that just fine...

- Jon

[Fredrik Andersson]

Things that doesn't work in space should instead be GPS modules, compasses and ultrasonic sensors (I'm sure I missed a lot of stuff though).

[paulstreats]

accelerometers work fine in space, they just don't measure acceleration due to Earth's gravity, so you can't use them as tilt meters. But if you apply an acceleration to one in out space (from say a thruster), it measures that just fine...

I was under the impression that the measurements were taken from microstructures inside the device deforming due to acceleration. If the gravity werent present then the structures wouldnt deform, the entire thing would just move without any stresses. I might be totally wrong tho. If so it makes these types of projects that little bit easier

[Kagi]

There's a book titled Vehicular Electronic Power Systems, Land, Sea, Air, and Space Vehicles from 2004 that has a chapter on the power systems required to run the ISS. It doesn't exactly pertain to robotics, but it is an interesting read. If you have access to engnetbase.com, they have a pdf of the book there.

[bukowski]

MEMS sensors would still work during acceleration and deceleration, I think... You would still have movement in the "fingers" (cant think of the right term right now). And, Ive never thought about it, but sonar wont work, as Fredrik said. That is fascinating.

[Admin]

Radiation is just part of it. What about circuits in a vacuum? Are they typically encased in a 'space suit' type box or left exposed? And the design of that box?

Another issue is thermal dissipation and cooling of electronics. Kind of difficult without air . . .

There must be a book out there somewhere on all of this. I feel this is a huge gap in what I know that could be useful in the future.

[paulstreats]

Thinking a bit more about movement sensors. I really dont think that most of them will work since they operate on the principle that drag is created when something is moved through a space. The drag wouldnt be created without gravity to cause the drag effect. Think about having a pendulum in a car. If the car moves forwards, the bottom of the pendulum tries to stay where it is because of the attraction of gravity, what you see is the pendulum 'appear' to swing backwards. In space this wouldnt happen. It would happen on the surface of the moon but to a much lesser extent, If you could calcute the difference then you could get them to work.

[hazzer123]

Thinking a bit more about movement sensors. I really dont think that most of them will work since they operate on the principle that drag is created when something is moved through a space. The drag wouldnt be created without gravity to cause the drag effect. Think about having a pendulum in a car. If the car moves forwards, the bottom of the pendulum tries to stay where it is because of the attraction of gravity, what you see is the pendulum 'appear' to swing backwards. In space this wouldnt happen. It would happen on the surface of the moon but to a much lesser extent, If you could calcute the difference then you could get them to work.

If you accelerate in a car with a pendulum on the moon, it will work to a much larger extent since the downwards component of the forces on the pendulum would be less.

In space, with negligible gravitational field, the pendulum would end up horizontal.

[paulstreats]

No it wouldnt, honest. In free space the end of the pendulum would accelerate at the same speed as the main mass since there is nothing to cause the drag effect on it. Although there would be some drag effect on the moon, it wouldnt be anywhere near the same as the effect on earth

[hazzer123]

I don't wanna hijack the thread, but in a car there is NO drag, since all the air is moving with the car. In space, as you and the car and the air in the car goes forward, the pendulum stays still due to inertia.
This creates tension in the string holding the pendulum. The force of tension accelerates the pendulum bob upwards until the string is horizontal.

[paulstreats]

But that inertia is due to the gravity though..... That is the drag effect that i have been talking about

[hazzer123]

Inertia is not due to gravity, it is due to the fact that a body in motion tends to remain in motion.

[paulstreats]

But you wrote that the pendulum stays still due to inertia. It is gravity that causes it to stay still

[hazzer123]

motion is relative, one person's 'still', is another person's 30 mph. So also a body at rest tends to remain at rest.

[paulstreats]

True, but it doesnt escape the fact that the pendulum is joined to a structure. Even though it is joined by a pivot, it would still move the same as its adjoined structure since there are no forces present to make it do otherwise

[Kohanbash]

Radiation is just part of it. What about circuits in a vacuum? Are they typically encased in a 'space suit' type box or left exposed? And the design of that box?

The Russian lunokhod's had a completely sealed interior (the giant tub portion) that was able to maintain its own environment (thermal (from a chunk of plutonium), pressure, and radiation hardening) when needed. Usualy the entire vehicle/craft is covered in a gold foil (with mylar) for thermal and radiation shielding. The actual components have many microscopic holes in them to allow the presure internaly to equalize (or it has positive presure to make sure nothing gets in)
http://en.wikipedia.org/wiki/Image:Lunokhod_1.jpg

Most flight hardware is made in either a 1000 or 100 clean room.

In addition to the electronic issues there are also a lot of materials issues. For example rubber will outgas in space, and metal parts of a similar crystalline structure will cold weld together in space.

Their is also the issue of dust management. So if you look at the lunokhod there are covers over its laser positioning array and on its cameras. Also the solar panels are on the inside of the top cover, so it could open it during the day and keep it closed during landing (and at  night).