[GAHD]

for testing to 100C, A large oven (such as found in pizzerias) would certainly do the trick. anything down to -40C will soon be testable by myself just by walking out my back door.

A parts list to withstand vacuum assuming central motor & transmission:

• +3* solid wheel, preferably a die-cast & machined unit
• 1* fluid less transmission (unless normal tranny fluid is replaced with something that won't boil-off in vacuum, mercury perhaps)?
• 1* fluid less differential (unless subbed as above)
• 2* RC boards & antennas (controller & vehicle)
• +1* battery pack(s)(which can always be made up pretty quickly)
• ?* bolts & other fasteners
• 1* basic chassis

Any part requiring lubrication probably won't work too well when it's lube boils off in the vacuum, so high-precision machining is our best if not only option if we go a mechanical route. Can you imagine trying to seal the system in such an environment? standard gaskets would freeze/cook and explode in next to no time.

[Jay-qu]

How can we precisely machine parts when they are going to be in a range of -40-100 degrees? wont thermal expansion make that impossible?

[TheBigDog]

Originally Posted by GAHD

anything down to -40C will soon be testable by myself just by walking out my back door.

Road trip to Winnipeg!

Any volunteers for engineering or locating a vacuum chamber for testing rovers? It will be easier to relocate the rovers than the chamber, so where should we look for locating it? I like the idea of having it in an environment that will provide good cold weather testing.

Bill

[Turtle]

Originally Posted by GAHD

...Any part requiring lubrication probably won't work too well when it's lube boils off in the vacuum, so high-precision machining is our best if not only option if we go a mechanical route. Can you imagine trying to seal the system in such an environment? standard gaskets would freeze/cook and explode in next to no time.

I think we need a library of sources on the pertinent topics so we don't unnecessarily reproduce work already done. Searching 'hazards of vacuum to space vehicles' I found this book for sale and some samples of chapters. Coinkydinkilly, the section quoted is on lubricants.

Space Vehicle Mechanisms: Elements ... - Google Book Search

[GAHD]

I've started a thread dedicated to a specific design of rover. Those with the will come join TEAM SOLID STATE.

The Goal: NO mechanically connected moving parts.

Originally Posted by Turtle

I think we need a library of sources on the pertinent topics so we don't unnecessarily reproduce work already done...

Great Idea! I stole it...

[Roadam]

Does one really need a transmission? Electrical motor can be mounted directly, speed can be changed with voltage/current. As for steering, I think that it too can be made without use of direct contract, but that fits into team solid state thread...

[Turtle]

Originally Posted by Jay-qu

How can we precisely machine parts when they are going to be in a range of -40-100 degrees? wont thermal expansion make that impossible?

Not at all. We could do worse than research what metal(material) NASA used for their mobile machines.

A point I have yet seen mentioned that is bothering me a bit is whether or not we intend to leave an orbiter circling the Moon and acting as a relay for our data signals??? I see most Mars rover signals go this route and the Apollo missions did as well?

Here's a nice bit for our Library titled Apollo TV and Communications Documentationhttp://history.nasa.gov/alsj/AWST690526Art.pdf

An article from the above link on the first color television signal sent to Earth from space. >> http://history.nasa.gov/alsj/AWST690526Art.pdf

[TheBigDog]

Originally Posted by Turtle

A point I have yet seen mentioned that is bothering me a bit is whether or not we intend to leave an orbiter circling the Moon and acting as a relay for our data signals??? I see most Mars rover signals go this route and the Apollo missions did as well?

I was not planning on orbiting the moon, or leaving an orbiting satellite. I figured we land on the moon so that our Lander is always visible to the earth. Even the low powered conversations between the rovers and the lander should be easily snooped on by earth based listening stations. The Lander will be intended for two way conversations with the earth directly, and relay of data to the rovers.

But it brings me to a question that I was holding for later when we get to the landing phase of the mission: what is the reason for entering lunar orbit as opposed to going straight to the surface of the moon?

Bill

[Turtle]

Originally Posted by TheBigDog

I was not planning on orbiting the moon, or leaving an orbiting satellite. I figured we land on the moon so that our Lander is always visible to the earth. Even the low powered conversations between the rovers and the lander should be easily snooped on by earth based listening stations. The Lander will be intended for two way conversations with the earth directly, and relay of data to the rovers.

But it brings me to a question that I was holding for later when we get to the landing phase of the mission: what is the reason for entering lunar orbit as opposed to going straight to the surface of the moon?

Bill

On the boldened, I don't get this impression that it is "easy", but I think this is going to depend on the specifics of our radio equipment. I will be careful drawing parallels to Mars rovers and our Lunar project given the Moon's "close" proximity.

I'm not sure of any reason to orbit if we don't plan on leaving an orbiter. We better ask a rocket scientist. Maybe so we can line up our shot?

Ok; on to some specific ideas for the rover drive. I was thinking we could possibly adapt the rings-on-a-piston-in-a-cylinder used in internal combustion engines as an axle bearing. Works in a broad range of temperatures and pressures, and tolerates abrasive contaminants; proven technology and simple.

To expand on that I envision a single motor internal to our pressurized black box & driving a flywheel whose bottom bearing is as above and whose shaft projects below and outside the rover. The wheels, rather than having high tolerance machined axles and bearings are "sloppy" fit, like the old erector sets. Motive force to the wheels is drawn from the protruding flywheel axle by "loose" fit belts or chains.

[TheBigDog]

I had not considered the idea of building earth based communications systems. I figured we would latch onto some existing antenna system for space based communications. If it is not too much we could always build a series of stations in the yards of Hypo members around the globe to maintain 24x7 contact with the moon. Another aspect of the mission to contemplate, but I would make it a later requirement of the mission.

Bill