Hypography X Prize Entry

[freeztar]

I found some great links to rover designs. Here is one from Carnegie Mellon that looks to be about 5 kg:
Carnegie Mellon shows off "Scarab" lunar rover - Engadget

Here's an online book about building your own electric vehicle that has some good info on the lunar rover. It apparently had a 1/2 hp motor in each wheel:
Build Your Own Electric Vehicle - Google Book Search

This site has some useful info under "Technical Issues":
Artemis Project: Lunar Rover Initiative

And a lunar rover building set:
http://ss49.shared.server-system.net...0a93b3b73715ce

[DougF]

I posted this in
Re: Team Solid-state - post # 20 & 22
but there has not been much going on over there and I'm copying some links over here for you to look at.

I was looking for off the shelf parts for our rover and found this article and thought it was a good idea, I don't think we would get stuck with this type of setup. check the link what do you think.

Planetary rovers
ATR Treaded HD2 Robot Kit Support Page
Lunar Rover Navigation
Robotics Institute: Lunar Rover Navigation


I found this handbook on line in PDF format it has quite a bit of information that we may be able to use, such as procedures, Electrical Power Subsystem and things we have yet talked about.

Lunar Rover Operations Handbook
Doc. LS006-002-2H
Prepared by the Boeing Company
LRV Systems Engineering
Huntsville, Alabama
April 19, 1971
Scanning and PDF formatting by Ron Wells.
Last revised 2 November 2005.

Lunar Rover Operations Handbook

[Roadam]

I just got an interesting thought. Well, as we all strive for many rovers in the lander unit, would the mileage be the sum or just frim the one rover that gets the farthest?

[DougF]

From the "Phoenix:Tasks En Route to Mars Include Course Tweak, Gear Checks" thread.

The second course adjustment had been postponed a week to allow time for carefully returning the spacecraft to full operations after a cosmic-ray strike disrupted a computer memory chip Oct. 6. Experiences with previous spacecraft have shown hits by cosmic rays are a known hazard in deep space. The Phoenix spacecraft properly followed its inboard safety programming by putting itself into a precautionary standby state when the event occurred. Mission controllers then followed step-by-step procedures to understand the cause and resume regular operations.

OK my question is: how much warning/if any is there before a hit by Cosmic Rays and what kind of safeguard (other then shutting down the computers) can we build into the system?

I'm having some trouble with this I don't like the idea of turning off the computers, can we incorporate a shield?

[CraigD]

Originally Posted by DougF

From the "Phoenix:Tasks En Route to Mars Include Course Tweak, Gear Checks" thread. [(link added)]

OK my question is: how much warning/if any is there before a hit by Cosmic Rays and what kind of safeguard (other then shutting down the computers) can we build into the system?

I think you’re misunderstanding the event described in the linked news thread.

A “cosmic ray hit” is typically the collision of a single very-high energy proton (less commonly an alpha particle consisting of 2 protons and 2 neutrons) with a computer memory chip, causing a single bit to erroneously change from a zero to a one or vice versa. When the memory is next read, and compared to its parity check bit, the error is detected. Because it’s impractical to determine quickly how severe the consequences of the error might be, the system “safes” itself, entering a “do nothing” state until a human controller commands it otherwise. A similar event can occur due to a hardware defect – though uncommon in PCs and other electronics built in recent years, most people with experience with 1980s PCs have seen the occasional, sporadic memory error, and possibly even gone through the exercise of tracking down and replacing the offending chip. (I have a wax candle studded with defective 8KB memory chips from such operations – it’s sole purpose is to cause somebody to ask me about the curio, allowing me to wield the pun “oh, those are just bad memories” )

Cosmic rays are very rare, but a single one can trigger one of these safing events. They don’t come in “storms” like the unusual high fluxes of high energy solar particles associated with coronal mass ejections – “solar storms” – which can be detected before they arrive due because the photons emitted by the event arrive before them.

Though there are lots of available approaches for allowing a computer to cope with hard errors due to any cause, the approach used by the Phoenix seems a good one for its current mode of spaceflight, which is basically coasting through space. I suspect the system is designed to react differently in other modes, such as when making critical maneuvers.

Originally Posted by DougF

I'm having some trouble with this I don't like the idea of turning off the computers, can we incorporate a shield?

As noted above, Phoenix doesn’t turn off its computer, and has no advanced warning of a cosmic ray hit. Since cosmic ray particles are charged, one could potentially shield against them with a strong magnetic field, or a massive layer of mater, but the energy cost for the first kind (since there’s no advanced warning, such a shield would have to be operated all the time at full power), and the mass cost of the second, would, I think, be excessive. Programming the computer to handle with them seems a better solution, particularly since such it must be able to handle these sorts of errors due to other causes, such as hardware defects, thermal problems, etc., even if completely protected from cosmic rays.


PS: The last 2 posts don’t have much to do with simulators, so should probably be in the general thread.

[freeztar]

I did a google search for "moon GIS" and came up with several links.
This one is great because it is shaded relief and has the GIS controls built-in, allowing anyone to view the data:
Map-a-planet

This should be a great resource for finding a landing site.

[CraigD]

Originally Posted by freeztar

I did a google search for "moon GIS" and came up with several links.
…
This should be a great resource for finding a landing site.

The wealth of lunar map data and software is wonderful. However, given that this mission is more technological than scientific – an exercise in successfully getting to and operating on the moon, rather than collecting and returning significant data – and that there’s a bonus prize for returning images of previous landers, I vote for a landing site within rover range of one of the Apollos.

[freeztar]

Originally Posted by CraigD

However, given that this mission is more technological than scientific – an exercise in successfully getting to and operating on the moon, rather than collecting and returning significant data – and that there’s a bonus prize for returning images of previous landers, I vote for a landing site within rover range of one of the Apollos.

Hear, hear.

If for no other reason, it would be nice to deal a good blow to the lunar mission skeptics.

I was originally thinking that a prime landing spot would be a space free of craters and large topographic features. I would imagine NASA was thinking the same with the Apollo lunar rover missions. It's hard to know without access to high-res imagery WITH known locations of vessels superimposed. Does anyone know the lunar coordinates for the various Apollo relics?

I find the link I posted to be much more detailed and usable media than the Google Earth version. I plan on downloading some GIS files and opening them in ArcGIS to create some scalable maps that can be reviewed for a proper landing area. My hope is that a suitable landing, and operating, site will correspond to human-based lunar relics.

[CraigD]

Originally Posted by freeztar

Does anyone know the lunar coordinates for the various Apollo relics?

This NASA document has them to a resolution of .001° latitude and longitude, less than 31 m.

[freeztar]

Originally Posted by CraigD

This NASA document has them to a resolution of .001° latitude and longitude, less than 31 m.

Perfect, thank you.
I'll get to work on some maps. They will be scalable, so detail is only limited by the resolution of the image. I'm thinking that visible and shaded relief are sufficient for our endeavors, but if someone has a valid reason for wanting IR or other media then let me know.