1/4 Scale Rover Project Options

[Bill Harris]

Oh, yes, I've been building plastic and cardboard-and-stick models since I was a pre-teen. I'm convinced that any child should be taught (or permitted) to build things from an early age, it teaches great hand-eye-brain coordination and a spatial sense.

I'm already having fun hammering the details out. Cut out the rough blanks for the solar panel wings and tailpiece last night.

--Bill

[AndyG]

I'll make pieces the size and shape of each group out of 1/64" plywood and glue the individual solar cells made of 1/64" ply to the groups and then glue the groups to the panel wings, thereby giving a 3-D quality to the assembly.

Hi Bill!

Given that the panels aren't quite rectangular, and you're considering thin plywood for the basis of these, and there's many, many of them: have you looked into CNC options for getting these cut? Or you could look into photoetching them in bulk?

You'd end up with all you'd need and as accurate as you wanted, without the hassles of having to hand-form hundreds of the little bleeders.

Just a thought (from a ship modeller and part-time UMSF poster).

Andy

[Bill Harris]

I checked those reference dimensions that I noted in Post#1 and Post#14 against another reliable source, and the dimensions of the Warm Equipment Box and the Rover Equipment Deck accurate as stated:

WEB: 33.4"L x 21.8"W x 14.9"D
RED: Based on an equilateral triangle 49.9" on a side.

I'll sit down tonite and figure an accurate size for the individual solar cells. I'll bet that Helvick is correct, but I want to double-check.

Andy, I am looking at options for cutting the solar cells. Cutting out 500 by hand is the Slobovian method, and gluing them into groups is going to be worse. I have an airplane model that I've got "in the works", and I could send the thin plywood panels for the solar cells off to the laser-cutter that is going to cut the wing ribs. And photo-etching is one option, too.

--Bill

[Bob Shaw]

Bill:

Or, print them out and laminate them, perhaps with a couple of layers...

Bob Shaw

[Guest_PhilCo126_*]

Please keep adding photos as You progress ... an interesting project !

[Bill Harris]

I'll keep updates on this project.

BTW, in the Yahoo Group that BobShaw mentioned one current thread is modeling the New Horizons spacecraft.

http://groups.yahoo.com/group/space-modelers/

--Bill

[djellison]

I'm making an NH with the HGA from Spacecraft Kits as a basis - it's totally the wrong shape though It's the thought that counts

Doug

[dvandorn]

For its final incarnation, Bill -- you know, the one with motorized wheels and moving IDD -- might I suggest that some of the solar panels might be *real* solar panels? Charging a battery located in the WEB, that would power the wheels and the radio system you'd use to drive it...?

Heck, you could even use the LGA as the antenna for its radio system.

And, of course, you need to put a few webcams onto the thing -- maybe below the deck, a couple of each facing forward and backward? And maybe, I dunno, four separate lenses on top of the PMA mast? I bet you could arrange some mirror assemblies.

Now, let's talk about launch vehicles...



-the other Doug

[Bill Harris]

For its final incarnation, Bill -- you know, the one with

Yes that would be most excellent! I need to start checking around in robotics forums to see what technology is available.

Here is a photo of the roughed-out RED (Rover Equipment Deck) and the solar panels. To give an idea of scale, the side panels (the "Wings") are about 16" long and 5" wide.

--Bill

[Bill Harris]

Just following up. I counted them again very carefully and now get 499. And by taking the published dimensions of the rover (1.6m x 1.2m for the deck) and doing a take off of about a dozen cells scattered around the deck I get an average width of 6.5cm and height of 4.0cm with an error of +-5%.

Just a followup to Helvick's followup: measuring solar cells on images of deck pans I get 7.0 cm x 4.0cm (2.8x1.6 inches). This works out to 0.70" by 0.4" for the 1/4 scale solar cells, which is not that bad a size to work with.

--Bill

[Bill Harris]

Couple of color questions:

On the Sundial/Calibration target, what are the reflectance values of the white and two gray rings in the center of the dial face? I'm presuming 100%,50%,25% or 100%,75%,50% but I'm not really sure. I've looked for an in-depth paper on this Pancam calibration target, but can't find anything detailed.

What is the color of the top of the Rover, the RED and solar panel wings? I would presume a dark gray, but calibrated images from early Sols suggest either a dark "olive" or a dark "brownish" color.

--Bill

[Airbag]

Couple of color questions:

On the Sundial/Calibration target,  what are the reflectance values of the white and two gray rings in the center of the dial face?

This link suggest 20, 40 and 60% for the gray rings:

http://www.highmars.org/niac/education/mer/mer00.html

Now the real question is - how will you ensure those values on your model, and perhaps more importantly, how could anybody tell?

Airbag

PS If you can find a "top down" picture of the target, you could just scale it as appropriate for your model and print it out perhaps? Saves a lot of work.

[Airbag]

As it happens...

http://planetary.org/mars/mer_marsdial_nyelabs.pdf

I think that may work just fine for your scale model!

Airbag

[djellison]

Also - http://www.planetary.org/rrgtm/press-photos.html


Doug

[Bill Harris]

Thanks a lot, I don't know why that didn't show up on my first Google search.

Those published gray values give me a good starting point. A photographic standard gray card is 50%, and I can figure out how things _ought_ to look from that point.

--Bill