1/4 Scale Rover Project Options

[Guest_PhilCo126_*]

I believe there're replica's of these Lego things as well as the Columbia logo disk is available (saw it on eBay I believe)

[Bill Harris]

I've been drawing and cutting out parts. Here is a Rover mystery part: any guesses what part this is?

--Bill

[jamescanvin]

I've been drawing and cutting out parts.  Here is a Rover mystery part: any guesses what part this is?

--Bill

OK I'll bite...

Solar cells on top of WEB (as opposed to those on the "wings"), hole is for the UHF antenna?

James

[djellison]

HGA gimble assembly

Changed my mind, IDD shoulder joint.

Doug

[Bill Harris]

We have a winner: it is the solar cell carrier on top of the WEB.

The HGA gimbal and the IDD arm are challenging pieces, but that will be another story...

--Bill

[djellison]

I've been Out MER'd

Doug

[general]

Nice project, Bill.

suggestion: could you add a 12 in/30 cm ruler or something in your pictures, so that we can get a sense of scale?

[Bill Harris]

Good idea. I'll add a virtual ruler to the existing images, and include a scale with future images.

This was really an obscure part, Doug. I didn't realize how intricate it was until I started tracing it out from images and drawings.

The difficult and critical part of this will be the solar cells: they are intricate and have been a visible and well-known part of the MER imagery. The PanCams and Rocker-Bogey will permit a little artistic latitude, but the topside will have to be just-so.

--Bill

[Bill Harris]

Here are thoughts on the solar cell arrays. This part of the project needs attention since their appearance is well-known andthey are very detailed and they will make-or-break this model's effect.

At 1/4 scale each individual solar cell will be 0.65x0.40 in size. Closely examining photos, they seem to be affixed to the Rover panels with a reddish layer; this is probably a double-sided tape adhesive which has to be flexible to keep the cell affixed over a great temperature range. I think that the "true color" is reddish. The solar cells are arranged in symmetrical groups and the groups are attached to the solar panels. The cells are in different orientations in the groups, probably for a parallel-series wiring arrangement. White wires connect the cells and groups.

What I propose is to make the 500 or so cells of 1/32" modeling plywood, and glue the individual cells to the cell groups, also of 1/32" plywood, and glue these cell groups to the four solar panels of the rover. The "background" cell groups will be the proper reddish color and the individual cells will be a dark greenish-grayish-or-blueish (whatever color I decide; I'm undecided at this point), with a bright, hard luster. This will give a total cell group thickness of 1/16" at 1/4-scale, which is a bit thicker than it should to be, but ought to give a good scale thickness.

I may get the 1/32" plywood cells laser cut, or I may do it by hand. Not as impossible as it sounds, you can stack 50 cells at a time and cut/sand en-masse.

--Bill

[Bill Harris]

More discussions of model solar cells at Mer Model For Your Desk.

--Bill

[Bill Harris]

The most critical part of the MER model project is proving to be the solar panels. They are quite detailed and will have to be accurate since they have been well-photographed.

Here is the test piece I made up for the model solar cell array. Each solar cell is some 0.6"x0.4" in size and made of 1/32" plywood. Instead of gluing the cells to the 1/32" solar cell group piece (as shown), I'm going to glue each 1/32" individual cell to the panel since that combined thickness of 1/16" seems too thick. This test piece will allow me to practice working with the solar cells and to develop realistic ways of painting and detailing the solar panels. The solar cells will need to be very dark grey or black but will need to be glossy; the solar panel 'body' will need to be a slightly lighter grey but a semi-matte (non-glossy, but not flat).

And yes, I know that I've got the wrong edge of the solar cells notched on the test piece. Chalk that up to a brainf@rt...

I've also included an image of the right-front Rover solar panel, "squared up" using the perspective correction function in my image editor. This makes the view of the panel perpendicular instead of oblique.

Work continues... sheesh there are a LOT of details on this model!

--Bill

[Guest_PhilCo126_*]

Bill ... You're doing a great job !

[Bill Harris]

Thanks, Phil. The devil is going to be in the details on this project.

I have a couple of questions about some of the gadgetry on the deck. Attached is an annotated clip from Dilo's Spirit Self-Portrait.

1) This device is on the solar panels and it is a electrically operated latch to hold the panels closed during re-entry and landing. I could guesstimate the angles and orientation from MER images, but I'd like to have an image of the this device holdiing the solar panels closed. Know of such an image?

2 and 3, 4 and 5) These are the hold-downs for the Camera Mast. Same question as item 1: do we know of an image of then holding the Mast?

6) These are obviously hinges with geared electric motors used to deploy the solar panels. But I can't figure out why there is a hinge PLUS a separate hinge/pivot on the motor shaft. Know why?


Picky questions, but one has to be a nut for details on a scale model.

--Bill

[djellison]

well 12345 - there are lots of high res pics at the KSC Multimedia Gallery ( www.ksc.nasa.gov ) - go back to the 6 monhts or so before launch and there's lots of photos, including nice one's such as the Equipment Deck just on its own with things stowed etc

as for 6 - I dont thin the motor has a hinge, I think it's two halves, one is the motor, one the planetary gear to down-speed it to the shaft from the array.

[Bill Harris]

Ah, I hadn't looked at the KSC Gallery-- that makes sense since this is where the completed Rover was mated to the rocket. Thanks!

--Bill