Phobos-Grunt

[Retired_for_now]

Keeping with the Martian landers, I think I'll try Phobos-Grunt next. It's a combined Russian, European, Chinese and US mission to return a sample from the surface of the Martian moon Phobos to the Earth.

Some pictures of the "final" configuration are out there





I think I'll stick with just the lander and return stage. The Fregat enroute module is both simple (just spheres) and tough (a bunch of spheres).

No real good info on exact dimensions. So, we'll get what we can and scale off of the various pictures ... Might end up using the Zenit launcher diameter as my reference.



Yogi

[Retired_for_now]

Step one is alway paper and pencil. A simple side drawing showing major parts that will compose the model. For PG, the list includes:
1: descent module - approximate with a flat top, conic (or two), and a cylinder;
2. return vehicle - flat top/solar panel, box (with side graphics for the internal, exposed tanks on two sides), several smaller equipment boxes on the remaining sides, conics and a mount for the thrusters;
3. lander - octagonal bus (always a bugger to get the fit right, something about the square root of two and other irrationalities), four top-side tanks (flat top, couple of conics), various equipment boxes (and the graphics to locate them), solar panels (plus brackets, antennae and sun sensors on the outboard edge - maybe the launching latches), three legs (upper strut, one piece lower struts simliar to Viking model, foot pad shallow conic), four thruster sets (mounting tripod, box/core, maybe conic nozzles or just graphics), four bottom thruster nozzles, and the drill/sampler (two mounting brackets, three structural rods, three triangular braces, drill column, drill head, sample delivery tube).



Initial workup scaled from two top/bottom graphics and a side shot from a trade show. I usually draw a simple shape of a part to scale (solar panels here) to start, then size the picture to match. Subsequent parts are drawn atop the picture, copied to a working page, and detailed (within my limited artistic skill set).

Yogi

[Zathros]

I wish we could do more space projects that could lead to a safer world. I was not aware of the nature of the joint venture. Very educating! Model looks awesome, as all of yours do.

[Retired_for_now]

Good words, John. It takes a while to realize that real space exploration is as exciting as war. Still holding out hope that Obama's pull back from an unaffordable program (given the American people's enthusiasm) with Constellation will result in a better focus. There's almost 3 billion more people in China, India, Brazil, etc. that are excited by their own space programs - get them all on board the ISS (and use the ISS as a station, not a destination) and we might see an interplanetary cruiser.

Link up an ISS module or two for the crew, a proven Russian nuclear reactor (they've decades of experience with their military/surveillance satellites), a set of ISS solar arrays, and a Vasimir engine all linked by a modified ISS truss and we can head out in style.

Meanwhile, still working Phobos-Grunt details. Someone put all the equipment on the outside of the dang thing, so lots of little boxes to worry about.



So far I'm happy with the relative proportions for the scale - but it doesn't seem quite correct (unless the one picture I'm using for full-scale is actually a sub-scale model and not a full sized mock-up.




May also end up doing two options for the solar panels. Big flat rectangles as above or narrower, more complex ones like this.



Ah well, back to work - I mean play!

Yogi

[Retired_for_now]

Still researching the scale. About the only thing I can find real dimensions for is the Chinese sub-satellite nested inside the tall truss between the lander and the enroute stage.



Found one reference with it as 750x750x650mm - which would give you 67cm or 26" across the width of one face on the bus. If so, then I'm currently just a tad under 1:12 scale with the model ...

Yogi

[jparenti]

This one looks really interesting. I've only seen passing references to this lander so far, so I had to do a little search to familiarize myself with it. Definitely a neat subject. I've been on a lander kick lately, too.

[Tapcho]

http://www.guenthernet.de/mars/phobo...llungsfoto.jpg

Would this picture help?

[Retired_for_now]

Actually, Tapcho - YES! Thanks. Assuming the date is recent, it looks like this shows the new sampling arm that replaced the drill and tower (a lot easier to design). Leo also passed me a reference that gives the arm's length as 1m (have to do a quick sniff check to see if that's each segment or total, extended length). Gives a definite answer for the scaling and lets me off the hook trying to design a buildable, swiveling, three rod, cantilevered drilling rig.

Enough parts to start doing fit checks. Bus, with added internal bits to prevent "oil canning."



And the simplified tanks and brackets went together fine.



Ah well, time to switch to another waiting project for a day or so (yours Alphonso). Then, we'll assemble a few more bits and draw up the sampling arm to substitute for the drill rig. The challenge here is to keep the model anybody-buildable and it's already got a lot of pieces with all the external equipment (probably due to the fuel tanks filling the interior).

Yogi

[Retired_for_now]

Puttering around with the first draft parts - cobbled up the tanks. Looks like I might need about a 2% reduction in the cylinders for fit on the deck. The structure worked out as planned (mark the date on the calendar!). Still, had to use quite a few more parts than I'd like.





Yogi

[Paperwarrior]

Looking nice, Yogi.
I'm looking forward to seeing more on this interesting project.