Phobos-Grunt

[Retired_for_now]

Still working on the fit-check article. I've decided to assume the wide panel, capsule on top version is the current design. Still need to redo the configuration for the star trackers and equipment on this stack to match Tapcho's photo. The reddish-brown capsule will return about 200g of material from Phobos to the Earth. That should tell us whether Phobos formed with Mars or is a captured asteroid.



Landing leg design is the same as the Viking model, except there are three legs on an octagonal bus. Makes the bottom a bit weird - I'll have to shift the graphics around. Also need to match the location for the top strut and the attitude jet supports. Need to rework the patterns also, the struts build best if you use the printed part as a pattern to make a plain paper strut (rolls a lot easier and is just as strong with additional laminations).





Sampling arm initial mounting - I'll have to fix graphics here as well to match the arm (if building a simple model) and shift the attitude jets' mounting for clearance. The sampler is a simple split cylinder that will take several "bites" from Phobos, drop them into the curved tube (no idea how it's engineered) for delivery to the return stage and various internal instruments.



Used a simple tri-beam for the HGA mast. I'll need to shift the equipment boxes here also to clear the mast. The mast attaches with a tab glued to the deck and rests against the side of the bus - if you only glue the tab the mast can be folded up for the stowed launch configuration.



Still a bit of work, but I think the "buildable" answer will require instructions that give a graphic-detailed simple version and then let the builder decide how many little boxes to add.

Yogi

[Retired_for_now]

The solar panels attach similarly to the HGA mast - flat glued tab on the top deck with an angle bracket along the side of the bus to hold it in position. Same option, glue it down or leave loose and you can fold the array up into the stowed launch position.



The latest sampler design uses a grabber (split cylinder) on the arm to drop the sample into a tube routed to the return stage. Still have no idea what's inside the tubing to shuttle the material along (research point). Tube is modelled with two sides intended to sandwich some thick card to bulk out the thickness (not done on this quick-check article).





This all the bits for this iteration - likely end up in a classroom so it should work fine. The attitude jets are a work in progress. An attachment boom, a central core, and four nozzles for each of four sets-I already reduced the parts count as a fully accurate rendering really doesn't add anything at this scale. I'll include a simpler block/graphic version as well.



Now, to finish up something else first; then get back to PG and modify the equipment locations for clearance, reposition the attitude jet attachments for the same reason, add locating graphics for all the new bits and tweak the return vehicle (thanks again Tapcho), tweak the various mounts, decide whether to color the entire top deck orange (insulation blanker per various pictures...), and finally build one for the Planetarium.

Yogi

[Retired_for_now]

I haven't stopped - just paused a bit.

Was referred to this over at Yahoo Groups - a right interesting bit of astro-gami perfectly timed for this build (once I get back to finish the final, clean up the instructions, and get it posted for y'all - and finish up something for Alphonso).


Phobos arts and crafts - The Planetary Society Blog | The Planetary Society

Yogi (easily distracted by shiny objects)

[jparenti]

Wow, you managed to get those seams really smooth! I haven't had the courage to try that one yet. I do good to glue straight seams together. :D

[Retired_for_now]

Joseph - the key seems to be the pre-forming noted above. I also worked fairly slowly. Seams were smoothed with finger/tweezer pressure, glued up less than an inch at a time (still using Titebond II so it sets almost instantly). Noting the craters and bending/burnishing them inward, then bending the mating edges was important as well.
Tabs/teeth are about 3/16" or 4mm wide at the base - lots of little tabs allows the surface to bend.

Collect the set?


Yogi

[Retired_for_now]

Still sitting on the file cabinet waiting for me to get back to it (should still get it done before launch). I need to start the rebuild with all the fixes - and all those little boxes around the outside ...

And I'm actually working a couple days next week ... having to shave every day and all that, bah!

Yogi (clean shaven whenever "She who doesn't like that prickly stuff" mentions it)

[Swampfox]

Yogi, I just found this thread and will follow it from this point on.

I worked on the Viking landers in ott'76 at JPL, and was on the site selection team with Carl Sagan. Lots of burning of the mid-night oil back then. Lots of big egos too;-)

This will go great with my Viking lander model sitting on my shelf.

Thanks,
Swampfox

[Retired_for_now]

Well, still haven't cleanup up the files and added directions. Maybe it's a sign as the probe is hanging around LEO (follow-on insertion rocket firings did not occur ...?).
Yogi

[Retired_for_now]

Not looking good ... the curse of Mars seems to be still working. Hopefully PG's sacrifice will result in the universe smiling on the Curiosity lander's mission...

[yoannc]

just for help, very good drawings of phobos grunt here:

"ÍÎÂÎÑÒÈ ÊÎÑÌÎÍÀÂÒÈÊÈ" :: Ïðîñìîòð òåìû - Ìàò÷àñòü ÀÌÑ "Ôîáîñ-Ãðóíò"