TEGA - Round 2 Options

[djellison]

I challenge you not to look at this and make a ping/spring/boing happy sort of a noise.

http://phoenix.lpl.arizona.edu/images/gallery/lg_14223.jpg

[CosmicRocker]

How about picking up some dry soil and tipping it into the back and bottom of the scoop. Then collect the ice cuttings, which would presumably land on top of and/or in front of the dry stuff. Hopefully the layer of dry sediment would prevent the ice from sticking to the metal and it would potentially facilitate the pouring/sprinkling of the ice cuttings from the scoop. Alternatively, perhaps they could "shake up" a mixed sample of ice cuttings and dry sediment by manipulating the scoop/arm. A mixed sample might be easier to deliver to the oven.

It may be that they would prefer to have a sample that was mostly ice, but it seems that they could never assume that any ice sample did not have some admixed soil, so using a little soil to facilitate the sample delivery is probably not a terrible thing.

[jmknapp]

It may be that they would prefer to have a sample that was mostly ice, but it seems that they could never assume that any ice sample did not have some admixed soil, so using a little soil to facilitate the sample delivery is probably not a terrible thing.

Seems like some good ideas. If placing some dry material at the back of the scoop is a go, I think that precludes delivering rasped material by the main route (through the back of the scoop around the baffles), but they could still scrape up the icy tailings with the front blade & they'd end up on top of the dry material. Said material might also act like an insulator if the problem is that the scoop itself is warm & melting the sample.

It depends on whether this material is just inherently clumpy/sticky no matter what Phoenix does (like floam ) or, say, if it's the heat generated by rasping and/or the rasp motor that causes it to clump. Maybe they could produce a good bit of tailings and leave them on the surface for a little while. Assuming they are granular and ingestible by TEGA at that stage, put the scoop in the shade for an hour or whatever to let it cool off completely, and then scrape up the tailings. They would have sublimed to some extent, but not completely, and maybe the grains would be a bit smaller--better to get through the screen.

[MahFL]

My take is they can't get an icy sample into the oven, despite their best efforts . It makes sense to go ahead with a "dry" sample as the clock is ticking. Also the spacecraft could at anytime fail, and that would be the end of the mission.