NASA's Phoenix Finally Fills Oven

JoeRobe writes "Phoenix has successfully filled oven #4 of the Thermal and Evolved-Gas Analyzer instrument (TEGA). They have spent several days now vibrating the screen above the oven, trying to get a significant amount of soil sample into it. From the article: '[T]he oven might have filled because of the cumulative effects of all the vibrating, or because of changes in the soil's cohesiveness as it sat for days on the top of the screen.' Either way, this is the first step toward getting some interesting data from this instrument."

Comments

Cookies

[LeoDavinci578]

Who wants cookies?

Re:Cookies

[Mr2cents]

Just imagine that in a few days from now, the news headline could be "NASA cooks the first extraterrestial life - tastes like chicken".

invalidate the tests

[phrostie]

couldn't this invalidate the tests.

it seems to me that the clumps could be caused by the very ice we are looking for.
by screening it out, the samples won't be representative of the soil

Re:invalidate the tests

[LBArrettAnderson]

From my limited understanding of the properties of H2O on mars, I would imagine that letting a clump of dirt sit up above the soil would cause the ice to sublime after being directly exposed to sunlight. Anyone know if this is possible? Obviously they aren't going to get a false positive... but a false negative seems likely (although I'm sure that they will know this if it happens to be the case, and will try again to find water).

Re:invalidate the tests

[osu-neko]

couldn't this invalidate the tests.

I don't think so. What would they be testing for that would be invalidated by this? If they find presence of life, or evidence of past life, the fact that they screened something out doesn't invalidate what they found in what was left. If they fail to find anything like that, there's no valid conclusion that could be drawn in any case (absence of evidence is not evidence of absence), so a conclusion of "there's no life and never was" would be invalid regardless of whether parts of the sample were screened out or not.

In short, if it's a partial sample, it reduces the odds of success, but does not invalidate any result.

Re:invalidate the tests

[osu-neko]

There's no such thing as a "false negative" for the kind of tests they're doing. They're not conducting the kinds of experiments that would falsify a theory. The only results possible from the tests they're doing are "confirmed" or "failed to confirm" (and nothing much can be concluded from the latter in any case).

Re:invalidate the tests

[SiliconEntity]

This is just the first test. At this point, Phoenix is supposed to be testing the soil, not the ice. Later, they are going to dig down into the ice. They have a special drill-like object on the digging tool which will drill into the ice and produce fine shavings. These shavings will then be scooped up and dumped into the oven. But that will come later, first they are testing the soil. This is what has been a problem so far, it's good that they have managed to make progress with it.

Re:invalidate the tests

[Anonymous Coward]

It is a real concern, but it isn't a mistake.

The JPL engineers who designed it knew from the start that certain compounds, including water ice, would begin to sublimate once the soil was disturbed. For this reason, they wanted to get the samples into the chamber relatively quickly. It is very likely that the 3-4 day delay caused some loss of volatiles. It doesn't completely invalidate this sample because it's unlikely that all the ice sublimated, and water isn't the only thing they're looking for.

Also, there are 7 other chambers in this instrument, and they believe they've figured out how to avoid this trouble in the future.

They did test the aparatus pretty thoroughly on earth, but the soil properties ended up being quite a bit different from what they expected. No mission before has handled soil in quite the way Phoenix does, and the soil at the north pole may well be different from that in locations where previous landers have touched down.

Re:invalidate the tests

[Anonymous Coward]

Phase diagram of water: http://www.lsbu.ac.uk/water/phase.html

Note the portion where solid and vapor phases are adjacent with no liquid phase in between (sublimation/deposition).

Re:invalidate the tests

[petermgreen]

Water doesn't sublime.
It does if the pressure is low enough, I think on mars there would be a liquid phase though it would be much much narrower than on earth such that it would be almost too narrow to notice.

Re:EZ Bake?

[rkanodia]

Sorry. Under Martian law, bakers and other wizards are forbidden!

Re:Vibrating the screen

[Harmonious Botch]

The martian critter sitting on the screen is probably tired of foreplay by now...

Too much vibration...

[Volante3192]

Great, now all Phoenix is going to say to NASA is TILT!

We're gonna have to fly someone up there to deposit a dollar in quarters into Phoenix now...

What were they thinking?

[elrous0]

Why would they have designed the thing to have such a low tolerance filter in the first place? Hell, most *terrestrial* soil wouldn't even make it into that oven. I sure wouldn't use it for a soil whose composition was largely a mystery. And, even if they get something, will it truly be representative of the Martian soil, or just the finest particles of it that finally made it through?

Re:What were they thinking?

[SBacks]

Why would they have designed the thing to have such a low tolerance filter in the first place? Cuz they had to strap it on a rocket and shoot it to Mars? I kinda doubt a full sized lab furnace would be under the weight requirement.

Re:What were they thinking?

[drrck]

We're talking about introducing material into an oven to be vaporized for Mass Spec analysis. You don't want or need to deal with huge amounts of material to tell what compounds are in the soil.

Re:What were they thinking?

[Sponge Bath]

1 mm diameter particles are tiny.

For the common man who needs a frame of reference: This is the same length as the distance between the solder balls of many BGA IC packages.

Re:What were they thinking?

[Changa_MC]

1 mm diameter particles are tiny.
For the common man who needs a frame of reference: This is the same length as the distance between the solder balls of many BGA IC packages. Good lord, that didn't help him at all. For the common man: a dime is about 1mm thick.

Re:What were they thinking?

[maxume]

The common man has long since spent his last dime.

Hooray

[Haoie]

We've come along way from the Easy-Bake Oven.

But I still bet the Phoenix can't make smores.

it's no turkey

[nguy]

To their surprise, NASA scientists discovered that, try as they might, roasting a phoenix in an oven never results in well-done meat.

Will it blend?

[kharri1073]

They should have consulted willitblend.com before they sent the craft to mars. I'm sure the people at will it blend would have had no problems getting some martian dirt through a micro screen.

I thought vibrators were for when...

[exp(pi*sqrt(163))]

...you didn't want a bun in the oven.

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Re:Once again...

[Anonymous Coward]

The actual oven is only about 1 mm in diameter. The screen covers a funnel that directs a small sample of soil into the oven. What happens when you let a 2 mm particle fall on a 1 mm oven? That's right...it cover the opening and nothing else gets in.

Believe it or not, there are people at NASA and JPL capable of seeing the big picture.

In this case, the soil turned out to be clumpier than anyone expected, and before you ask, yes they did try to determine what it would be like before launch, using data from the Vikings and the rovers.