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

Vibrating the screen

[bobwrit]

IT would be great(laughablity wise) if the whole thing tipped over because of them vibrating the screen.

Re:Vibrating the screen

[Harmonious Botch]

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

Re:Vibrating the screen

[Anonymous Coward]

Thanks, this was my first lol of the day.

Re:Vibrating the screen

[Anonymous Coward]

Either that, or they took one look at the rasp on the scoop after it was tested the other day, and decided they had a better idea.

Re:Vibrating the screen

[Anonymous Coward]

I wonder if the lander did tip over, could the robotic arm push the lander back onto its feet?

Cookies

[LeoDavinci578]

Who wants cookies?

Re:Cookies

[countSudoku()]

Oh, come on now people. Who modded this off-topic? It's completely on-topic. Think little, skinny, cookies made from Mars soil by a robotic travler? What's next? Mod down a Shake and Bake joke? NASA got that bot down, safe on the ground and their making sweet, soil cookies! What's not to love and laugh about?

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".

Re:Cookies

[steelfood]

Are you saying there's a bun cooking in NASA's oven?

I was going to say something else about phoenicis and bursting into flames, but it would've probably been too much.

Re:Cookies

[Anonymous Coward]

"The enrichment centre is required to remind you that you will be baked, and then there will be cake."

Re:Cookies

[Off the Rails]

Who wants cookies? I'd prefer a mars bar.

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

[SBacks]

Flawed data is better than no data.

Right?

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]

Flawed data is better than no data. Right?

No. But that's not the issue here. What we're talking about here is getting less data than we'd like (because of what was excluded from the sample). Data is not "flawed" for being a smaller quantity, it's just, less. Some data is better than no data at all.

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

[Anonymous Coward]

I don't see why, doesn't the oven heat the soil up anyway?

Re:invalidate the tests

[Anonymous Coward]

The GP made it very clear that that is what he meant, even if he used the term 'false negative.'

Re:invalidate the tests

[Bill, Shooter of Bul]

My first instinct was to dismiss your concern outright. I mean why wouldn't they have tested the apparatus in a lab on earth, before sending it to mars? But NASA is capable of making mistakes on complex missions,as we saw from the mars climate orbiter experienceFrom that incident we got this priceless quote:

"People sometimes make errors," said Edward Weiler, NASA's Associate Administrator for Space Science in a written statement.

Re:invalidate the tests

[jessemerriman]

(absence of evidence is not evidence of absence)

Yes, it is:

Absence of proof is not proof of absence. In logic, A->B, "A implies B", is not equivalent to ~A->~B, "not-A implies not-B".

But in probability theory, absence of evidence is always evidence of absence. If E is a binary event and P(H|E) > P(H), "seeing E increases the probability of H"; then P(H|~E) < P(H), "failure to observe E decreases the probability of H". P(H) is a weighted mix of P(H|E) and P(H|~E), and necessarily lies between the two.

(from this Overcoming Bias post)

Re:invalidate the tests

[DerekLyons]

couldn't this invalidate the tests. it seems to me that the clumps could be caused by the very ice we are looking for.

The instrument in question isn't looking for ice, but is measuring the chemical properties of the soil.

Re:invalidate the tests

[maxume]

Did the post include a hilarious pontification on being a Bayesian reasoner, with no hint of acknowledgment that a Bayesian decision depends on its input?

Re:invalidate the tests

[cetitau]

I don't want to sound like an expert in this field but I don't understand this response. This science doesn't look for life. Here it's looking for some specific chemical content in the oven at the conclusion of the test. If clumpiness was a result of soil mixed with frozen volatiles, i.e. soil particles stuck together by water or other ices, then evaporation of the volatiles over these days of shaking could certainly alter the outcome. I believe none of these tests are designed to prove or disprove the existance of life on Mars, only to produce results that could indicate or contraindicate the possibility that life could exist or could have existed at some time. The only sure proof would be a video of a drunk Martian Cubs fan stagering home after yet another loss at the park.

Re:invalidate the tests

[petermgreen]

another thing to realise is that afaict martian "soil" isn't something we have a huge ammount of experiance with. All our knowlage comes from instruments on probes which are way way behind what we have on earth.

has anyone even tried sieving the stuff before?

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]

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 Only if the result is negative.

Re:invalidate the tests

[JSchoeck]

Water doesn't sublime.

And with temperatures at below several hundred degrees Celsius it shouldn't evaporate quickly either. It would definitely be in its liquid phase first (and flow through the screen).

Re:invalidate the tests

[MichaelSmith]

has anyone even tried sieving the stuff before? No. But I thought they could have done better than spreading a mountain of the stuff over the oven lids when they only needed a few grains. They have contaminated the other ovens.

Re:invalidate the tests

[profplump]

Why isn't "flawed data" at least sometimes the same as "some data" and therefore better than "no data"?

For example, what if you had a rain meter that leaked -- you couldn't accurately determine accumulation, and you couldn't conclusively ascertain that no water had fallen just because it was empty, but if the meter read 1.28" when you looked at it you could conclude that at least 1.28" of water had fallen since last time the collector was drained. The 1.28" reading would flawed, but the device would still provide the same sort of data it was designed to collect; so long as your understand the nature of the "flaw" in your data it is still generally useful.

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

[antic]

"If they find presence of life..." ...let's cook it!

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

[Anonymous Coward]

On mars it does. Why do you think there isn't any liquid water?

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:invalidate the tests

[Anonymous Coward]

You're right. According to Wikipedia (shame on me, I know), the surface pressure on Mars is .7-.9 kPa. The triple point of water is just below 1 kPa. You're not going to see a whole lot of liquid water (note that this is regardless of temperature). At some lower elevations it would probably be possible for some liquid water to exist, however.

Re:invalidate the tests

[ehrichweiss]

While I'm sure you think you're being clever, in this instance absence of evidence is not evidence of absence. Just because I can't find evidence of a platypus outside my house does not prove that no platypuses(platypae?) exist on the planet. The mere fact that the page you referenced singles out probability theory as the exception should have been enough to figure out that maybe your assertion has limited application.

Re:invalidate the tests

[tweak13]

Water Ice sublimes even in the earth's atmosphere. Ever wonder why ice cubes shrink after they've been in a freezer for a really long time? It's also the reason that all the ice will "melt" off your car if you expose it to the sun, even if it's below freezing out. Freezer burn on your food is also caused by sublimation. So yes, water ice does sublime, and in low pressures would probably do so even more.

Re:invalidate the tests

[eonlabs]

What I'm sure the 'grandparent' article is referring to as a false negative is that if there were water (ice) in the original sample when it was taken, there's a risk that several days vibrating it in under low atmospheric pressure may cause it to evaporate. If it's a small enough sample, or the pressure is low enough, it could sublime, converting directly from ice into steam.

This would result in a false negative if the original sample did, in fact, contain water, because spending that much time between gathering a sample and analyzing it invalidated the test results. This of course, assumes that the first paragraph is true.

The reason for sifting it is probably because anything too large could damage their 'oven.'

Re:invalidate the tests

[sveard]

Ever wonder why ice cubes shrink after they've been in a freezer for a really long time? I know. I also prefer to use deuterium ice.

Re:invalidate the tests

[Anonymous Coward]

mod parent up

Re:invalidate the tests

[SEWilco]

Why do you think there isn't any liquid water?

Because the lake all ran out when that damn thing landed on the levee and punctured it?

Re:invalidate the tests

[pegdhcp]

Wrong, it is better to know that you have no data on a subject than, to hope that data you have might be correct on it.

Re:invalidate the tests

[JSchoeck]

There are substances that sublime 100% (like dry ice), and water ice certainly isn't one of them. Of course many substances have a vapor pressure even their solid state, but it's much less than in their liquid state.

So my statement was not completely true. I'd guess that in this scenario water ice still would be detected.

Re:invalidate the tests

[Urkki]

What do you mean, "water doesn't sublime"? Concrete counterexample: The laundry can be dried outside even in freezing temperaturs when it is windy or sunny (basically, when the air humidity is low enough). Are you saying that the frozen water in the laundry first melts (even though it's temperature is definitely below freezing point) and then evaporaters? Or are you saying that laundry doesn't dry outside below freezing point of water, contrary to common observation? Or maybe you mean that the wind erodes the frozen water and blows it of as fine ice dust? Or something else?

Re:invalidate the tests

[Ihlosi]

Water doesn't sublime.

I have a phase diagram of water here that disagrees with you (and anyone who modded you informative. geez, people, hand in your geek licenses please).

See that boundary line in the lower-left corner, where vapor and ice are directly adjacent to each other ? That's where water sublimes.

http://encarta.msn.com/media_461541579/phase_diagram_for_water.html

Re:invalidate the tests

[JSchoeck]

While this is true the statement that it sublimes due to the sun radiation (which was supposed to mean high temperature, right?) isn't correct. If it was meant that the sun heats up the water ice from -150ÂC (or whatever the surface temperature is at the landing site) to 0ÂC, okay, then I misinterpreted it.

Funnily enough Mars' atmosphere has pretty much exactly the pressure of the triple point (~6 mbar) of water.

Again, I was wrong. Shame on me! ;)

Re:invalidate the tests

[petermgreen]

wikipedia claims the triple point of water is 611.73 pascals which would put it just below martian surface pressure, so liquid water should be able to exist albiet in a pretty narrow temperature band.

Re:invalidate the tests

[bytesex]

Look man, I'll just wave into the camera next time I walk past it Ok ? I mean, I know where they landed the thing, it's just that I always walk through the park.

Re:invalidate the tests

[griffman99h]

The oven is being used to detect organic compounds in the presence of water if I'm not mistaken. Orbital scans have pretty much proven the existence of water up till now. any water ice sublimating would still leave the organics behind in the sample. Kind of silly to go all that way just to boil some water.

griffman

Re:invalidate the tests

[eonlabs]

based on this article: http://phoenix.lpl.arizona.edu/science_tega.php
the TEGA ovens go up to about 1000 degrees C...

This means they're likely to be able to vaporize water, many organic compounds, but not silicon dioxide (sand/glass), and not most metals. It would be interesting to know what they hope to detect at that temperature...

Re:invalidate the tests

[Muad'Dave]

Curiously, there's a triple point very near the mean the surface conditions on Mars shown on that diagram. It's almost as if water were intended to be useful on Earth _and_ Mars....hummm.

Re:invalidate the tests

[Anonymous Coward]

Carbon dioxide doesn't "sublime 100%" any more or less than water does... unless you're talking about specific conditions. Depending on the pressure/temperature, water can "sublime 100%" and carbon dioxide can pass through a liquid phase prior to vaporizing. On Earth your statement may be (broadly speaking) correct, but we're talking about Mars. I'm not sure how CO2 behaves on Mars, but as far as water goes, it looks as though conditions might be just right for it to behave much as CO2 does here on Earth...

Re:invalidate the tests

[Anonymous Coward]

This [http://phoenix.lpl.arizona.edu/science_tega.php] means they're likely to be able to vaporize water, many organic compounds, but not silicon dioxide (sand/glass), and not most metals. It would be interesting to know what they hope to detect at that temperature [1000 C]...

From TFA:

TEGA is a combination high-temperature furnace and mass spectrometer

Furthermore, TFA states that they will "measure the mass and concentrations of specific molecules and atoms in a sample." That's essentially what an MS is good for.

FYI, MS can even be used for protein sequencing. This is not as efficient as indirect sequence analysis via DNA sequencing, but it gives a first clue to what kind of stuff you have at your hands. Heat-induced decomposition of chemical compounds--like all chemistry--is not a complete random process.

Re:invalidate the tests

[fifedrum]

why back in '61, when they took Phobos out of orbit, the pressure climbed enough to keep ice in place below the datum

Re:invalidate the tests

[siglercm]

Water doesn't sublime. Huh? Ever had any instant coffee? Any freeze dried instant coffee?

Re:EZ Bake?

[rkanodia]

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

Sounds just like my wife

[Anonymous Coward]

Except for the "Evolved" part.

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...

Re:Too much vibration...

[Anonymous Coward]

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... 1) Drive Sprint/Opportunity Rover into Phoenix
2) ???
3) Tilted! (Profit?)

Re:Too much vibration...

[JosefG]

I hear they tried this already, but when they converted a dollar into quarter they ended up with three and the mission was a failure. At least they only wasted $0.75 this time.

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?

[Ihlosi]

Why would they have designed the thing to have such a low tolerance filter in the first place?

Probably because heating a larger amount of soil would have been too much of a drain on the batteries of the thing.

But I agree. 1 mm diameter particles are tiny.

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.

Re:What were they thinking?

[Anonymous Coward]

I already know what a millimeter is, you American clod!

Re:What were they thinking?

[videoBuff]

There are two different questions in your post - subject line and slightly different focus in comments.

Tolerance is not an issue here. It is highly likely that all components used were machined with a very high degree of tolerance (say +/- .01% or better of nominal value). Size of that opening 1mm, probably what you are talking about, is very close to what is used in an ordinary sieve. If soil is wet or even damp, it would not get through, as you mention. May be NASA thought that when they blasted the ground with retro rocket fire used in landing , it would have vaporized most of the water in soil, including any sign of possible life :-) Soil made sterile and powdery, just great for studying geological composition of Martian soil.

Your questions "What were they thinking?" is lot more provocative. Though these missions come under general category of "search for life," somebody pointed out that even if an alien is come and dance in front of that craft, NASA will not know it. There are no biological experiments that are in this mission. At best, NASA may infer possible potential life signs indirectly. These are geology experiments. It looks like geologists have bigger political clout in NASA currently than astrobiologists. May be fine particles are fine for geology. To answer your question, NASA was thinking like a geologist - totally interested in their field to the exclusion of everything else.

Re:What were they thinking?

[Original Replica]

You don't want or need to deal with huge amounts of material to tell what compounds are in the soil.

You also don't want half of the contents to sublimate by leaving them exposed to sunlight and friction/heat from a vibrating screen. Considering how important it was to land where there was ice (polar landings are tough) you think they would be a bit more careful to preserve that ice since that is where they hoped to find the organic compounds.

Re:What were they thinking?

[petermgreen]

1mm isn't really all that small.

Thing is that under a BGA you need a grid of vias and if you don't want to use blind vias (which are expensive and complicate the design process) you have to get tracks between the vias.

If you have a minimum hole size of .25mm and a minimum track gap and annular ring of .1mm (theese are not hypothetical figures, they are zot's "standard production" figures). With a 1mm pitch BGA you can get two tracks between a pair of vias on each layer. With an 8mm pitch BGA you only get one track between a pair of vias on each layer. In other words making BGAs even slightly finer pitch hugely drives up the PCB requirements.

For chips in more conventional packages with leads at the edge 1mm is actually quite a large pitch (just a tad smaller than the 1.27mm of SOIC) and easy to hand solder. Most modern convential chip packages have .5mm pitches.

Re:What were they thinking?

[Anonymous Coward]

a dime is about 1mm thick. I think your dealer ripped you off.

Re:What were they thinking?

[BradMajors]

1mm is not tiny when the diameter of the test chamber is about 2mm.

Re:What were they thinking?

[Anonymous Coward]

Gee, and all this time I thought of it merely as a tenth of a centimetre :-)

Another easy frame of reference is twice the diameter of the most common mechical pencil lead size: 0.5mm. Wooden pencils usually have 2mm leads. Virtually all of them are metric.

Re:What were they thinking?

[Anonymous Coward]

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. What's a "dime"?

Re:What were they thinking?

[Alpha Whisky]

For my fellow brits, used to BBC units of measurement, it's roughly 120 micro london buses (ub), 0.12 millibuses. And a dime is an American coin worth roughly 5p (at time of writing).

Re:What were they thinking?

[Jesus_666]

For the common man outside the USA: It's one of the small intervals on your ruler.

Re:What were they thinking?

[elrous0]

It's a U.S. coin that's worth less and less every day in the rest of the world.

Re:What were they thinking?

[Anonymous Coward]

Good lord, that didn't help him at all. For the common man: a dime is about 1mm thick. A dime is about 3mm thick.

Re:What were they thinking?

[Anonymous Coward]

Good lord, that didn't help him at all. For the common man: a dime is about 1mm thick. A dime is about 3mm thick.

Re:What were they thinking?

[confused one]

They also had to drop it on the surface without making a new impact crater. Again, low weight makes that easier.

Re:What were they thinking?

[Changa_MC]

A dime is about 3mm thick. You need a better ruler.

Hooray

[Haoie]

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

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

Re:Hooray

[Sponge Bath]

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

It could but it would require 1mm graham crackers and marshmallows.

Re:Hooray

[Chrutil]

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

Right. All they've got is "shake and bake"

Re:Hooray

[notdotcom.com]

I was just about to post a comment about the easy-bake. You're too quick... cooking cakes with that 100W light bulb and all.

Imagine how long an ez-bake would take today with all of our "green" CFLs using 20-ish watts and putting off a very small amount of heat.

"Mom, I just put the cake in the 'green EZ-bake', set the timer for 72 hours please!!"

Re:Hooray

[Bat Country]

That, dear poster, is priceless.

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.

Re:it's no turkey

[zobier]

I'd consider a pile of ashes quite well-done.

Re:it's no turkey

[Muad'Dave]

Yeah, but the minute you open the oven door, your roast flies out!

Shake & bake.

[Ihlosi]

Let the baking begin.

Re:Shake & bake.

[kryptkpr]

Pffft... Bake'n'Bake!

Mmmmmm....

[Anonymous Coward]

Martian soil!

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.

Re:Will it blend?

[Anonymous Coward]

Have they blended a blendtec blender yet?

Re:EZ Bake?

[arazor]

If only my mod points hadnt expired yesterday.

I thought vibrators were for when...

[exp(pi*sqrt(163))]

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

Late Breaking News:

[Spy der Mann]

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But first, a word from our sponsors:

----

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K'breel, speaker for the Council, calmed down the population:

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What is important is that the metallic creature does not record any sign of intelligence under our beloved red sky. But do not be afraid, for soon we will elliminate it, making it look like an accident. When a subversive traitor accused the speaker for the most Illustrious Council that the slowdown was simply a malfunction in the metallic creature's machinery, K'breel ordered to have him imprisoned and executed tonight for High Blasphemy.

Re:Late Breaking News:

[Anonymous Coward]

Perhaps after the execution the beloved Red Sky will return to it's proper beloved color a deep indigo with a smattering of stars.

Oven #4 is the first oven?

[otter42]

From my reading of the FA, it seems that oven #4 is the first oven they tried. That's important, because it seems that whether the soil gets there or not, they only get one try with each oven. So they still probably have 7 more to go. Hurrah, NASA!

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.

On your mark... Get set...

[davidbrit2]

GO!

These two teams are shakin' things up trying to fill four thermal and evolved-gas analyzer instrument ovens past the line. Whoever does it first will win $20, and control of the most interplanetary game show on television...

DOUBLE DARE!

Re:Once again...

[exp(pi*sqrt(163))]

> These folks aren't blinded by minute details and generally see the big picture. Tell me. How exactly does having the "big picture" allow you to see one flaw in a million little details? By definition of "big picture", the details are missing from it.

Microphotographs would be than analysis

[bsharma]

Considering all the difficulties in a shake & bake, a set of microphotographs at different magnifications, say 10X to 100X would have revealed more about the composition. Given a choice between seeing something and reading a chemical analysis to understand unknown matter, what would you prefer?

Oh great...

[Anonymous Coward]

they've got reactor number 4 online and they're gonna render the entire Red Planet uninhabitable

Re:Once again...

[rAiNsT0rm]

Wow, by your username, signature, and response I'm going to lump you into that "egghead" class I spoke earlier of and say that you are reading waaaay too much into an offhand comment on a slashdot story. I think you know what I meant.

I can't tell you how many times totally non-technical people have come up with crazy analogies that actually match a particular complex situation that you would never expect them to even begin to grasp. As much as I hate to admit it, the average scientific/tech type is generally lacking in standard common sense. Having a few "normals" around would probably do us good.

Tough?

[camperdave]

Why do you say polar landings are tough? Why would they be any tougher than landing anywhere else on the planet?

Re:Tough?

[Ihlosi]

Why do you say polar landings are tough?

Same reason why you usually don't launch rockets from the poles - delta-V.

Why would they be any tougher than landing anywhere else on the planet?

Because you need to deal with a much higher delta-V when landing on the pole compared to landing on the equator (provided that you're landing on the side of the planet that rotates in the direction that your spacecraft is coming in - if you try the other side, you're going to have to deal with twice the delta-V of a polar landing, so don't do that).

Re:Tough?

[camperdave]

Because you need to deal with a much higher delta-V when landing on the pole compared to landing on the equator

Let's see... Mars diameter... sidereal rotation... carry the two... 240 m/s. Earth-Mars velocity difference 2649 m/s. The delta-V due to rotation is a tenth of what needs to happen to burn off the delta-v from getting to Mars in the first place. It's an extra handful of seconds behind the heat shield, plowing through the atmosphere. It's not really all that tough.

Re:Tough?

[Ihlosi]

The delta-V due to rotation is a tenth of what needs to happen to burn off the delta-v from getting to Mars in the first place.

And 1/10 of additional velocity roughly translates to 20% more energy that needs to be dissipated.

Re:Tough?

[mollymoo]

The trajectory of the spacecraft will be in the plane of the solar system, which is pretty much the plane of Mars's equator. If you want to land near the equator you're already going the right way for aerobraking in an equitorial orbit; you more or less just spiral down (that is of course a gross oversimplification). If you want to land at the pole you'd need to transfer from the 'natural' equitorial orbit to a polar one, which requires a bit more than merely an extra few seconds of aerobraking.

Re:Tough?

[camperdave]

Mars, as seen from Earth subtends 25.1 seconds of arc, or 0.00697 degrees. The plane of Mars's orbit is 1.85 degrees off of the plane of Earth's orbit. So to do a Mars polar insertion means using a launch angle of 1.8535 degrees instead of 1.8500 degrees (and possibly as low as 1.8505 degrees depending on where Mars is in it's orbit at arrival time).

Look at it this way. Imagine you're at mid course in your transfer orbit and Mars is dead center in your crosshairs. It's going to take roughly the same ammount of energy to shift up and loop over the pole as it would to shift left and enter an equatorial. Remember, you're well outside either planet's gravitational influence, so the only thing you're doing is making a minor change to your solar orbit.

Ever had ice cubes evaporate in your freezer?

[MichaelCrawford]

Leave them in there long enough and they will noticably sublime - at atmospheric pressure even.

Re:Ever had ice cubes evaporate in your freezer?

[ivan256]

That's more likely due to having a self-defrosting freezer, and not due to sublimation.

Double Factors...

[Tablizer]

In this case, the soil turned out to be clumpier than anyone expected

There's another possible factor to this problem. One of the oven doors did not open all the way due to unknown factors. To compensate, they dumped more soil than originally planned into the slot to make sure enough got onto the screen. It turned out too much got on the screen because they were accurate enough, and the weight may have made the vibrator less effective and/or the soil clump more.

Thus, the problem is possibly due to a combination of soil clumpier than expected AND the door problem.

The soil was probably wet and dried out...

[tjstork]

I know that yeah, its too cold for that happen on Mars, but, maybe there's something or some chemistry that acts like a wetting agent. Thus, once the soil filled up the beaker, it had lost the effects of the wetting agent that had "glued it together" - just like mud can be sticky before it possibly powders up as it dries. So, really, the whole experiment is botched and the lander blew it, again.

Mmmmm...

[professorfalcon]

Nothin' says lovin' like Martian soil in the oven!

investment vs result

[r2kordmaa]

its depressing how feeble and unreliable the space probe design are compared to the insane amounts of investment. a shovel, to scoop up dirt, instead of some decent drilling apparatus that could get samples from much deeper and from harder surface. days to fill a small hole. solar panels that get covered in dust because someone is too lazy to add windscreen wipers. making things heavier and more robust than needed resulting in insane liftoff prices. everything designed like alpha stage prototype. no consideration of price. if businesses would be contracted to design and make happen space missions we would have 1000 men moon base by now. you could just give the budget and say use what you must to accomplish it and the leftover is your profit. competition would drive down prices and improve design

Re:investment vs result

[Ihlosi]

its depressing how feeble and unreliable the space probe design are compared to the insane amounts of investment.

And you're ... qualified to make this statement ? Are you any kind of engineer (ME or something along those lines would be best) ?

shovel, to scoop up dirt, instead of some decent drilling apparatus that could get samples from much deeper and from harder surface.

Yes, of course, a drill. How brilliant. So where do you get all the power to run that drill ? How do you keep it lubricated ? How do you keep your lubricant from polluting your samples ? How do you move the drill around to drill in different places ? And remember, this is a space probe. Weight is at a premium.

solar panels that get covered in dust because someone is too lazy to add windscreen wipers.

So how well do your windshield wipers work when its completely dry ? How do you avoid scratching the surface of the solar panels (which will permanently degrade their output) ? What do you do when the wiper breaks down in the middle of its operation (which will knock out that solar panel completely) ?Also, now we've learned that Martian winds are strong enough to keep the panels clean.

making things heavier and more robust than needed resulting in insane liftoff prices.

Hey, you're the one suggesting adding all kinds of heavy (and useless) stuff to probes.

if businesses would be contracted to design and make happen space missions we would have 1000 men moon base by now.

If business were contracted to do so, we'd have a lot of dead people on the moon, a couple of businesses that have gone belly-up, and some shareholders and CEOs that got insanely rich in the process. Not sure if that's any better than what we have now.

you could just give the budget and say use what you must to accomplish it and the leftover is your profit.

Great, give me the money, here's your space probe. Business closes, owners and CEOs make off with wads of cash, space probe fails because they've been cutting a few corners too many. And don't even think of delaying payment until the probe was successful - no businessperson in their right mind would accept such a delay in payment.

Re:investment vs result

[r2kordmaa]

heh not quite engineer but smth along the lines for sure, i doubt a drill would be heavier than a robot arm + shovel, the do manage all other moving parts wo lubricants, thre are plenty(arm joints, wheels etc). one could easily spend a lot of time drilling the hole so it could be powered by solar panels, it would still be lot faster and power efficient than robot arm + shovel method. you can brush anything clean of dust wo any liquid right? solar panels are covered with protective glass anyway so i wouldnt worry about scratches - wouldnt take the wind keeps panels clean story too seriously, first the atmosphere there is quite thin, second if high winds could get dust of how come i have to wash my car every now and then, even airplanes cant do without washing and you cant get much stronger winds than that. about the dead ppl on the moon, i still think it would be more of a success than nothing we have at the moment - remember a rocket blown up teaches engineers more than one successfully lifted up. you over simplify the business part of the deal, of your general space mission costs about a third is insurance just so you know. here lies the problem with space programs. there is no need to make things too complicated, simple solutions are always best when it comes to being error proof. for some reason public opinion of rocket science is just that, uber complicated near impossible to understand. when in fact the complexity is way below the level of more modern sciences like genetics, various fields of electronics, biology, mathematics, quantum physics etc... rocket engine in principle is one of the easiest engines there is with even steam engine being more mechanically complex, of course, it gets harder when you want to scale up the engine - lifting 20t to LEO is lot more than 20X more difficult than lifting 1t to same orbit. so wouldnt it be more economically efficient to lift more but smaller payloads? space shuttle weighs 2000t, can lift 24t to LEO and mere 3.8t to GTO, one liftoff costs $1billion. is it really efficient to use 2000t shuttle to get up 7 people? SpaceShipOne the ansari x prize winner could lift 3 people to space(true, not orbit) for mere nothing compared to 1billion USD, i think that compares private venture cost effectiveness quite well

Re:investment vs result

[Anonymous Coward]

Something along those lines, eh? You don't even know how to speak properly, and are apparently entirely unable to grasp the concept of dividing text to paragraphs.

I wouldn't trust you to design a non-mechanical toy, much less a spacecraft.

Careful there ...

[Ihlosi]

wikipedia claims the triple point of water is 611.73 pascals which would put it just below martian surface pressure, so liquid water should be able to exist albiet in a pretty narrow temperature band.

The pressure axis in the phase diagram doesn't refer to the total pressure, but to the partial pressure of water vapor (or, to be more precise, to the pressure of water vapor since the phase diagram assumes that there are no other substances present).

Since water vapor differs significantly from an ideal gas, the partial pressures of other gases do have an effect on water, but they cannot just be added to the pressure axis in the phase diagram.

Oh, a goatse troll...

[GameboyRMH]

How quaint...

how long is an experimental cycle?

[peter303]

They have to do some cooking and measuring. How long does that all take?

Mars phoenix on twitter

[proxima1]

You've probably seen the "real" Mars Phoenix twitter page: http://twitter.com/MarsPhoenix Check out the "alternative viewpoint": http://twitter.com/fakemarsphoenix

Tug of war between dirt and air?

[Anonymous Coward]

Probably evidence that when left out long enough, sublimation wins vs. the hygroscopic nature of the red clay dirt. So once it dries out, it loses its clumpyness and becomes dusty. (And there's plenty of evidence for Mars being dusty.) Anyone who has played by making mud-"grenades" or "pies" with red clay soil in their childhood probably has an idea of how Mars soil actually behaves already. It shouldn't be too hard for NASA employees to find an earthly parallel to the martian soil, it's probably as near as their as local softball diamond.

But what would be interesting is if they can figure out how long it takes for sublimation to dry out an exposed soil sample, or how deep one has to go for the hygroscopic soil properties to be stronger than evaporation... Mars might be a lot wetter than we may think, just in a muddy permafrost instead of easily observable free flowing water. (Which might help explain the signs of recent water activity, even though pools of free standing water aren't observable.) Possibly all anyone might need to do for water on a future Mars settlement is to dig up the dirt a foot or two and heat it up in an enclosed separator.

Re:Microphotographs would be than analysis

[ElAurian]

"Wow, that blue stuff is cool. I wonder what the fuck it's made of?"

"I'm afraid we can't find that out, since bsharma was in charge of the science mission and sent a microscope instead of a chemical analysis kit."

"Well, fuck!"