Slashdot Mirror
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."
We've come along way from the Easy-Bake Oven.
But I still bet the Phoenix can't make smores.
If each mistake being made is a new one, then progress is being made.
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.
...you didn't want a bun in the oven.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
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.
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.
Changa hates change.
But first, a word from our sponsors:
---- Tonight, in "Our Council Answers": The S'karr is a lie? Find out the latest conspiracy theory and the REAL reason why the traitors want to have K'Breel, our most benevolent and enlightened speaker from the Council of Elders, - Gfa'rdmn forbid - removed. After all questions are answered, you can witness how blasphemers have their gelsacs ripped appart, and then kicked to the *IMPROVED* Snarpat pit of death! You can't miss it! ----
K'breel, speaker for the Council, calmed down the population: Gentle Citizens, please do not be alarmed. The terrifying metallic creature sent here by the sinister blue planet has been slowed down. We have been reported that the plan to paralyze its feeding organs has been a success, with the creature unable to eat for at least five days. K'breel said that the creature was only paralized and not destroyed so the Council would have more time to think of an effective plan. The public cheered when they heard speaker K'breel say the following words: 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.
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.
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.
Note the portion where solid and vapor phases are adjacent with no liquid phase in between (sublimation/deposition).
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.