I haven’t written about the Mars Phoenix lander in some time — I figure y’all get your news from Emily — but just in case I think I’d better mention that the oven on board the lander may short out the next time it’s used.
This is bad news. The main goal of the lander is to take a sample of Martian "dirt" (really regolith), heat it up in the oven, and examine it for chemicals that are conducive for life. There were issues earlier, and they had to vibrate the oven to break up some stubborn clumps that were clogging the intake. This may have caused the short circuit. Engineers fear that the next time they use the oven it’ll blow, so they’ll treat every sample they get as if it were the one last chance to heat up a surface sample.
Therefore they’ll have to make it a good one. They found water ice under the lander, so they want to get a sample of soil with a lot of ice in it, maximizing the odds of finding what they want. This will happen early next week, after the July Fourth holiday.
 |
| This is the trench, dubbed Snow White, dug by Phoenix where it will get the next and possibly final sample of the surface of Mars |
Bummer. This has been a fantastic mission so far, and I really hope this last scoop gives the scientists what they need. But even if it doesn’t, I would count the mission as a success. It was able to do many things: it landed with nearly pinpoint precision at its destination, it was photographed on the way down (man I love that shot), it was able to scoop up the soil, heat it, test it, and use a microscope to examine it. Also, the mission lifespan was only a few months anyway, since they landed during late Martian winter summer in the northern hemisphere. In a few weeks, the Sun will be too low to power the solar panels. So this oven short is a problem, but not a major disaster.
And if they can get a good sample with ice in it for this last attempt, then I imagine the folks at Phoenix HQ will be very happy indeed.
July 3rd, 2008 at 8:53 am
Phil –
You said: Engineers fear that the next time they use the oven it’ll blow, so they’ll only get one last chance to heat up a surface sample.
Actually, the way I read Emily’s description, only the first half of that statement is correct. They were planning to deliver a sample from Snow White to both the TEGA and the Wet Chem. lab, but upon reflection of the short-circuiting problem rethought that decision and are going to wait to get a really ice-rich sample to dump into TEGA… but, quoted from Emily’s blog:
“they are actually concerned about the ability of TEGA to avoid short circuits and are planning to treat each sample delivery as though it were the last.
So although the next sample may be the last one they get, I didn’t read from that that it was the “last chance”, per-se. If they succeed without short-circuiting TEGA, I assume they’ll make as many dumps into TEGA as they can until it does… or am I missing some info there?
July 3rd, 2008 at 8:53 am
Definitely a bummer. Still, all in all, the mission HAS been a success.
July 3rd, 2008 at 8:56 am
Wait a minute: Doesn’t the Phoenix have eight ovens? So what kind of failure are we talking about? Is it one in the individual oven or one in the entire circuit? According to the link, the problem reads like it’s just in Oven Four.
July 3rd, 2008 at 9:15 am
Doesn’t the Maytag repairman make housecalls?
July 3rd, 2008 at 9:34 am
If it’s the same problem they were concerned about before then it’s in circuitry that’s used to generate the gases used to carry the vapor evaporating from the samples to the sensors. In any case, while there may be 8 separate ovens, there is only one “laboratory” (for that experiment) — just 8 repositories for samples. So a short in the whole equipment would kill everything in the lab.
I’m just hoping they’re being extra cautious. If there is a chance this is the last sample they can analyze then sure, they must get the best sample they can first time. But I still think there’s a good chance they’ll be able to do more — they’re just not banking on it.
July 3rd, 2008 at 9:35 am
Oops — “So a short in the wrong equipment…”
July 3rd, 2008 at 9:52 am
Phil, it’s actually summer in the Martian northern hemisphere. They’re still trying to get things accomplished while the sun is high enough in the sky. It’s winter where the rovers are, and that’s why their activity has been limited.
July 3rd, 2008 at 10:00 am
That’s a huge letdown, and I wonder what would happen if the final sample showed signs of organic molecules or some other interesting data. Would it be discarded if it couldn’t be reproduced, or might be a side effect of malfunctioning equipment?
Now that the development work has been done, would it not be cheaper and quicker to send up a replacement, maybe with some oven improvements?
July 3rd, 2008 at 10:07 am
Oops! OK, I meant to write that winter is approaching; that’s what I get for drafting a post before coffee. I also added a line to clear up the “last chance” bit.
Thanks!
July 3rd, 2008 at 10:11 am
Yeah, a single detection of organics could well be discarded. They could well be Earth organics that came along for the ride. Part of the TEGA package is a test sample, the ogranic-free blank (OFB). (MARS 2007 PHOENIX SCOUT MISSION ORGANIC FREE BLANK: METHOD TO DISTINQUISH MARS ORGANICS FROM TERRESTRIAL ORGANICS — http://www.lpi.usra.edu/meetings/lpsc2008/pdf/1067.pdf, half-megabyte PDF). After detecting organics, they need to also then bake the OFB in the TEGA to make sure they do not detect organics in it. Having that extra oven operation increases certainty a whole bunch.
July 3rd, 2008 at 10:15 am
I have got EVERYTHING crossed for Phoenix. This mission HAS been a success. I REALLY hope they get the data they need, want and wish for (whatever that is) Strange things happen on Mars (look at the unexpected longevity of Spirit and Opportunity) maybe the Martians will step in and fix Phoenix coz they are sorry for scuppering Beagle 2!
July 3rd, 2008 at 10:18 am
That’s http://www.lpi.usra.edu/meetings/lpsc2008/pdf/1067.pdf
And, rereading the procedure, after the OFB baking shows no organics, then they’d go to the Mars sample again and repeat it to validate the first detection of organics. So good organic results depend on getting several good bakes.
July 3rd, 2008 at 11:25 am
This may be a bit of a foolish question, but I would appreciate any help here.
If one of the TEGA ovens shorts out, how will that affect the others? Also, are the individual ovens identical, or do they have unique tasks with specialized equipment?
July 3rd, 2008 at 11:28 am
Phoenix sort of has the disadvantage of coming after Sojourner, Opportunity, and Spirit. Given the above-and-beyond successes of those rover missions, there’s an atmosphere of irrational expectation that Phoenix should deliver the stars and learn to read Hebrew, especially given it’s “just” a lander. Therefore it can be (and is) successful, and yet perceived not to be, which is unfortunate.
Heh, engineering conservatism. I know it well.
July 3rd, 2008 at 11:42 am
Whoops… Well, let’s hope it will survive a couple more tests at least
July 3rd, 2008 at 1:04 pm
Ravenor — I answered above — there may be eight ovens, but they are little more than sample holders that bake the samples until any moisture in them evaporates. There is just one “lab”, one instrument that is responsible for collecting the gases and analyzing the samples. If a short happens somewhere in the “lab” then the whole instrument is toast.
July 3rd, 2008 at 1:13 pm
Hey, still it’s an incredible amount of success from what it has already done!
July 3rd, 2008 at 2:31 pm
Boy, I sure don’t have the same definition of success. Yeah, the Orbiter photo was cool, but good grief! TEGA was the whole point. I’m crossing my fingers, too, because if this experiment is over, I’d call this mission a (qualified) failure. The one bright point, and it is significant, is confirmation of subsurface ice.
July 3rd, 2008 at 4:44 pm
The main purpose, to confirm subsurface ice, is accomplished.
Btw, while the TEGA ovens are identical for the purposes of analysis, their geometry differ. They will leave #5 (inner oven, both lids half open) open and open #0 (outer oven, expect one lid fully open and the other half open) instead.
Possibly #5 will be contaminated even if they return to it later.
And I do hope it isn’t the remaining MA filament that has an intermittent short.
I hear next rover (2009) will have 74 ovens.
July 3rd, 2008 at 4:50 pm
Mission success criteria usually err on the side of caution. There are just so many things that can go wrong, that achieving any significant results such as a couple of TEGA bakes, is very much a success. Sure, there will be disappointment in the team if they have to left a half-dozen ovens unused, but there are plenty of other instruments that are still operating and returning valuable data. The failure of one only of the instruments, after it has returned some results, is most certainly not a cause to call the whole mission a failure, even a qualified one.
July 4th, 2008 at 3:48 am
I am watching this mission with a big deal of excitement, and agree with most of what our BA wrote about it. But I’ve been wondering since day 1 why Phoenix landed well enough but just at the very edge of its 99 % ellipse, long and left (North) of the Bull’s Eye. As an engineer I am curious about the reason(s) for this.
July 4th, 2008 at 4:54 pm
Noooooooooooooooooo! It was gong so well
July 5th, 2008 at 11:41 am
Tacitus:
Sorry about that, I must have been more tired than I thought when I read your first post. *reaches for more coffee* Thank you for taking the time to clear that up for a very tired student.
July 6th, 2008 at 5:20 pm
OK the lander did make it, it is taking readings, it did bake 1 sample and might get 2, heck maybe they can get them all but it doesn’t sound like it. So if they do get 2 cooked samples that’s .250 average. In baseball you’d never make the All Star game and no one will remember your name really. So it is a qualified failure-ish mission. I still have trouble with them not taking into account you might get large clods of material clogging things up, especially when you are looking at, well frozen mud. Depending on when that short occurs they may not even get the second sample heated enough to get meaningful measurements. As for they found subsurface ice, well we already knew it was there, this was the chance to study it in depth, which might not occur.
Will we learn things yes, but if the full science mission isn’t accomplished then a lot was missed and all we get are some tantalizing results and some weather reports for the pole and a really cool picture of the entry, which is amazing to think about to me.
To open a can of worms this is why we need manned exploration. In all the time spent on Mars those great little rovers have only covered around 22kmand sampled a relatively small number of rocks, Apollo 17 did 35km in 22 or so hours and brought back over 100kg of rocks to look at. With a bit of engineering gusto a robot might be able to do that in a couple of decades and no doubt will, but man can do it as soon as he gets there. That is the hard part for humans.
Look at it this way, if the ability to examine the lunar rocks was left with only the technology available in 1969, a number of things wouldn’t have been possible. They are still studying the rocks returned. So if we look at the robots, they only the set of tools sent with them, they can’t be improved upon. Get the rocks back here, they can be studied over years with new methods as they are developed.
Anyone want change from my 2 cents worth?
July 6th, 2008 at 5:23 pm
PS please pardon my lousy grammar, I swear I read it twice before submitting and still missed several things. See I know what I want to say I just screw up writing it.
July 7th, 2008 at 12:11 pm
Kyle said: To open a can of worms this is why we need manned exploration.
I’ve changed my mind on this. There was a time when I would have said robotic missions are so much more efficient, but I now come down on the side of, “if a human were there, they could fix a short.” It just doesn’t seem to be possible to engineer these things to the desired level of reliability.
July 8th, 2008 at 10:08 am
Kyle Says on July 6th, 2008 at 5:23 pm :
“PS please pardon my lousy grammar, I swear I read it twice before submitting and still missed several things. See I know what I want to say I just screw up writing it.”
I sure know that feeling & I empathise entirely!
I also concur with the “That’s why we need people & NOt just machines there! Machines lack a certain flexibility and imagination and capability that comes with Humanity. I’m all in favour of using both too but we gotta get humans there! I can’t wait for the first woman landing on Mars!
July 8th, 2008 at 10:13 am
The Centipede said on July 3rd, 2008 at 11:28 am :
“Phoenix sort of has the disadvantage of coming after Sojourner, Opportunity, and Spirit. Given the above-and-beyond successes of those rover missions, there’s an atmosphere of irrational expectation that Phoenix should deliver the stars and learn to read Hebrew, especially given it’s “just” a lander.”
Why Hebrew? The language it should really be required to read is Martian isn’t it?
——–
PS. Been a few days now but ugh .. still can’t say I’m keen on this new version of the BA Blog. The old (non-Discover) oner was much better in my humble opinion. All orange & all squashed tothe left and gret font and just gnereally well .. yeck. Any chance of taking the blog back to where it once belonged?
(To misquote the beatles “get back!” song.)
July 8th, 2008 at 10:19 am
Incidentally coming after other probes could also be seen as an advantage as well – like standing on the shoulders of giants as Isaac Newton (?) put i things…
(Hmmm.. Corrected a typo there – it originally read “standing on the shoulders of gnats” instead – which wouldn’t get you anywhere near as far!
)
Personally, I’d rate ‘Phoenix’ a success – it landed successfully and has already managed many of its tasks even if the oven fails its still acheived a lot. If the ovens shorts it won’t be quite as much of a success perhaps – but Phoenix is a success all the same.