NASA's Phoenix Mars Lander Killed By Ice

coondoggie writes "NASA officially ended its Phoenix Mars Lander operation today after a new image of the machine showed severe ice damage to its solar panels, and repeated attempts to contact the spacecraft had failed. 'Apparent changes in the shadows cast by the lander are consistent with predictions of how Phoenix could be damaged by harsh winter conditions. It was anticipated that the weight of a carbon-dioxide ice buildup could bend or break the lander's solar panels. [Michael Mellon of the University of Colorado] calculated hundreds of pounds of ice probably coated the lander in mid-winter.'"

Comments

What?

[Mikkeles]

Frozen CO2 as "ice" makes as much sense as frozen iron as "ice".

Re:What?

[Anonymous Coward]

mods, ice this troll

Re:What?

[jo_ham]

In the science of cold, solid CO2 has had the colloquial name of dry ice for as long as I can remember. Saying "CO2 ice" gets the meaning across perfectly that you mean solid CO2.

In this context, it forms in the same way as water ice does here in winter conditions, it's just a different molecule.

Re:What?

[fuzzyfuzzyfungus]

Umm... Even on our rather aqueous planet, where the only CO2 ice is either synthetic or located in seriously inhospitable places, the term "dry ice" has been in common use for ages.

On a substantially drier and colder planet, it seems even more appropriate...

Re:What?

[Anonymous Coward]

http://en.wikipedia.org/wiki/Ice#Non-water_ice

and

http://en.wikipedia.org/wiki/Volatiles

Enjoy learning something new.

Re:What?

[Anonymous Coward]

At first I thought the troll mod was appropriate, but then I thought of all the people who are not familiar with the environment on Mars who might read the first part of the summary / article and think that "ice" refers to water ice, and I then realised that yes, Mikkeles has a point. At least call it dry ice.

Re:What?

[gyrogeerloose]

Umm... Even on our rather aqueous planet, where the only CO2 ice is either synthetic or located in seriously inhospitable places [...]

Just out of curiosity, is there a place on earth where there is naturally-ocurring dry ice? A Google search comes up empty.

Re:What?

[jo_ham]

Probably not, unless it's in very small quantities. Atmospheric concentration is pretty low, and either way, at 1 bar it doesn't freeze until about -78C. I don't think there are any natural places on Earth that cold.

http://en.wikipedia.org/wiki/File:Carbon_dioxide_pressure-temperature_phase_diagram.svg

That suggests you are going to need some serious pressure before you can solidify it at Earth-natural temperature ranges.

Re:What?

[MichaelSmith]

Umm... Even on our rather aqueous planet, where the only CO2 ice is either synthetic or located in seriously inhospitable places [...]

Just out of curiosity, is there a place on earth where there is naturally-ocurring dry ice? A Google search comes up empty.

Apparently it freezes at -78.5 degrees C which is uncommon but not impossible on Earth.

Re:What?

[osu-neko]

Frozen CO2 as "ice" makes as much sense as frozen iron as "ice".

Actually, it makes as much sense as frozen water as "ice". Anyone who thinks otherwise is simply not as fluent in the English language as they could be. Someone who isn't as familiar with the language is likely to try to puzzle out nonexistent rules because they aren't familiar with the linguistic conventions that apply in the case at hand. But those who are familiar with how the language is used know that "ice" is a word that applies to certain cases of solids without regard to their chemical composition. Indeed, the word "ice" long predates the knowledge that water ice composed of H2O, or that dry ice is composed of CO2. To assert that "ice" means "solid H2O" shows vast ignorance of the historical usage of the word.

Re:What?

[blueg3]

Astronomers refer to lots of things in their solid state as "ice", and almost always refer to what you would call "ice" as "water ice". And it makes plenty of sense.

Re:What?

[Hurricane78]

Yes there is. Those temperatures have been observed on the south pole. (Read a report about a team that did stay “overnight” [= over winter]) And that doesn’t even include the windchill effect. Which can make it feel like a horrible -140C. A temperature that literally smacks you in the face so hard you fall over backwards. A temperature that lets your breath crackle and freeze before it lands on the floor. A temperature where pissing in the snow may make you impotent trough freezing the inside of your penis all the way.
Yes, there you might find some dry ice... (e.g. the one that you just did breath out.)
But good luck finding it in nothing but endless planes of real actual ice. ;)

Re:What?

[Kjella]

and either way, at 1 bar it doesn't freeze until about -78C. I don't think there are any natural places on Earth that cold.

Actually it's been down to -89C in Antarctica, so -78C is well within the extreme. But you go find it first, I'll stay inside by the fire long before that...

Re:What?

[fustakrakich]

Wind velocity has no effect on actual temperature. Wind chill was originally meant to indicate how long it will take your skin to freeze in sub-freezing temps. It's supposed to be a time measurement, not temperature.

Re:What?

[Smauler]

The windchill effect is basically a made up term that is _supposed_ to tell you how likely the surrounding atmosphere is to give you frostbite, though no one can agree on a decent standard that works well. It is pointless trying to apply it to freezing rates of any substance (notice how ice (basically) always freezes at 0, whatever the windchill?).

Re:What?

[Smauler]

But those who are familiar with how the language is used know that "ice" is a word that applies to certain cases of solids without regard to their chemical composition.

That's what I told the judge. I asked her if she wanted ice in her drink - she didn't specify h2o ice.

Honestly... ice means h2o ice. I cannot think of any time anyone would use the word ice (alone without adjectives) to mean anything else, save for completely unrelated slang. Educate me....

Re:What?

[tool462]

The other problem I imagine you'd have is that the CO2 in the atmosphere is moving. Those very cold parts of the earth tend to also be very windy, and like how a flowing river can see temperatures below 0C and not freeze, I would imagine CO2 would have a hard time freezing out of the atmosphere while blowing around at high speeds.

Pure speculation on my part though.

Re:What?

[Kjella]

Ok, I just found a page with waaaaaaaaay too much information, but I'll give you the short brief. First by the lower pressure at the poles and higher elevation of the coldest measurement stations, you might not pass the freezing point at all, it seems right on the border. Secondly, because there's so little CO2 in our athmosphere the sublimation effect is much stronger than the freezing effect, dry ice won't last even if held below the freezing point.

Re:What?

[Chris Burke]

I cannot think of any time anyone would use the word ice (alone without adjectives) to mean anything else, save for completely unrelated slang. Educate me....

I can't think of any situation on Earth where "ice" would be used to mean anything but water ice, since everything else requires such otherworldly conditions. NASA scientists are a bunch of space cadets. Speak English not Martian!

Hintedy hint. :)

But seriously, it's not like they didn't specify at any point in the article that they meant CO2 ice. If you've ever heard the term "Martian icecaps", then you've heard ice used to mean not-water ice (even though there is some there, but we didn't always know that).

Re:What?

[henrym]

Been there, done that, got the t-shirt. You have a gift for exaggeration, but a winter at the South Pole isn't nearly as dramatic as you make it.

http://theglobalguy.com/world-travels/antarctica/the-300-club

Re:What?

[T Murphy]

Yeah right. I bet next you'll try to convince me chemists use "salt" to refer to more than just NaCl.

Re:What?

[fuzzyfuzzyfungus]

I don't know offhand; but, looking at its phase diagram, it struck me that there is probably some lurking somewhere dark and cold in the very deep ocean, or possibly at a few PPM among the normal snow in the coldest terrestrial regions. I know of nowhere where it has ever been observed in any quantity, outside of manufactured environments.

Re:What?

[apoc.famine]

Maybe, lurking somewhere, but probably not. The bigger issue is saturation levels. Solid CO2 at the ocean depths would be far higher in "CO2'" than the ocean water. Thus, it would be entirely soluble, and would be absorbed by the seawater.

Solid CO2 is far, FAR higher in CO2 than any air or water around. Due to that, it would quickly sublime or dissolve. There's really nowhere on earth you could find naturally occurring dry ice.

Re:What?

[dangitman]

I can't think of any situation on Earth where "ice" would be used to mean anything but water ice,

Seriously? You've never heard of "dry ice" before? You haven't heard of methamphetamines referred to as "ice"? Sounds like you have limited experience with the world.

Re:What?

[excelsior_gr]

Your link unfortunately didn't work...

because there's so little CO2 in our athmosphere the sublimation effect is much stronger than the freezing effect, dry ice won't last even if held below the freezing point.

What do you mean by that? In order for a phase transition to occur, there has to be some change, either in temperature, pressure or concentration. If the conditions are such that a solid CO2 phase is dictated, you can be sure that it will "last"...

Re:What?

[Remus Shepherd]

The vapor pressure of 'dry' CO2 ice is larger than the partial fraction of gaseous CO2 in our atmosphere. That means that it will sublimate, even if it's below the freezing point. You have to go far below the freezing point, until you find the temperature where the vapor pressure is lower than the partial fraction.

This is why water ice will sublimate in very cold, very dry air. If the humidity is low enough, a blanket of snow will slowly disappear, even at -20 C. You can see that in the Midwest every winter.

Re:What?

[Chris Burke]

Sounds like you have limited experience with sarcasm. ;)

Re:What?

[Hurricane78]

Yep, I half-knew that while writing the above comment. I wasn’t exactly sure. But since the non-windchill temperature still is below that dry ice point...
Thank you for reminding me. :)

Re:What?

[Hurricane78]

It’s not coming from me, but right from the report/blog. (A pretty cool read btw.... if I only could find it again...)

Re:What?

[Anonymous Coward]

Astronomers refer to lots of things in their solid state as "ice", and almost always refer to what you would call "ice" as "water ice". And it makes plenty of sense.

Well astronomers also tend to refer to anything higher than helium on periodic table as "metallic"...

Re:What?

[lmckayjo]

Don't forget about "metallic" hydrogen... so anything above OR below helium? Silly astronomers.

"Network World"?

[Anonymous Coward]

Why aren't we linking to a science journal instead of continually linking to a crap IT rag? Or is Taco getting some under the table compensation for NW clickbait?

Re:"Network World"?

[tenco]

That's sth i don't like about /. at all, too. Posts about news in science seldom link to the original article/source.

Are we adding "ice" to the no-fly list?

[rbanzai]

Destroying one of our rovers is a hostile act!

Re:Are we adding "ice" to the no-fly list?

[thijsh]

Rest in pieces little dude... You loved to rock!

Re:Are we adding "ice" to the no-fly list?

[whoever57]

While you succeed at funny, you fail at RTFA -- it wasn't a rover.

Re:Are we adding "ice" to the no-fly list?

[Anonymous Coward]

Nice Try, Ozymandis.

Re:Are we adding "ice" to the no-fly list?

[MichaelSmith]

Destroying one of our rovers is a hostile act!

I feel your pain. It destroyed a Boeing 777 a couple of years ago.

Re:Are we adding "ice" to the no-fly list?

[socsoc]

ICE ices ice.

Re:Are we adding "ice" to the no-fly list?

[Smauler]

The plane passed approximately 6 metres (20 ft) above passing cars on the A30 and the airport's Southern Perimeter road. It also passed near a car which had just dropped off the Prime Minister of the United Kingdom, Gordon Brown.

That's not a hostile act, that's just bad aiming.

Re:Are we adding "ice" to the no-fly list?

[FragHARD]

Jihad ---> Mars !!!

Re:Are we adding "ice" to the no-fly list?

[Arancaytar]

Mars is already considered a terrorist nation after destroying so many probes.

However, we can barely find liquid water on it, let alone oil, so what's the point?

Re:Are we adding "ice" to the no-fly list?

[Anonymous Coward]

I told them to put flame throwers on that, but noooooo. Who is the crazy one now!!!

Too bad they didn't use RTGs.

[LWATCDR]

If they had used RTG it could have functioned through the winter.

Re:Too bad they didn't use RTGs.

[Anonymous Coward]

Maybe when you build your own rover, you can show them how it's done.

Re:Too bad they didn't use RTGs.

[Iamthecheese]

it also would have been heavier and more complex, therefore less reliable. I can't imagine anything they should have done differently.

Re:Too bad they didn't use RTGs.

[LWATCDR]

A. It wasn't a rover.
B. They knew that this would happen.
C. The only reason they didn't use RTGs was because of cost and the nut cases that would protest the launch.

I know why they used solar. It was good enough for this mission.
But it would have been really interesting if they where given the budget to use an RTG and had kept gathering data over the winter.
So no knuckle head I was not criticizing their skills. Just lamenting that the mission was so limited in scope.

Re:Too bad they didn't use RTGs.

[Anonymous Coward]

NASA built the lander from a previously canceled project, hence Phoenix, no way to redesign the whole power system.

Re:Too bad they didn't use RTGs.

[LWATCDR]

Heavier yes.
more complex? How? the RTG is a very simple device. Actually a lot less complex than the unfolding structure that the solar panels required not to mention the batteries and charging system. Plus I will bet they already included a radio isotope heater on the lander.
The real reason they didn't use them is cost. It would have made the lander and launch vehicle more expensive. And yes for the mission requirements it would have added unneeded cost. It would have only made sense if the mission was more ambitious. Less reliable, can you give me a single mission that has failed because of a problem with an RTG?

Re:Too bad they didn't use RTGs.

[MichaelSmith]

Of course, an RTG would mass much more than solar power so every part of the system would have to be beefed up. Launcher, cruise stage, aerobraking. Before you know it you are paying for two missions when one at that location was all you needed.

Re:Too bad they didn't use RTGs.

[confused one]

It would have had to be an awesome RTG to survive a Martian polar winter. CO2 ice forms below -100C and we believe the probe was covered in nearly a foot of this stuff. The coldest temperature measured was -97C, while the Phoenix was still running... You'd have to keep it warm, keep the ice from forming, and melt any "snow". That's a formidable task.

Re:Too bad they didn't use RTGs.

[forkazoo]

If they had used RTG it could have functioned through the winter.

But, if the mass of the RTG's meant removing sensors in order to hit mass and volume budgets, there wouldn't have been any reason to care if it survived the winter. The MER's were done with basically the same launcher as Sojourner, so the fact that they accomplished as much as they did compared to Sojourner is truly amazing, IMO. Unfortunately, it's all about tradeoffs. Hopefully, Mars gets some serious attention and we can deploy some serious long duration hardware on the surface. Without major budget consideration, that just can't happen by itself.

Re:Too bad they didn't use RTGs.

[Chris Burke]

Which funnily enough is the concept behind the Mars Science Laboratory. A much bigger rover with a nice big RTG for power and heating. But we're only sending one. :)

Oh speaking of rovers, Spirit and Opportunity do have radioisotope heaters on them, but they wouldn't be enough to keep one alive through winter. I doubt they would have saved Phoenix if it was buried under that much ice.

Re:Too bad they didn't use RTGs.

[MichaelSmith]

Oh speaking of rovers, Spirit and Opportunity do have radioisotope heaters on them, but they wouldn't be enough to keep one alive through winter. I doubt they would have saved Phoenix if it was buried under that much ice.

If Phoenix was warm enough to sublimate all that CO2 away it might have not been able to investigate volatiles. It makes sense to send a big RTG heated rover now because this is a third generation vehicle, starting with Pathfinder. The risk of losing it during landing is smaller and the benefit a long traverse across the surface has been established.

But their "winch down" design for landing gives me the horrors.

Re:Too bad they didn't use RTGs.

[tenco]

Isn't that what the "T" in RTG is for? Since you can't shutdown the decay, it's always warm and in winter you should get an extra few Watts since the temperature gradient is steeper. Just in case if you want to warm sth up (if you really have to).

Re:Too bad they didn't use RTGs.

[catmistake]

Couldn't lots of Earth based lasers be focused on it to thaw it out? Just what are the sharks doing with those things?

Re:Too bad they didn't use RTGs.

[dominious]

Radioisotope Thermoelectric Generator

When you write an acronym, it's nice for your readers to mention what the acronym stands for.

Re:Too bad they didn't use RTGs.

[vlm]

more complex? How? the RTG is a very simple device.

Your analysis is 100% correct assuming the REST OF THE MACHINE could function for years without any increase in complexity and weight. My guess is no. Yes a radio that operates "forever" costs about as much as a radio that operates for a couple weeks. I'm not completely familiar with the science instruments onboard, some things like magnetometers operate "forever" but some things like gas analysis systems complete with reagents and vacuum pumps and purge gases have a very finite life. Optics get covered with dust, unless you add a heavy system to clean them. Stainless steel ball bearings in a windspeed meter will eventually wear out, unless you do something heavy and complicated.

Wasting all that money on an expensive RTG isn't so useful if all you end up with a year later is a working radio and ... not much else. Maybe a working seismometer and a working magnetometer and everything else used up and worn out? Interesting, but maybe not worth the bucks.

Re:Too bad they didn't use RTGs.

[vlm]

Since you can't shutdown the decay....

... and you designed it to give a 150 degree delta V to survive the winter, in the summer she cooks along at perhaps 175 degrees C. A bit toasty. Yes I know there are heavy and complicated compressed gas / spring control arm systems and other such foolishness available, but they're heavy. Perhaps if we removed all the scientific instruments we'd have the weight budget to land a survivable multi-year infrastructure platform, but it would have nothing to do since all the instruments had to be removed.

Re:Too bad they didn't use RTGs.

[necro81]

Perhaps, but there's still the part where the whole rover gets covered in hundreds of pounds of dry ice. Maybe an RTG could have kept it from being buried, who knows.

If RTGs get your heart going, just wait for the Mars Science Lander, scheduled for next year's launch window. It's an RTG-powered rover that should last on the surface for quite a while. How long? After 10 years, the RTG should still provide 100 watts.

The two Viking landers were also nuke-powered, and Viking 1 lasted for some six Earth years (2246 sols). Opportunity only just passed Viking 1's longevity record last week.

One other note about RTGs: it's not like you can just order them out of a catalog. They're expensive, they require a lot more intensive mission planning than solar-powered craft, and they are hard to come by. The RTGs that run on Pu-238 are in short supply, because Pu-238 is in short supply, because we aren't manufacturing nuclear weapons anymore. It is in part for this reason that the Juno mission to Jupiter will use solar panels.

Re:Too bad they didn't use RTGs.

[LWATCDR]

But at no time did you say that it would be less reliable. That was my main point. As I said for the scope of this mission solar was a good choice but it would have been interesting to get measurements of the the snow on the ground over winter and weather for the entire winter. At some point I am sure we will put another lander on the pole with an RTG for such a mission.

Re:Too bad they didn't use RTGs.

[confused one]

I knew the T was "Thermal". The point you missed was the magnitude required. It's one thing to keep the probe warm. It's another entirely to melt the snow and ice and prevent any accumulation. There's a significant amount of heat that would be absorbed in liquifying or sublimating that ice.

Then, as another poster pointed out, what do you do with the heat in the summer? All that heat dissapation might affect the soil in the area around the probe; the soil that you're trying to study.

Re:Too bad they didn't use RTGs.

[LWATCDR]

I can see your point. I mean it isn't like the US has ever landed an RTG powered probe on Mars right?
"http://en.wikipedia.org/wiki/Viking_program"

Re:Too bad they didn't use RTGs.

[LWATCDR]

With an RTG you wouldn't need any solar cells. With out the solar cells they would not have been broken off by that accumulation of snow and ice.
No need to melt all the snow off the probe. Just use the power to run heaters to keep the probe alive over winter and maybe some low rate data transmissions.

Re:Too bad they didn't use RTGs.

[LWATCDR]

I know all the reasons why they used solar cells. And it all comes down to cost.
You are right that it was a great mission. I think too many people think I am being critical of the people that built and ran the mission. Not at all.
I am just lamenting that it wasn't larger in scope.

Re:Too bad they didn't use RTGs.

[LWATCDR]

I thought that I was talking about a interplanetary polar lander on a web site with the tag line "News for Nerds".
Sorry next time I will make sure I don't make my comments too technical...

Re:Too bad they didn't use RTGs.

[confused one]

That's a good point. Phoenix ended up with, I believe, an estimated 7" to 8" of ice accumulated. The ice would have an insulating effect on the chassis. However, if you intended to maintain use of the arm, camera, or any externally mounted instruments, you'd need to supply their heaters. It is all possible, of course. You could put a 100kWe reactor on the pole and have it operate year round. It's a question of mass and budget. If you have funding them my argument falls on its face...

Re:Too bad they didn't use RTGs.

[Confusador]

But their "winch down" design for landing gives me the horrors.

And the bouncy ball design of the rovers didn't?

I think the controlled drop method that they used on Phoenix proves that they can hold it stationary long enough, which is the great thing about the approach they've been taking. Each missing adds some capability; with MSL they'll be demonstrating they can land something large gently. Eventually we'll be up to habitats, and will have done great science along the way.

Re:Too bad they didn't use RTGs.

[Anonymous Coward]

An RTG would preferably be deployed on an extendable boom, so as not to cause errors in the electronics. Much less complicated than unfolding solar panels, but comes with weight and complexity. In contrast to solar panels, the RTG would still work even if it could not be deployed properly.

Re:Too bad they didn't use RTGs.

[vlm]

But at no time did you say that it would be less reliable.

Well, you gotta read between the lines a little bit, dude.

So, you've got a weight budget of 1 Kg for a tank for the helium for the gas analyzer, for three months. Not a serious engineering problem.

You bolt on the RTG and the mission now lasts 10 years. No problem man, all you need is 40 times the helium. Which you don't have the budget to lift. But helium is pretty light, and metal is pretty heavy. We'll make the total WAG that if you lightened the helium tank by 50% that tank mass could be replaced by a 9.75 year supply of helium. I find that highly unlikely, but we'll be really optimistic here.

One tiny little problem. Now instead of a perfectly reliable and reasonable 1 Kg helium tank, you need a tank with 40 times the volume and half the mass. Good luck, you are so going to need it. Most likely that giant weak tank is going to crack from vibration during launch/landing, or corrode in storage while waiting for NASA, or split wide open when they try to fill it before launch, etc. After all, if you could engineer in an extra factor 80 safety margin, your mission budget would almost certainly have originally been to install a 1/80th of a Kg helium tank instead of a 1 Kg tank.

That's just the problems with the consumables. Now consider instruments. Ball bearings will run a wind speed meter for 3 months without lubrication in a sandy environment, if you don't care if they still work in 3 months. If you want it to run forever, then you have to do something more complicated, probably less reliable, but certainly more mass. Then take the mass of that out of ... what ... the parachute mass budget? Not good for reliability at all.

Call AAA!

[otaku244]

Those guys are pretty much everywhere!!!

Re:Call AAA!

[tenco]

Am I dreaming or was this a failed attempt to make a joke related to EVE Online?

Re:Call AAA!

[Anonymous Coward]

No, you're probably either not living in the US, or living in the US but too young to own a car. AAA = American Automobile Association.

This mission was not a failure.

[ProdigyPuNk]

Remember that the lander was not meant to last through the Martian winter, and in fact was only tasked with a three month long mission. It lasted five months, which was longer than expected. The newer rovers are supposed to be able to survive for much longer, but this mission accomplished all that it was supposed to.

Re:This mission was not a failure.

[c 0xFF]

Spirit and Opportunity, among other missions, have created an expectation that whatever we send out can last virtually forever. It's almost disappointing when these things are "only" completely successful, instead of wildly exceeding our imaginations.

Re:This mission was not a failure.

[TrippTDF]

If Spirit and Opportunity were really worth their salt, the would be on their way down to fix Phoenix... but they are such Divas after all the years of attention, you know THAT will never happen...

Re:This mission was not a failure.

[blair1q]

It's almost disappointing when these things are "only" completely successful, instead of wildly exceeding our imaginations.

There's a sarcastic joke about the difference between the Obama and Bush administrations to be harvested from that setup, but I'll be damned if I'm going to say Bush's administration was even slightly successful at anything we actually wanted to get done...

Re:This mission was not a failure.

[Hurricane78]

Hey, how can you be so heartless on those poor betrayed brave rovers, you insensitive clod! (Read the mousover. It breaks your heart.)

Re:This mission was not a failure.

[Anonymous Coward]

Iraq blown up....check

Afghanstan blown up....check

Sort of on the to do list.

Personally I think it would have been more productive to just simply buy a Prius or any other car that got over 50mpg for the entire driving population of the US (157M) than piss away the money that has been and will be spent on the two wars and their retarded cousin Obamacare.

Re:This mission was not a failure.

[Anonymous Coward]

xkcd: its teh bumzors.

The Real Story

[nacturation]

Filming was set to begin on another James Cameron movie and they had to clear out the Mars studio. Failure of the lander was the plausible story concocted to allow for the timely cessation of the project.

Re:The Real Story

[arndawg]

Pocahontas on ice?

Ironic

[wcrowe]

Perhaps "Phoenix" was not the best name for this project.

Re:Ironic

[Unbeliever]

It was a re-do of the Mars Polar Lander. (Failed due to an un-debounced landing sensor switch).

Phoenix rose from the ashes of MPL.

Now scheduled for Launch in 2012

[Anonymous Coward]

Phoenix Mars Snowplower

Not to worry...

[relikx]

The Phoenix will rise from the...well, not ashes, but dendritic crystals perhaps.

Late-Breaking News from the Council: FIRE AND ICE!

[Tackhead]

The Illustrious Council of Elders has declared today a day of celebration. K'breel, Speaker for the Council, spake thus:

"Despite the propaganda reports to the contrary, what we killed a year ago remains dead and frozen, crushed beneath a mountain of toxic dihydrogen monoxide. The perverse pendulosity of its plumb bob waves no more!

Some say this war will end in fire, others in ice.
Reporters' gelsacs know my ire;
they are those who went with fire.

We now confirm this blue death twice,
Our gelsacs engorged with delight,
We say that for destruction ice,
Not only might,
But did, suffice!"

When the Martian Poet Laureate reported a striking similarity between the recent press release and an ancient transmission from the blue world, K'Breel had the Poet Laureate's gelsacs bobbed, frosted, and then bitten.

De-icing?

[Hamsterdan]

Just a crazy idea, couldn't have they put defrost wires on the panels? I don't know what the battery capacity is, I'm just wondering if it would have been possible...

if the panels are lowered, just heat them enough so the ice will just slide to the ground.

Re:De-icing?

[Rakishi]

The solar panels provide power. You cannot provide more heating power than the sun does. The sun is putting energy into everything. Everything is still frozen. I hope you can work out the rest of the logic yourself.

Re:De-icing?

[georgewilliamherbert]

The sun was down too far on the horizon to generate any useful power (or absorb heat directly) during winter.

Mars has axial tilt of 25 degrees; Earth's is 23.5 degrees or so. So there's an equivalent Arctic Circle zone where the sun's below the horizon during the worst of winter. Earth's Arctic Circle is at 66 degrees north; with slightly greater tilt, Mars' Arctic Circle will be even lower. The landing site was around 67 degrees north on Mars.

The sun would have been down long enough that no reasonable amount of batteries could have kept it warm overwinter. A RTG could - as discussed - or little RHU units (Radioactive Heater Unit - it's like a mini-RTG heat source module, with the protection but no power generation units, just designed to keep parts warm). But there was a decision made that the lander was unlikely to survive with all the overwinter issues, so they didn't bother.

Re:De-icing?

[Hamsterdan]

I was not saying the panels power the defrosters directly. Let's say you use the batteries to heat up the panels, ice slides down, panels don't break and can recharge the batteries. I'm guessing that thing has batteries and was not running on solar power only.

(ie: use a couple of watts from the batteries and let them get recharged by the now de-iced panels)

Re:De-icing?

[Rakishi]

First of all, ice doesn't slide down just because you heat what it's on. Due to the whole objects having a tip and ice building on them like a cap on someone's head. Of course once you got a meaningful amount of ice on the rover would probably be a hunk of dead metal due to lack of electricity and thus heating of electronics.

Second of all, you're gonna need a lot more than a couple watts to do anything. Likely many orders of magnitude more than what you'd get from the solar panels.

Third of all, given the lack of sunlight you'd likely be covered in ice again long before you managed to recharge your batteries.

Practically speaking, the craft is dead ice or no ice. Mars winter is death to unheated electronics and solar panels simply don't provide enough energy to do enough with.

Re:De-icing?

[dakameleon]

By your logic, there's no point having defrosting wires on Earth, either. Or indeed there's no point cooking with anything other than a solar stove.

The sun provides the energy, true, but its energy is spread and available for a limited time - the defrosting wires would provide heating in a specific place and the idea posed above would be to use stored energy to extend the life.

Other practical considerations may have gotten in the way, but your logic is faulty.

Re:De-icing?

[Rakishi]

Sigh, honestly. I give people the benefit of the doubt in terms of logical thinking and this is the replies I get.

Mars!=Earth. If we had a magical energy storage device we could have the lander run at full power 24/7 without any problems. Clearly we don't in this one, I figured it went without saying. Batteries are very much short term. A RTG would work but the rover doesn't have one and the question was limited to the current situation.

It's all practical questions in these sorts of cases. Saying "in a magical world where X is true" is a foolish attempt to escape ones own stupidity.

Defrosting wires use external energy stored beforehand by other means or generated by other means. The Mars lander does not have this sort of energy.

The Mars lander has one long term energy source from the sun at roughly 5% efficiency I'm guessing. The same energy source that heats the environment. The environment absorbs more than 5% of the energy and is nonetheless below freezing. The panels cannot get above freezing for long durations with solar power alone. There is no other source of power.

If you used solar energy to heat a proportionally small insulated object such as electronics it'd work perfectly fine. It does work perfectly fine on most of Mars. The problem here is that the area you heat is the same as the energy you gather energy on. And it's not insulated in any way. Energy that on it's own is not enough to keep that area over freezing. 5% of that won't keep it above freezing.

Once you get frost on the panels you're screwed. Energy absorption, converted to electricity and plain heat, drops due to reflection. Ergo you need to keep the panels above freezing 24/7. Short term and one off solutions won't work. And as I pointed out in my reply to the other guy once you get any decent amount of ice it won't come off unless you sublime a sizable chunk of it. Even if you could you can't afford to wait for it to build up because you need that constant solar power to just keep the rest of the systems warm.

The full power of the sun cannot accomplish this. A smaller percentage of that won't accomplish it. There is no other long term energy source. You use your batteries and how will you magically recharge them? There isn't enough solar energy to just keep the panels defrosted so where the heck would you get the energy to recharge the batteries?

Re:De-icing?

[dakameleon]

I was taking issue at the argument that "you cannot provide more heating power than the sun does", because I would say that it's clearly possible to do so, as long as you're talking about a specific and limited heating. You are of course right in saying that heating would require an energy source, but you're also using a model whereby the batteries aren't taken into account, because you dismiss them as short term - it's not like Spirit and Opportunity's batteries haven't held out for this many years.

How about this for a hypothetical: model it on hibernation. The probe is sent with extra battery capacity. During the Martian summer, when (let's say) more energy is generated than used, extra capacity is stored in a spare battery.

During the Martian autumn, operations are wound down gradually in order to maximise the stored power and minimise drain.

Once winter sets in, all operations barring the de-ice circuit and the charge circuit are switched off. There will be periods where the battery is drained more than charged, but the lack of (or minimisation of) ice will ensure some charge is still gained during the Martian winter - net drain, sure. When the spring arrives, increasing charge can slowly switch on additional circuits, such as additional heating coils to clear off more of the panels & quicker. By the summer you'd be back to 100% operation and charging up for next winter.

I'm not a rocket scientist or anything, so I don't know what the pay-off point would be in terms of panel size, coil size, battery size, and total weight of the upgraded package. But don't write off the idea that more heating than the sun provides can be achieved.

Re:De-icing?

[Rakishi]

First of all, let's ignore the fact that the probe does not generate enough power during winter even without any ice for minimal heating much less storing anything. That pretty much kills your proposal.

Second of all, all operations cannot be shut off. Mars is cold. The sort of cold that is outside the safe temperature zone for even specially designed electronics and batteries. So you've got a constant power drain or your chance of anything working after winter are very low. Which as I said is in practice more than the sun will provide but let's say the solar panels are enough to provide minimal heating.

But ignoring all those things.

There will be periods where the battery is drained more than charged, but the lack of (or minimisation of) ice will ensure some charge is still gained during the Martian winter - net drain, sure.

No it won't, your batteries will never charge. That's the whole point of my argument. That you can't comprehend conservation of energy it is not my concern but let's try once again.

Let's say the sun puts 20k W onto the panels and the rover captures 1k W of that. The total is still 20k W. My point was that even the full 20k W of energy is not enough to keep the panels free from ice. As a result you need more than 20k W of energy on the panels to keep them ice free. The sun only provides 20k W. If you use batteries than you can achieve that but there will never be a surplus. You will always be draining your batteries. If 1kW goes into the batteries than there is only 19kW left for heating by the sun. So you need to put in at least 1kW of heating to break even which means you're using at least the 1kW you just stored.

As a result you'll never be able to charge anything, there is simply no left over energy. Ever.

When I said batteries are a short term energy source I meant you can never sanely stuff enough of them to provide heating for all of winter. Even a month at a pathetic 100W will give you batteries massing twice what the lander does. In practice it'd probably take more to keep that panels ice free than you'd get from the panels so there's no point.

This isn't nighttime heating, this is winter. Your argument only works if the temperature is below freezing only part of the day or week or whatever. I seriously doubt that is the case especially once you get into the deep winter.

Re:Late-Breaking News from the Council: FIRE AND I

[rickb928]

"dihydrogen monoxide"

Please contact K'breel and get an update - this rover was assaulted with carbon dioxide.

Or was it another tribe???

Oblig xkcd

[Daetrin]

I know it's not the same lander, but i still think this xkcd is somewhat appropriate.

Re:Oblig xkcd

[Ethanol-fueled]

*sniff*

Re:Late-Breaking News from the Council: FIRE AND I

[Tackhead]

Please contact K'breel and get an update - this rover was assaulted with carbon dioxide.

The Council wishes to correct earlier reports: no toxic compounds were strewn across the battlefield; the ice was environmentally-sound carbon dioxide, as commonly found in snow.

When Junior Reporter 54550 hastily reported on the Council's statement, his gelsacs were frostbitten without being bobbed. Ow, Ow, Ow!

For the next mission

[WinstonWolfIT]

Next time, send Wall-E and a cockroach.

Re: FIRE AND ICE!

[MRe_nl]

Thank you. Will you be here all night?

(and for the few and far that know not the original: i think it is exquisite also)

Some say the world will end in fire,
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.

Robert Frost

what's $1000 in mars?

[sabedoria]

is NASA paying the martian authorities $1000 for littering, or is the fine different there?

Re:what's $1000 in mars?

[confused one]

They're working up a Declaration of War now...

Frozen in CO2 or Carbonite?

[karlwilson]

Perhaps Pheonix owed someone some money...

A good example of NASA's low quality work

[Anonymous Coward]

It's things like this that are getting manned space flight axed. NASA outsources projects to the lowest bidder and then gets substandard results. Here is a fine example of how congress doesn't care about the science, but just the pork.

Even in death we still can learn.

[Anonymous Coward]

The story is missing the bigger picture, this only confirms the fact that there is water on mars!

Exploring Dynamic Space Environments

[Doc Ruby]

It's fascinating to watch NASA begin to really explore a place like Mars that has a dynamic environment. The Moon is mostly changeless (except for Earth's shadow periodically swinging by, and the occasional tiny meteorite). Planetary orbits are dynamic at only the subatomic (eg. solar wind) scale, except for the rare encounter with space junk. But Mars is a real planet, with weather and lots of energetic events lots of the time.

It's not just far away that makes it hard. It's being so close to the Earth in having a dynamic atmosphere and possibly even surface conditions that makes it hard.

And that is why we do it: not because it's easy, but because it's hard. Doing it makes us better, and shows how good we are. Go NASA!

Yet

[codecore]

Once it rises from the ashes (ice) next spring, the name will fit!

That's not "ice"!

[aqk]

It's DRY ICE. The common name for frozen CO2.
Geez... Get with the terminology, Coondooger!

Ice?

[Anonymous Coward]

If there's ice dosen't this confirm that there is most definitely water.

Well, actually that's two reasons...

[sean.peters]

C. The only reason they didn't use RTGs was because of cost and the nut cases that would protest the launch.

Although I'm betting that cost alone was a sufficient driver of the decision. Why spend the extra money to use RTG when solar is all you need? I'm all in favor of using nuclear power when it's called for, but I'll never understand this "nuclear uber alles" viewpoint that some people seem to have.

Learn...

[hesaigo999ca]

Hopefully they will learn from this, in hopes that the next gen of these rovers have the capability to set themselves up for a shutdown
with minimal damage or the possibility for a wake up from a dormant state, i am not sure if winter has passed, but now the ice has melted and the sun is shining on those panels...it would have been great to have it wake up and start all over again.....!