Mars Lander Faces Slow Death

Riding with Robots writes "It's the beginning of the end for the Phoenix Mars Lander. As winter approaches in the Martian arctic, NASA says it's in a 'race against time and the elements' in its efforts to prolong the robotic spacecraft's life. Starting today, mission managers will begin to gradually shut the lander's systems down, hoping to conserve dwindling solar power and thereby extend the remaining systems' useful life. 'Originally scheduled to last 90 days, Phoenix has completed a fifth month of exploration in the Martian arctic. As expected, with the Martian northern hemisphere shifting from summer to fall, the lander is generating less power due to shorter days and fewer hours of sunlight reaching its solar panels. At the same time, the spacecraft requires more power to run several survival heaters that allow it to operate even as temperatures decline.'"

Comments

NASA

[Sasayaki]

Honestly, as an Australian, it's great to see NASA in the news for something which can't be summarised as: "It blew up".

Needs more funding IMHO.

Re:NASA

[Pikiwedia.net]

NASA have been far more successful with the mars rovers and Phoenix than ESA's Beagle, which probably made it to the martian surface (in burning pieces).

Re:NASA

[Farmer Tim]

NASA may have a better record with robots, but ESA has never lost a single astronaut. Admittedly that is through lack of trying...

Re:NASA

[that IT girl]

Not to go all crazy-patriot on you, but at least the US is trying. It's not easy, you know. ;)

Re:NASA

[cdrudge]

Pfft. Anyone with security clearance over Top Secret knows that Beagle made it successfully and recorded 13 seconds of video before being destroyed. Has NASA's probes ever found aliens? I think not.

Re:NASA

[SimonGhent]

If we're going to name the seasons after their properties

We're taking this approach as of 2009 in the UK.

The new seasons will be "Cold and Wet", "Wet and Windy", "Wet" and "Wet and Dark".

Doesn't really matter how they map to the current seasons.

Re:NASA

[zippthorne]

Of course they haven't. Unless they run into another lander, they can only encounter natives.

Well, it's been a great track record lately...

[BTWR]

Ever since the two loses in 2000, NASA has had amazing success with Mars. We now have a fleet of spacecraft orbiting and on the surface of Mars. But the biggest kudos have to go to an all-around amazing guy, and my favorite professor during my undergrad education, Steve Squyres, who's "90 day" rovers are now toddlers on Mars.

Re:Well, it's been a great track record lately...

[BTWR]

Hmmm, I wrote "who's" instead of "whose." Well, there's a reason I wasn't an English major as an undergrad I guess...

I still remember the day he came into class and told us about the rovers. He had literally just gotten off the plane from JPL, and asked if there were any reporters in the room (for the school paper or otherwise). He then told us that since there wouldn't be a public announcement of the MERs for another month or so, that everything he told us was "off the record." it was so cool to learn that and all the other insider-info.

Re:Well, it's been a great track record lately...

[savuporo]

Yes, Mars they are doing. But do you remember when the last lunar soft landing happened ?
1976, Luna-24, a successful sample return probe sent by USSR.

There is a likelyhood that the next one to land will be a Google Lunar X-Prize participant ..

Re:Well, it's been a great track record lately...

[meringuoid]

Yes, Mars they are doing. But do you remember when the last lunar soft landing happened ? 1976, Luna-24, a successful sample return probe sent by USSR.

To be fair here, Luna 24 returned 170.1g of regolith. NASA on the other hand landed six 14.7 tonne probes on the Moon in the late sixties to early seventies. They deployed a total of twelve autonomous intelligent versatile exploration units, traversing a total of 97km of lunar surface, and gathered some 381.7kg of samples and returned them to Earth.

To follow that spectacular accomplishment with a few petty robot landers seems... pointless.

Re:Well, it's been a great track record lately...

[Cyberax]

But much cheaper.

Re:Well, it's been a great track record lately...

[savuporo]

So you are saying that sending robots to Shackleton crater to search for water ice, or sending prototype plants to test out ISRU technologies like cooking oxygen out of lunar regolith would be rather pointless, just because a bunch of astronauts already made some footprints there ?

I am not disputing the accomplishments of Apollo, but to say that lunar robots are pointless is naive.

By the way, looking at the launch calendars, it looks like Indo-Russian joint mission Chandrayaan II might beat GLXP to the lunar surface.

Its been sad that our closest neighbour has been basically forgotten for so long, and now with Chinese, Indians and Japanese entering the lunar exploration, things are looking up.

Why heaters?

[Richard W.M. Jones]

So honest question for all you rocket scientists out there: Why are heaters needed? Which parts of the spacecraft (electronics?) need to be above a certain temperature to operate? Is it possible to let the lander "freeze" and then revive it, or if not what components are sensitive to this?

Rich.

Re:Why heaters?

[MichaelSmith]

So honest question for all you rocket scientists out there: Why are heaters needed? Which parts of the spacecraft (electronics?) need to be above a certain temperature to operate? Is it possible to let the lander "freeze" and then revive it, or if not what components are sensitive to this?

Rich.

One issue is that solder joints between components can break if they are cooled down too much. Batteries and capacitors can fail if liquids inside them freeze and crystalise. While I think there is a chance that the lander will come back up next summer but the likelyhood of this is pretty slim IMHO.

Re:Why heaters?

[jm1234567890]

From the article

The heaters serve the purpose of keeping the electronics within tested survivable limits.

Re:Why heaters?

[danhuby]

The heaters serve the purpose of keeping the electronics within tested survivable limits.

IANARS, I just RTFA

Re:Why heaters?

[Anonymous Coward]

I don't think they use oil... in the past they used WS2 (tungstendissulfide), It is a powder that sticks to metal. but hey... IANARS

Re:Why heaters?

[camperdave]

No, the electronics are kept warm during transit.

Re:Why heaters?

[Lumpy]

It's the mechanical moving parts as well as the batteries and other delicate systems. Problem is these parts are larger than the rovers that simply use hot radiation pellets of plutonium dioxide to do the heating for them.

They CAN shut it all down, park the moving parts and let it sit dormant for all winter, but when you shut a system down there is a good chance that when you fire it up in the spring that it will not fire up. Blown dust cakes into an armature hinge point and now it can no longer move.

Re:Why heaters?

[Tony Hoyle]

It's pretty cold in space....

Well that really depends on how near you are to a source of heat... in fact overheating is a problem in the solar system as it's difficult to get rid of the heat from the sun.

Re:Why heaters?

[Radio_active_cgb]

The temperature extremes experienced in spacecraft (the Antarctic and Artic here on Earth) are such that considerable thermal expansion and contraction occurs. Because materials have different thermal expansion coefficients, everything is expanding and contracting at different rates, leading to mechanical stress. Such stresses cause hardening of materials - rather than flexing with the stress as when they were new, they break, and there-in lies the problem. (Remember bending wire coat hangers until they break? Even after a few bends, you would have problems straightening the now hardened wire.)

The break can take many forms - a solder joint fails, a bearing seizes or breaks, a screw snaps, or a structural weld breaks. Each of these can result in a failure that renders the device inoperative.

The heaters (often common power resisters) limit the cold extremes, and allows some predictability as to when failures can begin. In electrical systems, such heaters are used when the electronics can not keep themselves warm through continuous operation, or the electronics are shut down (you do want them to come back up, don't you?)

In any case, power consumption tends to be fairly constant whatever the operating mode is.

what I do not understand.

[apodyopsis]

here's what I do not understand.

so no sunlight = no power. the lander dies.

but in the next season, assuming it has not been buried in dust it will then get power again from the solar array, so what then? surely some basic SW should be functional as the power rises over a certain point. and it does not need a huge amount of power to transmit basic telemetry like temperature, light, perhaps the odd photo in low res broadcast at low power.

with all the research and development that went into the thing, I do not see why one season should kill it.

however, I recognize I am not an expert and the people who write the articles presumably are, so what have I missed?

corrosion in the environment?
batteries that cannot survive being fully discharged?
lander cannot run on solar alone?

anyhow, kudos to NASA for lasting well beyond the tables life span in the first place.

Re:what I do not understand.

[u38cg]

Metal parts can potentially crack, any components with liquids in them (batteries, capacitors, etc) can freeze and split. Certainly they will be keeping their fingers crossed that it might come back to life next year, but the odds are low.

Re:what I do not understand.

[timmarhy]

see this is why NASA is putting robots on mars and you aren't. try freezing your dick to minus -225 and see if it's still functional next season.

ok sorry i'm being a little harsh there it's been a long day. solder will crack and oils will freeze and expand busting caps etc. that's why the lander might not make it through the winter.

Re:what I do not understand.

[OriginalArlen]

You've got it. Firstly the batteries will be destroyed by the prolonged cold. The other thing is that the entire site will be cloaked in a couple of meters of CO2 ice over winter; as it accumulates on the solar panels, the weight is expected to physically snap them off.

Re:what I do not understand.

[Dr.M0rph3us]

What I'd like to see is the development of cold-resistant electronics. Can we use solid capacitors and batteries for that purpose?

Then the power-draining heaters won't be needed anymore and the power can be routed to more useful instruments (or the probes can be lighter, with lower launch costs).

Re:what I do not understand.

[Sobrique]

Actually, that's practically impossible on a living person - you're effectively putting something 250+ degrees hotter into the liquid nitrogen, and you're circulating nice hot blood around it continuously - you'll thus be flash-boiling the nitrogen, which has quite a low specific heat capacity, and the bubbles as the nitrogen boils off forms quite an effective insulator. http://en.wikipedia.org/wiki/Leidenfrost_effect

It's therefore possible to immerse parts of the anatomy in liquid nitrogen for a fairly substantial amount of time before it will freeze to 'shatter on a table' temperature. Of course, getting frostbite is somewhat faster, and not recommended, so don't try this at home :)

Re:what I do not understand.

[ColdWetDog]

Or even better, do the "rose in the liquid nitrogen" trick and slap it on the table - THAT will impress the coeds.

Idiot Geek. You GIVE the rose TO the coed (intact, NOT frozen). You go somewhere else and play with the liquid nitrogen.

No wonder you folks never get laid.

Oblig.

[cosmocain]

I, for one, mourn our dead robotic overloads.

Re:Pyrotechnic unit?

[Gordonjcp]

Lots of space hardware uses a small pyro charge to deploy antennas and things. On a lot of microsats, the antennas are rolled up like steel tape measures, and when the pyro blows they unroll and stick out.

and finally after the cameras fail...

[Anonymous Coward]

the native martians will appear and take it into their homes for the winter and nurse it back to health...

Happy to help a fellow geek

[MichaelSmith]

...with Melbourne conversation starters.

• Don't you just hate rugby?
• Funny October we are having. Almost as hot as February.
• Washed your car lately? Of course not (water restrictions)
• Sorry you are missing the Melbourne Cup? Do you like boozing up in the Flemington car park?
• What did you think of the Grand Final? Sorry that bunch of wankers from Hawthorn won it. Thought we had seen the last of them.

Should be enough to get going. No boobytraps there. I promise.

Re:Pyrotechnic unit?

[Isao]

Some amateur satellites actually USE steel tape-measure as antennas. Here's a shot of PC-SAT. (Full site article)

Nuclear batteries

[joshv]

Why the hell aren't we putting nuclear batteries on these things?

Re:Nuclear batteries

[Anonymous Coward]

The word nuclear scares the public. More specifically I live by the cape, when they launch nuclear powered missions like New Horizons Pluto mission local schools are required to keep children indoor and close their windows. This is a precaution. If the launch vehicle blows up nuclear fallout could be spread around by winds. So generally only missions where it is required because there isn't any sun light like a mission to Pluto do they use nuclear reactors.

Re:Nuclear batteries

[Tweenk]

Those are not nuclear reactors, but radioisotope thermoelectric generators (RTGs). Rather than harnessing the energy from steam heated by the fission of heavy nuclei, they get the power directly from the heat of natural decay of radioactive isotopes using thermocouples. Link.

Current nuclear reactor designs, even the compact ones used on ships and submarines, are too large and too heavy to be sent into space.

Re:Nuclear batteries

[Catmeat]

In this case, they aren't necessary as the lander has done all the science it was planned. What's the point of keeping it alive over the winter of all it's going to do in the spring is repeat the measurements it's already taken?

RTG's and RHU's are a massive, expensive, pain in the ass and are best avoided unless absolutely necessary.

Basically -

• They're heavy. They are must be designed to wishstand re-entry intact and not disperse Pu238 fuel everywhere if the rocket explodes during launch. Extra weight on the lander means there will be science instruments that have to be taken off.
• They're on 24/7 and they're only about 5% efficient so they produce about 20W of heat for every W of electricity. This is a huge problem when the spacecraft is buttoned up in it's Mars-entry aeroshell during the 9 month trip to Mars. Hundreds of W of waste heat must be dumped somehow or your lander will cook.

  This may well use some kind of fluid cooling loop that circulates through radiators on the crusie stage. This now gives you added problems of a pump (which must not fail or you'll lose the mission, so add a back-up pump) and how to disconnect the coolant pipes with absolute reliability when the time comes to ditch the cruise stage and enter the Martian atmosphere. More problems, cost and weight.

• Pu238 is on every terrorist's Christmas wish-list. You have the added problems and of turning the spacecraft assembly facilities into highly secure spacecraft assembly facilities. Assembling a Mars lander is already hard and expensive. You really don't want to add to this the cost and disruption of post-9/11 anti-terrorist, security paranoia. Donna Shirley discusses this in her book on the Mars Sojurner rover, and that was put together back in 96.

Re:Oooh aaahhh

[that IT girl]

...Who licked the red off your candy this morning? Geez...

Re:To Boldly Go

[flappinbooger]

No, but they do have Holden.

Re:From another Australian

[Sasayaki]

Very well.

The war in Iraq has cost America, at the time of writing, approximately 566 billion dollars.

The entire Apollo project, $25.4 Billion in 1969 dollars (or approximately $135 Billion in 2005 dollars.) Sources = (http://en.wikipedia.org/wiki/Apollo_program, http://www.nationalpriorities.org/costofwar_home)

So what I'm saying is, for the cost of the War in Iraq, America could have over four complete moon programs. Not moon missions, mind, four complete *programs*- built entirely from scratch.

Let's say NASA take one moon mission to *actually* return to the moon properly- with return trips, flybys, dozens of manned and unmanned missions, reuse of the hardware for other projects, etc. See http://en.wikipedia.org/wiki/List_of_Apollo_missions for what this one single "mission" is buying, and remember that still leaves three whole other missions and change to do other things.

Let's spend two missions on doing all of the above, but for Mars. That means multiple manned missions, return journeys, the works. Give Mars the full lunar "One small step for man" treatment and assume it costs twice as much (and takes a lot longer).

We still have one mission left. Let's do something crazy with it- and I'm open to suggestions here. Permanent lunar settlement? Completely and utterly explore our planet's oceans (which we know less about than space, BTW...)? Solar-system wide Internet? (Aliens need lolcats too..) ... the possibilities here are truly staggering. And don't forget your change.

This is what I meant by more funding. I mean to say that NASA, which has endured endless budget cuts since the 60's (which, I'll concede, have forged a more efficient government agency), deserves far, far, far more of America's money. America's money which is being horrifically misspent.

Essentially, what I'm trying to say is... yes, it's inefficient. Horribly so. So? Throw money at it. I'll say it again- THROW MONEY AT IT. The capslock shows I'm serious. NASA is one of the few (read- the only) organisation I'll say this about, but... throw money at it. Seriously. For the cost of the Iraq war, we could have had so much.