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

[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.

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...

[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...

[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?

[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.

Oblig.

[cosmocain]

I, for one, mourn our dead robotic overloads.

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: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.

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.

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...

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.

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: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: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.