Printable Version of Topic

Posted by: Stu Oct 27 2008, 09:22 AM

Sol 150 raws are up so this seems like a good time to start a new thread...

Hang on in there Phoenix...

Posted by: Enceladus75 Oct 27 2008, 11:21 AM

Yes, it's heartening to see Phoenix last way past its original 90 day mission. I'd say Phoenix will make it to 180 sols - twice the length of the primary mission. I just hope that they switch the microphone on before the end. I can't wait to hear the sounds of Mars.

Posted by: djellison Oct 27 2008, 11:29 AM

Firstly - I'd urge caution on expecting any number of sols for survival. Another 30 sols is possible, but a long way from being certain.

Also - don't get too excited by the microphone. It may not work - and if it does - it will almost certainly be unspectacular. If you want to know what Mars sounds like - go and stand 100,000ft above the Sahara at 4 in the morning when there are no aircraft around.

Doug

Posted by: Stu Oct 27 2008, 12:05 PM

I know there will probably be no real "background" sounds audible... no moaning martain wind, no rasp of dust grains trickling over the mic... but I'd settle for some clanks and clonks if they start banging those "Pots and pans" Peter Smith talked about...

Posted by: Ant103 Oct 27 2008, 05:27 PM

Frost on this sol I think
http://www.db-prods.net/blog/wp-content/uploads/2008/10/lg_42376rcoul.jpg

Posted by: Deimos Oct 27 2008, 09:43 PM

I'll echo what Doug said. Every downlink is precious now. I'm not suggesting Phoenix cannot reach sol 180, but there will be many opportunities between now and then for the capricious weather to throw Phoenix into safe mode or worse. TEGA, RA, and RAC are now living on borrowed time, and we'll need to see a smooth transition to post-RA ops before we can contemplate sol 180. A solar-powered life above the Martian arctic circle is a hard life right about now.

Posted by: 314karl Oct 27 2008, 10:07 PM

Full quote of previous post removed - Mod

Does anyone know of a website which shows the Earth date equivalent of the current Mars year? What is the Earth equivalent date and also sunrise-sunset times for the Phoenix landing site? Knowing this would make the changing season more easy to understand for us Earthlings.

Posted by: marsophile Oct 27 2008, 10:23 PM

This year, by coincidence, the northern hemisphere summer solstice on both Earth and Mars differed by only a few days. The Martian year is close to two Earth Years. Therefore, the coming winter solstice on Earth will be close to the Mars fall equinox. So it is now late summer at the Phoenix site. But Mars weather probably doesn't have much of a lag following the seasons like Earth weather does. So even late summer is getting somewhat dicey.

Posted by: elakdawalla Oct 27 2008, 11:45 PM

Download the http://www.giss.nasa.gov/tools/mars24/ and you can find sunrise/set times and also the current solar longitude. Solar longitude counts up from 0 to 360, beginning from the northern vernal equinox at 0. Earth's northern vernal equinox is around March 20; every 30 degrees of Martian solar longitude is equal to about another "month." So here are (very rough) equivalent dates to Martian solar longitude (give or take several days because of Earth's varying month lengths and because Mars' orbit is pretty elliptical, so some of its "months" last MUCH longer than others, but this is a first approximation):
Ls 0 - March 20
Ls 10 - April 1
Ls 40 - May 1
Ls 70 - June 1
Ls 100 - July 1
Ls 130 - August 1
Ls 160 - September 1
Ls 190 - October 1
Ls 220 - November 1
Ls 250 - December 1
Ls 280 - January 1
Ls 310 - February 1
Ls 340 - March 1

Mars24 tells me it's currently Ls 148.5, so it's now equivalent to somewhere in the neighborhood of the third week of August. Back to school!

I've got a page on the Martian calendar http://planetary.org/explore/topics/mars/calendar.html that tells you more about how the lengths of the seasons vary because of the elliptical orbit.

--Emily

Posted by: Stu Oct 28 2008, 05:15 PM

Couple of http://phoenixpics.wordpress.com/2008/10/28/the-changing-view-from-phoenix, if anyone wants a look... As usual, not offered as scientififically accurate or useful, just sharing a couple of unashamedly pretty pictures.

Posted by: 1101001 Oct 28 2008, 10:03 PM

The beginning of the end:

http://www.jpl.nasa.gov/news/phoenix/release.php?ArticleID=1918

Goodbye, robotic arm! Thanks!

Posted by: Phil Stooke Oct 28 2008, 10:12 PM

Oh well - guess I was wrong in the other thread, it is the end for RA. I hope we get a pic of the arm's final location. Inquiring cartographers want to know!

Phil

Posted by: TheChemist Oct 28 2008, 10:22 PM

Despite the repeated warnings, it still feels sad to see Phoenix fade away :-(

Posted by: mars loon Oct 28 2008, 11:59 PM

very sad to see fading away

like we are losing a close family member

lets enjoy our remaining time together and remember the great times we shared

ken

Posted by: tedstryk Oct 29 2008, 01:33 AM

Dang, I forgot about solar conjunction.

Posted by: ConyHigh Oct 29 2008, 04:13 AM

It's extremely sad for those of us who were close to Phoenix. Many long hours, around the clock, spent with this wonderful creature. I saw her -- within a few feet -- before she left this sphere. And spent hours and days with those wonderful minds who created this dream and made something happen so many tens of million miles away. It will be years before we realize all the possibilities that our little Phoenix has created. She will remain a testimonial and a tribute to the hundreds of people who worked to make her and the mission a success.
Cheers little Phoenix! We salute you!

Posted by: Flecks 'ray Oct 29 2008, 05:49 AM

There've been a few images of very light frost on the deck, but does anyone know if there are expected to be any images showing significant CO2 frost build-up on the arrays before it's "lights out". If so, when might that occur?

Posted by: 1101001 Oct 29 2008, 07:03 AM

From the http://www.nasa.gov/mission_pages/phoenix/images/press/Goldstein2_Chart_SD_Fix.html from the last briefing, CO2 encasement begins around February 2, somewhere a little beyond sol 240. But, encasement is probably solid CO2 with no daily break, growing thicker each day.

Before that there'd be partial frosts that sublimated away during the day. http://phoenix.lpl.arizona.edu/faq.php, probably written long ago, mentions CO2 frost:

So, maybe we'll see some just before the end. Probably all depends on how long she can last.

Edit: This by AJS Rayl, back in the sunny days of May, also says it will be close: http://www.planetary.org/news/2008/0525_Phoenix_Arrives_on_Mars_with_Flawless.html:

Posted by: ustrax Oct 29 2008, 11:22 AM

Hey...looks like I have some dust in my eye...

Man...this leaves me with a knot on my throat...truly does...

Posted by: MahFL Oct 29 2008, 11:45 AM

Here in NE Florida I scraped water ice off my car windscreen this am. Was about 2 C air temp. Compared to -95 C that is not too bad.
I sure hope we see a thick ice covering near Phoenix.

Posted by: Andrei Oct 29 2008, 09:18 PM

This decision to stop the RA and TEGA heaters remindes me of a song of Smallfaces - http://www.youtube.com/watch?v=bbwgKH2SqoY.

P.S. - hello all!

Posted by: nprev Oct 29 2008, 10:14 PM

The happy place here is that she made it, she's performing brilliantly, and she's an unqualified success by any reasonable standard. Consider the alternative if any of the hundreds of fatal things that could have gone wrong did.

It'll hurt like hell to lose her, but so glad that we had her at all.

Posted by: Stu Oct 29 2008, 11:37 PM

I know this might sound strange - almost heretical - coming from one of the Forum's most unashamedly romantic machine huggers, but I'm not feeling so distraught over Phoenix's demise. I read the report about the heaters being switched off and although I knew it represented the beginning of the end I couldn't help thinking "Well, fair enough..." I think maybe it's because, from the very start, it was made clear that she would almost certainly not survive to Christmas, it would just get too cold, too dark, too hostile for her to keep going. Or maybe it's because there's not a lot more science she can actually do now, not with power levels so low and all her ovens full or broken. I don't know. But in my mind Phoenix - unlike our seemingly immortal, Too Stubborn To Die rovers - has always been a butterfly: a delicate creature of elegant beauty that emerged from an ugly chrysalis, but was destined from the start to live a short, exciting life before fading away and dying.

I'll miss her when she's gone, too, but I'll always look back on her - and our - brief stay in Barsoom's arctic and smile.

Posted by: 1101001 Oct 29 2008, 11:47 PM

Safe mode.

http://www.planetary.org/blog/article/00001716/

http://www.jpl.nasa.gov/news/phoenix/release.php?ArticleID=1919 (October 29)

Posted by: Stu Oct 30 2008, 01:07 AM

Hang on in there, Phoenix...

Posted by: nprev Oct 30 2008, 01:28 AM

...and if you could teleport that stuff there, you would! Cool pic, Stu.

Posted by: peter59 Oct 30 2008, 05:09 PM

Mark Lemmon has deleted Sol 152 and Sol 153 from http://www.met.tamu.edu/mars/directory.html It's end ?

Posted by: Stu Oct 30 2008, 05:11 PM

Maybe just 'cos there are no images planned for those sols... ?

Our bird's http://cumbriansky.files.wordpress.com/2008/10/dying-phoenix.jpg though, that's for sure...

Posted by: Deimos Oct 30 2008, 06:40 PM

No, that was just clean up. The site will not be updated until new SSI data are expected, rather than cluttering it with sols of non-plans. So while the situation is grim and I cannot guarantee there will be more updates, there was no intent to signal the end. The engineering team is working hard. And even if all else fails, there's still a "test" of lazarus mode. The UA and NASA sites are a better way to get such news than trying to read between the lines elsewhere.

Posted by: peter59 Oct 30 2008, 07:20 PM

Thanks Deimos, I had hope that my assumption is erroneous. I have great hope that now, after the completion of work by RA and TEGA, the Happy Pan will be continued.
Greetings to the whole team. Thank you for everything you have already done.

Posted by: 1101001 Oct 30 2008, 09:16 PM

Yeah, getting grim.

http://www.jpl.nasa.gov/news/phoenix/release.php?ArticleID=1924 (October 30)

Posted by: Hungry4info Oct 30 2008, 09:46 PM

I'll side with Stu on this one.

Sure, It'll be sad to see Phoenix go, but when it comes, it comes. We've all known it will die over the winter. Perhaps since we've always known that it'll die from the cold, we've all been preparing ourselves for the inevitable. And perhaps, the rovers are easier for us to identify with. Spirit and Opportunity look alive. The Pancam looks like eyes, the robotic arm is... an arm... and so on. We find it easier to sympathize with the MER rovers than we do a tabletop lander with a bunch of instruments on it. With MER, we can go out and explore, with Phoenix, we're stuck in one spot.

I'll be sad to see it go, but I won't shed a tear. When one of the MER's die, then I'll probably be a bit tearful.
My mother says that praying for a successful launch is silly, "It's just an inanimate object" she says.
Oh she has no idea...

Posted by: bgarlick Oct 30 2008, 10:58 PM

> the wake-sleep cycling would have begun at an unknown time when batteries became depleted.

I find this surprising. As I recall, one of the reasons we lost contact [eventually forever] with Mars Pathfinder was because pathfinder's clock got off and earth had no idea when it was communicating. I believe there are other cases of lost space probes because out of out of sync clocks.

Not loosing track of time seems to be of utmost importance. A digital clock requires such miniscule amounts of power (think of those kid science kits where you power a digital clock by sticking wires into a potato) it seems like they would have had a separate power source for the clock for Phoenix (and all post Pathfinder missions). A single, tiny, buttoncell can power a digital clock for a decade!

If, instead, Phoenix still has a correct time reference, but the mode it has gone into was timed relative to when the 'batteries became depleted' that just seems like a silly software error. No matter when a fault happens, the space craft should always communicate at a deterministic time.

Posted by: mcaplinger Oct 30 2008, 11:11 PM

It can only do this if it has power to do so. And remember that Phoenix can only communicate when an orbiter is going overhead, which only happens four times per day for a few minutes each time. So communicating at a deterministic (Earth) time is not something that makes much sense in this case, without the lander remembering a lot more stuff than it would be a good idea for it to rely on to remember (like exactly when the passes are predicted to occur for a long time into the future.)

If you do things based on an absolute clock, they had better not fail if that clock goes nuts. It's easier to rely on things you can directly observe.

Posted by: Oersted Oct 30 2008, 11:59 PM

Too bad they didn't permanently park the arm twisting up one of the solar panels towards the sun...

Posted by: belleraphon1 Oct 31 2008, 01:14 AM

Ah.... what we know is that that "inanimate object" is the incarnation of the dreams, and blood, and sweat, and tears, and years, of love and effort to create a machine to answer a tiny set of questions about this strange universe we find ourselves in.

These machines are at the foci of our yearning to know...

I will feel sad indeed when we no longer hear from Phoenix ..... but she and the mission team wrought every drab of data
they could... and she, like a mayfly, will have lived her life to the fullest.

Craig

Posted by: mhoward Oct 31 2008, 01:19 AM

Well said. I would add, one isn't really praying for the inanimate object; one is praying that human understanding may be allowed to advance.

Posted by: 1101001 Oct 31 2008, 01:42 AM

The http://twitter.com/marsphoenix is sounding sad but brave:

Posted by: aggieastronaut Oct 31 2008, 03:14 AM

Man, wrapping up some of Phoenix's open-ended projects today nearly made me tear up... :\

Posted by: ilbasso Oct 31 2008, 03:30 AM

Now I see well why with such dark flames
your eyes sparkled so often.
O eyes!
It was as if in one full glance
you could concentrate your entire power.
Yet I did not realize - because mists floated about me,
woven by blinding fate -
that this beam of light was ready to be sent home
to that place whence all beams come.
You would have told me with your brilliance:
we would gladly have stayed near you!
But it is refused by Fate.
Just look at us, for soon we will be far!
What to you are only eyes in these days -
in future nights shall be stars to us.

(translated from Friedrich Rueckert, as used in Mahler's Kindertotenlieder)

Posted by: laurele Oct 31 2008, 06:04 AM

I know this probably sounds like a dumb question, but isn't there any way to put Phoenix into a state of hibernation and then wake it up when the Martian winter is over?

Posted by: centsworth_II Oct 31 2008, 06:14 AM

As I understand it, the extreme cold will physically break electrical circuits and kill batteries.
Phoenix will actually be encased in dry ice (frozen CO2).

Posted by: ElkGroveDan Oct 31 2008, 06:19 AM

.....however in the extremely unlikely event that Phoenix does survive it has something they call the Lazarus mode where it would signal its condition if it was still functioning when solar power levels rise next Martian spring.

Posted by: centsworth_II Oct 31 2008, 06:30 AM

I suppose the most likely positive result would be detecting a slight sign of life in Phoenix, but no sight, hearing, taste, smell, sense of touch or ability to move. Kind of a vegetative state.

Posted by: paxdan Oct 31 2008, 09:22 AM

Wired RIP @MarsPhoenix: http://blog.wired.com/wiredscience/2008/10/rip-mars-phoeni.html

Posted by: jamescanvin Oct 31 2008, 10:22 AM

Phoenix Lazarus mode worked and she was contacted successfully on Thursday evening, according to http://www.nytimes.com/2008/10/31/science/space/31lander.html?_r=1&ref=us&oref=slogin linked from the Phoenix twitter feed.

Posted by: ustrax Oct 31 2008, 07:22 PM

Stupid I know but I'm avoiding this thread...like if it would bring bad luck to our brave, beautiful bird...

Hang in there Phoenix!

Posted by: tedstryk Oct 31 2008, 07:57 PM

I am really hoping that there some thicker frost deposits (a la Viking 2) that show up while SSI is still active. Might happen, might not.

Posted by: bcory Oct 31 2008, 08:28 PM

Latest image of "Holy Cow" taken Oct. 18 (Sol 142)

Some filling in by the sand storm perhaps?

Posted by: vikingmars Oct 31 2008, 09:43 PM

This is THE image showing the MAXIMUM 100% frost coverage seen by VL2 in 1979 (real colors).
This frost was able to stay during daylight hours, only because of extreme low temperatures encountered at her landing site :
- early morning at 06:00 : -122°C
- early afternoon at 15:00 : -92°C
I doubt (but still hope also) that the Phoenix lander will be able to live long enough and withstand such conditions to see such frost coverage...

Posted by: PaulM Oct 31 2008, 11:55 PM

Even in my most optomistic moments I can not believe that Lazarus mode will suceed in rebooting Phoenix next Spring. Broken tracks and components will make this impossible.

However I do believe that if contact is lost with Spirit next winter due to lack of power that Spirit will phone home again in the following Spring. The great advantage that Spirit has over Phoenix is that Spirit has a well insulated warm electronics box with 8 little radioactive heaters to keep it warm.

http://marsrovers.nasa.gov/mission/spacecraft_rover_body.html

So far as MSL is concerned I think that MSL's RTG will ensure that MSL will continue working on Mars for decades after broken wheels have turned it into a fixed lander.

Posted by: laurele Nov 2 2008, 03:55 AM

"The great advantage that Spirit has over Phoenix is that Spirit has a well insulated warm electronics box with 8 little radioactive heaters to keep it warm."

Why wasn't this feature put on Phoenix?

Posted by: Stu Nov 2 2008, 06:50 AM

I've written another - probably my last, for obvious reasons - poem about Phoenix, which some of you might be interested in. It's rather long (gasps of shock from everyone... I don't think! ) so I'm not posting it here, and it's probably a bit too much for some people anyway, so here's a link to it on my poetry blog.

http://astropoetry.wordpress.com/2008/11/02/preparing-to-sleep

Not intended to be an obituary, as such, more of a celebration of a short life well lived.

Hope some of you like it.

Posted by: BrianL Nov 2 2008, 03:25 PM

Because Death by Winter was the accepted fate for this mission. Waste of space, time and money to add such heaters for a few extra sols.

Posted by: nprev Nov 2 2008, 04:15 PM

Stu, I thought your poem was excellent! A bit sad, but simultaneously evoking the history of terrestrial arctic exploration. Thanks for sharing it with us.

Posted by: Greg Hullender Nov 2 2008, 07:12 PM

Actually, I did like this one. (Nitpick: shouldn't "arboreal" just be "boreal" in stanza 1? I see no trees here. :-)

Stanzas 1 and 2 are very strong, I think; although "in fear" jarred me in #2, I thought that "I don't think I can stay awake much longer" was VERY powerful.

Stanza 3 almost worked for me, but, again, things like "have I make you proud" were jarring. (Maybe I just want a more fatalistic rover -- "That which we are, we are" and all that. Or maybe just a stoic one.) But from "I reached out" down I loved it -- minus "TEGA".

Below that, I thought a comparison with Scott would have been much more powerful than with Shackleton, but I loved the general idea. Of course, a Scott quote like "God this is an awful place" would have been a bummer. ;-)

In fact, the poem reaches such power with Shackleton's quote that (for my money) it needs to end there. The last stanza felt like a let-down to me. Some nice images there -- "Glorious days, when a Phoenix flew to Mars!" -- but the shade of a Hero is a tough act to follow.

--Greg (Okay, now I'll go back to preparing for my "Random Processes" midterm) :-)

Posted by: hortonheardawho Nov 2 2008, 08:11 PM

Very nice poem, Stuart.

I think the role of a poet is to connect the dots and create a "true" metaview of being. There are a lot of very good dot creators here, but not many dot connectors. You, sir, are a very good dot connector.

Stuart, this will not be your last Phoenix poem.

The "true" meaning of life comes after death.

Perhaps a poem about bright eyed children staring at Phoenix in the Prehisory wing of a Martian museum?

One of my knee weakening epiphonies occurred holding a Cambrian worm cast in my hand while fossil hunting with my children and realizing this that very trail could have been made by one of my direct ancestors -- and that my own trail in the mud leading to an unimaginable future was now made.

Think about that for a moment.

Posted by: Stu Nov 2 2008, 11:10 PM

Thanks for the feedback guys, much appreciated. I'm tidying up the poem cos after reading it back at work during a break I spotted a few improvements I could make, too, and I think it,s now much better.

Very profound thought, Hort...

Posted by: vikingmars Nov 3 2008, 09:49 AM

A lot of frost seen on sol 151.
=> Dedicated to Stu's nice poem.
Not the imaging epitaph I hope. Enjoy !

Posted by: Sunspot Nov 3 2008, 11:33 AM

So is Phoenix still "alive" then?

Posted by: MahFL Nov 3 2008, 11:53 AM

I don't see any pictures past Sol 151...anyone know if Phoenix is alive ?

Posted by: peter59 Nov 3 2008, 12:22 PM

I hope that it will be like in the case of death Twain and you will soon receive a message from Phoenix "The reports of my death are greatly exaggerated"

Posted by: tedstryk Nov 3 2008, 02:59 PM

After the low power fault, they decided to let it spend a few sols recharging before doing anything new.

Posted by: 1101001 Nov 3 2008, 03:37 PM

Better news from http://twitter.com/marsphoenix:

Posted by: MahFL Nov 3 2008, 03:42 PM

Great....hang in there !

Posted by: centsworth_II Nov 3 2008, 03:43 PM

Richard Feynman: http://books.google.com/books?id=1HxzLaPYo2IC&pg=PA254&lpg=PA254&dq=feynman+dying+is+boring&source=web&ots=qUqj9OOMxs&sig=v_ZX47DP_WXt9tnFuKA4DHB64p4&hl=en&sa=X&oi=book_result&resnum=5&ct=result#PPA254,M1

Posted by: Andrei Nov 3 2008, 10:08 PM

Not to be a pessimist now that Phoenix is not doing quite well - just thinking of further discoveries that can be done with Phoenix, I wonder how will the EDL hardware look in the spring in hirise images. I guess it will be a reference in the search for MPL.
And just out of curiosity, in the very (very) unlikely case of Phoenix actually surviving the winter, will there be a new mission extension?

Andrei

Posted by: mars loon Nov 4 2008, 01:24 PM

there is limited communication and team will try for more science. any day could be the last

here is the latest UA update from 3 Nov 08. http://phoenix.lpl.arizona.edu/11_03_pr.php

NASA Hearing Daily From Weak Phoenix Mars Lander

Posted by: MahFL Nov 4 2008, 02:06 PM

That sounds very very bad. But it's been a great mission to watch, and I eagerly await the science to follow after the data is analyzed fully.

It also sounds like the batteries were not able to be fully charged. Did the commands to turn off the heaters ever work ?

Posted by: Phil Stooke Nov 4 2008, 02:44 PM

There is still plenty to be done with the images we have. Step-by-step movies of scraping in Snow White, or compiling all feature names from the TAMU descriptions on one mosaic, for instance. The mission's not over yet!

Phil

Posted by: MahFL Nov 4 2008, 03:28 PM

Seems the sun is now 10 degrees below the horizon at night now.

http://www.public.asu.edu/~sbporter/MarsSundial2.1.html

Posted by: MahFL Nov 5 2008, 05:41 PM

I wonder if they have any new pictures from Phoenix......if someone from the team is reading can we see it please ?

Posted by: elakdawalla Nov 5 2008, 05:44 PM

They don't. As of yesterday they had still not commanded Phoenix out of Lazarus mode, in which it is only trying to communicate, not do anything else. We'll have to wait until they can get the terminal science mode sequence uplinked. Even then, we may not get pictures -- pictures require more power than pressure, temperature, and TECP measurements, so those will be done and telemetered first before Phoenix tries to take any pictures with any remaining power.

--Emily

Posted by: MahFL Nov 5 2008, 06:11 PM

Any idea what the terminal science mode sequence consists of ?

Posted by: PaulM Nov 5 2008, 06:25 PM

I presume that Phoenix is transmiting a small packet of engineering data each day?

Does engineering data normally included a temperature reading? If Phoenix is returning temperature readings then do they show that increased dust in the atmosphere has actually raised the temperature?

Can engineering data be mined for other scientific results? For example can the electricity output from the solar panels be used to estimate the atmospheric dust level?

Posted by: fredk Nov 5 2008, 06:34 PM

See http://www.planetary.org/blog/article/00001724/

Posted by: MahFL Nov 5 2008, 06:47 PM

I think we are all suprised at how quick the power situation went downhill.

Posted by: helvick Nov 5 2008, 10:49 PM

It was always going to be hard to figure out precisely when Phoenix was going to start to die but we did know that the power loss situation was going to start getting dramatically worse around now. I had estimated that, all thing being equal, http://www.unmannedspaceflight.com/index.php?showtopic=5189&view=findpost&p=117297 of initial solar panel power per sol around now and dropping dramatically towards zero. The sudden storm has thrown a wobble into that and I am certain that my estimates of available power tended to overestimate the power from the panels at low solar angles but even so I'm somewhat surprised that she's gone into near death mode this early - I had thought we'd be closer to Sol 200 (and ~25% of initial power levels) before she started to die from loss of power. Clearly though my original estimates were quite a bit out of kilter with reality.

Posted by: tedstryk Nov 6 2008, 03:23 PM

The status updates mention that on the day they turned off the heater, they made their last use of TEGA. Was this completed? Also, are there any results from the now-defunct instruments still on board? I would think that downloading these would be a top priority now.

Posted by: Deimos Nov 6 2008, 04:53 PM

I'm not aware of any recoverable science data still on board, other than maybe in the MET/Lidar flash. The Biblical Lazarus may have come back with memory intact, but Phoenix comes back thinking it is the day before launch (or some such) and wondering why the touchdown sensors indicate she has landed. And so, Phoenix realizes something has gone very wrong, and begins the Lazarus mode comm strategy.

It looks like the weather situation may have improved, but there is no science and little engineering data to directly confirm that. As Emily said, once there is a good comm session, JPL can regain control. If control is restored, getting into terminal mode science will probably take precedence over anything other than maintaining or improving control. Risks will be avoided due to the already precarious situation. The terminal mode would be very repetitive and would extend the period for which Phoenix returns weather info as long as possible. It is just not obvious Phoenix can handle more than that in Lazarus mode. In the best possible future, the lander's abilities are much diminished, and the ability to respond to conventional science commands is gone, so the commanding strategy is new. So beyond met-related data, expect maybe 30 or so repeated images per sol (sky & frost monitoring) from SSI, and maybe attempts with RAC and maybe attempts with MARDI. And frankly, even that will soon be overly ambitious.

I don't think the situation should be that big a surprise. Before landing, sol 150 was the conventional answer to "how long could the mission last". The power available hit the power needed curve at that time. Weather had been unseasonably favorable, so it looked like Phoenix could go longer before moving to desperation strategies like sacrificing instruments. When the weather turned, it was just to the seasonal pattern that should be in place by sol 150--cloudy and stormy. Sol 200 was never realistic, except maybe as the end of waking up in Lazarus mode for a month, in good circumstances. One factor, by the way, is that it is not just the low power, but also the cold. More power is needed to stay alive; much more was always needed compared to the rovers. Spirit has just set a new record low power level, but still maintained more activity compared to the previous low in winter. Why? It is warmer than in winter. And that is for a tropical location, with RHUs.

Posted by: fredk Nov 6 2008, 06:32 PM

A few more details in a new http://space.newscientist.com/article/dn15136-dying-mars-lander-to-enter-groundhog-day-state.html including

Posted by: CosmicRocker Nov 7 2008, 06:30 AM

I was looking for something that summarized the mission accomplishments versus the goals, and that NS article was helpful in that regard. Thanks, fredk. It appears as if Phoenix managed to perform many of the tasks that were assigned to it. It seems to have been a success, but who is keeping the scorecard?

Posted by: climber Nov 7 2008, 08:40 AM

Forget me for a very innocent question.
Spirit was nearly lost because her flash memory was full of informations gathered before landing that she didn't need anymore at that time.
Now Phoenix is fooled by the touchdown sensors, an information that, in absolute, could have been deleted.
What are the rationales for keeping this on bord? Can "we" build on these exemples to change, in the future, the post landing strategies regarding these issues?

Posted by: elakdawalla Nov 7 2008, 06:13 PM

I don't think Deimos meant that anything that Phoenix is doing is the result of some problem with the touchdown sensors. It's just that Phoenix' clock gets reset every time the power goes out, same as the clock on your microwave. "Lazarus mode" is designed to deal with this problem.

--Emily

Posted by: Deimos Nov 7 2008, 08:10 PM

My understanding is the physical touchdown sensor, not file clutter, is useful to Phoenix right now, to know that Lazarus mode is needed (as opposed to sitting and patiently waiting for launch or some other unproductive thing). This is not part of the problem, but of the solution.

Posted by: nprev Nov 7 2008, 09:31 PM

I'm curious now. Assuming that somehow the available energy comes back up to a suitable level for basic operations, how would functionality be restored? Would the flash have to be purged & reloaded (which would presumably require several orbiter passes), or are the basic functions a sort of firmware & therefore immune from power glitches?

Posted by: mcaplinger Nov 7 2008, 10:13 PM

Yes, of course. As far as I know there is no issue at all with the flash, the problem is that the spacecraft clock keeps getting reset to 0. The explanation about the spacecraft thinking it's before launch isn't what I would have expected (most missions have "mission phase bits" that are kept in a nearly-bulletproof type of non-volatile memory) but I don't think any of this has anything to do with the contents of flash.

Posted by: climber Nov 8 2008, 06:14 PM

Thank you Mark & Emily. Very interesting to see how one (at least me ) could guess the oposite of the reality.