I was there, it was awesome:-) Among other things, I learned:

1. There is no hope that Phoenix will survive more than about half an Earth year. It stands no chance to be going on for several years.
2. I saw the engineering model of Phoenix, it was really cool. I saw the PIT, the Payload Interoperability Testbed area, very neat.
3. A UA instrument detected water ice near the Martian poles, prompting a UA camera to look for a spot to land a UA spacecraft. Got to love the University of Arizona;-)
4. I answered several questions about alot of things, I wore my HiRISE tshirt, it made me a bit of a target...

So, the whole thing was really cool. Oh, I also saw the room where the MER cameras are programmed, that was pretty cool too. Lots of fun stuff happening:-)

phrasemorphing: "There is no hope that Lunar Surveyors will survive much beyond lunar sunset... " 3 of the 5 successfully landed spacecraft transmitted pictures following one to 3 lunar nights. Surveyor 1 transmitted a signal in response to an attempt to wake up Surveyor 6 on 6's second lunar day. (Like rovers and MRO, they assumed they could recycle the old mission's receiver frequency!

I'd assume battery death, but not necessarily total spacecraft death until confirmed otherwise.

The Lunar Surveyors didn't get burried for > 6 months in frozen ice and CO2. Yes - there's a chance that Phoenix might survive it, like there was a chance that NEAR could have survive 6 months + on the surface of Eros, but I would be astonished if it were to happen, utterly utterly astonished.

Doug

There's even less chance that that for Phoenix. Phoenix will be in shifting polar caps, even the slightest movement will shatter the spacecraft, and would destroy the spacecraft, not merely cause it to stop functioning, but quite literally leave it to shreds. Perhaps HiRISE will photograph it after, I imagine some scientific knowledge could be gained from it. Just imagine though, a warning of disturbing images coming from a camera at Mars...

I think you are overestimating how dynamic an ice-cap is. Remember there are no calving fronts on Mars, and ice-falls are apparently decidedly rare too. Unless Phoenix falls into a crevasse on landing I find it unlikely that it will be "shredded" or even damaged by shifting glaciers.

tty

I hope that it survives for a fair period as the deposits accumulate...would love to see a time-lapse sequence of the build-up!

In fact, is bona fide precipitation possible in any way? Could the CO2 freeze out of the atmosphere in fat flakes, like snow? THAT would be an awesome sight!

I have little doubt they'll try to get as much out of it as they can. They will probably take pictures until it won't function any more, time-lapsed pictures, maybe one a day, would certainly be really cool. And, it will be relayed by MRO, so it'll have alot of bandwidth avaliable, power will be it's limiting factor.

I have no recollection of estimates what temperatures various parts of the Surveyors got down to. Most of the electronics was in insulated, passively thermally controlled boxes, but the camera, for example, was suspended on struts above the bulk of the spacecraft and pretty thermally isolated. The electronics boxes had second-surface mirrors (glass on the outside) on top, so the mirror surface would bounce direct sunlight while the IR opaque glass would radiate efficiently to black space. They had bimetallic thermal switches that were to go "open" when they got cold enough and break the thermal path from the inside of the box to the glass. These turned out to be "sticky" and not all of them opened. To a good approximation, the surveyors that had most of the switches go "open" worked better on subsequent lunar days. Surveyor 3 had the fewest switches open and was never heard from again.

I suspect the camera got well below CO2 ice temp during the 2 week lunar night, It may have varied between spacecraft in the electronics boxes. The big damage was thermal expansion/contraction breaking solder joints and stuff. Of course, this was pre-<mostly?>-integrated circuit hand-wired electronics. No vaccuum tubes etc, other than probably TWT transmitters.

Once Phoenix is shut down and cools down to ambient temp (are there any isotope heaters, like the ones in the rovers "warm electronics boxes"?), it will end up at CO2 ice temp of 150'ish kelvin (lower pressure and thus frost temp on mars than earth) and pretty much stay at that temp all winter. It's really hard to get much below CO2 ice temp on Mars.

I doubt we'll hear from Phoenix after winter, but unless there's some thing that they *KNOW* will fatally disable any communications ability, I will hope that it can revive to some limited extent after the winter. I'd expect battery failure, but that might not preclude all chance of operations.

Does the Phoneix has greater solar panel surface than MER?

It would be a good idea that the Phoenix bring bright colors on its solar panels so that MRO can spot it easier after a long Martian winter.

How long will last the Martian winter at the Phoenix position?

The only way to permit to Phoenix to survive the Martian winter is to have a proper design to keep warm the vital instruments in a box and also have its panels solar well stowed as it was immediately after landing on Mars.

Rodolfo

I can't help but laugh when people start suggesting design changes to a spacecraft with less than a year till launch. Do you know how silly it is to suggest those sorts of things?

Solar Panels are dark in colour for a reason - and in actual fact, dark solar panels will appear more contrasting to the ligher coloured terrain in the polar region.

And look at the HiRISE MER image - it's the shadow that stands out, not the vehicle itself - with Phoenix, those shadows can at times observable by HiRISE be very very long.

And - once you stow the solar panels again ( which seems unlikely as such operations are usually one way with latches involved) - where do you intend to get the power from to run the vehicle, accept commands and open them up again?

The 'proper' design for Phoenix is the one that gets it on the ground and survives for around 6 months - all the time it will need to do the measurements it is being sent to do. This isn't MER - longevity will not bring anything particularly new. The advancement and retreat of the polar cap is better observed from orbit via HiRISE .

Doug

Doug...You weren't THAT rude intentionally were you?...

The problem was that I haven't expressed well on the previous post that it was like a "list of wishes".

Yes, I have assumed that the Phoenix design won't be changed for obvious reasons. A good project, is to finish all things within the objectives, budget, and time.

The dark color of solar panel is a good but not as good as an orange color. However, it is probably that Phoenix will land on a dark surface and not on a white surface of dry ice.

About the Phoenix's shadow will be very long and hence big toward the end of winter is a good hint but, if Phoenix lands on dark surface, it would be very hard for MRO to identify it. During its live time, MRO can take pictures 4 times per day: midgnight, 6:00 am, noon, and 6:00 pm.

I was afraid about the solar panels that were designed to open only, only one way. They have no motriz force to close.

About the warm electronic box is a well know solution which are applied to many spacecrafts. For the case of Phoenix, the project design was already defined. Hence, that project won't last no more than 6 months. I knew that.

I don't have to laugh for your comments. I understood your reaction. I am sorry of my bad writing hability to express well.

Rodolfo

Going on how I read the orig post - yes I was. Going on how I now see it was more a 'blue sky' as opposed to 'realistic' train of though, then no I wasn't.

Doug

It is true that the polar regions don't shift much, but even the slightest shift of a few centimeters would be enough to brake the camera, arms, solar panels, etc. Any added weight from the CO2 panels would do the same thing. Just face it folks, Phoenix isn't meant to survive longer than a few months, if we get 6 it'll be lucky. And the change won't really do that much.

I'd also like to add my agreement to Doug's comments. It is silly to request a change in a spacecraft now. And it is the shadows that stick out, we're finding with HiRISE that many of the "dark" regions of Mars just appear to be that way, due to the shadows of rocks. I reviewed a caption to one of the images where that was very apperant. Not to say that that holds true everywhere, but in many places, it does.

My prediction is that due to the height above ground, and albedo of Phoenix's solar panels, it might stay ice free for longer than we think, and that it will defrost well before the rest of the cap around it.

It will be funny to watch the SSI sticking above the ice, a la R2-D2 in the swamp, as the cap freezes over.

As the cap starts to defrost, maybe we'll get lucky and have an "ice blow"/"geyser" form. If those geysers are caused by dark spots under the ice collecting heat, a large, dark, "rock" under the ice should cause a nice display!

I don't know if "silly" would be the right word to use in this context... ...believe me, LOTS of people want to make changes right up to the minute of launch. I'm battling against some of them on my project right now.

RN, the sad fact of the matter is that designs have to be frozen at some point in order to meet project cost & schedule requirements. This is particularly true for interplanetary UMSF since the launch windows are generally quite restrictive. A major change late in the game usually means significant delay if not outright cancellation. In fact, Phoenix is a prime example of this: it is a recycled & revamped version of the Mars 2001 lander, which was scrubbed after the Mars Polar Lander failure.

Hope that helped a little...and I would urge some of our fellow members to appreciate both the difficulties and dedication of those of us participating in this forum who are non-native English speakers and choose our comments accordingly.

I would still argue that suggesting changes should be made to the Phoenix platform to increase the chances of survival of winter is silly. I'm not saying "OMFG WHAT TEH MORON". I'm saying I think it's silly. Silly is about the least offensive word I could possibly use.

I'll be more verbose.

Making the solar panels a bright colour to make the spacecraft more visible from orbit is silly. It's already going to be visible from orbit - very very clearly with HiRISE. It's a larger spacecraft than MER, considerably larger. It will have a two dark solar arrays and a bright spacecraft deck - any one of which will be as visible by HiRISE as MER is on their own. Furthermore if the terrain is a little darker then the spacecraft deck will be even more visible. If the terrain is a little brighter, the two solar arrays will be even more visible. Fundamentally, when it comes to contrast with the environment - the Phoenix design has all possible bases covered. Not only that, but you're saying that on Sol X - you're prepared to kill the spacecraft for a full Martian winter in the hope that the avionics will survive at 100 deg C colder than the MER WEB.

Folding up the solar arrays for winter - that would involve a MAJOR redesign of the avionics. You would kill the spacecraft in doing so, and would then require some form of batteries etc that could survive a -150C and below soak for > 6 months and then somehow trigger the thing back up again once spring arrives.

Phoenix has a quick, focused job to do, which it will get done before winter arrives. Any changes that try to expand this envelope, particularly in adding complexity to the spacecraft are unjustified. Better is the enemy of good enough.

Doug

No argument, Doug, believe me...I have been there & done that!

Primarily, it becomes a problem of communication, and that can be tedious & time-consuming indeed, esp. if a user has an idee fixe at the last moment that just has to be no matter what or they'll throw a full-fledged hissy-fit (which in my world usually means nastygrams to very senior people, who thereupon start asking questions and themselves have to be educated on the issue)....it never ends!

Certain prefatory phrases now alert me to things that don't have to be. For example, "Gee, wouldn't it be nice if.." raises my hackles instantly! The overarching focus has to be on accomplishing the core mission and satisfying the fundamental requirements that gave birth to the mission in the first place or nothing's gonna happen, a fact of reality which often puts users and project managers at odds with each other.

This is why project management meetings usually drag on for uncounted, acrimonious eternities. This is also why project management people often drink quite heavily...

Agree the solar panels operation will be one way only, i.e., open. But I would guess the drive to open the panels is capable of operating in reverse direction after what happened to Galileo HGA.

Hi Doug et al,

Right again Doug, the Phoenix solar arrays open but do not close (the design uses a metal tape to pull them open).

I agree that we should be able to see the lander pretty well from HiRISE. The one color we should probably consider changing on future missions is the orange & white gores on the parachute (same as on MER). They look nice in test (easy to video in drop and wind tunnel tests) but they do not stand out from orbit (at least I think so). I hope we get some good shots of VL-2, VL-1 and MPF from HiRISE. On none of these missions have we "found" the backshell and parachute (MPL too of course). I have some EDL questions from those missions that s good HiRISE pict will clear up.

-Rob

PS I am one of the worst offenders for violating the "better is the enemy of good enough" principle. Or maybe my idea of "good enough" is off a bit at times.

Likewise I too have unfullfilled wishes (e.g. I wish I could have lifted the MPF side petals after the second month on Mars to see the effect - if any - of dust off loading). It is the inevidible pine of the curious mind. When you get a roomfull of folks loaded with these Martian wishes, things can get down right rowdy.


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Comments made here are the author's and do not represent NASA Caltech nor JPL.

It'll be nice to try and pin down how much of the MPL and Beagle 2 hardware is on the floor - and I've REALLY scoured the MOC imagery in the direction of the alleged MPF backshell ( and thus chute ) with no luck.

Here's one - is 'second colour' of the flight chutes orange for a reason. Blue would seem the obvious choice, and I'm sure I've seen white+blue chutes being tested somewhere.

Doug

Way out there question - wouldn't it be better to have the second colour something that flouresces - that should cause a chute to be even more visible?

Rob,
I wonder what you can learn from HiRISE images now that you've seen Oppy's backshell from THAT close, I mean even with the microscope?
Would you mind telling us a few words about what you've learnt from Oppy's exploration of her backsell?
Thanks for your very interesting inputs. It's good to speculate here, but once in a while, we need to know the reality

They saw the heatshield up close....but not the chute and backshell

And I still think the opportunity for a self portrait in the reflective insulation on the heatshield was a tragic miss
Doug

Oh yes I fully agree. I hope we'll not miss this with MSL. The Crane will be large enough to find a place of reflection, and it will land not very far. May be not too late to think about this. Even of no scientific value, the image will be very inspiring, and not only for UMSF'ers. A very wild idea would be to provide MSL with a mirror she can position with her IDD for self portrait. A mirror can also be used to survey places otherwise not reachable by the cameras. This would have may be of some help back at Purgatory.

Ahh - I don't think I would want to get close to the decent stage of MSL....pressurised tanks....nasty chemicals... a heatshield is fairly benign thing to visit, but a parachute, and a crashed pressurised decent stage...I'm not so sure....

On the upside, Mastcam's got a fair chunk of zoom on it, so we won't need to get too close

Doug

MSL will have a laser that'll KILL the Crane from a distance.

As said before, Skycrane is not name of the "lander", it is called the descent stage. Skycrane is the name of the concept.

Doug and friends,

I remember asking the Pioneer gang why "international orange" and "natural white" (nylon) was used, but I do not recall the answer. I should also double check the colors from MPF and Viking. (My fading memory from MPF was that that chute had undyed dacron-like polyester fiber so had a bluish tint. I really should know for sure ...)

Other colors (like florescents) might be a good idea but there are other material property issues that have to be checked and / or tested. (e.g. outgassing during cruise).

I am glad you mentioned the MSL descent stage, given how much angst there was about driving to Opportunity's heat shield I too doubt that MSL would be allowed to get close to so much potentially caustic material. The angst I am talking about was due to the appearance of dust smotes on the rear hazcam as the rover rounded the heatshield crater on its way to the heat shield. The team was very concerned that the dust was from the heat shield char and that it would ruin the ability to use the hazcam or even the other cameras.

We were able to investigate the heat shield (as fast as we could). I do not think there are yet published reports (mostly due to everyone being busy - still), but in a nut shell we confirmed the char depth (approximately) but more importantly the close up images revealed an answer to a minor EDL mystery. There was a surprising amount of oscillation build up (but still small) in the seconds before parachute deployment. We did not know what caused it. However once we saw that there remained a small amount of outer thermal blanketing on the heat shield, we finally found our answer. (It was supposed to burn off.) The blanketing acted like an unwanted trim tab. There is a paper in the works on this one.

All and all, I would say that there always seems to be something to learn by studying the flight data and the vehicle. Pictures really help. (Ever wonder what that long yellowish tape was doing on the MPF solar panel after Sojourner was off the lander? Yep, we goofed.)


-Rob

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Comments made here are the author's and do not represent NASA Caltech nor JPL.

By the way, I never thought to consider a self portrait using the heatshield inner mylar blanketing as a mirror. I guess we were distracted and in a hurry to get away fromn the char dust. Oh well. (it is always thus).

-Rob

If memory serves was there not a white object identified in Pathfinder images that was likely the backshell?

As I recall there was an attempt to do a super res image of it.

I think the point was that the backshells and 'chutes from VL1, VL2 and MPF have never been seen in MOC imagery. Even though the backshell was tentatively identified in MPF surface images, nothing that looks like it (or its 'chute) has been seen in MOC images of the area, even though they're fairly certain they've identified the lander's location.

-the other Doug

Yes and so we thought until we had the MOC C-protos of that area. The "object" turned out to be too close and too small to be a backshell. It was only a few pixels across even in the IMP super res images. It could have been a piece of an airbag cover that came off during our long (and un-measured) bounces.

Although we try not to, we tend to leave small bits when we land .. nothing an astronaut could not tidy up in a day ot two. (Ever see the cable ties from the decent bridle sitting near the base of the Pancam mast? (Spirit I think). Similar with the "bunny ears" from Opportunity (I think it was from the airbag thermal packing near the gas generators - but can not know for sure), the kapton tape on MPF (on the ground near the lander), and the fine thread (probably Vectran) in the early Opportunity microscopic images in Eagle crater. All of these are a natural but irritating side effect of landing on a foreign planet. We prefer that that they stay attached.

I think that the reason that we have not seen the backshells and parachutes is because we have not imaged in the right places yet and/or the signal-to-noise ratio at the highest MOC resolution was to low. I could be wrong, but I hope that will change with the new MRO HiRISE capabilities. I am really excietd about HiRISE.

-Rob

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Comments made here are the author's and do not represent NASA Caltech nor JPL.

A few months ago, we also had thoughts about cruise stage(s) making it to the ground. Is that possibe? Did it (they) crashed down range or further ? That could be a nice target for MRO too.
Back to parachuttes; do we know about the colours of the one from Mars 3? Beagle?...

Now there I must beg to disagree!

For one thing that statement seems to be implying that the study of the advancement and retreat of the Martian polar cap only involves studying large scale changes, the sort best observed from above; and on an intermittent basis at that (since HiRISE will not be observing the cap's advance and retreat constantly or even consistently; ie it will most likely only be able to observe the same places on an intermittent basis).

But that issue aside why should the study of the advancement and retreat of the Martian polar cap only involve cameras? Phoenix also carries a meteorogical station. Are you suggesting that there is nothing to be learned about Martian seasonal change and its interaction with the polar cap over the course of a Martian winter from data collected by such a station?

======
Stephen

I agree, LIDAR obs during winter would be interesting, but during martian winter, Phoenix is going to be very very very dead.

And HiRISE can and will follow the advance and retreat of the icecap.....a job almost designed for MARCI which will obseve the site at LEAST daily, and because it's near polar it may well get imaged several times per day. An equatorial site, yes, HiRISE would struggle to image it regularly ( MARCI would still do so however ) but because it's near the pole the 'overlap' of the orbits is so much closer that repeated, higher res observations ( with CTX or even HiRISE ) will be much easier.

Doug

No one's disputing the death of Phoenix, Doug. (Albeit I suspect that most of us probably harbour some hope, however small and slender, that miracles can happen and that the thing will live up to its name! ) Even if the pressure of all that snow and ice building up on top of it doesn't crush it (or the more delicate parts of it at any rate, like solar panels and radio antennae), being buried for months in ice, especially CO2 ice, will doubtless do bad things to the electronics inside of it.

But that wasn't the point I was making. There are some things that can be better done from orbit and there are some things that can't. I'm sure there were people out there who would have argued before the MERs were launched, for example, that there was no need to send rovers--and two at that--to find proof of water on Mars when all the proof that would ever be needed to settle the issue could be found using orbiters equipped with cameras, spectrometers, and radar.

======
Stephen

Yes - there are things that are best done from the ground....but following the advance and retreat of an ice cap of hundreds of km's isn't one.

It's clear that we're talking about different things and an argument is brewing - so I'm stopping it here and now.

Doug

Space.com article

There's quite a nice picture of the harware...
Do you still plan to go for launch?

Yes I do...

Can I push the button?

I could care less about how Phoenix meets its fate after its mission... I just hope its thrusters work beautifully when it's descending to the ground at the beginning of its mission

Sorry, the place is taken...there's a crowd dying to do it before you do...

OK then. No ride on my avatar for you.

One of this days I'll buy one of those...

Gorgeous artwork of the lander on the ground at twilight...

It is now a mouse click. The buttlon has been removed and was given on a plaque to the last person that pushed it.

Is that true? Who was it? What launch?

Has anyone noticed the newly re-designed Phoenix website?