[X] My Assistant

[RNeuhaus]

This topic is for posts concerning to any preparation of Phoenix Lander Mission to Mars programmed to launch on August 2007 (less than 2 years... but the time will fly)

http://marsprogram.jpl.nasa.gov/missions/future/phoenix.html

Overview

The Phoenix mission is the first chosen for NASA's Scout program, an initiative for smaller, lower-cost, competed spacecraft. Named for the resilient mythological bird, Phoenix uses a lander that was intended for use by 2001's Mars Surveyor lander prior to its cancellation. It also carries a complex suite of instruments that are improved variations of those that flew on the lost Mars Polar Lander.

Canada Will Land Instrument On Mars To Study Weather

http://www.spacedaily.com/news/mars-future-05t.html

Rodolfo

[climber]

An article on Space.com where we can also "see" the real lander :
http://www.space.com/businesstechnology/06...oenix_tech.html

[Guest_BruceMoomaw_*]

Principal Investigator Peter Smith has just answered perhaps the two biggest questions about Phoenix:

(1) The precision-landing test, using guided entry, has indeed been cancelled -- so MSL will be the first Mars lander to try that.

(2) Phoenix will, with luck, be able to detect methane in Mars' air at 10 parts per billion -- although "we will not know if this is doable until the first full TEGA test in May."

[Phil Stooke]

Where is this from, Bruce?

Phil

[Guest_BruceMoomaw_*]

Smith E-mailed me personally, in response to my query last night. (We've talked before.)

[Spacely]

Didn't see this elsewhere on the boards. The AO for Mars Scout '11/'12 went out on Monday.

http://www.marstoday.com/news/viewsr.html?pid=20314

Anyone have any info on the types of proposals we can expect?

[RNeuhaus]

At the 37th Lunar and Planetary Science Conference (LPSC), held March 13-17 in Houston, Texas, Phoenix team members presented both excitement and nervousness about the Phoenix Mars endeavor—specifically, addressing the dangers lurking at the spacecraft’s landing zone.

These worries are :

1) NASA wants to land down the Phoenix in a zone where does not have "egregious landforms" in terms of safety. Needs more pictures from MRO, MGS, MEX and Odyssey.

2) Additional uncertainties include air density, winds, lander attitude control…and just how well Phoenix will deal with slopes and rocks, Guinn explained. Fortunately, the northern plains of Mars are very flat and low.

3) The other trouble is that the Phoenix belly is so low, up to 35 cms of clearence above the surface. Depending the force of landing, the legs can lower even further. Hence, need a clean surface, no rocks bigger than 25 cms. So "If there is a pointy rock that you come down on, the belly pan [of the lander] could hit that rock…and that would be of serious concern," Golombek said. "So there is concern here. We will be looking at the MRO data with great interest," he concluded.

Up to now, not yet has determined the landing place for Phonix

Rodolfo

http://www.space.com/businesstechnology/06...oenix_tech.html

[Guest_BruceMoomaw_*]

Several interesting new tidbits I've recently run across about this mission (in addition to the two I mentioned earlier):

(1) All its possible landing areas seem to have a very thin layer of dry soil over the underlying permafrost -- only 4-6 cm thick in most places. This presents problems for one desired science goal: using the MECA and TEGA to analyze chemical gradients with depth in the soil layer -- they may have to settle for only one or at most two scoops of soil before they get to the ice, instead of the hoped-for three.

For this reason, the planners are now placing greater emphasis on analyzing the permafrost itself on this mission -- but that, in turn, presents problems. Permafrost is very hard stuff, and Deborah Bass' blog ( http://phoenix.lpl.arizona.edu/features/we...eborah_bass.php , Nov. 13 and 21 entries) reports the problems they've been having designing the scoop to properly handle it. The robotic arm by itself, even with the digging tines fastened to its scoop, isn't nearly strong enough to rake up an adequate pile of the stuff without taking days -- during which any shreds of ice it manages to detach will probably sublimate away before enough can be accumulated for the scoop to pick them up. Thus the decision to add the Icy Soil Acquisition Device -- a rotating "ice shredder wheel"-- to the rear of the scoop to both quickly detach shreds and kick them straight into the scoop.

(2) The best description of the reasons for the choice of "Region B" as the overall landing region is at http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1328.pdf -- which can be summarized by saying that it's scientifically as good as the other two regions, and somewhat safer.

(3) Bass' Aug. 27 entry talks about the measures being taken to keep chemical contamination of the site by the thrusters' hydrazine within acceptable bounds. (Note that the Vikings reported no problems from this.)

(4) The Dec. 8 entry talks about the fact that the lander will be swaying rapidly during its parachute descent, which may somewhat blur the descent images (as it might have on Polar Lander).

(5) Each MECA wet chemistry cell will finish its analysis by dropping two chemical pellets into the water: an acid one to reveal any carbonates, and another to reveal both sulfates and soil oxidants.

(6) Besides the meteorology measurements made by the lidar and temperature and pressure sensors on the MET experiment, and the periodic air analyses done by the mass spectrometer, the "TECP" probe on the arm scoop to measure soil electrical and thermal conductivity (which has a heated prong surrounded by temperature sensors) can double as a hot-wire anemometer, and an air humidity sensor is also built into the TECP. There are also strings dangling from the thin mast carrying the MET temperature sensors to serve as photographable wind sensors, like the windsocks on Pathfinder's mast.

Didn't see this elsewhere on the boards. The AO for Mars Scout '11/'12 went out on Monday.

http://www.marstoday.com/news/viewsr.html?pid=20314

Anyone have any info on the types of proposals we can expect?

ARES and MARVEL will be resubmitted, with only minor changes; but I haven't yet been able to find out whether SCIM will be. Bruce Campbell is also resubmitting his Mars Scout SAR orbiter, now christened "Eagle" ( http://www.lpi.usra.edu/meetings/lpsc2006/pdf/2188.pdf ). Ames Research Center is trying to one-up Langley and its ARES with "MATADOR", another Mars airplane that might actually be able to survive its final landing ( http://www.aviationnow.com/avnow/news/chan...ATADOR11174.xml ) Bruce Banerdt is submitting some kind of single lander focusing on geophysics, and somebody else is submitting some kind of Phoenix-like lander with a mini-rover. Finally, besides ARES, the Langley center was planning to submit an atmospheric orbiter ("MARS": http://www.spaceref.com/news/viewsr.html?pid=18893 ) -- but the new plans for a big 2013 atmospheric orbiter may upset the chances for both that one and MARVEL.

Update: SCIM will be resubmitted in 2011 ( http://www.space.com/missionlaunches/06012...e_capsules.html ). I regard it as a major contender, especially given the new delay in the flat-out surface Mars sample return mission.

A Bit more on MATADOR at http://research.hq.nasa.gov/code_s/nra/cur...MT/winners.html :

"Lawrence Lemke / Ames Research Center
MATADOR: a Mars Advanced Technology Airplane for Deployment, Operations, and Recovery"

"Current Mars airplane missions typically begin by deploying the aiplane in a nose-down attitude, involve a dive below the cruise altitude in order to establish flight speed and end with an uncontrolled crash into the planet's surface. This proposal is to demonstrate technology which would improve this scenario by allowing controlled deployment of the folded wings at the beginning of flight without a negative altitude excursion and which would allow controlled impact of the aircraft into the planet's surface at the end of flight in a nose-high, low-energy approach which will leave the airframe in a condition to relay on-board data to an overhead spacecraft.

"The technology to accomplish this consists of a delta planform fuselage to contribute intrinsic pitch stability to the folded airplane at high angles of attack and a cold gas reaction control system under control of the autopilot to provide direct thrust vectors, independent of flight speed. This demonstration will be accomplished through a work plan to design, construct, and flight test an unpiloted aerial vehicle, named MATADOR.

"MATADOR is a blended wing-body rocket powered aircraft of 4m wingspan designed for steady-state flight on Mars at 4km above datum at 0.6 Mach and 0.6 Cl. The 3-year work plan calls for 2 high altitude flight test demonstrations of MATADOR to be conducted by carrying the airframe to approximately 30km altitude with a helium balloon and releasing it to begin flight. In addition, the plan calls for a series of ground impact tests in which the incidence angle and velocity and surface slope and roughness parameters will be experimentally investigated to determine their effect on the ability of the airplane to survive and function for the purposes of data communication."

[Bob Shaw]

A winged Mars lander which might survive after touchdown? What a good idea! I wonder if anyone has thought of it before?

Bob Shaw

Attached thumbnail(s)

 

[climber]

Here are 2 Phoenix model pictures I took at the Planetary's Society event called "Wild about Mars" on Spirit day landing. You can also see a Lego model of MER landers in the back ground. Note how big if Phoenix as compared to both MER and a person in front of it :

Climber

[djellison]

Cool pictures - I guess those are spare Cosmos 1 'sails' behind?

Doug

[climber]

[quote name='djellison' date='Apr 20 2006, 12:09 PM' post='51277']
Cool pictures - I guess those are spare Cosmos 1 'sails' behind?

Doug

You're right. As was amazed by both Phoenix (high & big arm) as well as Comos 1 'sails' size.
By the way, here is Pathfinder sitting nearby :

[Bob Shaw]

'Cool! Check out the *bling* on that, Victoria! Do you want a pair in Burberry?'

Bob Shaw

[lyford]

(3) Bass' Aug. 27 entry talks about the measures being taken to keep chemical contamination of the site by the thrusters' hydrazine within acceptable bounds. (Note that the Vikings reported no problems from this.)

Pardon my newbie question, but are there any issues with "temperature contamination" from the lander? If we are trying to study pristine permafrost conditions, what affect would hot thrusters and the attendant gasses have? Would there be any delicate CO2 frost or ice melt that might change the local conditions? Or will the low temperature and pressure of Mars' atmosphere sufficiently dissipate any excess heat quickly enough?

[RNeuhaus]

...

Thanks Bruce for a very informative post.

[Guest_BruceMoomaw_*]

Pardon my newbie question, but are there any issues with "temperature contamination" from the lander? If we are trying to study pristine permafrost conditions, what affect would hot thrusters and the attendant gasses have? Would there be any delicate CO2 frost or ice melt that might change the local conditions? Or will the low temperature and pressure of Mars' atmosphere sufficiently dissipate any excess heat quickly enough?

I haven't heard anything about there being any problem with the temperature. Presumably the arm has a long enough reach to get beyond any places on the surface that might have been temperature-modified. (Nor did I ever hear anything about any such problem with Mars Polar Lander, which had similar engines and a similar arm.)

[Bob Shaw]

I haven't heard anything about there being any problem with the temperature...

Bruce:

It's OK, for safety reasons they'll cut the engines at 30m above the surface.

Bob Shaw

[Guest_BruceMoomaw_*]

Ho ho, yuk yuk, har de har har. While going through the report of MEPAG's "Mars Human Precursor Group" on the necessary safety measurements for Mars' atmosphere (more on that soon, down in the "MTO Cancelled" thread), I found the following little note: "Phoenix landing thruster system may erode 0.3 cubic meters of soil, which is a cloud containing a few hundred kg of loose soil and dust." Gaaack. However, they never made a fuss about this for Mars Polar Lander -- which had the same system using touchdown sensors on the foot pads themselves to shut down the engines.

[djellison]

So on one hand we've got reports of a terrain so hard they'll struggle to dig through it, and on the other reports that the engines will blow away 1/3rd of a ton of the stuff.

Doug

[lyford]

Upside down creme brulee?

um, i mean the hard permafrost UNDER the dust....

[centsworth_II]

If the "blow zone" is four meters in diameter, the average amount of surface dust removed by the landing blast would be a couple centimeters. This is still a surprising amount to me.

[Guest_BruceMoomaw_*]

What they're apprehensive about blowing away is the 5 cm or so of loose soil on top of that hard permafrost -- and what they're apprehensive about contaminating with hydrazine is both the soil and the surface of that permafrost. (As I said last night, however, Deborah Bass' August 27 blog entry suggests that they're not all that worried about it.)

[helvick]

(As I said last night, however, Deborah Bass' August 27 blog entry suggests that they're not all that worried about it.)

It bears repeating that Deborah Bass' Blog contain's lots of excellent material and Suzanne Young's has a load of relevant info on the risks (or not) of Hydrazine contamination

[climber]

Hydrazine contamination

Is this still a problem when you know exactely the contaminant and the quantity of it ? I mean, not talking about soil/ice disturbance, can we "remove" Hydrazine from the analysis ?

[chris]

Is this still a problem when you know exactely the contaminant and the quantity of it ? I mean, not talking about soil/ice disturbance, can we "remove" Hydrazine from the analysis ?

In order to be able to remove it from the analysis, you would need to be able to know what
it had reacted with. Since part of the reason for going is to find out what the geochemistry is,
I guess the answer is at very best "perhaps", and more likely "no".

From reading Suzanne Youg's blog, it seems that the engines are very efficient, so hydrazine
isn't a big worry. The ammonia produced by the breakdon of hydrazine may still be an issue though,
as approaching 80% of the exhaust gas is ammonia.

Chris

[climber]

Since part of the reason for going is to find out what the geochemistry is,

Oh Yes! Exploration is. I kind of forget the reason we're doing this, didn't I ?

[Joffan]

Given our struggles to get the power required for Spirit from solar panels, with the sun at about 50degrees up (midwinter midsol at Gusev), how well are the Phoenix panels going to manage? Is there any plan to tilt the panels and catch a few more rays? Or does Phoenix have another power source that I don't know about? (in which case why are the panels there??)

[djellison]

Phoenix is just arrays, they will be almost parallel to the ground - but it will get 24 hr sunlight early in the mission (check the website for an animation that shows this) so a tilt would be a bad idea as you would get from one side only what you would drop on the other.

Phoenix is going to be a short lived mission, the very long, very cold polar night will kill it.

Doug

[helvick]

Given our struggles to get the power required for Spirit from solar panels, with the sun at about 50degrees up (midwinter midsol at Gusev), how well are the Phoenix panels going to manage? Is there any plan to tilt the panels and catch a few more rays? Or does Phoenix have another power source that I don't know about? (in which case why are the panels there??)

Phoenix has a very well defined mission and there will be more than enough energy available for it during it's 3 month primary mission as it will occur during the late NH spring-summer season when insolation at high latitudes is high (higher than at the equator in fact because the sun will never set at all at the height of summer) and it may have enough energy to continue to do some science for up to 190 sols. Extending Phoenix's mission may be only of marginal value though since it has very specific objectives and extending the mission will only really make sense if scheduling difficulties mean that it can't complete it's planned tasks in the first three months or if some of the secondary instruments yield something really dramatic.

I've attached my estimate of the power that would be available from a 1M^2 panel, 26% efficiency cells with an 80% power subsystem efficiency for the Phoenix landing site (70degN) starting on the exected landing date of 10 May 2008. I've put in fairly aggressive dust loss parameters (0.2% per sol) and modelled Tau using the 1997 dust storm model from Viking (which was a medium scale global storm) which is fairly conservative. As you can see there's lots of power for 120 Sols or so but then it rapidly tails off as winter arrives and since it is above the martian arctic circle it will eventually get to a stage (around Sol 320) when it is dark 24.65979 hours of the Sol.

I've no idea what the actual solar panel area for Phoenix is or what the cell types are but 1m^2 seemed reasonable from the pictures I've seen online and 26% efficiency should be about right if they are using recent Triple Junction GaInP cells.

[Joffan]

Thanks helvick, very attractive graphs.

I'm surprised at the idea that you can get more power near the poles than the equator even in summer, since you'll need many hours of 5º sun to equate to an hour of 90º sun. However the trig is too hard for me to do without some serious thought and lots of envelopes with plenty of space on the back, so I'll take your word for it (for now)!

And I guess the other thing is the limited mission, as you say. Once the analysis reagents are used, the most interesting part of the mission is done and the quiet slipping away of the Phoenix will be easier to bear.

[climber]

This is an article from Space.com :
"Backhoe Ho-Down on Mars
The next robotic arm headed for the red planet is ready for final testing and installation onto NASA’s Mars Phoenix lander, due for liftoff in August of next year.The backhoe-like arm was built by Alliance Spacesystems, Inc. (ASI) of Pasadena, California. Once on Mars in May 2008, the arm is assigned a key duty of digging a two-foot deep trench in Mars’ north-polar region.
At the business end of the arm is a scoop about the size of a garden trowel that will do the digging down to an ice layer that is potentially rock-hard. The arm will deliver soil samples to a suite of devices on the lander’s deck for detailed analysis. A camera mounted on the arm will view layers in the freshly-dug trench wall.
The agile arm has a 7.5-foot reach (2.3 meters), with the aluminum and titanium device weighing less than 22 pounds (9.7 kilograms). The robotic arm – inherited from a shelved 2001 Mars mission to the equator – could not dig into hard icy soils at cold temperatures and had to be completely redesigned. Mars Phoenix is a three-month mission expected to yield new clues to the history of water on Mars and whether the environment was ever conducive to life."

[mars loon]

This is an article from Space.com :
"Backhoe Ho-Down on Mars
The next robotic arm headed for the red planet is ready for final testing and installation onto NASA’s Mars Phoenix lander, due for liftoff in August of next year.....
...The robotic arm – inherited from a shelved 2001 Mars mission to the equator – could not dig into hard icy soils at cold temperatures and had to be completely redesigned. Mars Phoenix is a three-month mission expected to yield new clues to the history of water on Mars and whether the environment was ever conducive to life."

I have actually seen and handled an engineering prototype of the completely redesigned scoop and have written an article that I'm trying to publish somewhere.

There was a full scale model of Phoenix at the 2005 JPL Open House. The mission may last up to 5 months and will likely end when the craft is buried under an accumulation of frozen carbon dioxide ice.

[edstrick]

Interesting item on SpaceRef: NASA is going to procure laser-retroreflectors to install on the Phoenix lander so that it can be precisely lidar-bounced and located from orbit.

http://www.spaceref.com/news/viewsr.html?pid=20608

"NASA Stennis Solicitation: Phoenix Mars Scout Laser Retroreflector Arrays "
"NASA/GSFC intends to purchase an Engineering Model and two (2) Flight Laser Retroflector Arrays from ITE, Inc ..."
"GSFC intents to acquire a set of reflector arrays for the Phoenix Mars Scout mission due for launch in the summer of 2007. These arrays will enable the Phoenix lander to be located from Mars orbit"

[Guest_BruceMoomaw_*]

A bit more on the new ice-sampling tool in Deborah Bass' lastest blog entry ( http://phoenix.lpl.arizona.edu/features/we...eborah_bass.php , Apr. 24 entry).

[Cugel]

spacedaily

If you can't make it as a MER rover driver, this could be an interesting job vacancy: Mars arm operator.

[djellison]

reads much like the testbed they put together for Beagle 2 here in Leicester.

Doug

[dvandorn]

spacedaily

If you can't make it as a MER rover driver, this could be an interesting job vacancy: Mars arm operator.

Oh, gee -- that sounds like a really bad come-on line: "Hey, baby, wanna come back to my place and watch me operate my Mars arm???"



-the other Doug

[RNeuhaus]

Interesting interview with Chris Mckay about Phonix mission.

http://www.marsdaily.com/reports/Digging_D..._Mckay_999.html

The north pole is most desirable than the south pole because of the following factors:

1. The north is lower and smoother than the south. Easier to land
2. South is higher and heavily cratered terrain and harder to land.
3. South needs deep drill to get interesting data.
4. North needs less drilling to find liquid water (probably) at the surface in the more recent past.
5. In the north there might be more young ice.

He does not believe to find any organic materials...

Rodolfo

[centsworth_II]

....He does not believe to find any organic materials...

I believe this statement was in reference to MSL and Exomars which will land in areas where no ice is present to protect organics (if they ever existed) from oxidants. As far as Phoenix goes, he says that, if present, organics could be protected by the ice and detected. He doesn't say if he expects phoenix to find organics.

[Guest_AlexBlackwell_*]

Public Invited to UA's Phoenix Mars Mission Open House Oct. 21
By University of Arizona Communications
October 11, 2006

[antipode]

Hi all

Not sure if this has been asked before, but here goes.

Assuming Phoenix outlasts its 90 day warranty - what will finally 'kill' it first - declining temperatures or oncoming polar darkness? I ask this because it seems that at this latitude, the winter frost/snowpack will be pretty deep - it would be wonderful (and sad) if the lander could document its own burial in snow! (until it WAS buried of course).

Is this likely, or will the lander be dead before any snowpack builds up around the vehicle? I always thought the Viking 2 frost pictures were evocative, and here we have a chance to go one better, and presumably catch all sorts of other polar weather processes (development of the polar cloud hood?) as well.

Phil

[Rakhir]

I don't know the creation process of martian frost/snow, but if some snow is able to build up on solar panels, even if the solar power and the temperature are still good enough, the death might be quick.

[helvick]

Without snow\frost degrading the panels power output will follow something like this:

CODE

Sol   0: 100%
Sol  30: 102%
Sol  60: 96%
Sol  90: 88%
Sol 120: 76%
Sol 150: 60%
Sol 180: 44%
Sol 210: 31%
Sol 240: 16%
Sol 270: 5%
Sol 300: 0%

My guess is that there can be no precipitation effects until insolation drops well below the levels we've seen at the MER sites ie 30% of the initial max. So frost/snow effects if any should only come into play after around Sol 210.

[Julius]

Looking at the MRO image of the region close to where Phoenix should make its landing,I would think JPl should be concerned about stone slabs littering the whole area.Has anyone given any consideration as this may be a serious hindrance to a safe landing.

[tedstryk]

Unlikely as it is, I think it would be really cool if Phoenix can be reawakend after the winter. Even if it can't do much. It would be neat to take a panorama for change detection, especially with regard to its trench, which will have experienced frost coming and going.

[Phil Stooke]

Julius: "Looking at the MRO image of the region close to where Phoenix should make its landing,I would think JPl should be concerned about stone slabs littering the whole area.Has anyone given any consideration as this may be a serious hindrance to a safe landing."

Yes. One of MRO's jobs is to look for areas without too many rocks.

Phil

[climber]

Looking at the MRO image of the region close to where Phoenix should make its landing,I would think JPl should be concerned about stone slabs littering the whole area.Has anyone given any consideration as this may be a serious hindrance to a safe landing.

Phoenix Home page show this as a future possible landing site : http://phoenix.lpl.arizona.edu/multimedia/...site_8_3_06.jpg
Can you provide us with the link of the MRO picture you're talking about ?
Thanks

[RNeuhaus]

Phoenix Home page show this as a future possible landing site : http://phoenix.lpl.arizona.edu/multimedia/...site_8_3_06.jpg
Can you provide us with the link of the MRO picture you're talking about ?
Thanks

After visiting the following Hiroc Web page. The closest ones are ones of polygonal terrain (TRA_000828_2495).
Specifically, around the Phoenix landing zone, up to now, MRO haven't yet posted any additional picture. Soon these pictures will come soon.

Rodolfo

[Julius]

Thats the MRO image I was talking about except you have to zoom in!The rocks are described as being part of the ejecta blanket from exhumed craters.

[Anoolios]

University of Arizona news article; Full-scale Mars Lander to be Unveiled at Phoenix Mission VIP Event: http://uanews.org/cgi-bin/WebObjects/UANew...ArticleID=13235

Hopefully I can make it down there on the 21st to check it out.

[tuvas]

University of Arizona news article; Full-scale Mars Lander to be Unveiled at Phoenix Mission VIP Event: http://uanews.org/cgi-bin/WebObjects/UANew...ArticleID=13235

Hopefully I can make it down there on the 21st to check it out.

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:-)

[edstrick]

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.

[djellison]

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

[tuvas]

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...

[tty]

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

[nprev]

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!

[tuvas]

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.

[edstrick]

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.

[RNeuhaus]

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...

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

[djellison]

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

[ustrax]

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?

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

[RNeuhaus]

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

[djellison]

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

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

[tuvas]

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.

[hendric]

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!

[nprev]

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.

[djellison]

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

[nprev]

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...

[mchan]

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?

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.

[MarsEngineer]

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.


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

[djellison]

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

[helvick]

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.

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?

[climber]

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

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

[djellison]

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

[climber]

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.

[djellison]

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

[climber]

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....
Doug

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

[Jim from NSF.com]

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

[MarsEngineer]

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

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

[MarsEngineer]

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

[ElkGroveDan]

VL-2, VL-1 and MPF from HiRISE. On none of these missions have we "found" the backshell and parachute

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.

[dvandorn]

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

[MarsEngineer]

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.

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

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

[climber]

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?...

[Stephen]

The advancement and retreat of the polar cap is better observed from orbit via HiRISE .

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

[djellison]

the course of a Martian winter

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

[Stephen]

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

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

[djellison]

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

[ustrax]

Space.com article

[climber]

Space.com article

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

[ustrax]

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

Yes I do...

[ElkGroveDan]

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?

[punkboi]

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

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

[ustrax]

Can I push the button?

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

[ElkGroveDan]

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.

[ustrax]

OK then. No ride on my avatar for you.

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

[Stu]

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

[Jim from NSF.com]

Can I push the button?

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

[lyford]

...to the last person that pushed it.

Is that true? Who was it? What launch?

[Guest_AlexBlackwell_*]

Has anyone noticed the newly re-designed Phoenix website?