So has a landing site been chosen yet, anyone know? and what is the specific (or general) location... and don't just say "up north", latitude and longitude would be better.

Well

"Latitude (centered): 68.2 ° Longitude (East): 233.2 °"

From http://hirise.lpl.arizona.edu/PSP_007207_2485 - which is inside the ellipse.

If you said 68 / 233 - you couldn't be considered wrong.


http://www.nasa.gov/images/content/183675m...label-hires.jpg

and

http://www.unmannedspaceflight.com/index.p...amp;#entry98551 for more.

Doug

Oh that answer my question, but it begets a new one: how big is the landing ellipses? isn't it suppose to be smaller then MERs?

MSL - with an actively guided entry will be smaller ( something like a 10km circle ) - but Phoenix is going to be basically the same as MER I would expect. Something like 80k x 20k - someone may be able to put my right on that though.

Dog

So, are those frost-heave cracks that form the polygonal terrain really flat, or do they present a certain amount of vertical relief?

I feel like we're trying to blind-land this thing in a garden amongst hedgerows -- it's lovely if you land in the garden, but landing on a hedgerow could ruin your whole day...

-the other Doug

Well, the description does say "shallow" troughs with CO2 frost. If all the frost has currently sublimated, then a new Hirise image would show the degree of shallowness.

To be more specific, the illustration with three ellipses shows target ellipses (roughly 100 by 20 km) for three launch dates. As Phoenix launched at the start of its launch period, only one of the three is the actual landing ellipse. It is the one running from lower right to upper left in that map. The ellipse reflects all uncertainties before launch. As they approach, the trajectory and timing will be known better, so the ellipse will shrink.

I had hoped for papers on the Phoenix site at LPSC next week, but there isn't much. Still, we should see an updated map soon.

Phil

Looking at the HiRise landing site images, I'm reminded
of a jigsaw puzzle with no picture on it. Even with one
descent image provided by Phoenix and the capability of
HiRise to resolve the lander, I imagine it will take quite a
bit of searching before Phoenix's actual location on the
surface is found. Am I being too pessimistic?

A lot depends on whether any distant topography is visible. If any distant hills can be seen it will be found quite quickly.

Phil

I thought Phoenix was going to test high precision landing before MSL? I know that ran some navigation test using the Martian moons with MRO, what became of that?

Those tests were not for Phoenix but for future use. They require a camera to be used during approach, imaging the moons so triangulation can give an accurate spacecraft position. Phoenix can't do that because it can't take images of the moons during approach.

Phil

Ok, another question: how likely will it be that phoenix will land in the desired terrain (small boulders, crack surface, ice in range of arm, etc) in short what is the size of the optimal landing sites photographed in box A & D and how likely is it phoenix will land in that site?

I had a dream last night that Phoenix didn't make it down OK While still in the heat shield it started to "rock" side to side. Weird.

Zero descent images. MARDI operations were deleted from Phoenix.

Has anyone managed to do any radar soundings of the landing ellipse? I recall reading descriptions of the MER landing sites based on (Arecibo?) radar results, and they proved to be very accurate (from my limited perspective, at least).

Is the Phoenix landing ellipse too far north for that sort of thing? Would the radars on MEX or MRO be useful? Or is that sort of thing entirely redundant given the resolution of HiRISE?

Earthbased radar at normal incidence angles is limited to the equatorial zone, between the summer and winter solstice latitudes. (Earth's orbital tilt relative to the martian orbit extends this a little.

Earthbased oblique radar can reach further north or south from the tropics. Mars is relatively "shiny" as I recall, compared with Moon and Mercury, and doesn't give high signal-to-noise data from high off-vertical viewing. There's other complications I've never fully understood. I don't know what the 2 sounding radars are telling us about the scattering properties (I've heard nothing about subsurface structures in most of the circum-polar plains) of the surface and near surface materials at high mid-latitudes and sub-polar latitudes.

I can't find any mention that a a site was picked 100 % confirmed?

Isn't it strange that no site has not been mentioned?
Or did I miss something?

Yes, you missed something! This is the site:

http://www.nasa.gov/images/content/183675m...label-hires.jpg

See the posts above, especially mine in Post 7. I expect we'll get more details close to the landing date. In this image, the ellipse running from lower right to upper left is the actual landing ellipse - the other ellipses were for different launch dates.

Phil

Thanks. Speaking for myself, I think the confusion was that it was said that
adjustments could be made to the landing site during the first two course corrections
if needed or desired. I take it there were no adjustments made, but I don't recall
any official announcement that the original site was being retained.

edit: But since your #7 post was long after the second course adjustment, I guess the
possibility of change was already moot.

Could somebody provide a global map of Mars with the landing spot marked on it? I don't have a map of Mars with coordinate grid.

Here ya go, best I can find quickly...

Click to view attachment

... or if you want my fancy Outreach version...

Folks,

I had a bit of a tinker to try and come up with a possible view from the Phoenix lander using some Earth Arctic imagery as a starting point.

What do you think?

Artistic impression of the view from the Phoenix landing site.
Credit: Brian Cameron

Adapted from "Polygon-shaped features in the Dry Valleys."
Credit: David Marchant / National Science Foundation

Website containing starting image: http://www.nsf.gov/od/lpa/news/03/pr03149.htm

Direct original image link:

http://www.nsf.gov/od/lpa/news/03/images/polygons_cen.jpg

Enjoy !

Brian

Nice pic Brian, and a gorgeous place, but Peter Smith said in the spacEurope Q&A (replying to one of my questions, actually):

There are few slopes in the neighborhood and the horizon should look extremely
flat, no hills... Finally, the site is a shallow valley and has undergone erosion which may leave signatures.

Thanks Stu,

Yeah I know it is probs a bit too hilly but I guess it is my Scottishness showing through ;-)

However, what do you make of the near ground polygons with ice?

Even more impressive in the original pic by David Marchant of the NSF.
http://www.nsf.gov/od/lpa/news/03/images/polygons_cen.jpg

Cheers

B

Hey, no need to apologise for hilly... I've many beloved memories of the times I spent up on Skye and in the Orkney and Shetland Islands, doing Outreach in the tiny schools up there... stood on a beach al Elgol, staring out across the water at the Cuilins glowing marmalade-orange at sunset and fell in love with the place...

I like the polygons... I think we're going to see some lovely ground features on Phoenix images. And, personally, I'm crossing my fingers that we see some beautiful atmospheric effects too... have always wanted to see a glowing halo around the Sun from Mars...

This is the best I've been able to make with Photoshop, a Gusev image and a "polygon" image...

Click to view attachment

Version 2 here and Version 3 here... which (if any!) will be more accurate do you think?

Nice work Stu! I wonder if anyone else is going to have a bash at this?

I saw the competition being run from http://spaceurope.blogspot.com/ . Will you be entering?

Cheers

Brian

I can't... I'm a judge!

How has the response been so far? A while to go yet I suppose though.......

Yep, a while yet, and you'd have to ask Rui how many entries there have been so far. We were kinda hoping there'd be some entrants from within the UMSF ranks (actually, there might have been, for all I know... )

Here's my latest "possible view..."


Click to view attachment

Great image Stu, that definitely has a realistic appearance to it.

Alas even at this site there are still boulders to reckon with.

Thanks Yeah, the boulders... just spent half an hour trying to add those realistically and got absolutely nowhere, so in MY world Phoenix lands in a remarkably boulder-free area!

That's the right attitude!

I like this "StuWorld", sounds like the place to be. I bet your Gusev is swept by regular windstorms too, right?

These images of terrestrial polygonal terrain posted above, and the HiRISE imagery, is not calming the gathering butterfly storm in my stomach. The boundaries of each 'hexagon' marks a point where frost heave has lifted thesurface of the inner area relative to the border areas (if I have my mental image of the process right?) So far as I can judge scale from Stu and Doug's simulations of Phoenix-by-HiRISE, there's a high probability that the lander will end up either straddling, or leaning down into, the 'ditches' around the polygons. I wonder what the maximum survivable tilt is.

Ah well, I suppose that lack of ground truth is what makes any Martian EDL so... "interesting"!

I must admit I'm struggling to make sense of the scale and nature of things at the Phoenix landing site... I'm going from pictures like these...

Click to view attachment

The top three images are terrestrial, the lower two crops from HiRISE landing ellipse image... I'm sure someone out there can give us a guide to what we're actually seeing on the HiRISE image..?

Stu my friend...a pity you can't compete...why don't you use another identity?...
All the others...I'm still waiting for your entries...

Well, you got mine!

Phil

And a winner I must say...
Somehow I've got me this strong desire for a cup of good strong coffee...

Unfortunately I've been disqualified, so I'm posting mine here. Warning, it involves "flagrant digital plagiarism"

Phil

Click to view attachment

Disqualified?!!
What do you mean by desqualified?!!
That was MY favourite so far...
Phil just didn't handled the pressure of being a favourite...

Just a a teaser for those who haven't sent participations yet, the prizes are being gathered this week at the US to cross the ocean on the upcoming week...these include the posters signed by Peter Smith and some of these beauties...

Genius

The lawsuit is in the post, by the way.

BTW, some good Mars-related blog posts (including Emily's excellent piece on Mars Express images of Phobos) over at this week's Carnival of Space - the 50th!

Possibly of no relevance at all (and I know there are lot of other articles where the fulltext IS available), so just FWIW...:

http://www.jstor.org/pss/521255

..describes frost-heave polygons in Antartica "15 to 20m in diameter, and small frost mounds, 1-5m high".

15-20m sounds about right for the scale of some of the HiRISE images Stu's posted here (I think?) - I hope that doesn't imply 1-5m of vertical relief as well...

OK I'm no Stu, but here's my attempt:

These images are great fun - thanks all. I notice, though, that while terrestrial poygons tend to be light with dark outlines on Mars it seems to be the other way round. So far I don't see that reflected in the simulated views. And yes, I think they'd be pretty big - maybe only the nearest one or two clearly visible.

OK,

Another effort.

Cheers

Brian

I just spent a lot of time working up an entry, but I've got two problems.

1) I'd love to show it in this thread, but since at least two of the judges
are here, I think that would be a disqualification.

2) I have never successfully sent a full resolution photo by e-mail,
but I guess I have time to figure that out.

Why don't you hold on until the 24th of May to show it here, who knows, as a winner?

Dan...why didn't you send THAT great image?!
Come on...do me another version and e-mail it...
The same to all of you still thinking about it...get also the kids doing it, there's two categories!
Carla Bitter, Mission's Education & Public Outreach Manager, just e-mailed saying that the goodies were already shipped...

Excellent! - that one gets my vote.

I have to report that my attempt is making very slow progress. I've found some promising boulders and figured out how to work a digital camera, but I'm still trying to locate a dried up reservoir and someone willing to donate an industrial quantity of shaving foam . . .

Oooh, you might just have nailed it with that one Brian! Very nice.

I'm just worried we might see something like this when the first raw images come down...

Click to view attachment

Or this:
http://images.google.co.uk/imgres?imgurl=h...l%3Den%26sa%3DG