Landing Site Options

[nnyspace]

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.

[djellison]

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

[nnyspace]

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?

[djellison]

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

[dvandorn]

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

[mchan]

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.

[Phil Stooke]

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

[centsworth_II]

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?

[Phil Stooke]

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

Phil

[nnyspace]

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?

[Phil Stooke]

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

[nnyspace]

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?

[Guest_Sunspot_*]

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.

[mcaplinger]

Even with one
descent image provided by Phoenix...

Zero descent images. MARDI operations were deleted from Phoenix.

[Gsnorgathon]

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?