[X] My Assistant

[RichardLeis]

Huh? So for most images, you won't be making use of the full resolution the camera can produce?

The 1 to 2% of Mars the HiRISE camera will image during the initial 2-year imaging mission will be accomplished through a mix of binning modes that are chosen depending on a variety of factors, including season and the scientific rationale for a particular observation (for example, does the image need to be high resolution or is it part of a martian terrain sampling campaign where quantity of samples is much more important than resolution?) With great power comes great responsibility

[tuvas]

Huh? So for most images, you won't be making use of the full resolution the camera can produce?

Well, we won't take all of the pictures in the highest resolution. But, if we're looking for something such as one of the landers that we don't know exactly where it is, well, taking full resolution pictues would take a whole lot longer, and not really produce any signifigant gain in return... What I would suspect we'd do if and when we take on the search for a lander such as Viking is take either binned 2 or 4 images, without the color bands, compressed, and transmitted to us. Then when we found the lander (Which might take a while), we'd take a high-resolution color image in the imediate area nearest to the lander. But, I'm not a member of the OPs team, in fact, I have almost nothing to do with such decisions, this is just pure speculation on my part.

For those things that need the absolute highest resolution, we will take the highest resolution pictures. For others, well, it might be lower resolution. In fact, not all of the pictures we've released are the fullest resolution. During Transition Imaging, we did alot of experiments with different binning modes, some use of images compressed using a look up table to half their size, some other things as well. Even in the super-capable MRO mission, we still are transmitting images across a large void, bandwidth still is very valuable.

[djellison]

Disappointing...

But realistic. Whilst MRO's pipe to the ground is bigger than any previous downlink you've got to consider two 'feet on the ground' realities....
HiRISE doesn't get it to itself ( as any Glog reader will tell you, it's only about a quarter ) -
and HiRISE images are bloody ENORMOUS data products. A full resolution HiRISE image is like stacking every 360 pan that Spirit has taken on top of one another.

VERY rough, VERY back of the envelope that don't really tell the truth and don't include compression.
( 20,000 + 4000 + 4000 ) x 40,000 x 12 = 13440 Mbits.

Now - get creative with the binning and the compression and drop the colour, and you can have 4, 6 or more images within that same data budget. Quite a lot of those images in the Transition phase were only 2x2 binned, not full res, and they were still spectacular, and would be more than enough to identify an MER, Pathfinder or other known lander.

Doug

[ustrax]

I really hope for some lucky shot that might capture those soviet probes...:
We were not far from Mars 3...It's half the way between these two images:
http://marsoweb.nas.nasa.gov/HiRISE/hirise...RA_000866_1420/
and
http://marsoweb.nas.nasa.gov/HiRISE/hirise...RA_000878_1410/
Who knows?...

"Mars 3 arrived at the planet on December 2, 1971. The lander successfully touched down on the surface, becoming the first spacecraft to land there. However, it failed after transmitting a mere 20 seconds of video data to the orbiter."
mere 20 seconds? Where are they?...Useless?...

[tty]

Even more so in light of the fact that we could learn a lot about modern Martian erosional rates by observing the landing sites of the earliest probes. Mars 2 & 3 have been on the surface for 35 years...

The Vikings have been there for 30 years and are much easier to find. And additionally we know exactly what the surroundings looked like back then.

I do hope they will try for Mars Polar Lander. In that particular case the state of the lander might actually tell us whether the suggested failure mode happened or not.

tty

[monitorlizard]

For you guys and gals who want to work with hard numbers to estimate how many HiRISE images are actually possible in the near future, I offer the following info from the Oct. 26 update to the MRO mid-range planning schedule (mgsw3.jpl.nasa.gov/seq/images/mromid.pdf) :

On Nov. 1st, 550 kilobits/sec downlink is indicated, with two DSN passes of 8 hours each per day
this continues until Nov. 19, when "near continuous" DSN coverage is shown from that point on
on Dec. 16, the chart says "higher data rate available" (presumably because Mars and Earth are again getting closer to each other)

For those interested in such things, there's some red meat for ya (apologies to any vegetarians who may be reading this).

[ustrax]

mere 20 seconds? Where are they?...Useless?...

Don, in spite of his absence, has all the answers...
http://www.mentallandscape.com/C_CatalogMars.htm

[djellison]

MPL will be a must-have I think...for lots of reasons We know fairly well where to look for that one...I hope.

THat 500ish kbps will go up to basically, 10x that over a period of 12 months - as a really really rough guide - you could just add 500 kbps each month for 10 months, and then hold it at the highest rate for 5 or so months...very very very ballpark guestimate figures.

25% of near continuous 500kbps is 10,800 Mbits

20,000 x 40,000 x 12bit with, hopefully, 2:1 compression when I spoke to Graff at IAC = 4,800 Mbits.

Scarey isn't it.

Doug

[tuvas]

A few corrections:

1. I can't tell you where I saw it, but I can tell you that it is public knowledge that HiRISE actually has closer to 1/3rd of the bandwidth of MRO. I think CTX and Sharad are 15%, HiRISE and CRISM are 30%, and MCO and MARCI get whatever's left over, but those aren't nessicarily accurate. I can't find my source on that, but I know I saw it somewhere... I've done a bit of searching, to no avail, but those numbers should be within about 5% of each instrument.
2. HiRISE images are actually 14 bit, not the 12 previously quoted. Aditionally, they are sent in 16 bit segments (For alot of reasons), so...
3. The max size of an image is about 25 Gbits, or about 3 Gigabytes. Pictures can be taken of longer strips, so long as that limit is strictly followed, but the 20k pixel length is a maximum.

So, well, just to give you a bit of an idea... It would take quite a while...

[MarkL]

Disappointing...

Come back in 3 months and repeat that. I double dog dare you!

[monitorlizard]

(mgsw3.jpl.nasa.gov/seq/mromin.html) is a listing of minisequences for MRO, and near the bottom of the list is something called "MER-A/Spirit Overflight" scheduled for day-of-year 310, which I think is November 6. This sounds pretty exciting. Maybe a nice HiRISE image is in the works?

[djellison]

That will be the Electra UHF relay test I presume. If it's near-nadir then they might do some observations but if it's not, then I doubt it.

Doug

[Guest_Sunspot_*]

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

A super-powerful camera orbiting Mars may help discover the fate of long-lost spacecraft that never phoned home after reaching the red planet.

[edstrick]

Beagle and Polar lander's locations are known pretty well. The target elipses are long, but the actual inferred landing ellipses are decidedly smaller. For Beagle, there's a "try this spot first" candidate which might actually be where it wiped out. For Polar Lander, the candidate object they were suspecting was ruled out by a cproto image.

The impact/landing points for Mars 2, 3 and 6 have only been quoted to about one degree precision, unless my memory's gone. That's an enormous area compared with the search zones for Beagle and Polar Lander.

Vikings and Pathfinder are as readily hit as the MER rovers. Essentially one pair of frames (for stereo topography) is all that would be needed for each of those 3 sites.

[Lorne Ipsum]

Vikings and Pathfinder are as readily hit as the MER rovers. Essentially one pair of frames (for stereo topography) is all that would be needed for each of those 3 sites.

If memory serves, don't we have MGS cproto images of the Viking and Pathfinder sites? If so, these will be VERY accurately targeted by MRO.

Lorne