Looking For The Landers Options

[Guest_Sunspot_*]

http://mars.jpl.nasa.gov/mro/spotlight/20050412.html

Mars Reconnaissance Orbiter will follow clues to where the lost Mars Polar Lander and Beagle 2 might be.

[edstrick]

They will want to image all known landing sites in addition to searching for Polar Lander and Beagle-2. There's plenty of geology to do with better images of the 5 sites with "ground-truth"

There's also things to search for, but MRO won't be looking for them: Mars 2 <no signal after atmospher entry>, Mars-3 <failed after 20 sec of surface transmission>, and Mars-6 <signal lost essentially at retrofire and/or surface impact> The landing/impact regions of these missions are reported only to the nearest degree <or so>

Most missions also left jettisoned hardware like the heat shields and parachute/backshells for the Rovers. Vikings never saw any of their "junk"... it was apparently beyond local or distant horizons in both cases.

There may also be scattered debris from Mars Climate Orbiter. It's not clear how much, if any, of the spacecraft exited the atmosphere on a "Hyperbolic escape trajectory"... the rest either burned up or is scattered over a long groundtrack like debris from Columbia. (Some debris could have exited the atmosphere and re-entered <literally> a partial orbit later.) Now there's some junk for future space-collectors!

[djellison]

Things that we should be able to find...

Viking 1 lander, Heatshield, Backshell & Chute

Viking 2 lander, Heatshield, Backshell & Chute

Pathfinder lander, heatshield, Backshell & Chute, and Sojourner of course - approx 5m, or 15 pixels away from the 1.5m or 5 pixel lander.

and of course - the same for Spirit and Opportunity ( we know exactly where they are but the higher res and colour imaging will be interesting )

and THEN....

MPL lander, perhaps heatshield, perhaps backshell and chute, perhaps just a crater.

Beagle 2 lander, perhaps backshell and chute, perhaps just a crater.

We know ROUGHLY where to look for those.

The observations of luck will be the earlier mars probes I would imagine. Mars 2, 3, 6 - and they were very small - B2 sized bodies iirc - so who knows what chance we have of finding them

As for the discarded cruise stages and MCO which will have burnt up on entry - I have no idea how much of them will have survived entry. Perhaps just the odd fuel tank a-la Delta II seconds stage earth entry - but we have no idea where to look

Doug

[Guest_Sunspot_*]

http://space.com/missionlaunches/050502_mpl_search.html

The search is back on for a spacecraft that disappeared during a landing attempt nearly six years ago. And there are hints that the probe might have been found.

[remcook]

what is the footprint size of HiRise? how long does it take to scan a reasonable area?

[tedstryk]

"The Mars 3 descent module was mounted on the bus/orbiter opposite the propulsion system. It consisted of a spherical 1.2 m diameter landing capsule, a 2.9 m diameter conical aerodynamic braking shield, a parachute system and retro-rockets. The entire descent module had a fueled mass of 1210 kg, the spherical landing capsule accounted for 358 kg of this. " - This is much larger than Beagle-2. Mars 6, although I don't have exact numbers, was larger still. These were small landers for the Soviets, but the Soviets didn't build truly small spacecraft.

[djellison]

HiRise is a BEAST

20,000 pixels across, and images typically 40,000 pixels tall

The centre 4000 pixels is in both Red and Blue

Each pixel will be about 30cm on a side projected onto the ground - giving a typical image size of 6km x 12km

To scan a full image wont take that long - but relaying back to earth at around 1.5Mbps will take about 15-20 minutes

Doug

[dvandorn]

HiRise is a BEAST

20,000 pixels across, and images typically 40,000 pixels tall

The centre 4000 pixels is in both Red and Blue

Each pixel will be about 30cm on a side projected onto the ground - giving a typical image size of 6km x 12km

To scan a full image wont take that long - but relaying back to earth at around 1.5Mbps will take about 15-20 minutes

Doug

OK -- 30cm resolution (on average) is awesome -- that's about a one-foot resolution for those of us who don't yet think in metric, right?

How does this compare to the single-axis (push-direction) resolution of cPROTO MOC images? Since the cPROTO images have been able to resolve the MERs and the MER landers (even suggesting shape), I'd have to think that they are giving at least 50-60cm resolution, at least in one axis.

IIRC, the best Apollo pancam images of the Moon had about 2m to 3m resolution, and that was deliberately softened from the absolute capabilities of the system because DOD imposed restrictions on how good they would let ITEK make the cameras for NASA (since NASA was basically asking to use the same camera system that was flying on DOD's KH surveillance satellites at the time).

This leads to the question -- is 30cm resolution *really* the best achievable, or does DOD still refuse to allow NASA to use the *real* highest-resolution imaging systems that have been developed?

And will just asking that question impose the risk of me just disappearing somewhere into the night...?

-the othe

[John M. Dollan]

Out of curiosity...

How far do you suppose the chutes from the Viking landers might have travelled in the intervening years? I know the winds are strong on Mars, but is the atmosphere thick enough to allow an entire chute to travel very far, if at all (I have to admit, the idea of those massive winds and a thin atmosphere have always boggled me)? Or are the chutes permanently connected to the backshells?

...John...

[djellison]

MOC can do 1.5m/pixel - but the downrange sampling is upped to 0.5m/pixel with CPROTO.

As for higher resolution - it would be hard, given that there's an atmosphere in the way, to go any higher than that -and even if we could, we dont have the bandwidth to send much more than that back to earth at the moment

Doug

[dvandorn]

MOC can do 1.5m/pixel - but the downrange sampling is upped to 0.5m/pixel with CPROTO.

As for higher resolution - it would be hard, given that there's an atmosphere in the way, to go any higher than that -and even if we could, we dont have the bandwidth to send much more than that back to earth at the moment

Doug

Yeah, you'd have to use adaptive optics to adjust for atmospheric shimmer (even in such a thin atmosphere as Mars'), and that would be prohibitively heavy and expensive to get into Martian orbit...

So, we're going to see a total increase from the absolute best MOC resolution of 50cm in downrange sampling to to the HiRise resolution of 30cm in all dimensions. It might not sound like much, but it is nearly twice the resolution, and will be the standard operating parameter for the camera, not a "pushed" mode. I am SO looking forward to seeing the first images...

Will MTO's arrival in 2009 help increase the total bandwidth such that MRO and other orbiters (including possibly a *really* venerable MGS) might take advantage and toss as much down the pipe as possible? Or is MTO not designed to support other orbiters?

-the other Doug

[djellison]

I cant imagine a data-pipeline that would work from MO2k1, MGS or MEX to the MTO, except, perhaps, for UHF forward (which can be done by MEX and MO2k1, but not, I believe, by MGS) to the Orbiter then Orbiter back to earth. Infact, MO2k2 could do 256kbps UHF-> MTO then MTO at >1MBps to earth.

BUT

The orbiters there now are basically designed in terms of instrumentation - to match the downlink ability they have. i.e. You wont find HiRise on MGS because MGS couldnt handle the downlink from it. Sure, another few Gbits/sol might be nice, but not essential

If you consider MGS-MOC's normal imaging - 1.5m/pixel - MRO-HiRise will have 25 pixels on the ground for every one of MOC's pixels.

Using C-Proto, MGS gets 0.5m/pixel downrange, and 1.5m/pixel cross range - and HiRise will have about 8 pixels for every CPROTO pixel..

In colour :0

Or 6km wide in Black and White

[edstrick]

Lunar orbiter 2 and 3 were capable of 1 meter resolution with the high resolution frames. Orbiter 1 had it's image motion compensation system fail, and the high rez pics from low orbit were smeared.

Orbiter 4 had 50 meter rez from periapsis in it's eccentric mapping orbit. Orbiter 5 was in a higher periapse orbit than 1 through 3 for science site mapping

As far as resolution possible from Mars orbit...

Remember a bit of physics called the "diffraction limit"

Hubble-sized optics in low earth orbit have a diffraction limit of maybe 5-10 cm on vertical pointed images... Hubble sized.. that's the big recon sats. You can see a licence plate but not read it. (that's what I understand, I've never seen real performance numbers)

Mars Recon orbiter's gonna be working essentially at it's diffraction limit, I hope and expect. If you want to do better, you're gonna have to buy a spare KH-11 or some such sat from the spooks. It wouldn't be easy to get it to Mars even if you had it!

[tedstryk]

Lunar orbiter 2 and 3 were capable of 1 meter resolution with the high resolution frames.  Orbiter 1 had it's image motion compensation system fail, and the high rez pics from low orbit were smeared. 

Orbiter 4 had 50 meter rez from periapsis in it's eccentric mapping orbit.  Orbiter 5 was in a higher periapse orbit than 1 through 3 for science site mapping

As far as resolution possible from Mars orbit...

Remember a bit of physics called the "diffraction limit"

Hubble-sized optics in low earth orbit have a diffraction limit of maybe 5-10 cm on vertical pointed images... Hubble sized.. that's the big recon sats.    You can see a licence plate but not read it.  (that's what I understand, I've never seen real performance numbers)

Mars Recon orbiter's gonna be working essentially at it's diffraction limit, I hope and expect.  If you want to do better, you're gonna have to buy a spare KH-11 or some such sat from the spooks.  It wouldn't be easy to get it to Mars even if you had it!

I want to look into myself. Edstrick (or anyone else for that matter), do you have any info on MRO's optics? I don't even know aperature.

[djellison]

http://marsoweb.nas.nasa.gov/HiRISE/instrument.html

The PDF's in particular.

Check out the CCD array - it's HUGE

It's so advanced, I dont think 'push broom' is a sufficient descriptor anymore, it's more like an array of 22 brooms, eash with 2000 bristles with....ah..pah

I cant figure out a metaphor for the TDI technique which is very clever.


Doug