Mars Hi-Res & Thermal Images Payoff

eldavojohn writes "The Mars Reconnaissance Orbiter & Mars Odyssey Orbiter took high resolution images (and shots of each other) earlier this year and after studying them, experts believe that there are too many boulders around the proposed Phoenix Mars Lander landing site. From the article, 'At the end of January 2007, scientists will meet to see if there is an obvious choice for a landing site. If not, they will keep analyzing the data until summer 2007. They are comparing HiRISE's data with that taken by the Thermal Emission Imaging System (THEMIS) camera on the Mars Odyssey orbiter. Since boulders hold heat better than soil or sand, they show up in THEMIS images taken early in the morning.'"

Comments

this is good

[xsalmon]

I would prefer that they exercise careful scrutiny and second-guessing of their decision here. Considering how long it actually takes us to build, launch, and deploy these bots, I'd rather them take their time and get it right, rather than dropping it on the surface and then WTFing when they encounter an "unforseen problem".

It's the Blizzard approach to NASA that is preferable :)

Re:this is good

[Josh Lindenmuth]

I agree 100%. The Mars missions are 100% worth the investment if they can reduce the crash likelihood of future robotic explorers (or even manned explorers). As NASA gets closer to a manned mission, unmanned missions will likely become more sophisticated and costly, so spending the money now on relatively inexpensive surveyors is far preferrable to embarking on multiple multi-year missions just because of poor landing site selection.

Night shots?

[Darlantan]

Wouldn't it make more sense to take thermal image shots a little while after sundown instead? Doing in the morning strikes me as being less accurate, as depressions in the ground/shadowed spots will heat less quickly than other areas. At night, once the sun has gone down, soil should more or less cool at about the same rate. It seems like they'd get less false positives at night. Maybe I'm just crazy.

Re:Night shots?

[RNLockwood]

The boulders in the image are black which suggests that they are colder than the surrounding terrain. On the other hand this is a false color image so the boulder's color could have been mapped to black for display.

Re:Night shots?

[SilentOneNCW]

I'd generally trust NASA and its scientists on this one.

Re:Night shots?

[Darlantan]

Well, sure. They're bound to have a reason. I just want to know why they're opting for that method.

Re:Night shots?

[guywcole]

I don't think you know what "early morning" means. Think of just before sunrise- everything has done all the cooling it can before the sun rises, so slow dissipators will be clearly distinguishable the fast dissipators.

Re:Night shots?

[Paradise Pete]

Fill in your four or five-letter word of wisdom here _ _ _ _ _.

T o o t h.

Re:Night shots?

[camperdave]

I'd guess it's much easier to pick up reflected heat than reflected cold.

At sundown, the entire area will be at about the same temperature, having been heated all day. Picking up reflected infrared sunlight on the warm landscape doesn't leave for a lot of thermal variation. In the morning, however, all of the landscape is cool. Picking up reflected infrared sunlight against a cool background gives you a lot larger thermal contrast.

Re:Night shots?

[Dolphinzilla]

based on my own experience, and a quick zoom in on the picture, the black signature of the boulders appears to be due to shadows cast by the boulders - not any kind of temperature differential.

Re:Night shots?

[RNLockwood]

Good observation.

Re:Night shots?

[Telvin_3d]

My guess? The orbit has the orbiter going over the proposed landing spot in the morning. Yes, if they wait long enough or re-task it evening shots might give them a more accurate result, but it is likely a case of 'what we have is good enough'. The shots they have give the information they need, so it is not worth the time and effort to take better ones. More useful to move on to other tasks.

Re:Night shots?

[Anonymous Coward]

"Any landing you can walk away from is a good one." - Flight Simulator Pilot

Naval Aviation has requested return of its witticism.

Re:Night shots?

[mopomi]

The reason they wait until early morning/pre-dawn is due to a property called thermal inertia (the rate at which an object responds to changes in energy input). Boulders have different thermal inertia from sand or dust.

Have you ever gone for a walk on the beach in a warm place (southern California or Florida, for example) in mid-day? The sand is usually too hot to walk on. This is because sand has a low thermal inertia and responds quickly changes in energy input. If you walk on that same beach in early evening, after the sun's light has faded, it's nice an cool

Now, if there was a boulder on that beach, its behavior would be slightly different: At mid-day, the rock is relatively cool (compared with the sand). By early evening, it's warmed up quite a bit and stays warm through most of the night. By about 5 AM, it'll be the only (natural) thing around that has any "memory" of the temperatures the day before. It will be warm enough compared to its surroundings to detect via thermal imaging.

So, this is why they compare visible-light images of the area (HiRISE) to nighttime thermal images of the area (THEMIS). The rocks in the scenes are still warm compared with the dust in the scene at 5:00 AM.

You might expect that the imaging would work just as well in the day, but with inverted temperatures. This is true, except that reflected sunlight becomes a problem and cannot be de-convolved from thermal emission.

Re:Night shots?

[Darlantan]

Pre-dawn makes a lot of sense. A lot of others have said the same thing. I was thinking 'early morning' as in shortly after sunrise, which didn't seem like a terribly good idea to me.

On the plus side

[Shadow Wrought]

If it gets cold it can just use its phasers to heat a nearby boulder for warmth.

Intelligent?

[Anonymous Coward]

"experts believe that there are too many boulders around the proposed Phoenix Mars Lander landing site."

Uh huh. It just happens to be by RANDOM CHANCE that there are too many boulders around the proposed landing site. Sure. I think that the chances of there being too many boulders is astronomically unlikely. Boulders require a "boulderer", as it were. This must be the result of Intelligent Geology. How else can you explain it?

Re:Intelligent?

[Tablizer]

Boulders require a "boulderer", as it were. This must be the result of Intelligent Geology. How else can you explain it?

I found the Boulder Gods! Created them in their own image: http://www.sacredsites.com/americas/chile/easter_i sland.html

(Looks like one drank too much and is pukin')

Re:Intelligent?

[Tablizer]

And the sacralige:

http://cgi.ebay.com/MOAI-STATUE-TISSUE-BOX-COVER-E aster-Island-Face-Head_W0QQitemZ260056214458QQihZ0 16QQcategoryZ66744QQrdZ1QQcmdZViewItem

They're gonna burn in hell next to the Danish cartoonists.

Re:Intelligent?

[karnal]

Ever play Gradius or Paradius?

There's whole teams of developers goin' to hell. :)

waste?

[Anonymous Coward]

billions of dollars and we now know: if we send something to land on mars, it may or may not land on rocks.

Re:waste?

[Dunbal]

if we send something to land on mars, it may or may not land on rocks.

      Provided it doesn't mysteriously disappear while it's in orbit...(cue twilight zone music)

Re:waste?

[Anonymous Coward]

Scout missions are cost-capped at about $500M. Even with overruns, Phoenix will not cost billions.

Welcome to Slash-New-Scientist-Dot

[Anonymous Coward]

It seems the weekly quota of links to New Scientist has not been filled yet.

Get clicking people, make sure the New Scientist logs show lots of referrals from Slashdot!

Re:Welcome to Slash-New-Scientist-Dot

[Anonymous Coward]

http://www.google.com/search?q=new+scientist+site% 3Aslashdot.org

Only mentioned 8,090 times.

Nuke the site from orbit.

[eddy]

First of all, it's the only way to be sure! Secondly, it should produce a nice glass "mirror" to land on. Problem solved.

Re:Nuke the site from orbit.

[Tablizer]

First of all, [nuking is] the only way to be sure! Secondly, it should produce a nice glass "mirror" to land on. Problem solved.

Ever since you damned neocons took over NASA...... :-)

What would the martians do?

[stunt_penguin]

Offtopic I know, but here's a flipside question that occurred to me when RTFA: if we were an alien species sending probes to land on Earth, where would we pick to land based on imagery of at the resolution we're getting back from Mars?

And don't say here

Re:What would the martians do?

[Tablizer]

if we were an alien species sending probes to land on Earth, where would we pick to land based on imagery of at the resolution we're getting back from Mars?

If you know about the oceans, then a floating probe may be the safest way to go. No boulders, no quick-sand, etc. The Titan probe Hueygens (sp?) was actually designed to float in case Titan had hydrocarbon oceans.

Re:What would the martians do?

[Anonymous Coward]

And don't say here

Of course not there, that's forbidden.

Re:What would the martians do?

[Viadd]

Well, since we know that Mars-like conditions are required for intelligent life, the most promising region is Chile's Atacama desert. There are places in this optimal region that can go for centuries without being bombarded by corrosive dihydrogen monoxide falling from the sky, as too often happens on other places on that desolate planet.

It is rather hot, but not far beyond what some extremophiles face here on Mars.

The dry valleys of Antarctica are also promising.

Re:What would the martians do?

[dontknowdidley]

The runways.

Life on Mars?

[Anonymous Coward]

Since boulders hold heat better than soil or sand, they show up...

Err.. has someone discovered soil on Mars? Damnit, I miss all the real news.

Moo

[Chacham]

there are too many boulders around the proposed Phoenix Mars Lander landing site.

Boulder? On Mars? That must be why its called Boulder Colorodo (Color Red-o).

*groan*

+5 Funny

[stunt_penguin]

heheheh, you made me snort cornflakes :D