APOD: Intrepid Crater on Mars (2010 Dec 08)

[APOD Robot]

Intrepid Crater on Mars

Explanation: The robotic rover Opportunity has chanced across another small crater on Mars. Pictured above is Intrepid Crater, a 20-meter across impact basin slightly larger than Nereus Crater that Opportunity chanced across last year. The above image is in approximately true color but horizontally compressed to accommodate a wide angle panorama. Intrepid Crater was named after the lunar module Intrepid that carried Apollo 12 astronauts to Earth's Moon 41 years ago last month. Beyond Intrepid Crater and past long patches of rusty Martian desert lie peaks from the rim of large Endeavor Crater, visible on the horizon. If Opportunity can avoid ridged rocks and soft sand, it may reach Endeavour sometime next year.

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[Wayne]

As far as I know, "impact basin" is a specific term for a crater much larger than 20m!

[neufer]

You can almost feel the face hugger moving inside, just like in the movie

[Thomas]

Hi,
why isn't the sky black like on the moon? Mars has no atmosphere.

[owlice]

http://en.wikipedia.org/wiki/Atmosphere_of_Mars

[rstevenson]

It seems a tad disingenuous to say that Opportunity has "chanced across" these craters. It's being driven towards them quite deliberately, while travelling in the general direction of Endeavor Crater.

Rob

[orin stepanek]

Opportunity; The Little Robot that could. I got the picture from wiki

[neufer]

[b]Opportunity has been following [color=#FF0000]the red stick pin trail[/color][/b]

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It seems a tad disingenuous to say that Opportunity has "chanced across" these craters.
It's being driven towards them quite deliberately, while travelling in the general direction of Endeavor Crater.

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The Planetary Society Blog
By Emily Lakdawalla

The goal of Opportunity's trek
May. 24, 2010 | 12:00 PDT | 19:00 UTC

Opportunity's kilometers-long march across the sands of Meridiani Planum is a great story, and the journey is fun to follow; but what could be worth such a long march? The answer: Smectite.

Smectite?

Smectite clays are famous in some parts of the world because they tend to shrink when dry and expand dramatically when wet. This causes problems for basements, foundations, and hill slopes.

It's a worthy goal, really. Smectite is an iron- and magnesium-bearing clay mineral, a type of mineral known as a phyllosilicate. Phyllosilicates are minerals that have a platy crystal structure and frequently form by the alteration of other silicate minerals in the presence of water.

The presence of phyllosilicates on Mars is a relatively recent discovery. Mineralogists have been looking for them for a long time, because of their ubiquity in wet environments on Earth. In fact, if you have water in contact with olivine and pyroxene, some of the more common Martian minerals, for any length of time, it would be hard not to make phyllosilicates. If you want to find possible habitable environments on Mars, you need to be able to find places where there are phyllosilicate minerals. But if all you see is olivine, that's pretty strong evidence that water wasn't ever an important Martian substance.

Olivine and pyroxene are, in fact, all over the place on Mars, while definitive evidence for phyllosilicates proved harder to find. Like any other mineral, they are searched for from orbit based upon their telltale absorptions of certain wavelengths of (mostly infrared) light. As early as the 1960s, researchers performing Earth-based spectroscopy found hints of their presence, but the evidence wasn't definitive and could be explained away. Even when the Thermal Emission Spectrometer on Mars Global Surveyor mapped the entire planet in the late 1990s (revealing, among other things, the hematite hot spot that led NASA to choose Meridiani for Opportunity's landing site), evidence for phyllosilicates was present but not conclusive. However, a few spots were identified, such as Nili Fossae and Mawrth Vallis, where their presence was considered most plausible.

Conclusive evidence was finally unearthed (unMarsed?) in 2005 by the Observatoire pour la Mineralogie, l'Eau, les Glaces, et l'Activité (OMEGA) instrument on Mars Express. The paper explained why the phyllosilicates had been so hard to find: they were only found in special locations, among the oldest rocks of Mars, rocks of so-called "Noachian" age. These rocks are only exposed on the Martian surface in special locations where geologic activity has stripped off overlying, younger rocks or tilted whole blocks of crust to expose the more ancient materials. Previous methods of searching for the phyllosilicates couldn't resolve the spatially limited exposures of these Noachian bits of rock.

Another interesting fact emerged from the early OMEGA results: there were also lots of sulfate rocks on Mars, and virtually nowhere were the phyllosilicates and sulfates found together. The two types of minerals form in different kinds of watery environments; phyllosilicates form under neutral to alkaline chemical conditions, while sulfates form under highly acidic conditions.

In a nutshell, Mars' history can be divided into three ages based upon what was happening chemically. The first age could have been warm and wet (it was at least wet underground); the second age was volcanically gassy and wet; and the third, the one Mars is in now, is cold, dry, and, well, rather boring. The wet and possibly warm age occurred in the early to mid Noachian period and resulted in the phyllosilicate rocks. Then there was a huge burst of volcanism that filled the atmosphere with gases including sulfur dioxide, resulting in a period of acidic alteration of surface rocks, producing the sulfates. This period extended into the Hesperian age of Mars's history. Finally, the present (Amazonian) age, comprising most of Mars' history, is characterized by slow alteration of surface materials without liquid water.

So where does Opportunity come in? Well, throughout its mission it's been rolling across sulfate rocks formed during that middle, acidic age of Mars. Water is important in the story of these rocks' formation, but due to the highly acidic conditions that they formed in, it's considered unlikely that there was any kind of Martian life in those environments.

But, off in the distance, in the rocks along the rim of Endeavour crater, there are signs of Smectite, one of those elusive phyllosilicates. That's according to a paper by James Wray and seven coauthors from the Mars Reconnaissance Orbiter CRISM team, published last year.

So if Opportunity can complete its drive across Meridiani Planum to the rim of Endeavour, it could potentially sample rocks that formed in watery environments during Mars' wet and possibly warm geologic youth. These kinds of rocks have never ever been sampled by any landed mission. Opportunity's examination of these rocks could test the unifying theory of Mars' geologic history advocated by the OMEGA team. More importantly, though, it would be the first time that a landed mission could directly examine the ancient rocks from environments that might once have provided a habitat for Martian life.

What can Opportunity do, if it gets to Endeavour? Wray and his coauthors say that the Mössbauer spectrometer can confirm the presence of the minerals that are proposed to be visible from orbit. The Mössbauer does rely on a radioactive source that has decayed since landing, so it takes a REALLY long time to perform its measurements, or "integrations." So they will have to be careful about how many spots they choose to do Mössbauer measurements of. They also say that the Mini-TES could confirm the presence of phyllosilicates, but that would be quite a trick, since the Mini-TES on Opportunity was rendered unuseable by dust contamination of the mirror in its periscope during the 2007 dust storm. The APXS can do its usual determinations of major and minor element abundances, and all the camera systems are still working well, so Pancam and Microscopic Imager would yield first-of-their-kind close-up views of these ancient rocks from Mars.

That's the destination -- but what about the journey? One type of rock that lies along the ground in between Opportunity's current location and the rim of Endeavour is hydrated sulfates -- that is, sulfate minerals that contain lots of water molecules in their chemical structure. Now, Opportunity has seen hydrated sulfates before, lots of them. But where Opportunity has seen these minerals, the orbiters have not seen them on the ground where Opportunity has been. The rover will soon be venturing into terrain where orbiters have spied those hydrated sulfates. So Opportunity will soon be gathering data to solve the mystery of why these materials should be visible from orbit in some places but not others where they are proven to exist.>>

------------------------------------------------
The Graduate (1967)

Mr. McGuire: I want to say one word to you. Just one word.

Benjamin: Yes, sir.

Mr. McGuire: Are you listening?

Benjamin: Yes, I am.

Mr. McGuire: Smectite.

Benjamin: Just how do you mean that, sir?
------------------------------------------------

On 4 July 2005 at 05:52 UTC, Tempel 1 was deliberately targeted by one component of the NASA Deep Impact probe, one day before perihelion. The impact was photographed by the other component of the probe, recording a bright spray from the impact site. Initial results were surprising as the material excavated by the impact contained more dust and less ice than had been expected. The only models of cometary structure astronomers could positively rule out were the very porous models which had comets as loose aggregates of material. In addition, the material was finer than expected; scientists compared it to talcum powder rather than sand. Other materials found while studying the impact included clays, carbonates, sodium, and crystalline silicates which were found by studying the spectroscopy of the impact. Clays and carbonates usually require liquid water to form and sodium is rare in space. Observations also revealed that the comet was about 75% empty space, and one astronomer compared the outer layers of the comet to the same makeup of a snow bank. Astronomers have expressed interest in more missions to different comets to determine if they share similar compositions or if there are different materials found deeper within comets that were produced at the time of the solar system's formation. The probe's spectrometer instrument also discovered the presence of silicates, carbonates, Smectite, metal sulfides (like fool's gold), amorphous carbon and polycyclic aromatic hydrocarbons.>>

[r0blar]

Click to view full size image

Now there is that nasty Mars Rabbit again !

[zbvhs]

Ok, so we want to send humans to Mars. How are we going to do that? Fact is, no one has any idea what all is involved. We have this marvelous facility called ISS that is intended for research in space. Instead of developing a whole lot of dedicated hardware to get back to the Moon, why not use ISS? Add propulsion and guidance and you have a bonafide space craft. Send it out to Lunar orbit and use it as a base for exploration there. Is it even feasible to rotate and resupply crew members or will costs skyrocket out of sight? Send the thing off on, say, two-month excursions beyond the Moon's orbit. Would it be feasible to resupply a Mars-bound craft at points mid way? We have millions of questions to be answered and nobody is proposing ways of answering them.

[neufer]

Mars attacks
by Mike Brown

<<One of the fun things about having a book coming out [TODAY, IN FACT] is that you get invited to do guest posts here and there around the web. You can, for example, watch for me from now until the solstice over at BoingBoing. One of the most fun so far was a chance to write at Babel Clash, about my take on life on other planets. Here is what I had to say:

I grew up in a universe teeming with life. Alien forms lived on and traveled throughout the planets. Sometimes they could even be found on neutron stars or giant rings constructed around a sun, or, shockingly, returned from the earth’s own upper atmosphere. When people meet me for the first time and realize I am an astronomer, the second thing they ask is often: What do you think about the possibility of life on other planets? (The first thing they ask, of course, is: What happened to Pluto? To which I have a book-long answer to hand them).

For years, my stock answer to this question has involved pointing out that, while I do have opinions, they are not any more informed than anyone else’s. When there is no science to aliens the only scientifically defensible position is to be an alien agnostic.

These days, though, I have been become a convert. I consider myself no longer an alien agnostic, but a true believer. A range of scientific discoveries over the past decade makes the possible of life outside of the earth appear -- to me, at least – not just possible, but actually inevitable.

Inevitable! That’s a pretty strong word from a former agnostic, so let me clarify what I think is inevitable. I believe that, within my lifetime, we will have solid evidence of currently living microbial life forms on Mars. That’s not quite telepathic natives yearning for earthlings, but it’s a lot closer to the universe of my childhood reading than I would have ever guessed we would come.

There are three key insights that make microbial life on Mars seem inevitable. First, one of the most profound things that we’ve learned about life in the past decade is that, on the earth at least, it can eke out an existence almost everywhere: in the deepest parts of the ocean, far underground, up in the atmosphere, in arsenic pools, inside nuclear containment vessels, on your kitchen counter even after a generous application of disinfectant. Life is very difficult to get rid of once established. While the surface of Mars is currently quite inhospitable to anything we can imagine, sterilizing an entire planet is likely impossible. If life ever had been established on Mars it would certainly still be hiding in little cracks today, perhaps in near-surface hot springs or deep underground caves or somewhere else we haven’t yet looked.

The second key scientific insight is that life could well have become established on Mars earlier in Martian history. The armada of orbiters and rovers and telescope circling, driving, and staring at Mars over the past decade have general come to an agreement that the cold dry bleak Mars of today -- which seems an unlikely spot for the development of life -- was warmer and wetter billions of year ago.

But simply saying that Mars could have evolved life and then would have kept it if it had does not mean that it did evolve life. It certainly does not make it inevitable. We have absolutely zero understanding of the probability of life developing, even if it has ideal conditions.

This is where that the third and most important insight comes in. Planets don’t live in isolation. We have found pieces of Mars and of the Moon on the surface of the earth. These pieces were blasted off of their home planets by a meteor impact, which caused them to lift into space, travel in orbit for a while, and then plunge to the earth. The reverse must also have happened: chunks of the earth which have been blasted off by meteorite impacts have inevitably landed on Mars (and elsewhere) throughout solar system history.

Experiments now show that microbes can live dormant in space for years and years – longer than the shortest travel times between the planets. We can now say with pretty good certainty that microbe-containing rocks have been blasted off the face of the earth and that some of these have landed on Mars with the microbes still alive. We can also be pretty sure that this same process occurred back in the time when Mars was warmer and wetter. If enough terrestrial microbes landed on Mars, some would have found a way to survive.

And if they did? They’re still there. Somewhere. It is inevitable.

It’s still not quite hive-minded colonies of insectoids accidentally destroying humanity. The inevitable aliens that I believe we will find will simply turn out to be colonists sent from the earth long ago. Or maybe not. Some scientists have speculated that Mars might have been an even more hospitable place than the early earth for life to have evolved. Perhaps early in earth’s history the first Martian microbial colonists landed on a lifeless earth and, finally, four billion years later we finally return to pay our respects to the now destroyed mother world. I think I read that book when I was a kid, too.>>

[NoelC]

Is it even feasible to rotate and resupply crew members or will costs skyrocket out of sight?

Very appropriate choice of words.

If even possible, what would happen to the regular and obnoxiously expensive resupply missions when the economy here on Earth tanks? Would you like to be out there?

-Noel

[rstevenson]

Ok, so we want to send humans to Mars. How are we going to do that? Fact is, no one has any idea what all is involved.

Your tone suggests you want to argue rather than learn, but I'll try anyway. "Fact is" many people have spent a lot of effort working out exactly how we could do that. A quick search at Google will yield results.

... why not use ISS? Add propulsion and guidance and you have a bonafide space craft.

No, you don't. You have the ISS -- which was not designed for that sort of movement -- with some propulsion and guidance systems attached.

We have millions of questions to be answered and nobody is proposing ways of answering them.

We? Millions? Nobody? How about you asking one question. Please be specific and I'll try to provide a specific answer.

Rob

[DavidLeodis]

Click to view full size image

Now there is that nasty Mars Rabbit again !

And there's a face in the sand to the right of the rabbit. Looks a bit like the Lion on the Wizard of Oz.

[Dean Sloan]

To refer to the image as “approximately true color” is typical of either “psy-ops” or those with blinders on. The image link enclosed referred to as “false color” is very close to true color. 'Calypso' Panorama of Spirit's View from 'Troy' (False Color) posted on 26-Aug-2009
http://marsrovers.jpl.nasa.gov/gallery/ ... as/spirit/
http://marsrovers.jpl.nasa.gov/gallery/ ... 7F_br2.jpg
Because of the “iron” rich soil, Mars is referred to as the “red” planet when viewed from Earth, but the thin atmosphere is light blue when viewed from Mar’s surface oh wise academic ones.
Dean Sloan

[rstevenson]

Are you saying that the scientific teams that put out these images are referring to true colour images as false colour, and the false colour images as true colour? Why would they do that?

Rob

[Wayne]

The colour of the sky very much depends on time of day and local conditions. On Earth we're used to Rayleigh scattering giving us a lovely blue sky. On Mars, however, Mie scattering dominates most of the time, giving a pinkish sky and bluer sunsets.

A Martian day that's exceptionally clear of dust (e.g. winter at the poles) will have a dark blue sky and redder sunsets due to Rayleigh scattering but that'll be rare anywhere else on the planet.

[neufer]

• The Stand-In

--------------------------------------------
JERRY: I could envision you going out with him.

ELAINE: If you were a woman would you go out with him?

JERRY: If I was a woman I'd be down at the dock waiting for the fleet to come in.

[size=175]Opportunity following the fleet[/size]

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This 90-mile-wide view of Mars shows Opportunity's location last spring and its future goal, Endeavour, the big crater at top right. Credit: NASA

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<<The odometer on the Mars Opportunity Rover recently rolled past the 15 1/2 mile mark as the sturdy robotic explorer continues on its way to the next big target, a 14-mile diameter crater named Endeavour. Last month it stopped to take photos at a much smaller crater, which mission scientists named Intrepid, after the lunar module of NASA’s Apollo 12 mission, which landed on the moon Nov. 19, 1969. Intrepid carried astronauts Alan Bean and Pete Conrad to the surface of Earth’s moon while crewmate Dick Gordon orbited overhead in the mission’s command and service module, Yankee Clipper. Rover scientists name Martian craters after historic ships of exploration. In addition to Intrepid, there are craters for the Yankee Clipper and Eagle (Apollo 11). Intrepid was selected because it was the 41st anniversary of its landing in November.>>