But... how are we currently looking (or have any idea how to look for) non-DNA-based life?

Gets back to my earlier post. It appears that every life-detection experiment is *only* looking for life identical to that found on Earth -- DNA-based, made of organic molecules, using the ADP-ATP cycle to generate chemical energy. It's almost a slam-dunk that any life such sensors *do* detect is a result of contamination... isn't it?



-the other Doug

Gentlemen! You can't fight here! This is the War Room!



-the other Doug

Considering the shape of the body and the location of the large crater (hinting at an impact that *just* came short of being energetic enough to blast the entire body apart), what this looks like to me is:

1) A roughly disk-shaped object was hit broadside by an impactor.

2) The entire body stretched into the impact -- the "point" of the diamond is the deformation along the velocity vector of the impactor.

3) The shock wave crenelated the edge of the disk, causing what appears to be a crater chain along its circumference.

That's what it looks like to me...

-the other Doug

Potato. Definitely potato.



-the other Doug

And, hey -- this just gives me more impetus to get moving on my moribund blog. Now when I want to discuss space history and such, I can use that to motivate myself to go blog...

-the other Doug

I also note that you merged the two "Miscellaneous" categories into a single one, Chit Chat, which is fine by me. I was always a little unsure as to which of those categories I should post for truly miscellaneous observations.

-the other Doug

Nope -- can't complain at all.

There will be times, I'm sure, that in appropriate context, scientific lessons learned and applicable data that has been generated from things like Apollo may be acceptably cited, especially in such fora as the lunar exploration forum. (It's impossible to discuss lunar origins, geochemistry, etc., in an Apollo vacuum, after all.) But that kind of thing isn't what has been causing problems, anyway.

So -- as one of the guys here who has a lot of things to say about manned space flight history, I'm totally satisfied with these developments. Thanks for being good admins, guys.

-the other Doug

Well, Shaka -- just go ask all of Willy's friends who figured all they had to do to reach the Moon was to build a big enough balloon how their assumptions are doing for them these days...

-the other Doug

Poison: $1

Antidote: $1 million



-the other Doug

No, Mike -- feasibility, by definition, is a projection of what is not only possible but actually achievable, based on your best information. Once something happens, feasibility is a dead concept for that phenomenon.

As for life processes, we're going to have to start thinking outside of the box in order to make any major progress in this area, I think. Life sciences are (rather necessarily) very terro-centric right now. For example, even our Martian life experiments all look for organic compounds, and if we don't find any, we state assuredly that there is no possibility of extant life.

Instead of making the (almost definitely false) assumption that any and all life forms in the universe will *always* be made of what we recognize as organic compounds, that it will *all* be powered by ADP-ATP chemical reactions, and that it *all* will require liquid water and free oxygen to become abundant, maybe we need to start asking things like:

What alternative chemical engines to ADP-ATP can be successfully hypothesized?

What other compounds than classic organic compounds could support life processes? Does silicon have enough chemical reactivity to produce living tissues? Does sulphur?

Completely regardless of its chemical composition, what do life processes *do* that we can identify from probes? *Must* it respirate oxygen? *Must* its internal tissues be water-rich? *Must* it reproduce, and how often?

I know some people have been trying to address these issues for decades -- and yet, we still see Mars probes that are designed to look for organic compounds, on the theory that life *must* incorporate the same compounds it does on Earth.

I personally think that one of the first non-terrestrial forms of life we will find will be composed of something other than organic compounds, and all of the textbooks will need immediate and thoroughgoing rewrites!



-the other Doug

Leaving politics and funding issues aside, I think it's worth discussing the safety aspect of any decision to extend the Shuttle fleet's operational lifetime past 2010.

The 2010 date was not set for political or even budgetary reasons. It was one of those very strong recommendations-cum-orders that came out of the Columbia Accident Investigation Board (CAIB) report.

The CAIB set the bar very, very high in terms of safety -- essentially, to reduce the possibility of another loss of crew and vehicle (LOCV) accident to such a remote level that one could confidently predict that we would never lose another Shuttle crew. In this regard, they studied not only the sequence of events leading up to the loss of Columbia, they also studied the engineering history of the orbiter fleet.

The general trend of the observations was that the fleet was flying fewer total flights per vehicle than it was designed for, but over a longer period of time. So while the process of refurbishing between flights was doing a decent job of catching and fixing flight damage, there were far fewer processes in place to catch and fix issues of senescence -- of aging components and wiring that could be developing fatal flaws.

This was reinforced by the late 1999 launch of the first Shuttle flight commanded by Eileen Collins, during which deteriorating wiring harnesses throughout the orbiter caused several short circuits which brought the Shuttle stack one electrical failure away from losing from one to all three SSMEs during the first few seconds of climb-out.

The CAIB studied this and other incidents, looked at all of the (at least partially) applicable data from the aircraft industry, and concluded that one of two things needed to happen:

1) The entire fleet needed to be completely rebuilt, checking and replacing every wiring harness, avionics box, and even high-stress portions of the airframe, if it was to be safe to fly beyond the end of the decade, or

2) The entire fleet needed to be retired by 2010.

Since option 2 is one heck of a lot less expensive than option 1, NASA decided to retire the fleet and redirect post-2010 Shuttle operational funding into CEV development.

Now, you can easily debate the political and funding issues surrounding a decision to abandon the 2010 retirement date. But I find it very difficult to ignore the original driving force behind that date -- the aging condition of the orbiter fleet.

I do understand that we have a corps of astronauts who will take the risk of flying a vehicle that may not be 100% safe. But, solely from a safety standpoint, do we *really* want that to be our national policy?

-the other Doug

So, you know that rather low-end 17" LCD I mentioned last year, that I got about two and a quarter years ago, now, that I was liking a lot?

Well, I liked it pretty well, all the way until it died.

I was puttering around on my computer last weekend, playing Yahtzee, in fact. I had just rolled a Yahtzee when my screen just went black. I power cycled the monitor a couple of times, nothing happened. Rebooted the computer, nothing happened. Then the monitor powered itself off, and refused to power up again.

Well, I figured, I paid something like $260 for that monitor a couple of years ago, I ought to be able to find something a little bigger, maybe 19" or 20" diagonal, for the same price these days. So, later that same day, I went off looking at various stores around here to see what I could find, relatively cheap (it's not like I had budgeted to replace my monitor this month).

Went to Sam's Club, where you can often find quality stuff for low prices, and all they had were three sizes of a Samsung wide-screen monitor. The cheapest, a 17" diagonal, was around $170. I was tempted, since Samsung is one of the best brands out there, but I really wanted something a little larger, and I was really looking for a standard 4x3-ratio monitor, if I could find one.

Went to Target, they had four different sizes of a Westinghouse (the same brand that had just died on me, and that had suffered a slightly annoying amount of pixel burn-in along the static browser frame lines), with the cheapest running about $200. Again, they only had monitors in wide-screen format.

Then I went to a small franchise, MicroCenter, and they had some serious sales going on. They had a 20" diagonal for only $159... well, OK, $189 and a shot at a possibly-nonexistent $30 mail-in rebate. I ended up getting that.

But, once again, the only monitors they really had were in the wide-screen format, so I now have a 20" diagonal wide-screen LCD monitor. Acer brand, which isn't that bad a brand, I've worked with their hardware before.

I'm suddenly discovering what can be done with panoramic images as desktops...

The only drawback is that my graphics card isn't smart enough to deal with certain programs (mostly games) that are designed to operate full-screen in 4x3 ratio, so when they run on this monitor, they look all stretched out. And with only 128MB of video memory, while I *can* connect with a dvi cable and have the computer control the resolution modes (trying to achieve a 1:1 mode with those games I mentioned, to avoid the stretch), the card just can't handle the wide-screen very well in that mode. There is literally no way to get a screen resolution in that mode in which text and images aren't squeezed or stretched everywhere, and the games still insist on going full-screen, even when I fudge the scaling factors. So, for now, I'm connecting with a standard VGA cable and getting a beautiful image at 1280x800 pixel resolution.

Thinking about getting a new video card, though -- I figure a more capable card will be able to do more things. There are 512MB AGP cards (the most compatible with my data bus) out there for less than a hundred bucks...

Maybe next month.

-the other Doug

OK, I'm feeling quite guilty about this, so I need to pull its thorns.

There is a hurricane building in the Gulf of Mexico, just swept a path of devastation across the western tip of Cuba. It has the potential to be a more powerful and damaging storm than Katrina of three years ago, and may also strike New Orleans.

It's name is Gustav.

And whenever I hear or see that name, a little correction voice in my head says "Don't you mean Gusev?"

Like I say -- feeling guilty about that, but there it is...

-the other Doug

I dunno -- unless she turns again, looks like she's heading to a landing just south of Bicknacre.

-the other Doug

And doooowwwwwnnn she comes... and back up a bit... and back down again.

Caught an updraft on the parachute?

-the other Doug

Ya know, EC... back when the forum was deciding (in some poll or another) that Rhea was undoubtedly the most boring single object in the Solar System, I vehemently disagreed, noting many of the features you're pointing out in these excellent images. Especially the massive proliferation of what are either endogenously-controlled graben or exogenously-controlled crater chains.

Thank you very much for bringing into focus this quite fascinating satellite.



-the other Doug

NOT!

-the other Doug

Oh, and as for this particular crater -- I may be imagining things again, but I have a very definite memory of looking over detailed MGS pics of this crater, very high resolution in fact. I was impressed by how different this crater looked from other Martian or even Lunar craters, that *this* looked like a recently-dug hole in the ground. I also recall a discussion in the detailed caption about the origin of the separated dark rays, though airburst wasn't one of the options I recall being mentioned by Malin et. al.

Anyone else recall seeing this feature in the MGS archives sometime in the last five to ten years?

-the other Doug

You know, I've heard that a lot lately. And yet... there do not appear to be any gross changes at either Viking site more than 30 years after they landed that could be intepreted as ejecta damage from close impacts. And neither site has obviously suffered an actual recent impact, at least from the lander's POV from horizon to horizon.

Granted that the Pathfinder site was only established a little over 10 years ago -- but there's no sign of changes to that site attributable to direct impact or secondary debris impact, either.

Doesn't appear that a habitat at any of those locations would have felt the need to duck and cover over the past few decades, anyway.

The longer this discussion goes on, the more desperately I desire a seismic network on Mars. That would answer the question once and for all.

-the other Doug

I prefer the S&G version of the song, for a couple of reasons: first, they wrote it; second, it's one of those sliding-key things that Art Garfunkle liked to play with, and that his voice seems uniquely suited to; third, it's the first version of the song that I was familiar with, and in such things are preferences forged.

Besides, we sang that song in Chorus in high school, and performed it at a choral concert in the fall of my senior year, and it was the S&G tempo and presentation we used as a guide. The Bangles' version is punctuated differently, from a percussion and general rhythm perspective.

Now, if you were to ask me for a preference between the Bangles and S&G for sitting around and chatting in a clothing-prohibited sauna, well... the Bangles win that, hands down. I'll always Walk Like an Egyptian for those girls...

As for the lines that feel to me very much a part of what Phoenix is doing right now, there are two little clips I'd like to point out:


Seasons change with the scenery,
Weaving time in a tapestry,
Won't you stop and remember me...?


and...


Look around,
Leaves are brown,
There's a patch of snow on the ground....


-the other Doug

A note in another thread brought me to wonder how many of us have been to various sites that are significant in the history (or ongoing prosecution) of space flight.

I'll start off. I've been to the Air and Space Museum in Washington, D.C. (many times), and to the Garber restoration facility of NASM in Silver Hill, Maryland.

I've been to the Kennedy Space Center twice. The second time, there was a Shuttle on the pad. The first time, there was a Saturn IB with an Apollo spacecraft out on Pad 39B; Pad 39A was in the process of being reconstructed. (That ought to let people isolate that timeframe within no more than a year or so...)

I've been to the Johnson Space Center once. To give you a clue as to the timeframe, the MOCR wasn't in use (i.e., no flights were active), but instead of a TELMU console, there was an EGIL console. (Again, that ought to bring the timeframe into perspective, as well.)

That's about it for me in terms of visiting famous space-related places. How about y'all?

-the other Doug

Hmmm... an hour and ten minutes after Peter's post, and I can get into Exploratorium, no problem. All of the folder listings are there when I go look.

How many people are having an issue?

-the other Doug

Do also remember that whatever definition of planet upon which we achieve consensus doesn't only need to account for solar system objects. Such a definition ought also to include bodies orbiting other stars.

I can conceive of a lot of solar systems in which major planets have not (yet) cleared their orbital neighborhoods. Young systems, for example, where accretion is *nearly* finished, or older systems where large planets are migrating closer to, or farther away from, their stars. Or systems in which a hot mega-Jupiter, orbiting its star in two or three days, finally spirals in and hits the Roche limit.

Are all of the bodies in such systems not planets because of these circumstances? Does "planet" only and forever describe only eight bodies in orbit around our Sun, disregarding bodies that are already described as "extrasolar planets"?

Or do we need to get better data on other systems to find out just how many adjustments we need to make to *any* definition of planet based only on our experience of our own solar system?

-the other Doug

All I'll say on the topic of the thread is that no one ought to be surprised that a manned vehicle development program is taking longer than the initial work flows had projected. Not a single manned vehicle has met its initial flight readiness dates -- I know that this includes the Americans and the then-Soviets, and I suspect it's also true of the Chinese.

Mercury flew manned two years behind schedule. Gemini flew a year and a half behind schedule. Apollo flew two to three years behind schedule, and Shuttle flew between two and three years behind schedule. Skylab was between one and three years behind schedule, as well, and I imagine the early Salyut program flew behind its initial schedules, too.

I actually thought that Mike Griffin did a good thing by setting the 2013 internal goal. His mission is to get Orion flying by 2015; the 2013 date is pretty much what you had to set in order to actually meet the 2015 date.

I'm sure there are any number of people here who have worked on managed projects with deadline dates. Haven't you all been on projects where the deadlines are set well ahead of the true drop-dead dates, just to ensure that the *real* dates could be made?

There are still some sticky technical issues to be overcome, to be sure. But I don't get the feeling that this news is either a critical blow to the program *or* unexpected.

-the other Doug

Yeah -- in fact, in the 6-7 mosaic a similar crack has a slightly more well-illuminated floor, and the dark "islands" appear to resolve into cracks within the lighter-toned material. I'm beginning to lean towards the concept that the dark cracks are vents, and the lighter-toned materials are mass buildup as some of the escaping water vapor condenses out into ice along the sides of the vents.

That feeling is reinforced by a couple of details from the 6-7 mosaic, where what appear to be vapor effects swirl off the top of small deposits of the light-toned material. I think it actually shows vapor coming out of the vent, with part of the plume spraying off of the slowly building ice construct.

It remains, though, that the light-toned materials and the dark areas that *may* be vents do meander. I see no indication of dendritic branching, so there is no surface drainage involved, but the dark streaks and the light materials meander within the confines of the floors of the large V-shaped valleys. Could we possibly be seeing the surface expression of underground flows of hot ice, or even liquid water? That might explain the meandering quality of these units.

-the other Doug