Wanna trade, Daniel? Where I am, I don't think there have been more than two days in the last 30 when is has been warmer than -10C. In fact, I'd be willing to bet that the average temperature here in Minneapolis has been colder than the average temperature at Meridiani!

In any event, happy birthday, Stu! Just think what you'll see in the next 44...

-the other Doug

Mumma also said during the press conference that results from other areas of Mars that are being reduced for future publication were totally verboten for discussion at this time. Quite sharp and no-follow-ups in tone.

Is he really saying that these relatively confined areas are the *only* methane plumes on Mars as a whole? If so, why such a sharp cut-off of any discussion of some other areas that have been analyzed? (Or maybe there are other things being discovered in other areas that they're trying pin down before discussing them?)

I guess I just don't see anything unique about the landforms associated with the plumes that you can't find methane-free elsewhere. Seems odd to find methane over only *some* examples of cratered terra-style surfaces but not a majority; same with areas like Nili Fossae, there are at least a few other areas that resemble it, but seem to lack methane. I think it might be difficult to pin down sources and origins of methane that seem to have little to no relation to the landforms from which the gas is being released...

-the other Doug

Not trying to be a sadonecroequomasochist, here, but one request for clarification, on the "biology question," if I could.

I imagine that any future landers or orbiters which would feature biology-oriented sensors would provide allowable bases upon which discussion of those sensors and the data they collect would in fact be proper. And that, for example, any credible new interpretation of the Viking biology experiments might be allowable, but again within the strict context of the experiments themselves and the specific data returned.

Am I understanding this correctly? It seems inherent in the standing argument for the ban (with which I do agree, I'm happy not to have to see anyone here deal with the whackos).

-the other Doug

I've had this program saved on my DVR since last November, and have watched it several times. But in late developments, I started planning to get an HDTV a few weeks ago, and while I needed to wait for my "extra" paycheck of the month to go get the HDTV, I went ahead and got an HD DVR from Comcast a week ago. (I feel gluttonous -- I have my old SD DVR in my bedroom now, and a brand-new HD DVR in my living room.)

I noticed that "Five Years on Mars" was being re-run in HD on the NatGeo HD offering here during this last week, so I recorded it, figuring I'd want to play it in HD as soon as I got the new TV.

Well, I got the new TV last night. Decent brand, 32" 720p LCD, which works for the room it's in, and which gets an outstanding picture. Also does very good surround sound without any separate speaker deployment.

As soon as I got the thing connected up (really easy to do with an HDMI cable), I started playing "Five Years"... in HD.

Oh.

My.

God.

I ran out of swear jars, guys.

If there's any way for you guys to catch some of this recent programming in HD, I highly, highly recommend it. (Also got to see the end of the Kaguya special on Nat Geo in HD this evening, BTW, shaking myself for not noticing it was on earlier. Also worth several swear jars. Seeing the Moon pass underneath as the Earth rises, in full HD... 'twas superb.)

-the other Doug

Hmmm... old Snoop was put into a heliocentric orbit that would have been very similar to Earth's orbit around the Sun. Its deviation from Earth's orbit was less than that of the A12 S-IVB, and we know that the S-IVB has slipped into and out of a wide Earth orbit, spending some of its time over the last 39 years in a heliocentric orbit and some of its time in a geocentric orbit.

I'd think it would be so unlikely as to be nearly impossible for LM-4 or the A12 S-IVB to have encountered Earth or the Moon in such a geometry as to pump the orbit significantly, either higher or lower relative to the Sun. So I'd speculate that the haystack you need to search for either would be very near to Earth's orbit; anything much outside of 1AU is so unlikely as to be dismissed, for search purposes, I would think...

I can tell you that Snoopy was tracked for no more than eight hours after its final APS burn, as its batteries and cooling water were only loaded for a short-term flight. It was an 18-hour spacecraft, as LM-3 was, loaded for a very short time of independent flight, so its lifetime after jettison was short.

-the other Doug

While there will be an awful lot of study and theorizing about the source(s) of the observed methane, and an awful lot of modeling of said sources, I think perhaps one of the things that needs to be really pinned down hard before those models gain any credibility is the volume of methane being released over time. I know they have some figures right now, but they're only showing plumes in three small-ish areas of Mars. Are those the *only* sources? Or have we not looked closely enough at the rest of the planet to find others?

Once you know how much you're releasing, you can project total release levels over much longer periods, like millions and billions of years. If it turns out, for example, that the current release rate (which is really very low on a planetary scale, I believe) would over a billion years require that a methane ocean has to have been sealed up and slowly leaked out over that period, that makes the ancient origin theory unlikely. If it would only require a few thousand tons of clathrated methane, spread out over only perhaps several thousand total cubic kilometers (a very small percentage of Mars' upper crust), then the ancient origin theory looks a lot better.

If the release volume, as projected against a variety of assumption sets, seems to require constant (if very low-level) production of methane over time, then the various other theories gain more ground.

(And yes, I know that release rates have probably changed over time. You can plug such changes into the release-over-time models, if you wish, as long as your changes are in some way supported by actual data.)

One thing that was just mentioned at the press conference (I recorded it on my DVR and am watching it now) is the possibility that there might be a layer of permafrost under the entire Martian crust, even the equatorial plains. Do we have any real evidence of this from either of the radar experiments? Or is this simply another model they're tossing around?

More and more, I want to get heat flow data from Mars. An awful lot of what's actually happening under the first few km of Mars' crust depends on the temperature regimes of its crust, mantle and core. We have very little idea of how much remanent heat may yet be contained within the planet, how heterogenous (or not) its distribution might be, and very specifically at what locations and depths water (and other things, like methane) might exist as solids, liquids and even gasses.

-the other Doug

Those look like Pot-o-Gold style "rotten" rocks that have eroded from the inside out, leaving the armored shells behind.

-the other Doug

I have what I hope will be a fun idea for a thread, here.

We're all on a tour bus, and as we go along, the conductor points out interesting space-related things. The catch is, the picture caption, in the form of the conductor's narrative, has to be a comedic look at the item.

I'll start it off, I think you'll get the idea from this:



"Ladies and gentlemen, if you'll look out the left side of the bus, you'll see a relic we have here. Yes, that is one of the original boxes that the Saturn V's came in. If you look closely, there is a small label in one corner which says 'Some Assembly Required.'"

-the other Doug

p.s. -- picture acquired from Collectspace.com, to whom all rights belong.

Now, here's an idea that's perhaps less despicable than the old Name a Star deal.

How about Name the Planets?

Any new planetary system is likely going to have its planets "officially" categorized by some kind of star name / increment system, like Sol III, for example. But you could actually sell the naming rights for the planets of a given star. These wouild be "friendly" names, names like "Earth" for Sol III or "Jupiter" for Sol V, for example.

There would be limits, of course, and different types of contracts with different parameters. For example, you would pay a lot more for naming rights by you or your heirs into perpetuity than you would for a 10-year or 20-year naming rights window. You could buy naming rights for each and every planet found around your star during your contract period, or pay less for the rights to name the first, second or third planet discovered around given star. Even less for planets five through n.

If you could set up a program in which these "friendly" names for new planets are actually recognized by the IAU in some kind of special "friendly name" category, you could probably get thousands of dollars, minimum, for even 10-year shots at naming rights for planets around some of the closer stars. (Where those funds would go, and the purposes to which they would be put, are topics for another discussion, I think...)

You'd have to have some kind of regulation on the types of names that would be acceptable -- i.e., nothing pornographic, nothing extremely frivolous, and nothing already in use (i.e., no "Earth" or "Mars" in more than one solar system). But you might want to allow local placenames with descriptives attached, things like "Big Jupiter" or "Nueva Brasil" or even "New Chicago" (the latter with a moon named Evanston, for which the origin shall someday become obscure... ).

If you allow these names to become official "friendly" names for newly-discovered planets, you'd really have something marketable. And to eliminate the current problem with stadium naming rights, maybe you'd have to keep corporations from buying naming rights. After all, who wants to live or work on "MacDonalds Prime" or, even worse, "IBM System/3"??????



-the other Doug

The one event that would explain a real "darkening event," it seems to me, would be the very close passage of a dust devil. (Or at least the passage of a dust devil between Spirit's immediate surroundings and the Sun -- i.e., in the DD's shadow.)

Anyone check the solar panels since that observation? Or the watt hours?

-the other Doug

The Russians have tried radio telescopy from LEO before -- for example, the KRT-10 they hung off the back of Salyut 6 back in 1979. As I recall, they didn't get much in the way of good data from it...

-the other Doug

I dunno -- from some angles, it looks a lot like my old Centuri Payloader...

-the other Doug

Great comparison presentation, Phil. Very easy to compare the albedo features mapped by each team.

I do want to point out that the Mariner 9 map was prepared with far greater contrast than the other two maps, which attempt to present realistic-to-the-eye contrast levels. So it's easier to compare features between the Viking and MGS maps. Variations between the Mariner 9 map and the other two maps seem just as likely to be artifacts of the preparation as they are actual changes over time.

Also, I think it bears mentioning that Viking and MGS overflew the terrain at different times of day nadir LST. IIRC, MGS flew over terrain which, at nadir, was at roughly 2pm LST, and I believe Viking had a couple of different windows (with the two different orbiters) but saw nadir at generally lower sun angles (I want to say between 3 and 4 pm LST, but I just can't remember with confidence... *sigh*... ).

We all know albedo features can vary somewhat by sun angle, so at least some of the variations between the Viking and MGS maps may be due to different sun angles.

However, all of that said, there are obviously places where large gross changes (and also small, subtle changes) have occurred in the times between the three eras. And that is very definitely fascinating. Plus, I seem to recall that some people already have done analyses of albedo variations in telescopic images/drawings from oppositions since, oh, probably 1840....

In fact, I remember reading a book when I was a kid that presented Mars images from several successive oppositions, comparing the albedo features and noting observed changes. It might make a good thesis for some astrogeology postgrad out there to pull up all those old telescopic analyses and plug them into the patterns of changes we've seen from our orbiters from 1971 to present...

-the other Doug

I can't tell from the images I've seen, but I'd bet that you don't see a whole lot in the way of ripples forming directly onto blueberry-armored soils. Perhaps we're seeing an ejecta distribution of blueberry-rich boulders and rocks which left behind an armoring that results in the bare, non-rippled patches? I've always thought I could see a certain degree of organization to the bare patches out in the ripple fields that look for all the world like splash patterns...

-the other Doug

I sort of wish that Spirit had navigated around to the other side of Bonneville and taken some closer-range images of her own heat shield where it augered into the side wall of the crater. I understand that the crater is just an impact hole into the thicker-than-anticipated lava cap over Gusev's floor, and there was nothing mineralogical of interest in the newly disturbed crater wall, but it would have been an impressive set of pictures.

-the other Doug

Now, my understanding is that this particular Falcon 9 that is being assembled contains "many" flight systems but also contains some non-flight components, and will never fly as a unit. That it's rather like the 500-F version of the Saturn V, that was stacked and rolled out to the pad as a test vehicle to validate the procedures needed to get the bird ready to fly.

So, before a Falcon 9 actually flies, the article we're seeing right now will need to be taken apart and a full flight vehicle will need to be assembled. Correct?

Ergo, it's not like we're on the verge of seeing this bird take to the skies... and in fact, this particular bird never will, in its present configuration.

So I wouldn't worry about it flying before they have a chance to get a couple more Falcon 1 successes under their belts.

-the other Doug

Also, these MIs look suspiciously like the MIs I recall from the dark soils north of Victoria (in the deposition vs. sweeping investigations). Are we certain these are MIs from recent sols? And not just old images being flushed from the flash?

-the other Doug

I'm just waiting for someone to target a rover mission to one of the Martian caves that's been discovered in orbital imagery. Then it can be the Off-Track Heat Engine Rover Doing Observations Under Ground...

-the other Doug

My "space" folder in my Pics folder contains 629 MB worth of images, everything from Mercury, Gemini, Apollo, Shuttle and ISS through Pathfinder, MER, HiRISE, Cassini and even a little from Galileo.

-the other Doug

Wait a second -- Stu, aren't those your pieces of Mars meteorite sitting in the debris pile next to the trench????

NOM NOM NOM NOM NOM!!!!!



(Just kidding, Helen!)

-the other Doug

Happy birthday, Doug!

You do realize that 29 is the peak of one's existence -- it's all downhill from here...

-the other Doug

I've always been amused that the American comedian and actor, Albert Brooks, had to change his real name. He just couldn't see himself using his real name -- Albert Einstein. (His brother, who played the idiot character Super Dave back in the 80s, kept his real name, performing under the name Bob Einstein.)

-the other Doug

When I finally figured out (with Phil's appreciated help) that Jason was speaking of tectonic compression features, I felt sorta stupid. Well, we all have days like that...

I guess one of the $64,000 questions here is the length of time we think this particular era of crustal spreading has been going on. And to have any real idea of the amount of new crust formed in a given timeframe, we need to know how fast the spreading is taking place. I think we may lack the data to confidently answer either of those questions.

However, you can toss assumptions into the equations, and get ideas of various ranges. That lets you put together a variety of models, which you can then figure out how to test.

If compressional forces are piling up a very thick mass of hard ice in a given region, and yet we don't seem to see constructional forms (i.e., mountain ranges or big, obvious bulges), we've got to conclude that the thickest part of the pile is sinking into an elastic mantle. It may not be subducting as a plate under another plate, but if it's being recycled into the mantle, it's at least a subduction-like process.

I'm not sure that it's actually melting into the mantle. I think we may have a somewhat unique "warm ice" process going on at several places in the mantle, where the material is solid but has elastic properties. I have no idea when or how the phase change from either amorphous or crystalline water ice to this warm ice with elastic properties takes place -- I'm not even sure the physics of that proposed state of ice are all that well thought-out right now. (Obviously, if anyone has any references to the current thinking on the subject, I'd love to see them... )

But I think we need to know more about properties of the Enceladan mantle that underlies such subduction-like processes before we can model what's happening, how long it's been happening, and how fast it's happening. And as much as I'd enjoy getting enough information to answer these questions, I'm not positive that Cassini is capable of gathering enough of the right kind of data to do so.

-the other Doug

I think the real point is that they really don't compensate for it. So what if the orbit shifts laterally? The major lateral movement is the nodal regression, which is extremely well understood and can be predicted pretty well to the nth degree. Other vectors applied to *any* spacecraft in LEO (be they large and busy with lots of movement and contact, like ISS, or small, compact and quiescent) likely don't add up to even a few percent of the nodal regression effect. And remember, all of those random vectors applied to a spacecraft push it in all sorts of directions, not just those that would "push it sideways."

Of course, pretty much every spacecraft in LEO is being ground-tracked, all the time, so to an extent we don't need the ability to accurately predict the result of random orbital perturbations over periods of months or years. We always have the "ground truth" of the direct tracking to establish the exact orbital parameters of anything in LEO. So it's possible to just crank in the actual location numbers and use those for any positional-sensitive maneuvers (like rendezvous and, perhaps more important, debris avoidance).

Heck, even rendezvous maneuvers are forgiving of errors in estimated location of hundreds of meters. Once you begin your terminal phase, you end up using things like radar and lidar to establish exact values for relative positions and velocities, and any errors can be steered out as the rendezvous maneuvers reach their conclusion.

Final analysis -- there's no need compensate for lateral regression movements of spacecraft; as long as you can observe spacecraft directly, you can always correct your understanding of your position, at almost any time. And there is nothing that requires the ISS (or most any other spacecraft in LEO) to be at an exact location predicted more than a few days before.

What needs compensating, much moreso, is the loss of total orbital energy to friction with the extremely tenuous atmosphere present at 300 or so km. In this case, ISS sees a more profound effect than other spacecraft, since its solar panels present an awful lot of surface area. I know ISS is big and heavy by now, but the ratio of surface area to mass is still probably quite a bit higher than your average satellite in LEO. So, with more drag, it's slowed more quickly. Add to that the fact that the upper atmosphere "breathes," puffing out and snugging back under various circumstances, and you get a much more dynamic situation. Of course, that kind of orbital perturbation is slow enough that a need to give the station a boost can be identified in March and not be executed until November...

-the other Doug

As I understand it, though, what's now being speculated is that Beagle 2 failed to successfully cross transition boundaries, not that the heat shield failed during the heat pulse. The shape of the entry vehicle is critical to how the vehicle maintains stability through hypersonic to supersonic velocities, and there are a lot of factors, including the actual atmospheric deceleration rate, that affect how the shape and the regime interact.

Huygens continued to decelerate at a faster and faster rate as it dug into Titan's thicker atmosphere. Beagle 2 continued moving faster for longer after it hit its maximum deceleration (which would have been less decel than Huygens saw, since Mars' atmosphere doesn't thicken with depth to the extent that Titan's does). I would be extremely surprised if Huygens and Beagle 2 were traveling at similar airspeed velocities a minute after the end of peak heating.

You would have to plug in speed, deceleration rate and air density throughout the descent profile for each probe to determine the differences in transition boundaries between the two events. I guess what I'm thinking is that Huygens was slowed more quickly and effectively, and thus plowed through the transition boundaries very quickly, with very little time for the vehicle to become unstable (and, as I recall, there *are* some indications that Huygens tumbled briefly at some points during its descent). Because of the thinner air, Beagle 2 slowed more slowly and spent more time passing through transition boundaries than Huygens did, thus increasing the possibility that both its spin rate and any inherent instability in the aerodynamics of the vehicle's shape would cause the craft to tumble while still in a fairly challenging heating regime.

Make sense?

-the other Doug