Remember, the ellipse boundary line as shown on this unofficial route map is nothing more or less than the width of the line that was arbitrarily used on the landing ellipse map from which the ellipse was transferred onto the route map. (PHEW!)

Assuming the ellipse line is transferred correctly to the route map, then one could make a good argument that the actual ellipse is defined by a line (with length but no width nor depth) which lies exactly halfway between the edges of the arbitrarily-sized line.

By that reckoning, Opportunity exited her landing ellipse during her last drive.

Hooray for Opportunity! Long live MER-B!

-the other Doug

OK -- first off, are you saying that MEX is finding no sign of hydrated iron oxides in the very soils that seem to be giving off a fair amount of hydrogen, as detected by Odyssey, and therefore are assumed to be covering significant ice deposits? Or at least that contain a significant admixture of ice?

So, which set of readings do we believe -- the ones that show a lack of hydrated iron oxides, or the ones that indicate a significant ice presence within much of this region?

If there is ice in close proximity to the surface of the northern portion of the northern hemisphere, how can that ice exist within and under soils that show no signs of hydration? And if the soils were emplaced after the ice was emplaced, then the non-hydrated soils could be covering an ancient sea floor and MEX wouldn't have a clue.

Another point -- is MEX looking at the very surficial layer, which may be dust and soils generated from non-hydrated basalts dating from the Tharsis development, or does it "see" deeper than the very surface layer? Is it possible that non-hydrated dust deposition may have covered any hydrated iron oxides that might still lie rather close to the surface?

And finally, is there any correlation between the places where MEX sees hydrated iron oxides and those places where the erratic magnetic field seems to be shielding the surface from solar UV? If you want to test UV effects, and if you can assume that these erratic magnetic "loops" that form bubbles of partial UV screening are long-lived, then it makes sense to identify these areas as precisely as possible and then compare surface characteristics inside and outside of them...

-the other Doug

I think it would be easier to simply build a Bussard ramjet-style system, where you take all of the mass you collect (via magnetic field scoops) and use it as reaction mass. No wasteful sorting of different elements -- just squeeze it all down, heat it all up, and shoot it all out the back end.

Of course, that's just as far beyond our current technologies as a scoop to collect all the atoms and molecules, sorting them out, storing what we can use and discarding the rest... but it might be a less difficult path to trod.

-the other Doug

Nope -- more like rock science...



-the other Doug

You took my number, Chris!

OK, I guess I have to back up one and say Sol 998. I have in my head that we'll make it to Victoria, and at the moment we begin to take the panorama of all panoramas, the S1K bug will wipe out the flash memory and that will be the end of that...

-the other Doug

Yes -- welcome, Phil! I think you might enjoy hanging around here -- the signal-to-noise ratio is remarkably high for such internet fora. You will be a very welcome addition to the place!

-the other Doug

Considering that the Tagish Lake meteor seems to have been composed mainly of clays, and considering that the Tagish Lake meteor behaved like a volatile-rich body when it entered Earth's atmosphere (acquiring some odd vectors as pockets of volatiles were released, and finally exploding well above the surface), we have some fairly decent proof that cometary bodies *can* contain clays. And that such bodies also have a good admixture of volatiles.

It's more a matter, I think, of trying to come up with a set of mechanisms that accounts for such differentiation and clay formation in cometary bodies...

-the other Doug

Ah -- you're showing the early signs of a disability known as CRS. I, myself, have suffered from CRS for many years, and unfortunately in my case, it's progressing on to the more serious condition, CRAFT.

There's really no treatment available at present, either.

Oh, BTW -- CRS = Can't Remember S**t. CRAFT = Can't Remember a F***ing Thing.

Isn't it impressive how someone with such a serious condition as mine can actually use such technical, medical terms with such alacrity?



-the other... um, hold on, I'll get it...

There are several of us here, I bet. My favorite JLA member was always J'onn J'onzz, the Martian Manhunter. Some of the people who were involved in Mars exploration back in the '60s might have traced their interest back to Edgar Rice Burroughs' John Carter -- but my interest started, when I was five years old or so, from wanting to see where J'onn came from...

-the other Doug

I'll bet this "Mars Mafia" sits around and endlessly reinforces their own notions that we ought to cancel all non-Mars planetary exploration, on the theory that all the money that's being "wasted" on these flagship missions to non-Mars destinations will automatically get spent on more Mars probes -- eh, Bruce?

-the other Doug

In re the Avro Arrow:



Remember, though, that the cancellation of the Arrow was a veritable windfall of talent that was infused into the American manned spaceflight program. The Arrow was canceled at just the right time for NASA's Space Task Group (later to become the Manned Spacecraft Center) to absorb the engineers that Avro let go. So, NASA's first steps into space were supported by a large number of talented Canadian engineers!

To all you Canadians on the forum -- thanks!

-the other Doug

Actually, there is good reason to believe that the youngest *sampled* lunar basalts are not the youngest basalts that actually exist there. Comparing the eastern Procellarum surface detail with that seen at the western Procellarum Surveyor I landing site suggests that the Surveyor I regolith is significantly younger and thinner than that at the Apollo 12 / Surveyor III site -- possibly only a billion to a billion and a half years old. And some small pockets of extremely dark, smooth mare may be less than a billion years old.

It is possible that the Moon may have retained, due to tidal heating, a molten or semi-molten magma layer that separates its solidified mantle and its now-believed-to-be-chondritic core -- some recent motion/gravity studies of the Moon have been suggesting that the Moon's core actually rotates at a slightly different speed, and along a slightly different axis, from its mantle and crust. That would require a pretty high degree of ductility, I would think -- a layer that is molten or something very close to it.

I grant you, it's been at *least* hundreds of millions of years since there has been significant volcanic activity on the surface of the Moon. But that does not necessarily preclude the possibility that molten or semi-molten rock does not still exist somewhere deep below the crust. It just means that it is *so* deep, and in such a relatively non-pressurized state, that it is no longer capable of reaching the surface.

-the other Doug

Seems to me the best way to get the solar wind oxygen isotope data we'd like to have would be to piggy-back such a collector on some other dust-collection mission. For example, if we flew a comet rendezvous with sample return significantly *inside* Earth's orbit, you could piggyback a set of Genesis-style collectors into the return package and collect this additional dataset.

-the other Doug

The one I always liked best, that you don't list here, was strapping to your body dozens of sealed bottles of water (or was it perspiration?), which, as it evaporated, would rise, lift each bottle a little, and have a cumulative lift sufficient to lift a fully grown human being (*and* a chair for him to sit in) all the way to the Moon.

Space travel was a *lot* easier when we were ignorant of things like the total energy required to move a given mass a certain distance through a gravity well...
*sigh*...

-the other Doug

All of the issues aside, I would just *love* it if I were to have reason to start a new thread here entitled "Nasa Dawn Asteroid Mission Told To 'Stand Back Up'...



-the other Doug

Thank you, Stephen. Exactly spot-on.

-the other Doug

Ecxellent work, Philhippus!

I just have one minor disappointment -- nowhere on the boundaries of your wonderful map do you tell us where there be dragons...



-the other Doug

In re this first press conference...

First, why no mention of the organic materials we've been hearing rumors about? A lot of discussion of minerals, but it took a reporter's question about organics for them to discuss it at all. And when they did, all they discussed was how difficult it is to differentiate between real organics in the samples and contamination from the lab. Are we to take it that we won't get *any* discussion of possible organics in the samples, because they're too gun-shy to ascribe organics to the samples themselves?

Second, these guys seem really blown away by seeing high-temperature-differentiated minerals (olivines, pyroxines, anorthosites, etc.) in a body that accreted in the outer solar system. Anyone ever mention the T-Tauri winds to these guys? It's been known for a long time that the Sun blew all of the loose material from the solar nebula out into a shell at *least* as far out as the Kuiper belt during its T-Tauri stage. So why does it surprise anyone that we find grains of high-temperature minerals in bodies that accreted in the Kuiper belt? After all, those bodies had to have vacuumed up a lot of the dust and gasses pushed out from the inner system during the T-Tauri epoch, right?

I guess it's just surprising to me how amazed these guys get when their results support decades-old theories...

On the plus side, I heard one of the panel members state that Stardust@Home ought to get going in the next couple of weeks. I'm looking forward to hearing from them.

-the other Doug

Yeah -- I also remember Jason assuring us all that it *must* be a camera artifact, since identical "plumes" had been seen on then-recent images of Rhea and Tethys. Of course, over the next few weeks, several people challenged that statement, and Jason backed off from it... but he sounded tremendously certain of it, at first.

-the other Doug

I have visited a number of websites which feature their own chat systems. They usually provide a java applet-based chat client that loads via a webpage.

However, I would imagine that this would require more support (and possibly bandwidth) from Doug's provider than he is currently paying for. If they can support it at all.

But, for a "pure" UMSF chat experience, that would be a marvelous thing. And since you'd have to be a registered member to log into such a chat function, that would tend to keep the salt-of-the-Earth types (you know -- morons) from ruining the signal-to-noise ratio...

-the other Doug

As we all know, Isaac Newton was the first person to codify and organize a coherent description of mass and forces and how they interact. This system is called Newtonian physics.

Then Einstein came along, and taught us all that Newtonian physics only accurately predicts behaviors in unaccelerated states. His new system of rules for accelerated systems, defining both special and general relativity, is now called Einsteinian physics.

I guess the next major breakthrough, as small a chink in the wall as it may be, has been Steven Hawking's work to try and reconcile Einsteinian physics to quantum physics.

Will the new physics that comes out of all this be called Hawkingian physics?

If so -- how would you pronounce that?

-the other Doug

So.... Enceladus may well have a subsurface ocean of carbonated water? Opens up a whole universe of marketing, doesn't it...?

Then again, with that small admixture of CH4, it might be difficult to market pure, unfiltered Enceladian fizzy water -- at least to people who don't live next to overflowing cesspools.

-the other Doug

That was a really fine summary of the current thinking on Enceladus, Bruce. I knew there was a good reason for wanting you around here...

As you say, though, pinning this issue on the relative ratio of rock to ice in Enceladus vs. the other Saturnian moons may be a McGuffin, in that Enceladus has been ejecting significant amounts of mass for an unknown period of time. And it has been *preferentially* ejecting mass -- you don't see any of that rocky core getting ejected in these plumes. Just the ices that cover the rocky core.

I'm positive that one could develop boundaries from currently available data for the rate of mass ejection that's happening right now, and from that come up with a time scale that tells us when the ratio of rock to ice in Enceladus will rise from 57% to 58%, and thence on to 60%, etc. Assuming, of course, a steady rate of mass ejection. One could then work that backwards and determine how long, at present mass ejection rates, it would take for a Mimas-sized moon (for example) to dissipate itself down to the size and rock/ice ratio we see at Enceladus today.

My gut feeling is this -- we see several rather similar Saturnian moons, with relatively small rock cores and large ice mantles, and then we have this much smaller moon with a much higher ratio of rock to ice than the others. And this much smaller moon is, right now, actively ejecting mass -- something the other moons aren't doing, and don't show any major signs of having done in the past. That tells me that Enceladus started out very much like Rhea, Tethys and Mimas, and has dissipated itself down to its present size over billions of years due to this continuing mass ejection. It explains why Enceladus is unique in its size, mass and rock/ice ratio when compare to the other icy moons of Saturn.

-the other Doug

Max Faget was from Louisiana -- the name was French in origin. It was pronounced Fa-zhay.

-the other Doug

What sort of stuff did Max Faget design? Lessee -- the Mercury, Gemini and Apollo spacecraft, for a few... he also did a lot of design work for the Shuttle, though his main design ultimately was not used (the first time an American manned spacecraft did not come more or less directly from Faget and his nuts-and-bolts design engineer, Caldwell Johnson, who fleshed Faget's concepts out into detailed mechanical drawings).

-the other Doug