I really have to think Phil is right, that the dark areas have been windswept "clean" of the ubiquitous bright dust. Which means that Oppy ought to be able to get a nice panel-cleaning by placing herself in the path of those winds!

-the other Doug

I'll also point out that a somewhat similar strata over by Home Plate read out to be quite basaltic, in keeping with the chemistry of the plains basalts. I'd like to think otherwise, but I betcha these "berries" turn out to be basaltic in content, as well.

-the other Doug

I've listened through a long Usenet argument about the legal ownership status of man-made items left on the Moon. The gist, as I recall it, is that you can make a good case for the equipment having been abandoned, and therefore it would legal for a third party to salvage it. If the two governments (and one putative private owner) intend to make a case for ownership at some future time, I think it's incumbent upon them to make such declarations at the time of apparent abandonment.

I believe the rule is that the equipment still belongs to the respective original owners until/unless a legal attempt at salvage is made, however.

Of course, this all has to do with legal matters (international ones, at that) and so I could be completely wrong... But I believe the above is what a few lawyers came up with in that overly-long Usenet discussion.

-the other Doug

I think I prefer "Enceladan"...

-the other Doug

Well, yeah -- if they let people who actually *work* in planetary science enter the contests, what do you expect???



Seriously, congrats.

-the other Doug

I think that the "dust swarms" which make up the various meteor showers pose a small but quantifiable risk to both manned and unmanned spacecraft, be they in LEO or on Luna.

I believe that the ISS has recorded micro-impacts during meteor showers, but the fact that there's never been a serious damage event on such a large structure, after it has passed through several annual encounters per year, speaks to the probability of such an event.

I don't have density-per-square-kilometer figures to back this up, but I'd bet you that you're in greater danger from earthquakes in California than you would be from Leonid dust on Luna or in LEO.

-the other Doug

Well... except for the fact that it's spelled "Congratulations," I'd say it would make a perfect cake!

-the other Doug

Just a mild suggestion to the moderators -- perhaps the subtitle of this thread is, um, inappropriate? At least until we know whether or not we'll get MGS back, it seems mighty incorrect to be discussing these rescue efforts in a thread subtitled "still going strong"...

-the other Doug

I will point out that the Apollo 13 situation isn't entirely applicable to Cassini. The RTG fuel element for Apollo 13's ALSEP was not stored in its RTG. It (as all Apollo ALSEP fuel elements) was stored in a graphite fuel cask which was specifically designed and located on the outside of the LM to *survive*, intact, an entry into Earth's atmosphere at circumlunar speeds. (The astronauts removed the fuel element from this cask and installed it into the ALSEP RTG during the ALSEP deployment.) That's not exactly the same thing as a fueled RTG, which is likely to break apart under stresses such as entering any significant atmosphere.

However, the Apollo RTG fuel elements were quite different from the elements that fuel modern probes such as Cassini and New Horizons. The Apollo ALSEP RTGs used a simple rod of plutonium which generated an awful lot of heat -- it was strictly forbidden for the astronauts to touch the rod directly, mostly because of heat effects. Modern RTG fuel is, as far I understand it, encapsulated in many small spheres of reinforced graphite. The entire mass of the fuel generates less heat than the ALSEP fuel rods, but modern thermocouples are able to efficiently turn this somewhat smaller heat flux into ample amounts of power.

This makes the modern fuel elements safe to launch within their RTGs -- in case of a launch vehicle explosion, etc., each small sphere within the RTG fuel will survive without releasing any of the toxic plutonium inside. In Apollo, that fuel rod's cask had to survive intact, with *all* of the fuel in one container.

So, as I said, the situations aren't exactly comparable.

-the other Doug

I also go to the "top page" of the forum when I bring the site up. I use the indicators to see where there have been new posts; from the top level, the large forum icons indicate which ones have new posts, and within the fora, threads are marked as having new posts with a red flag. I simply click on the red flags and am taken directly to the newest posts in each thread.

And yes, I read every new post. Every day.

-the other Doug

I started thinking about the problem of finding places in the Solar System where humans could live. The main problems are 1) energy sources, 2) sources of water and oxygen, and 3) protection from energetic cosmic rays.

Assuming Europa does have a global subsurface ocean, wouldn't this ocean provide all of the things mentioned above?

Also, a refuge of human knowledge (and perhaps terrestrial life) deep in Europa's oceans would survive most of the disasters that could wipe out life on Earth, including close supernovae events and exposure to catastrophic cosmic / gamma ray events. It would take an *awful* lot of energy to strip the ice off of Europa's oceans, I would think.

Perhaps, in the name of the survival of humanity, you could make a case for placing a colony within Europa's oceans...?

-the other Doug

I'm not all that enthusiastic about the Sci-Fi Channel's adaptations. Ever see the mess they made out of "Riverworld"?

They done some good stuff, but made some really bad shlock, too. To be decent, I think any adaptation of a good sf novel would have to be done by a producer and director who were committed to filming the piece properly, not someone who's looking to see how many flashing lights and kewl explosions he/she can cram into 92 minutes...

-the other Doug

Yes, it's now possible to present on film just about anything. Ringworld, Rendezvous with Rama, you name it -- it can be done.

I'm actually sort of amused that the people who run the Star Trek franchise have picked up on a suggestion I made several years ago. They're re-releasing the original series episodes for syndication, with "sweetened" special effects. They've replaced those fuzzy colored-ball planets with real-looking planets, made the old Enterprise look much better (and move more realistically), along with other little enhancements. They also digitized the old film stock and brightened/balanced the colors. It's a much sharper-looking show, with far better effects than were possible in the 1960s.

They didn't go as far as I would have, though (probably because it would have been way too costly) -- redesigning the interiors of the ship. It could be done, they could change the look of the panels and displays, even change the colors and all the minor detailing. But they'd have to work around the actors as they moved through the scene, and that probably would be prohibitively time-consuming and expensive for the entire run of the original series.

-the other Doug

There's a couple of rovers on Mars
That drive a lot slower than cars.
As they crawl millimeters
They aren't world-record beaters --
But their world floats along midst the stars!

-the other Doug

I will add to this discussion, that while only very low-angle impacts create elliptical craters, depressed-angle impacts do produce (to a greater or lesser degree) asymmetrical ejecta blankets. While the shock of the impact creates a spherical blast wave (which manifests as a roughly circular crater), the angle of the impactor and the direction in which it was traveling when it impacted (among other things) determines how the ejecta is sprayed.

There are many circular craters on the Moon with very non-circular ejecta blankets, mostly due to angle of impact...

-the other Doug

There were two reasons why the Ranger series was abandoned after they finally got the Block 3 version to work:

1) Lunar Orbiter and Surveyor were in the works and designed to provide orders of magnitude more data than the Block 4 and Block 5 Rangers could ever provide. It seemed a waste of money to continue to pour it into Ranger when much more capable spacecraft were about to come online.

2) Ranger had a very limited view at high resolutions. The way in which field of view decreased as resolution increased limited the ability to understand fine-scale structures in context with their surroundings. The three Rangers which returned imagery served their designed function of imaging the lunar surface at very high resolution and determining some of its basic properties (slope, cratering, etc.). But additional Rangers would have given very little more data and wouldn't have been all that helpful in studying the Moon.

-the other Doug

While you did some great work with these images, Ted, they're still really poor images -- always have been. How anyone involved in MPF thought they were going to get any significant scientific or engineering information out of those cameras is beyond me.

-the other Doug

The moment that caught me in a very surprising and stunning sense of recognition was the Spirit final bounce-roll, as the airbag-studded lander bounded across Sleepy Hollow, leaving the airbag marks we all saw a few hours later. I saw that and a voice inside my head screamed "I know that place! That's the real place where Spirit landed!!!"

Knowing what to expect, watching Oppy roll around the inside of Eagle Crater as it settled gave a very similar sense of recognition -- but this time, I savored the moment.



-the other Doug

Also recall that the Lunar Orbiter series worked in a similar fashion to the Mars-5 system, taking pictures onto photographic film and scanning the film with a photomultiplier system for read-out and transmission. That system resulted in very high resolution images of the Moon, but had an inherent issue with the seams between the readout lines.

-the other Doug

Ah, yes -- "Have Spacesuit, Will Travel."

-the other Doug

I can recall, back in 1966, there was a sweepstakes advertised in the back of a few comic books to win a full-sized model of a Gemini spacecraft. I believe I entered that contest a few dozen times. Didn't win the Gemini, though...

-the other Doug

I just have to add my $.02 here...

I grew up on Gerry Anderson's "Supermarionation" work. I loved Fireball XL-5, and can still sing the theme song. My absolute favorite piece of Anderson-tech was Supercar. I was so taken with that vehicle that I was crushed when I failed to receive a toy model of it on my 8th birthday. (No matter how many times I told my parents that I *really* wanted a Supercar for a birthday or Christmas, over at least a three-year period, I never, ever got one. I had to make my own Supercar models using Tinkertoys and/or Legos.)

But...

Maybe it's because I was older when Space: 1999 came out, or maybe it's because it was a highly-touted live-action s.f. TV offering, of which there had been relatively few good examples. But I found Space: 1999 a pretty lame attempt to combine space opera with hard science fiction.

The base concept -- that an explosion in an expended nuclear fuel dump could hurl Earth's Moon out of orbit and accelerate it to such a great speed that it would leave the Solar System in a matter of days -- was such bad *science* that I was turned off by it. I mean, do y'all have *any* idea of how much energy it would require to propel that much mass that quickly? If you tried to apply that kind of energy to the Moon within the very short time frame presented, you wouldn't propel it out of the Solar System, you would shatter it into a gazillion pieces.

The Eagle spacecraft were very kewl-looking... but I didn't care for the clouds of dust they kicked up on the airless Moon. By the mid-1970's, we all knew quite well that dust doesn't hang in the "air" on a body with no atmosphere. Again, bad science began to ruin it for me.

And finally, I just wasn't all that impressed with the characters and situations presented in the stories. The acting direction didn't bring out the cast's strengths, and the whole thing just sort of sat there, leaden and lifeless. At least, thus it seemed to me at the time.

Had the same concept and stories been presented in Anderson's Supermarionation and presented as a Saturday morning "cartoon" entry, I probably would have been somewhat fond of the effort. But as a very highly touted "next coming of Star Trek" into "adult" TV science fiction, it fell far short of expectations and was a rather severe disappointment to me.



-the other Doug

Depends, both on the suit design and the level of safety you're willing to risk.

You can get into a Russian EVA suit pretty easily -- you just open a hatch in the middle of the backpack, wriggle in, and close the hatch with a conveniently-placed lever. Attach your comm carrier into the suit comm circuit, turn on the backpack, don gloves, lower your visor, and you're ready to go.

An Apollo A7L suit, on the other hand -- you could put it on by yourself, but if you had to don and hook up a PLSS, your safety level might have been impaired. (The Apollo CMPs regularly donned and doffed their suits alone, perfectly safely, but they had no need to don a life-support system on top of that.)

By the time we send people to Mars, I would hope we will have designed suits that are relatively lightweight and easy to don, operate and maintain. And which have gloves that don't maim the fingers of the wearers...

-the other Doug

"...That's one small step for... <buzz, crackle>... Mr. Haney!"



-the other Doug

Heard this morning that a final Hubble servicing mission has been given a go-ahead. I guess they'll have another shuttle sitting on the pad in advanced preparation status for this one, in case a rescue is needed.

-the other Doug