Since it seems all but certain that MGS is lost forever (I simply cannot imagine it being revived at this point, after this amount of time out of contact), I think it's time to have our own memorial.

MGS showed us the real Mars as we never even guessed it could have existed. The detail it has provided has been invaluable in understanding Mars as well as we do today.

Hail MGS! May her data live long and result in still more surprises down the line.

-the other Doug

What strikes me as funny in this particular article is that the Viking life-detection experiments were *always* designed to sterilize their samples at some point during the process. In other words, the experiments were *designed* to kill Martian life, if it existed. It would have been difficult to determine if there was life or not had they not run the same tests on sterilized vs. non-sterilized samples, and IIRC at least one of the experiments ran its gas-release tests and *then* heat-sterilized its samples before running further tests on them.

At least the astronomer who talked with Keith Olbermann got all of that straightened out, so anyone who watched Countdown that night got the story straight...

-the other Doug

Yow!!!!! No wonder she broke up... I'm pretty certain that the airframe was never rated for exceeding C!

-the other Doug

The first comet I tried to see was Ikeya-Seki in 1968 (I believe it was). It flew too close to the Sun and disintegrated, if I recall correctly, and so the impressive display we were supposed to see in the northern hemisphere never materialized. (I think I have this right -- I was only 12 at the time, and all I recall really clearly is that I was never able to see the thing, which was a big disappointment at the time.)

The first comet I remember actually seeing was Bennett in 1970. I had received a small telescope (3" reflector) for Christmas, and so when Bennett became clear and naked-eye visible in the early spring, I was out in my back yard (at ridiculous-o'clock-in-the-morrning, especially for a 14-year-old) with my 'scope, looking at the comet. I never saw a nucleus; I think all my 'scope was able to resolve was the coma. The tail was well defined, though, and some very nice knots and streamers were visible, if fainter than I would have expected.

As for more recent comets, Hyakutake wasn't nearly as impressive to me as Hale-Bopp was. Perhaps we in the northern hemisphere didn't get a really good viewing angle on Hyakutake, but all I ever recall seeing of it was a fuzzy blotch in the sky with a tail that you had to look away from it to see -- it faded to invisibility if you looked directly at it.

Hale-Bopp, however... that was the most impressive comet I've ever seen. Its tail was also not as bright and noticeable as I would have expected -- after a certain distance from the nucleus, it was best seen out of the corner of one's eye. But in very clear and dark skies, it was an amazing site.

Especially from the air... you see, in April of '97 I went to England on business, and as we flew through the (very short) night along the Great Circle route up north of the Arctic Circle, I saw the most impressive sight I can ever recall: green curtains of auroral displays draping the horizon, with Hale-Bopp hovering barely five degrees above the horizon, its dust tail forming a great sweeping filament that seemed to flow up and out of the auroras, its ion tail flashing brightest of all, bluish against the green of the auroras.

It was a view worth the price of the trip...

-the other Doug

I don't know that the impact rate is enough to cause huge problems for individually pressurized buildings and facilities. On Earth, there are several hundred lightning strikes per second, many of which occur close to buildings and people. And yet, while there is a certain amount of damage (mostly to trees) from lightning strikes every year, rather few people are injured or killed by lightning each year.

Now, compare the frequency of lightning strikes to the frequency of impacts on Mars, and factor in the percentage of those which are large enough (those that make craters of, say, 100m or more in size) to blast you even if they don't hit you directly, vs. those which create craters of only 10 or so meters or less in size (which could land 100 meters away and not damage your habitat), and I bet you're far less likely to get hit by a meteor, or have your domicile destroyed by a close impact, on Mars than it's likely you would get hit by lightning on Earth.

Also, look at the number of pieces of the space shuttle Columbia which fell onto a couple of towns in Texas. Out of all of those pieces, very few actually hit buildings, and *none* hit any human beings. Heck, I don't think there were any documented cases of any pieces hitting any animals, even. So, you can drop a good number of objects onto a fairly densely populated area without actually hitting anyone.

Now, I grant you, if you built big transparent pressure domes on Mars, you'd increase the probability of a meteor causing a depressurization event... but I'd bet you're not going to see anything beyond relatively small metal tubes in Martian colonial building styles for quite a while...

-the other Doug

The problem isn't that ESA can't muster the equivalent -- it's that they somehow don't seem to see a need to do so.

I think there is more to it than a lack of money -- the incremental increase in funding which would make outreach possible is a tiny percentage of what ESA spends on its other projects. I think that ESA actually believes that they have only one audience -- the scientists and engineers employed by the projects -- and that there is absolutely no reason to serve any other audience. They almost seem arrogantly aggressive about it.

If I were a member of the EU, I would try and get political action going. Contact my MP or whatever and insist that, if ESA can't serve the needs of the people of the EU and is unable to see themselves as anything but a service to a handful of scientists, then perhaps ESA needs to just go away. Eventually, spending large sums on things for which the people aren't given any pay-off will become a political liability, and if ESA can't manage the process, then someone else needs to step in and do it. Or else Europe will end up withdrawing from space activities... and we all know that's a bad idea.

-the other Doug

Actually, there is an APOD from 2001 that shows a single lunation, which I think even more graphically illustrates the Moon's perceived "wobble" during a single orbit of the Earth:

APOD - Lunation

I dunno, this one seems even more illustrative of how the Moon changes its aspect as it orbits us.

-the other Doug

Interesting... the MERs are about 200 sols from individually equaling the time the Viking 2 lander remained operational, and the total number of sols for both rovers is about 200 sols short of the time the Viking 1 lander was operational.

In about 700 sols or so, if the rovers last that long, they will have equaled the total operational time of both Viking landers.

Pretty durned impressive for solar-powered wheeled vehicles...

-the other Doug

Let's see, a couple of responses, here...

Doug, I'm not sure we have a really good idea of what the MPL remains might look like. The greatest rate of landform change observed on Mars is in the polar regions; an awful lot of material moves around every Martian year when literally trillions of tons of solid CO2 gets laid down and then sublimates off.

Just for starters, I have to wonder what the simple weight of the dry ice built up on and over the crash (and the backshell & heat shield, for that matter) might have done to them. Just how deep does the dry ice layer lay down at MPL's latitude, anyway? Even if it wouldn't cover over MPL entirely, I'd think you would see some serious effects from being buried in dry ice.

Ditto for the 'chute. I don't know what was used to pigment MPL's 'chute, but I know a lot of dyes fade in extreme cold. After three winters, and dust deposition from the winds during sublimation season, I'm thinking that the 'chute may not be recognizable anymore.

And, yes -- the winds. We see that polar latitudes sublimate somewhat unevenly, with "warm" spots (thinner ice layers or rocks which receive more insolation through the dry ice cap and sublimate the frozen CO2 from below) clearing off and blowing dust onto adjacent dry ice surfaces, which creates more preferential sublimation, which creates more clear spots, until the whole surface is clear. The lander and any of its related EDL equipment might have created warm spots and been the sources of early clearing spots -- which means they might have been exposed to pretty stiff winds as pent-up CO2 gas blew through the ice ceiling. Hey, we *know* they blow through energetically enough to spray dust out onto adjacent dry ice-covered surfaces. What would such events do to the 'chute fabric (especially if it's super-cold)? What would they do to the wreck of MPL itself?

I mean, it's even possible that some pieces of MPL have been blown several meters away from the main crach site.

And to Bob, I'm on the fence as to whether the DS2 impact points would be obvious. We know that Spirit's heat shield drew a gouge into Bonneville's rim, which was extremely dark and contrasty with the surrounding materials. It was quite obvious in both MOC imagery and in the ground-level images from the far rim.

However, while MRO's view of Bonneville shows the heat shield, the albedo difference seems to be almost completely gone. I'll grant you, wind smoothing is probably at its peak effect at crater rims, but this would seem to argue against there being much in the way of identifying marks on the craters made by the penetrators. It might well be possible to identify the impact sites in other ways, but (especially after three Martian winters) I'm not all that sanguine that we'll be able to find them.

-the other Doug

I understand your point, Shaka, but in this case, I think the selection of forum is valid. We're talking about landforms which reveal themselves best at larger scales. I was mostly pointing out that the plains and the annulus appear to be the same unit at larger scales, but don't seem to have an obvious connection as to how they formed.

Since it's a discussion about large units which became even more apparently similar at the MRO observation scales (which are nicely zoomable from large scale to fine scale), I figure it belongs here. An MI tells you what something looks like in a portion of the surface the size of a postage stamp. Yes, you can draw conclusions from differences in MIs, but MIs can vary a lot in distances of meters within the same unit. There's nothing like seeing how many kilometers, not meters, that a given unit extends, and how its boundaries are characterized. That's actually done better from orbit than from the ground...

So, now that we can see how the boundaries are characterized in the MRO images a lot better than we could in the MOC images, I figure it's time to start geologizing about them...

-the other Doug

Interesting -- that means that there is now no remote sensing in or around Mars still in working order that arrived there in the 20th century.

That's some type of milestone, I'd say...

-the other Doug

I was looking at the MRO image of the Opportunity landing site, and I was struck once again at how incredibly similar the plains on which Oppy landed and the annulus around Victoria look. They could be the exact same landform, looking at it from orbit at MRO's resolution.

The soils and drifts in the annulus also look more like the plains outside of Eagle and Endurance than anything we saw in the dune seas of the "etched" terrain. Granted, the concretions in the annulus are smaller and more conical than the more spherical concretions up north -- but all in all, the surfaces are remarkably similar.

Now, the annulus around Victoria *seems* to be arrayed in an ejecta-like pattern around the crater -- but the crater itself seems too old to exhibit an intact ejecta blanket. And -- and this is the crucial question -- if the terrain in Vickie's annulus is in some way a result of her ejecta blanket, then how do you explain almost identical terrain to the north, which isn't in any way visually associated with any ejecta blanket from any size of an impact?

I'd be tempted to think that such a strong visual similarity would have to indicate similarities in composition and/or origin.

I've read an initial geological analysis of the plains unit. I fail to see why the processes suggested in that analysis (early aqueous alteration, polygonal cracking due to dessication, and finally aeons of aeolian stripping and re-deposition) could cause a very similar unit that seems to be defined by the boundaries of Victoria's ejecta blanket. There are even traces of the same dessicative cracking in the annulus, which seems entirely absent (or masked) in the etched terrain.

Anyone want to take a shot at why these units seem so similar, and if they *are* the product of the same processes, how these processes can modify *only* the annulus around Victoria, not affecting the large drifts and exposed evaporitic sandstone that surround it?

-the other Doug

Hmm... this is a question that, for me, has several answers, depending on the epochs of my life.

When I was a child, it was unbearable weeks of waiting, helping Dad find and trim a tree, being as good as I possibly could, listening for reindeer paws on the roof on Christmas Eve, being forced to eat *something* (I usually managed to choke down a piece of toast) for breakfast before opening our presents on Christmas morning, the smells of baked ham, candied yams and pumpkin pie making me hugely hungry as I played with new games, assembled new plastic models, or just read a new book, helping my Mom make ham salad out of the leftover ham the day after Christmas...

When I was a young man, fresh out of college and married, it was rushing to get all the presents wrapped, going to my Polish mother-in-law's for a Christmas Eve dinner of roast goose, polish sausage and pierogi (yum!), opening presents, rushing home, trying to get to sleep early so we could get up early, pack up the car on Christmas morning, driving three hours to my folks' house, explaining we'd already eaten (if we had or not), opening more presents, sitting down for the familiar (and still scrumptuous) ham dinner, helping Mom make ham salad Christmas evening, and then rushing back another three hours home...

On one very, very dark Christmas eight years ago, it was sitting at my folks' house, staring at a hastily-raised artificial tree and wondering bleakly just how many more days my aging and ill Dad was going to live (turned out to be only another fifteen days). Getting the flu (from hanging out at a hospital for way too many hours a day for the previous six weeks) and spending Christmas Eve and Christmas Day being violently ill.

During my second marriage (after I had become a confirmed Wiccan, which is a pagan religion to all those who aren't familiar with the term), it was buying Yule presents, having a pleasant Yule ritual with friends on Winter Solstice, in which we would act out the old dramas of ignorance in which men beseeched their gods to *please* let the days start getting longer again, exchanging Yule presents, and gathering around our brightly decorated Yule tree...

Nowadays, it's having about thirty seconds of private contemplation of the cycles of life on the Winter Solstice, trying to find one of my high-school-kid managers at my Pizza Hut who can run my store for two days without causing a major disaster so I can visit with my 75-year-old mother, helping her make a small ham steak for us and my brother, exchanging a few presents, and driving the 18-hour round trip between Minneapolis and central Illinois praying that no ice storms or snow storms keep me from getting back to my store in time to finish my year-end inventory, which has to be completed and logged in the computer by midnight, December 25 -- and arriving to find that the computer has everything AFU, my inventory counts are primarily set to zeroes, I can't set new closing inventory amounts, and the help desk is a recording rather diffidently wishing everyone a Merry Xmas... *sigh*...

I think, of all of them, I'd rather be a child again... Heck, between now and eight years ago, I'm not totally sure which is worse.

-the other Doug

You know, I was in grade school 46 to 40 years ago, so I don't have the clearest memories of exactly what kinds of science I was taught way back then. However, I do recall an event...

My brother was in 3rd grade and I was in 1st grade. My brother's class was doing its science lessons, and his teacher, Mrs. Ambrose, asked the class if anyone knew why the Moon had phases. My brother, a bright child and as interested in matters extraterrestrial as I was, raised his hand and proudly explained about how it (the Moon, not his hand) orbits around the Earth, always showing us its same face, and as it went around, its aspect to the Sun changed and so we saw different portions of it in illumination.

Mrs. Ambrose scolded him in front of class, told him he was wrong, and told the class that the Moon shows different phases because its distance from Earth changes as it orbits.

My brother got suspended from school because he stood his ground and told his teacher that she was wrong. In front of the class. The suspension was lifted and the teacher was disciplined (thankfully, was "retired" from her position after that school year) when my parents went to the school's principal and could (and did) demonstrate that even my brother's little kid brother (me), only in first grade, knew the subject better than their teacher did.

All I can really recall in my early space education is that when I was about eight or nine years old, I had read every single book in my school library and every single book in my public library's children's section. My parents went with me to the public library and talked them into giving me an "adult" library card, which you supposedly had to be 16 years old to be granted. I browsed through most of the subjects, but gravitated to the space books. By 1966 or so I had read every single book in my public library on astronomy, geology, meteorology and physics, as well as every scrap of science fiction available... When I entered high school, I was lucky enough to attend the local university's laboratory high school, so I not only gained access to the high school's library, I gained access to the university's library, as well.

Sometime in the middle of high school, I hit puberty really hard and it hit back just as hard -- but the upshot was that my interests widened (read: girls), and I sort of slowed down in my voracious reading. I stopped reading everything just for the sake of reading it, and concentrated more on new materials on space exploration. And, as I grew, got an education, started working and got a "life", even my reading on space topics slowed.

This is partially why I have this vast storehouse of information (some of it quite trivial) about astronomy, geology, and many other subjects, but much of the basis of that knowledge is a little dated. I've kept somewhat up to date in the physical sciences, and very up to date in space exploration (and only somewhat less in geology), but the vast amount of data I acquired as a child, that forms most of my knowledge base, is, admittedly, 40-plus years from when I acquired it and was probably 5 to 50 years old when I first read it.

So, when some of my comments may seem to have outdated concepts, just remember that I'm almost entirely self-educated in science and technology, and much of that is based on the voracious reading I did as a child...

-the other Doug

Oh, there is definitely a story out there in terms of cratering rates and how the current erosion rates work on erasing cratering remnants. And I'm sure that somewhere someone is working on it.

However, while we are at a point where we can do *comparative* dating of various geological strata, we just are not and cannot be in a position to do *absolute* dating until and unless we have samples in hand (or we figure out how to do rock dating remotely, on in-situ landers).

In fact, for the larger-scale landforms, we already have a comparative dating system (Noachian, Amazonian, etc.). But the actual date ranges in which these land-forming events took place on Mars is still nothing more than energetic arm-waving, at this point. And, again, this will continue to be the case until we can pin down absolute ages in some fashion.

-the other Doug

As long as they remain these tiny little links that you can barely notice, I'm all for it, Doug. Check the fine print of any agreeement you sign, though -- this is one site that doesn't flood me with pop-ups (that my browser has to spend time & resources to suppress), or throw flashing multi-color ads at me, or load tracking cookies. As long as your agreement doesn't give them the right to do any of these things in the future, I'm just fine with it.

-the other Doug

And I suppose HAL's final breakdown was caused when there was an extremely unlucky flip of the bit in its programming that turned on the "Become monomaniacal and murder the crew" subroutine?

I think the question then becomes the sanity of Dr. Chandra for including that subroutine in HAL's programming in the first place...

-the other Doug

Since MSL will travel faster than the MERs and Sojourner (if only marginally), it will be the fastest moving thing on Mars.

So, why not call it Bottomos?



-the other Doug

p.s. -- if someone could name the short story from which my reference comes, I'd love the reminder. I remember the piece clearly, but have not the slightest remnant of the title or author left in this rotten gray thing I call a brain... *sigh*...

Bob, your return has made this one of the happier Christmases I can remember!

Good to have you back!



-the other Doug

wowsh!!!!!!!!!! im so glad to be alive

I'll add a hug from me, too, Doug and Helen. I've had many cats in my life, and lost several of them. It's always painful.

But I also find that my dear, departed feline friends are still with me, and always will be. Suzi will haunt your footsteps, always just out of view; she'll be there, nuzzling your hand in bed just before you wake up; she'll make a noise behind you and you'll twirl to find... nothing. But she'll have been there.

Have a safe and happy holiday, Doug. You too, Helen. And remember, the pains of death are all reserved for those of us who have to go on.

-the other Doug

Hmmm... not *all* of the worlds in that range, since Venus and Earth are of near-identical size and mass. Earth has a lot of tectonic activity, but its shattered crust seems to exert more control over the orientation of rifts and crustal cracking than whatever it is on these other worlds that causes equatorial tectonics.

-the other Doug

Oh, dear, he's found us out... I suppose we'll have to kill him now...



-the other Doug

Perhaps... though, when you look at the numbers, it seems that the majority of Mars probe failures fall into distinct categories:

Decent engineering, bad workmanship: This plagued a lot of the early Soviet Mars probes.

Launch failure: This is responsible for 40% of the American failures -- Mariners 3 and 8.

Simple mistakes: In addition to MCO and Phobos 1, I would add the failure to fully evaluate how the MPL software would react when the landing gear deployed as a "simple" mistake, making this category responsible for another 40% of American failures. Granted, this probably doesn't qualiify as "most," but it's only equaled by lauinch failures, at least for the American program. (And, hey, wasn't one of the Viking spacecraft accidentally shut down for good by a bad command load? That sort of falls in here, too...)

Plain old bad luck: I put a few failures in this category, including the Mars 6 lander, Beagle 2, the DS2 penetrators, and even Mars Observer. In any complex mechanism, you will always have mechanical failures, and these missions tended to run into them at critical points in the missions. Either that, or had the bad luck of hitting the ground at the wrong angle, or onto a badly placed rock, or onto the side of a hill, or during a global dust storm... in other words, just getting on Mr. Murphy's bad side.

So, OK, maybe "most" isn't appropriate. But you gotta admit, of the various categories, it ain't insignificant, either...


I totally agree with the old engineering maxim that "Better is the mortal enemy of good enough." I just think that, in some cases, you have to raise the bar a bit in your definition of "good enough." I would say that, for example, a full simulated run of the EDL software, with all expected events represented accurately in the simulation environment, ought to be an absolute requirement for all Mars landers. The failure of this box being checked off (or even existing on the checklist, for all I know) in the MPL development cycle most likely caused its failure. It's this kind of thing -- flying the mission with a fatal flaw in its software that could have been caught with a single full-sim run of the EDL software -- that I think you just have to commit yourself to achieving, regardless of its impact on development costs.

Of course, as with anything I write here, that's just my own $.02's worth...

-the other Doug

Exactly, Doug. There are some things you *can* test end-to-end (like the software, for example), and this should always be done (would have likely saved MPL). But on some things, you just have to rely on engineering soundness. The engineering will either work, or it won't, and being thorough in your engineering studies and designs is the best you can ever really do.

Besides, most of the lost Mars probes were lost due to fairly simple mistakes. I'm reminded of that "Red Mars" set of animations someone put up on YouTube recently -- the one where the Red Rover and the Blue Rover are just standing around, talking, when suddenly a probe flashes overhead, burning up in the thin air, screaming "How many feet in a kilometer? How many feet in a kilometer?????"



-the other Doug