Yes, but... can you imagine the following scenario?

ARMSTRONG: OK, I'm gonna step off the LM, now. That's one...

CRONKITE: Thanks for watching. A full video of the rest of this Moonwalk will be available for purchase sometime in November. Please tune in to the CBS Evening News for another twenty seconds of this amazing scene. Until then, I'm Walter Cronkite, looking forward to a huge bonus in my paycheck. Good night.



-the other Doug

Thanks, Fred! Though, I have to say, this isn't a lot of info. I agree that the berry size observations seem to place this layer at a similar place, stratigraphically, as the surface we've been driving on, but I'm interested in things like variations in bromine and chlorine levels in the salts. What are the layers we're looking at now telling us about where we are in the entire Meridiani sequence?

Maybe I'm just desiring too much, too soon... *sigh*...

-the other Doug

This discussion is interesting in that it seems to reduce the question down to whether or not Europa alone is intrinsically more interesting than the rest of the Jovian system.

I have to agree with Jason -- I think that, given a choice between the JSO and EE mission profiles, I like the JSO better because it gets most (if not all) of the data you need about Europa to plan the next mission, and gives you a lot more data about the rest of the system than EE would.

Recall, please, that some Galileo results suggest that Ganymede and even Callisto may have "molten ice" (i.e., liquid water) mantles below their solid ice crusts. Granted, Europa is the most interesting from an astrobiology perspective (more access to sunlight and tidal heating), but any body with a hard ice crust and a liquid water mantle can teach us an awful lot about such worlds.

And it may be a very good idea to learn about them -- it's always possible that there are more habitable worlds of the Europa type out there than there are of the Earth type. After all, a Europa could form around pretty much any gas giant in a huge expanse of a solar system's domain, while an Earth has to reside in that narrow little Goldilocks band. Statistically speaking, you might expect more life to arise in Europa-like worlds than on Earthlike worlds, just from sheer numbers.

-the other Doug

Yes, but... by this time after we began the Endurance campaign, we were hearing preliminary reports about the kinds of salts that were being found in the layers of rock.

Has anyone heard a single thing about what Oppy is finding within Victoria? Or has JPL farmed out Oppy's future explorations to ESA?

-the other Doug

Here's a question that seems appropriate in this context:

What is thought to be the primary cause of nutation in planetary moons? Is it gravitational, and does nutation by gravitational perturbance require a body to be significantly non-homogenous? Or is it thought to be remnant motion imparted by large impacts? Or is it a range of influences, no one of which can be cited genercially as "primary"?

I ask because while you might expect to see impact-related nutation on a scarred body like the Moon, you don't seem to see large basins on Titan whose formation could have been expected to toss a body out of kilter...

-the other Doug

I can see a sustained 25km lunar orbit, maybe, but I think a 10km orbit would be pushing it. A lot. After all, the Moon is lumpy, and not just gravitationally -- there are some mountains (well, basin and crater rims, mostly) that rise nearly 10km up from their surrounding terrains.

And, as the gallows humor that surrounded the Apollo 8 flight had it, "60 miles? Just wait 'til you get a load of that 61-mile-high mountain on the Far Side...!"



-the other Doug

There is one factor that I don't think even the MER drivers are taking into account, here. Winds. Or lack thereof.

Oppy has had several cleaning events since the Storm, and Spirit has had really none. Oppy is in and around a big crater, which intensifies winds. Spirit seems to be in a mostly wind-dead area, a depositional trap more than anything.

If we want Spirit to survive the winter, I think we need to find a wind-positive location somewhere near Home Plate. I'm hoping the north edge will have more winds than LRH did and than we've yet seen, but with all the dust I see deposited at the foot of WH3, I have my doubts...

-the other Doug

Here's a question I've always wondered about and never heard a satisfactory explanation for:

AFAIK, the later Soviet Luna landers, from 16 on, utilized a "direct descent" trajectory, where they simply were aimed at a given spot and descended directly without going into lunar orbit first. (Rather similar to what the U.S. used for Surveyor.)

Why, then, did Luna 15 go into lunar orbit when it arrived at the Moon? You'd need an entirely different type of descent trajectory and descent engines to pull off both an LOI and a PDI -- seems to me the later landers had to have been somewhat simpler in design and construction.

I've always heard that Luna 16 was a successful re-flight of the failed Luna 15. If so, was the lunar orbit strategy for Luna 15 one of the causes of its failure?

-the other Doug

As far as I know, however, all of the lava tube caves we've seen from orbit occur in the Tharsis bulge, many along the flanks of the great shield volcanoes.

Those areas are significantly above "sea level" on Mars. Quite significantly. So much so that you have an even harder time landing anything there -- there's just not enough air to slow you down enough to be able to land anything as heavy as a MER, much less an MSL.

-the other Doug

Percival Lowell. He may have been utterly wrong about a lot of things, but his energy prompted a rennaissance in the field that launched modern astronomy.

-the other Doug

And yet, on that Stage6 page nop linked to, there is something to make the blood pressure rise...

There is only one comment left so far on the clip. "nice cg"

Makes ya wanna spit...!

-the other Doug

Great list, Mongo!

A few updates, of course...

Japan: Kaguya, Hayabusa

ESA: SMART-1, Venus Express

China: Chang'e

U.S.A.: Messenger, New Horizons

For those last two -- OK, they haven't completed their missions, so we can't classify them automatically as "successes". But NH has already had a quite successful Jupiter encounter, and Messenger has done some nice work at Venus. I say we ought to count them -- and consider adding Rosetta to the ESA count, on the assumption that she'll hold together long enough to accomplish her extended mission.

I'm less certain about adding Dawn and Phoenix to America's talley; neither has actually done much data gathering yet. But they are in flight.

Anyone think of any more?

-the other Doug

I've always pronounced it with a short 'a' sound in the first syllable, with a second syllable pronounced "pahss". With emphasis on the first syllable. (Rhymes with "tapas" as in a tapas bar.)

I wish I could easily type in phonetic symbols...

-the other Doug

But remember, Delta IIs only look cheap in comparison with Delta IVs and Atlas Vs. We're still talking significant expense. The expense of launchers has driven a lot of commercial users to less costly -- and less reliable -- systems.

What we really need is some revolutionary new propulsion technologies that will make access to LEO a lot cheaper than can be accomplished through the sole use of chemical rockets. (And while I'm wishing, I ought to toss in a good thought for World Peace, too, I guess...? )

-the other Doug

The problem with this concept is not just that we're comparing apples and oranges -- we're comparing apples, oranges, bananas, pears, strawberries and kumquats.

Apples: Doing *anything* first earns you a special place in a list like this -- which is why the lack of Luna 9, Lunar Orbiter 1, Luna 16 and Lunakhod 1 are somewhat glaring. Sounds like the author of the piece just plain isn't interested in the Moon, and therefore delegates lunar probes to a back seat. In a time when Apollo hadn't happened, the first good images of the Moon from the surface and from orbit were powerful, compelling, and scientifically important. There are tons more of these in this category -- Mariners 2, 4, 9 and 10, Lunas 2 and 3, Surveyor V... and many more than don't come to mind at the moment.

Oranges: Making major discoveries certainly distinguishes a mission. The Voyagers, Mariner 2 and Cassini certainly stand out in this category. So do the MERs. The Viking landers aren't at the head of this list, though -- they belong in the Apples group, but while they returned a lot of interesting data (and some great images), they didn't make any amazing new discoveries about the Martian surface. We already knew it was iron and sulphur rich, and there was nothing particularly surprising about finding a lot of iron-rich lavas covered with sulphate salts. The hydration/oxygenation in some of the materials was predictable, so even its (somewhat ambiguous) discovery wasn't all that much of a major thing. Mariner 9 and the Viking orbiters told us more about Mars than the landers did.

Bananas: Observing stars (our own and others) and celestial phenomenah is worth a mention, too. From OAO to WMAP, from OSO to Ulysses to SOHO, from Compton to Hubble to Spitzer -- these deserve recognition as great probes, too.

Pears: Missions that provide a (for want of a better term) spiritual satisfaction deserve a special category. The first views of a full Earth, the oblique view of Copernicus from L.O. 2, the first views from the surfaces of the Moon and Mars, the view of backlit Saturn and its rings in all their glories -- these are views that nourish the human spirit's need to explore. Almost every good mission has provided this to one degree or another... but some more than others.

Strawberries: Almost every mission returns more data than the last one. As time and technology progress, each new spacecraft is more capable than the last, each can return more data than the last, each is more productive than the last. By this standard, the most outstanding mission flown is usually the most recent one accomplished. (Differences in scope between Flagship missions, Discovery missions, etc., notwithstanding, that is.)

Kumquats: There is something to be said for the inherent interest generated by the body or bodies being studied or probed. If you feel that icy moons are inherently more interesting than rocky bodies, then you're going to be interested in Voyager, Galileo and Cassini data more than in Viking or Luna data... now, in my mind, there is no such thing as an uninteresting Solar System body, so I tend to discount this category as being much of an overall criterion. But that's me.

So -- maybe we ought to be nominating missions in categories like the ones above, rather than in an overall "10 Best" kind of format...?

-the other Doug

There is no way on God's Red Mars that I could resist driving Oppy over to Cabo Verde and have her spend a few months working over that rock face.

It looks like there is sun for much of the day along this side of the promontory, and that there are approaches where Oppy would only be riding along at a 20 degree slope or so. I'd bet Oppy could safely work the rock face.

Anyone wanna speculate?



-the other Doug

The only corroboration I can find right now that the 2003-2005 MSR concept was to use military hardware is Steve Squyres' comment, in "Roving Mars," that the mini-MAV being planned for use in conjunction with the Athena rovers was "based on a classified Navy program." He also mentions the program had been in existence since 1958.

Squyres says that the payload this mini-MAV was to have lofted into low Mars orbit would have been about the size of a coconut. I imagine this would have weighed significantly less than 100 kg -- maybe only 20 to 30 kg.

The 2003-2005 MSR concept was that two different MSR landers would be flown, each serviced (i.e., loaded with samples) by one of the Athena rovers. An RTE vehicle would then rendezvous with and "gobble up" each of these coconuts and then burn back out of Mars orbit into an Earth return trajectory. (No matter what else happened, this means the two coconuts would have to have been launched into identical orbital planes, or else the RTE vehicle would never be able to carry enough fuel to rendezvous with them both.)

-the other Doug

Apollo's Lunar Rover used bee's wax to cool its Lunar Communications Relay Unit (LCRU), the self-contained comm system that allowed good comm (and TV) from wherever the Rover was parked. It cooled at the phase change between solid and liquid, and was pretty effective up to about 150 degrees C. (It *may* also have used the phase change from liquid to vapor for cooling, I just don't recall right now. But I know it used bee's wax.)

-the other Doug

Yeah -- the bloke just likes to hear the sound of his own bloody voice...

Seriously, Doug, I can recall just how fed up you (and many of us) were becoming with the discussions taking place on Usenet and on the couple of other fora out there (like the infamous "yellow" forum). My understanding was that you created this place 'cause you were sick of the crazies.

I mean... when you have to spend half of your energy explaining to someone that no, Mars did not see its molten core solidified due to its oceans streaming into Valles Marineris and "putting out" the core -- well, that ends up being less than enjoyable. Right?

-the other Doug

Lovely! That crack is a little thinner than it looks from above... but the system still looks constructional to me (as opposed to dessicative).

Oh, how I wish we still had a working RAT on Spirit! I'd love to take a good close look at the vertical faces in the top 10cm of the crack (i.e., the exposed face).

-the other Doug

I dunno, Dan -- the last MSR concept I saw (back in the late '90s) used some leftover, off-the-shelf solid-fuel military missile as its basis for an ascent vehicle. I bet there are at least two or three of them left that haven't been fired in anger yet...

-the other Doug

CEV Block IA is designed to ferry supplies to ISS, unmanned. It will have something like a 3,500 kg cargo capacity, all packed within the pressurized re-entry vehicle, and it will be able to return materials to Earth from the ISS.

CEV Block IB is designed to ferry crew to and from the ISS. It will have a 400 kg cargo capacity in addition to up to 6 crew, and will be able to remain in orbit, quiescent, for up to 180 days. (ISS crew complement will increase to at least 5 and perhaps 6 when this vehicle goes into service.)

CDV (Cargo Delivery Vehicle), a version of the CEV Block IA which delivered materials in unpressurized form (possibly without any docking equipment save for robot-arm grapple points) was canceled nearly two years ago to "speed the production" of the CEV.

Both Block I CEVs are currently being designed to use the Russian probe/drogue docking system, not the APAS docking system. It's possible that, after the final Shuttle visit to ISS, one or more of the PMAs on the station will be modified with a Russian docking drogue replacing its APAS. In any event, either of the Block I CEV designs will be able to dock with ISS's Russian segment.

The biggest issue with the CEV is that it cannot deliver rack-sized equipment to ISS, as the Russian docking tunnel is not wide enough to allow anything so big and bulky as as full ISS rack to pass through it. Anything rack-sized is either going to have to go up in pieces, or will have to use some other means of transport.

Of course, this is just the current design. No metal has been bent on anything except boilerplates as of yet -- I'm not even positive that "final" engineering drawings for either variant of the Block I CEV exist yet. That's a pretty big caveat in this kind of project...

-the other Doug

I really think Spirit ought to traverse along the western edge of HP to get to the north slopes. I'm still intrigued by the large crack that runs parallel to the west edge -- I can think of a lot less interesting places to visit on HP than that long crack.

If we're going to find anything different on top of HP than we found along the edges, that crack is the first palce I'd be looking for it.

-the other Doug

There is a somewhat famous piece of cover art from an anthology featuring, and named after, A.C. Clarke's short story "Transit of Earth" (published by Playboy, 1971). Of course, this particular piece, while it shows Earth from Mars, shows it as it transits the solar disk.

Might not be exactly what you were looking for...

-the other Doug

Well, the last time we tried to fix a space station solar wing, it was a mite bit different...

First off, we had only a few tens of hours of experience in zero-G EVA at that time, and while we sort of basically knew the need for footholds and handholds, we didn't know as much about how you had to anchor yourself properly in order to apply force through your body. Which is how Pete Conrad ended up flying, in his own words, "ass over teakettle" after he used his legs to exert pressure on a tether that was hooked to the end of the solar panel. Panel breaks free, the line goes slack, and Pete flies off the surface of the Skylab with all the power his legs had mustered.

Good thing the umbilical attaching Pete to the airlock was strong. He hauled up to the end of his line, stopped suddenly, and after positioning himself he pulled himself back along the umbilical.

Problem is, there were no TV cameras pointing at the right places to truly capture the event! We sort of saw Pete's legs go flying out of the picture when the SAS deployed, but only have his own colorful telling of the story for the details of what followed...

BTW -- I was 17 years old and followed the Skylab flights quite closely. Oh, for that amount of enclosed space again within a habitable volume! Nothing else has ever come close. (And if you've ever visited the backup Skylab, on display at the NASM, you'll realize that it wasn't all THAT huge in and of itself...)

-the other Doug

p.s. -- not only do I remember Skylab, I actually submitted a proposal for the Skylab student experiment program. It wasn't accepted, alas -- I was proposing studying cancer growth in mice in a microgravity ennvironment, and the hassles of keeping the mice were more than NASA wanted to deal with for a "simple" student experiment. But as I say -- I not only remember it, I tried to get an experiment flown on it! DVD