Exactly -- just try telling the French that something must be able to have sex in order to have a gender-specific pronoun. In the Romance languages in general (and French in particular), every single noun in the launguage is assigned either male or female gender -- for instance, a pencil is male, a table is female, etc. The entire structure of the Romance languages depends upon each and every noun having either a male or female "identity." There is no such thing as a genderless pronoun in French.

And you're right, I think only the Russians (at least of the European societies) refer to a ship as "he."

Americans (and, to a lesser extent, the British) have embraced scientific rationalism to the extent that they've tried to distance the English language from such non-rational concepts as a female chair or a male shovel, and I'm sure that more Americans refer to Spirit or Opportunity as "it" than they do "him" or "her"... but there is still enough irrationality to our language that we can safely use feminine pronouns for the rovers.

-the other Doug

Ah, but you also get windblown deposition on hills, too. Especially in "wind traps," like the subtle bench that lies between Spirit's current position and the summit of Husband Hill.

Add to that the fact that what your impression tells you is harder-packed pavement was unclimbable on the north face of the hill, and I think it's going to take more in-situ observations to determine the truth of the matter...

-the other Doug

Technically, of course, they're asexual, and the proper pronoun would be "it." But these rovers really grow on you, and it's natural to anthropomorphize them. Since the English and American tradition is to give ships a female gender, I think the feminine form is more appropriate.

Besides, there used to be a great Live Journal set in which someone posted to a blog as Spirit, followed by someone else who created a blog ID as Oppy. They both took on female personalities, and developed a bit of a following. I haven't seen them post anything new lately, but in the early days, it was fun -- Oppy lording it over her big sister by finding evidence of water first, nyah, nyah! And Spirit writing cold, depressing poetry and falling into a deep depression after only 16 sols, refusing to talk to anyone for just *days*...



-the other Doug

I'm concerned about the "rockless area," since the last attempt to scale to the summit through a fairly rockless area ended up with Spirit slipping down as much as she climbed up. I think it likely that any rockless area on the slope of this sized Martian hill is going to appear rockless because the rocks have been covered in wind-deposited dust, and therefore will be harder, not easier, to climb for the MER's wheel design.

What we want is a path paved with a large population of fairly small rocks that are well-seated into whatever soil fills the inter-rock areas. That should give Spirit the best chance of success, I would think.

-the other Doug

I'm somehow reminded of the climax of the film "Tin Cup." Just keep driving in, getting stuck, pulling out, driving in again... and sometime around Sol 800 we'll finally get through the thing!

-the other Doug

Hmmm... could be. But I doubt either the lighter drift material or the darker "stained" material are very fresh.

The stain might be the remnants of a rock or clod tossed out from a nearby impact, that made a crater in the drift a *long* time ago. The drift built up, covering the crater and the clod that produced it, and now the new prevailing winds are deflating that old drift and exposing its remnants.

Or perhaps a small impact produced a little crater in a light-colored drift, and that event was followed for a little while by a change in wind that deposited a darker dust. Now, the old drift is being deflated, the darker layer has been blown off of the remnant drift but the dark dust that once filled it is visible in what used to be the very bottom of a larger hole.

I *don't* believe it was a fairly recent crater that was filled in with dark dust, because if that had happened, we'd see more evidence of mantling of other features by this dark dust. And we really don't see any major layers of this shade of dust anywhere else that you could state with any certainty is a part of the same material as the "stain."

So much of the Martian surface is being deflated at larger scales, as is obvious from a lot of the orbital imagery, that it shouldn't be surprising to see surface deflation occurring at local levels, too.

-the other Doug

Don't tell me they're *really* going to approach Purgatory from the exact same direction they approached it when they got stuck????

-the other Doug

Remember, we have a certain baseline of observations from the earliest part of the mission. Spirit landed in late summer/early fall, local time, correct? And the DD activity at that time was minimal -- we never saw much in the way of them until we were well into the following spring.

We also saw the begining of DD season in early spring, and it seems to have peaked and has been trending down for a week or two, now.

I guess what I'm wondering is whether higher levels of insolation will, in fact, result in the formation of even more DDs? I think it's possible that the process of DD formation might not be directly related to insolation levels.

I also find it fascinating that DD formation seems almost more related to terrestrial tornado formation than simple terrestrial dust devil formation. Have you noticed how many of the larger DDs seem to start out with two, and sometimes more, small funnels dancing around the area in which the larger funnel shortly appears? This same fundamental observation has recently been made of terrestrial tornadoes -- that small, transient "whirlpools" dance and rotate around a larger low-pressure dip, "spinning up" the main funnel.

I think there are hints that we're seeing the same basic process in the Martian DDs, too.

Finally, I'll point out that whirlpool activity in fluid gas is driven more by pressure deltas than by temperature deltas, and that the Martian atmosphere's thinness gives other factors (including topography) more impact on pressure deltas than heating effects do. And observations from Viking, Pathfinder, MGS, MO, MEX and the MERs all show that local heating of the air by ground re-emission only strongly affects the air temperature for a few feet above the ground. Thermal homogenization occurs very, very low in the atmosphere. Topography, affecting air pressure directly and controlling most of the fine detail of lower atmospheric heating, seems to be the largest factor in local weather events. (Just look at how DD tracks are mostly isolated to very small patches, usually just off-center from the centers of large craters.)

-the other Doug

I think you're right. They might want to re-think the design of the wheels for MSL to increase the surface area and perhaps increase traction. If we're only going to get one MSL, we need to make it as capable as possible of traversing any of the terrains it's likely to encounter.

And from what I can tell, there are sand/dust drifts and dunes overlying almost every terrain on Mars, so it makes sense to design your vehicles to be able to handle them.

-the other Doug

I was speaking of MTO, not MRO, Doug -- but I'm sure you're right.

Let's see, MRO will be able to resolve (barely) Sojourner, right? All we have to do is take several pictures of the Pathfinder site on different days, and see if it's in the same position each time (as I imagine the odds are overwhelming it will be).

If it isn't, then I imagine there would be a scramble to see if they could pick up Sojourner's radio signal from orbit...

-the other Doug

Yes, I noticed it. I also noticed a circular feature in the interdunal soil that Oppy drove over just before it got bogged down in Purgatory.

If I had to guess, I might think that this dark circle is the nearly obliterated remains of a tiny crater. I've seen a few other circular marks in these dunes that seem to be tiny craters in various states of degradation -- this dark circle could be one that has been almost completely obliterated, leaving only a coloration "scar."

-the other Doug

OK -- I know this is probably The Stupid Question of the Year, but here goes...

Sojourner was programmed to circle its lander indefinitely if it lost contact. We know that the Pathfinder lander lost its batteries and died after about 90 sols, but, if I recall correctly, Sojourner had not shown any indications of failure up to that point.

I know it's *extremely* unlikely, but there is a *very* tiny chance that Sojourner is still waking up every morning, looking for a signal from Sagan Memorial Station, and failing to get one, is continuing its endless circle.

So, here is the really stupid question -- will MTO have the ability to pick up signals from Sojourner, and/or send it commands as if they had been sent from the Pathfinder lander? I know that wouldn't be part of its design -- but would it have the capability?

I guess I still remember Steve Squyres saying, back in '97, that he wanted to take Sojourner and head off to the Twin Peaks...

-the other Doug

Why is it a problem?



-the other Doug

One of the reasons that NASA looked the other way on some of the perks offered the astronauts was exactly because they couldn't afford to pay the guys great sums, and also couldn't offer them life insurance. During the 1960s, no insurance company in the world would write a policy on an astronaut's life. So, the financial perks were tacitly allowed, to provide the families a certain safety net in case a crew ran across a really Bad Day.

NASA didn't develop much in the way of new technologies -- they made use of some cutting-edge technologies, yes. But microwave ovens were around as early as 1963, and were more the by-product of radar technologies developed during and after WWII. Electronic miniaturization is also often attributed to NASA, but it's really more due to missile technology... we miniaturized electronics to make fusion bombs and their guidance systems small enough to fit on the rockets we could build.

NASA made some strides in things like freeze-drying foods, too -- but again, NASA didn't invent those technologies. They just made use of them before a lot of other people did.

Unfortunately, that's not legal. IIRC, the descendant of someone who received a moon rock as a present from the U.S. government inherited the rock and then trried to sell it on Ebay. The U.S. government put the nix on the sale quickly. (IIRC, there might also have been an ownership issue -- the rock might have been stolen from its original owner. But I believe the position of the U.S. was that even rocks that had been given to other governments were the property of all mankind and that no individual should be allowed to profit from their sale.)

-the other Doug

This discussion points out why I have a certain distrust of mathematical models that predict real-world behaviors -- they often don't account for the occurrences that lie on the shallow edges of the bell curve.

It's all well and good to talk about the number of joules generated when a body enters an atmosphere, and describe on paper what happens to such a body when that many joules of energy are transferred to it. But such a simple calculation doesn't take into account such facts as abalone describes -- golfball-sized objects that survive entry into Earth's atmosphere and whose deeper structures aren't even significantly heated.

Models are good ways to understand how the real world works -- as long as you constrain your expectations as to exactly what you'll let those models predict. The real world is "fuzzy," it includes chaotic phenomenah that cannot be predicted by models. And models are always more simplistic than the behaviors they attempt to predict -- any model complex enough to predict all of the observed phenomenah in the universe will be no less complex than the universe itself.

-the other Doug

Ah, yes -- I remember from the Voyager releases the mention of the "pizza-colored" Amalthea. I hadn't been aware that Metis and Thebe were also tinted orange-red, though.

Am I right in my recollection that the red color comes from sulphur sputtered off of Io (the same source as the sulphurous torus that accompanies Io in its orbit)?

-the other Doug

What seems odd to me about any excitement over finding calcium on the Moon is that plagioclase is a mineral made up of silica, aluminum and calcium (and other trace elements). And the Moon's crust was formed from an ocean of plagioclase, creating the anorthositic gabbro that forms most of the current surface.

That right there would argue for there being a considerable amount of calcium on the Moon, and for people to have known this for quite a while.

The only reason I can think of for calcium to be an as-yet undetected major lunar element would be if the plagioclase on the Moon is somehow different from terrestrial plagioclase. And we have a fair amount of plag in the lunar samples -- has there been some calcium anomaly detected in the lunar samples?

-the other Doug

There aren't very many good articles on the web about it, so I'll tell you some details here.

During the early years of American manned space flight (Mercury through Apollo), astronauts were celebrities and heroes and got a lot of lucrative offers and deals. For the most part, NASA looked the other way as car dealers gace them free cars, bars gave them free drinks and restaurants gave them free meals.

There was also a well-established trade in objects that had flown in space. Each astronaut got a Personal Preference Kit, weighing few pounds or so each, in which they could carry anything that fit under the weight cap. The guys carried things for friends and relatives, and they also carried items that were later sold, the proceeds going back to the astronaut in some fashion.

One of the more popular things that astronauts carried were stamps, since you can carry quite a few of them without taking up much space or much weight. NASA approved a lot of stamps, carried for later sale by the USPS and other agencies -- with no special renumeration going back to the flight crew. On Apollo 15, they were supposed to carry something like 50 pre-stamped envelopes and a canceling stamp to cancel them while on the Moon.

They actually carried more than 200. The extras were given to a dealer, the proceeds were to be given back to the crew in the form of trust funds for their childrens' college educations.

Apollo 15 also carried a small original sculpture called "The Fallen Astronaut," which was placed on the Moon along with a plaque listing all of the astronauts and cosmonauts who had died to-date in the pursuit of manned space exploration. The sculptor had arranged to sell copies of the sculpture, starting no less than a year after the flight, with one-quarter of all profits going into trust funds for the crew's childrens' educations.

What happened to the Apollo 15 crew was that the sculptor (or his manager) started selling copies almost immediately, bringing the deal to the notice of NASA and the press. The crew disavowed the deal and refused any payments, but this caused a Congressional subcommittee to hold hearings on astronauts profiting from side-deals resulting from items they took with them on their flights. That was when the stamp deal became public.

The Apollo 15 crew was chastised by NASA because they initially denied that they had ever been involved in the stamp or sculpture deals, then later admitted their involvement. They had been named as the back-up crew for Apollo 17, but after NASA issued letters of discipline, they were relieved from active duty and were replaced by John Young, Charlie Duke and Stu Roosa. Scott and Irwin transferred to other NASA centers and then retired, while Worden (IIRC) returned to Air Force active duty for a couple of years.

The guy who really got shot down was Jack Swigert. The Congressional investigation revealed that Swigert, on Apollo 13, took along a pretty sizable number of stamped covers and profited from their sale, and when asked about it told the investigators to go to hell. He refused to admit anything and never admitted to his actions. Swigert was Deke Slayton's first choice as one of the ASTP crew, but his non-cooperation in the stamp scandal investigation earned him a permanent seat on the bench, after which he resigned NASA.

Poor Jack -- he was elected to Congress in 1980 (if I'm remembering the dates properly), but died of cancer before he could take his seat in the House...

-the other Doug

I'll reply in a new thread in the EVA forum for Manned Spaceflight.

-the other Doug

A lot of those little craters make up very straight crater chains, too -- just like we've seen on some of the larger icy moons, like Rhea.

In fact, a *majority* of the craters of a given size range are located in crater chains.

I'm impressed by the two chains that form an "X" in the last image on the right. Is it possible that we've found Planet X, the source of the shaving cream atom?

-the other Doug

I think you're right. Well, the drifts around Oppy's stuck position show layering, especially in places where older drifts appear to be in the process of deflation. Some of those layers are a lot darker than others, and in the color images I've seen, look grayer.

There are a few ways you could get layers of basaltic dust interleaved with layers of evaporite dust and blueberry paving/dust, including deposition during large dust storms and cyclic variations in prevailing wind directions.

If the layers in the drifts are from dust storm deposition, these drifts must be dynamic and young features, indeed, since we get major dust storms every few years...

-the other Doug

Yes -- as I understand it, they moved the wheel from its seven-degree toe-in position to what looked in the pics I saw about 90 degrees to straight forward (continuing in the toe-in direction), then moved it back as far as it would go, which was back to the seven-degree toe-in. It won't move any farther towards a toe-out position.

They don't want to exercise it a lot further, since it's now only a partial actuatior failure. I guess the theory is that it could become a full failure at any time, and that, of the positions they can get that wheel into right now, the seven-degree toe-in is the "least bad." Moving it *at all* runs the risk of it getting stuck in a worse position.

-the other Doug

It didn't get so far as to have a design of EVAs or a specific targeted landing point, but the sampling objectives were (as I recall):

1 -- recovery of Apollo 15 equipment, for sale back on Earth to help defray the cost of the flight.

2 -- rocks from the supposedly volcanic craters of the North Complex (Pluton, Icarus and Chain).

Since Harvest Moon would have been limited to two walking traverses, I'd have to think they would target the landing site to the north of the Apollo 15 landing point, allowing one walking traverse to the south for purposes of scavenging the original mission's equipment, and a second walking traverse to the North Complex.

I know what a lot of you are thinking -- why not just recharge the Rover's batteries and use it? The problem, of course, was that those batteries were not rechargeable and the Rover's EPS was not designed for refurbishment in-place. Taking the batteries out and replacing them would have been difficult, if not impossible. (That's the Rover's main power batteries. The LCRU batteries, that powered the comm unit and TV camera, *were* replaceable in flight.) Besides, collecting pieces of the Rover was one of the higher-priority sampling objectives.

-the other Doug

As I recall from Spirit's wheel problems, though (which had nothing to do with the steering actuator), the wheels cannot be left to just turn freely. When Spirit was trying not to use its one bad wheel, that wheel was simply turned off and Spirit dragged it along. That's why Spirit had to drive backwards -- it could maintain good speed and controllability dragging a "back" wheel, but not a front wheel.

In Oppy's case, the wheel turns fine, it just can't be straightened out. As I understand it, it can move from its seven degree toe-in position all the way hard over in the same direction, and back, but no further the other direction.

When Oppy got stuck, it was using its bad wheel but it was driving backwards to lessen the impact of that wheel's toe-in position. The controllers had run into some issues making Oppy drive straight in this configuration, and had made some changes that helped, just before we got stuck. That *may* be one reason we got stuck -- Oppy has to make smal "turns" as it drives backwards just to keep moving straight; it may have made one of those small turns with its "front" wheels just at a point where such a slight turning of the wheels caused them to dig in to the drift it was traversing. I'm sure that's one of the things the MER Team will be examining when it takes a very close look at Purgatory Dune.

-the other Doug

Slightly OT here, the thing I always found fascinating about Harvest Moon was that it proposed to use the leftover CSM and LM from the *original* Apollo 15 mission, the H mission (45 hour stay time, no rover, two EVAs) that was canceled during the final round of mission cutbacks in 1970.

One reason it went nowhere was that the people who were trying to sponsor it costed it out by referencing declassified NASA budget lines, but they never discussed the possibility with NASA itself. They quickly discovered that while they *might* have a shot at buying surplus Apollo hardware, they'd have to arrange for the NASA Apollo "Army" to support such a flight, from the launch preparations and support at KSC through the crew training, flight operations support, etc., at MSC (now JSC), not to mention the millions of dollars worth of support NASA got from the Navy and Air Force. Not only was NASA unwilling to fly surplus hardware for a private company interested in profits, the armed forces weren't interested in supporting such a thing, either. So Harvest Moon died a-borning.

It also didn't help that the Harvest Moon people wanted to return the Apollo 15 crew itself to the Hadley-Appenine site, announcing that Scott, Irwin and Worden would fly the mission, and just after their announcement, the stamp scandal hit. NASA was NOT going to allow Scott and his crew to fly in space for them again, much less support anyone who was going to use their skills to make profits from sending them back to the Moon.

-the other Doug