Remember that the eye needs something to put an image into scale to make it appear impressive. Consider that while there are many images of Earth from cislunar space and lunar orbit, it's the ones framed against the lunar horizon that get put on postage stamps...

As Chang'e's landing site is at 45 degrees north and about 20 degrees west, I'd think that the Earth is no lower than about 45 degrees up in the sky at any given time. An image captured of it using Yutu's camera would likely show only the Earth, and nothing of the horizon below. In that way, it would be indistinguishable from a picture taken of Earth from lunar orbit which also included no portion of lunar surface in the frame. Just another pic of Earth from a lunar distance, nothing really special.

Now, if Yutu pulls up against a nice-sized piece of surface relief, spotting the Earth as it sits above a peak, or a rock, could be a dramatic shot. Not seeing anything in the near vicinity that would fill that bill (except maybe for heading down into a deep crater), I dunno when we might see that kind of photo op.

-the other Doug

Oh, yes -- a sliver of the footpad is visible, and the ground around it is in deep shadow.

I guess what I was noting was a difference in philosophy between the American (and to a somewhat lesser extent Soviet) engineers and the Chinese engineers. On American unmanned landers, the cameras were specifically positioned to provide initial images of a footpad on a lighted surface. The Chinese did not specifically position their cameras to be able to do this.

I'd bet this is a sign of confidence in the current knowledge of surface conditions. On Surveyor, the flight engineers wanted an initial confirmation that their craft was planted firmly on the surface. The surface conditions were far less well known at that time, and an image showing the footpad firmly on top of (not hanging above and not sunk deeply into) the surface was an important confirmation of the potential for successfully completing the mission.

The Chinese, on the other hand, are starting out with a far better operating knowledge of the surface conditions, and with more sophisticated IMU-based navigation than was available to early Luna and Surveyor craft. Therefore, there is less of an urgency to position a camera just so it can give you a confirmation that a footpad is firmly resting on the surface. Other imaging priorities come in to play, and hence you don't get the classic footpad shot.

Again, just an observation.

-the other Doug

I find it interesting that earlier American and Soviet unmanned landers made, almost immediately after landing, images of the interaction between the landing gear pads and the surface. Heck, the famous first shot from Surveyor 1 is of the landing gear pad and shows how it pushed back the lunar soil. (Yes, there were some Soviet landers that had no landing gear, much less footpads, and I know that the final Soviet sample return mission landed in the lunar night and didn't return a lot of scenic photos. But for those with landing gear pads that landed in sunlight, the first pics seemed always to be of the gear-soil interaction.)

In addition, I believe that pretty much all of the American Mars landers that used gear and footpads did the same thing. Remember the first image from the Viking 1 lander? A pic of the footpad sitting on the ground.

Chang'e 3 didn't take such images from the lander, at least that I've seen. But the latest images of the lander from Yutu seem to show very definite piles of freshly disturbed regolith sitting radially outwards from each pad. Not radially distributed around the circular pad -- radially from the lander itself. Out along lines drawn between the center of the vehicle through each footpad.

The only dynamic I can think of that would preferentially throw soil outwards from each pad would be one where the gear actually flexed outward, away from the octagonal lander body, at touchdown and then recoiled back to their normal deployed position. As the gear and struts look rather similar to the Apollo LM arrangement, this doesn't sound like something they would be designed to do.

Just an observation...

-the other Doug

Hellas appears to be depleted in hydrated minerals -- at least, everything except its northern outer flanks. (As per the map of hydrated materials generated from MEX data.) I'd have to guess that the impact that created Hellas occurred after the height of Mars' warm, wet period. While there is volcanic activity and small-scale river and stream formation observed in the northern ramparts of the Hellas basin, very little is seen in the inner walls and floor.

And that's too bad, since as a very low point on Mars the atmospheric pressure on the floor of Hellas is higher than at most locations on Mars, which would make it easier to land a heavier vehicle there (more potential parachute braking effectiveness). As an impact basin, as well, most of the original materials of the Hellas basin floor would consist of impact melt, from which a lot of work would have to be done to sort out the nature of the original rocks of the target area. (Impact melt reflects the total composition of all of the units melted, so it's a rather big job to sort out what went into making up the melts. Lunar scientists are still trying to sort out the original Imbrium target rocks based on the rather basaltic impact melt obtained in Apollo samples from the Fra Mauro formation...)

-the other Doug

Beautiful! Very familiar interaction pattern between the rocket exhausts and the regolith. Also, looks like at least one of the landing jets kept firing (at least in pulses) for several seconds after touchdown.

And really, really cool how the distant mountainous rim wall slowly sank below the near horizon.

However, as I saw that big crater edge into the scene from lower right, all I could think of was that it seemed like a very long final phase, because the auto-targeting was taking it right into a football-field-sized crater with a large number of big boulders and rocks...

-the other Doug

A couple of observations about the imaging thus far:

First, the images from Yutu's mast camera seem a little over-saturated. At least, the brightest elements in the images (the rock faces reflecting sunlight right back into the camera) look rather over-saturated to me.

Second, the color rendition from the lander's panoramic camera seems to be biased towards a very brown image, while the rover's color camera is registering more of the expected grayish coloration of the regolith, almost trending towards a slight greenish tinge. Interestingly, these are the same range of color biases that were achieved from the various color film stocks used during Apollo. It took until the later flights for the photo processors to achieve a consistent representation of the grayish lunar regolith; this shows how difficult it can be to get good, representative color from the lunar surface.

I wonder if the mission controllers will be adjusting the color balances and saturation in the released images as time goes on?

Also, looking forward to more of the full video feed from Yutu. That was pretty impressive from the quick flashes we saw during the rover deployment.

-the other Doug

All right -- ship in port, Captain's gig launched. Way to go!

Congrats to the Chinese Space Agency for grabbing the brass ring on their first try.

-the other Doug

Yep, no obvious problems here, either, using Chrome 31.0.1650.63 m on a PC running Win7.

-the other Doug

I find it fascinating that the Science channel has been advertising a special called "Supercomet ISON" that will air this coming Saturday, IIRC. Even well past perihelion they were using the old ad copy saying it's 3 miles across and will soon be bright in our evening skies.

They are going ahead with the special program, but the ads now say (slightly paraphrased) "It's just gone around the sun -- but what happened then? Tune in and find out!"



-the other Doug

I doubt there is a huge amount of straight scientific data about the surface to be gleaned from examining the wheels. However, there is good engineering data about the interaction of this particular wheel design with a fairly representative Martian surface to be acquired.

There has always been a dissonance between "pure" scientific data gathering during space flights, and the acquisition of engineering data that can be useful in the design phase of the next vehicle to come along. Both are "scientific" goals, but the engineering data is used to both improve future spacecraft and to better understand and improve our engineering models (which usually led to the designs and materials being used and evaluated).

Or, to put it another way, the "pure" scientific data is usually all about studying the environment we've come all this way to look at, while the engineering data is to look at the systems that got us there and keep us running so we can pursue the pure science goals.

-the other Doug

Jade Rabbit: "Hey, everyone, I've landed on the Moon!"

Eight Lunas, 5 Surveyors, 2 Lunakhods, 6 LM descent stages and 3 LRVs: "Yutu?"



-the other Doug

With today's imaging technology, I'm hoping for HD video from the lander of the landing itself, and also of Yutu deployment and operations.

-the other Doug

You know, that may not be a bad idea. Depending on the volume of images we get from the Chinese, it may be possible to follow the traverse somewhat real-time.

I would imagine we will have to wait to see if we get enough imagery to warrant it, but I'm beginning to think that we may need a dedicated Chang'e/Yutu folder, just as each of the Mars rovers has its own folder and LRO has its own folder, etc.

I am just on pins and needles waiting to see our first new lunar surface vista in decades!

-the other Doug

Yeah -- I'm not sure where they get the line that the "US succeeded only in its sixth," when the first two American probes aimed at Mars were Mariners 3 and 4 -- and Mariner 3 didn't so much fail at Mars as it ended up on the floor of the Atlantic Ocean, having failed to make its parking orbit. The next complete failure of an American Mars probe was Mariner 8, for the same reason as Mariner 3 -- it failed to reach orbit. In between those two failures, Mariners 4, 6 and 7 all completed their missions.

After Mariner 9's success, the next American failure was the Mars Observer, followed by the Mars Climate Orbiter and Mars Polar Lander (all of which were lost at or approaching Mars). All other American Mars missions have been rather highly successful. The actual American won-loss on Mars probes is 15 successes, 5 failures. This counts the Vikings as one mission each (you could make a case for them being 4 missions, two landers and two orbiters, but I just counted them as one each for a total of 2) and it counts MPL as one mission, not splitting out the Deep Space 2 hard landers. Basically, of 20 American launches to Mars, five have failed and 15 succeeded.

-the other Doug

Google translates the first paragraphs of it thus:

Japan Aerospace Exploration Agency is (JAXA), extreme ultraviolet spectrometer on board planet spectroscopic observation satellite launched by the Epsilon rocket testing machine to September 14, 2013 "Hisaki" in (SPRINT-A) (EUV) We had to November 19 the spectroscopic observations of Venus and Jupiter by. As a result, it was confirmed that it is possible extreme ultraviolet spectrometer (EUV) is functioning properly, and subjected to scientific observation.

In addition, prior to this, we confirm the functions of the camera field of view guide (FOV), and has confirmed the normal operation of the function to be tracked with high precision astronomical object.

As a result, "Hisaki" is scheduled to exit the function confirmation of initial orbit, starting a steady observation operation.

That by observing over a long period of time planet in the world's first extreme ultraviolet, to gain new knowledge about the environment of the planet, and contribute to the increase of knowledge of the human race is expected to "Hisaki" future.

-the other Doug

It was actually Mike Collins who made the bunny girl comment. Unfortunately, there are a number of transcriptions of the Apollo missions out there, some of which are unreliable when it comes to correct attribution. In this case, not only does your linked transcript give Collins as the person who said it, but also, Collins reminisces about the exchange in his memoir, "Carrying the Fire."

That exchange was the first I had heard of the ancient Chinese myth of Chang'e, after which I read up on it a little. When I found that China was naming their unmanned lunar exploration program after Chang'e, I was literally tickled pink.

-the other Doug

Jade Rabbit? Really?

For those who know the Chinese myth of Chang'e, this makes perfect sense. It also means that we ought to be able to identify the intended landing site.

Since Change's companion, a large rabbit, was always seen sitting in the shade of a large cinnamon tree, all Phil has to do is find said large cinnamon tree in Sinus Iridum, and we have our landing site...



-the other Doug

I know that the Endeavour impactor is supposed to have impacted into a nice thick layer of ejecta from Miyamoto, but the layered rocks along this ridge look really nicely sequenced to me -- really looks like the exposed edge of a nice intact unit. The layers line up right down the ridge line.

I suppose this could be our old friend, the sulfate sandstone, but I thought the sandstone unit was emplaced after the Endeavour impact...

-the other Doug

And it's $50 from me. Hope we push over the goal.

It told me that my contribution was designated to amateur imaging. I'm assuming it went to the right place.

-the other Doug

I will note that, as mentioned in the route map thread, this terrain looks a heck of a lot more rugged in the orbital images than it seems to from the surface. Even with the 3D imaging, it's obvious that the dips and rises are on the order of a few feet in extent, whereas Cooperstown, for instance, looks like a multi-storied wall of rock in the HiRISE images. However, from here, it looks as if the mast would extend well above the top of the Cooperstown wall if we drove MSL right up to it.

-the other Doug

They appear to be concerned only with LROC NAC imagery in re capturing "before" images. The exact quote from the LROC site is:

"If we are lucky, the LROC team might have a before picture to compare to any after pictures of the Chang'e 3 landing site (the exact planned landing coordinates have not yet been released). Currently all LROC NAC investigations must rely solely on 'after' images of landing sites. Obtaining a before and after set of images of the Chang'e 3 will facilitate a much better understanding of the delicate processes involved in regolith redistribution due to lander rocket plumes."

-the other Doug

I read at the LROC site that they are looking forward to the Chang'e landing so they can get good "before" images of a landing site as well as "after" images, since they have no such thing at present. They are hoping they have decent resolution imaging of the eventual landing site -- they can't be certain because the Chinese have not specified the exact planned co-ordinates.

-the other Doug

Extraordinary work, James.

I notice we can now see the rim of Gale pretty clearly all the way around the horizon (except where blocked by Mt. Sharp, of course). Is tau decreasing lately? Or are we just getting some exceptionally clear days?

-the other Doug

...ain't gonna make fun of itself!



-the other Doug

Yeah -- this thread is plummeting through the atmosphere, burning up, shouting "How many feet in a kilometer? HOW MANY FEET IN A KILOMETER???"



-the other Doug