Tag: Lunar Reconnaissance Orbiter

Using LRO to find Chang’e-4

8:49 am

LRO image of Chang'e-4 landing area

The Lunar Reconnaissance Orbiter (LRO) science team has released a high resolution image from 2010 pinpointing the area on the floor of Von Kármán crater where Chang’e-4 landed. On the right is a reduced and partly annotated version.

They have not actually found the lander/rover, since this image was taken long ago before Chang’e-4 arrived. However, this image, combined with the Chang’e-4 landing approach image, tells us where the lander approximately landed. It also pinpoints where to look for it when LRO is next able to image this region, around the end of January.

By then, Yutu-2 will hopefully have traveled some distance from Chang’e-4, and LRO will be able to spot both on the surface.

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A young lunar impact crater

9:57 am

Lunar crater

Cool image time! The science team from Lunar Reconnaissance Orbiter (LRO) today released a new image, taken on November 3, 2018, of a relatively young small crater not easily seen from Earth.

The unnamed crater, just 1.8 kilometers across, is too small to see from Earth with unaided eyes. It is in the Moon’s wild west, just past Oceanus Procellarum and close to the line dividing the nearside from the farside, so it would be hard to glimpse in any case. If you stood on the crater rim, you would see the Earth forever slowly bobbing up, down, and sideways close to the eastern horizon.

The image above is a cropped and reduced-in-resolution section of the released image. If you click on it you can see this section at full resolution.

What I find fascinating about this crater are the black streaks that appear to only run down the outside slopes of the eastern rim, but nowhere else. At first glance it looks like prevailing winds, blowing from the west, caused this, but of course that’s wrong because the Moon has no atmosphere. The website explains:
» Read more

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The fractured floor of Komarov Crater

10:35 am

Fractured floor of Komarov Crater

Cool image time! The Lunar Reconnaissance Orbiter (LRO) oblique image on the right, reduced significantly from the original to post here, shows the deeply fractured floor of Komarov Crater on the Moon’s far side. As noted at the image link,

The spectacular fractures that cut across the floor of Komarov crater [about 85 kilometers or 50 miles diameter] were formed when magma rose from the mantle, uplifting and fracturing the crater in the process. In this case the magma did not erupt to the surface, thus the fractures remain visible.

The Komarov fractures are quite large, the major left-to-right fracture that cuts across the center of the scene is over 500 meters deep [1,600 feet] and 2500 meters wide [1.5 miles]. When did they form? The large number of craters superimposed on the floor and fractures testifies to their ancient ages. Likely they are of the same vintage (>2.6 billion years) as the Mare Moscoviense lava plains just to the north

An overview of Komarov Crater as well as other LRO images of it can be found here.

The question that comes to my mind is the relative rarity of craters with such large fractures on their floors. I have noted this for Mars as well. It is expected that there is melt on the floor of all large impact craters. Why do a few produce such pronounced fractures, while most do not? This website posits one explanation, but its complexity leaves me unsatisfied. It also doesn’t explain why it happens only rarely.

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The central peaks of Copernicus crater

9:41 am

Central peaks of Copernicus Crater

Cool image time! Lunar Reconnaissance Orbiter science team has released a new image of the central peaks of Copernicus Crater, shown on the right cropped and reduced in resolution.

Copernicus (9.62°N, 339.92°E), which is easily seen with a moderately powerful backyard telescope, is one of the best-known craters on the Moon. Despite its age (around 860 million years), it is well preserved with over 4000 meters of relief from floor to rim, and the tallest of its central peaks rises approximately 1300 meters above the crater floor. This image, centered on the central peaks, was captured just after dawn (86° incidence angle) as the Lunar Reconnaissance Orbiter slewed west to a 67°angle.

The image is similar to one taken back in 2012, but has a higher resolution because it was shot from 50 miles elevation instead of 75.

This crater was also the subject of one of the first breath-taking images ever taken of the Moon from lunar orbit, by Lunar Orbiter in November 1966.

The wider view taken by LRO gives some context for the image above. The peaks shown in closeup here are part of the lower right grouping. If you go to the first link above you can zoom in and explore all parts of the full image, and see some quite amazing details, including the large boulders scatter throughout the hollows between the peaks.

Copernicus Crater

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Mountains on the Moon

1:53 pm

Mountains on the Moon

Cool image time! The image on the right, reduced slightly to post here, shows several high mountains on the far side of the Moon. If you click on the image you can see it at full resolution.

The summit of the unnamed peak in the foreground (50.2° S, 236.6° E) has an elevation of 6710 meters, about 7000 meters (about 23,000 feet) of relief relative to the low point at the bottom of the image. The two peaks on the horizon, 200 kilometers in the distance (about 125 miles), have summit elevations of 4320 meters (14,200 feet) and 4680 meters (15,350), respectively and both rise more than 6000 meters (almost 20,000 feet) above their surroundings.

In the Lunar Reconnaissance Orbiter (LRO) science team release in June, they noted that the high peak here is actually taller than Denali (Mount McKinley), the highest peak within the U.S. And it has no name. They also note that the peak is likely 4 billion years old, and has experienced extensive erosion in that time, meaning that it is also likely shorter than it once was.

I don’t have anything to add, other than this would be an amazing place to put up a resort, with trails taking you to the top of the mountains. In the lighter gravity, the hike would actually be somewhat easy, even wearing a spacesuit. And you wouldn’t have to worry about a thinning atmosphere as you climbed higher, as you do on Earth. You’d be carrying it with you.

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Oblique view of lunar crater

9:51 am

Wallach Crater

Cool image time! The Lunar Reconnaissance Orbiter (LRO) science team this week released an image showing Wallach Crater as seen from the side. The image on the right is a section of that image and has been reduced to show here. The full image of 3.5-mile-wide crater and its surrounding terrain can be explored at the link. From the link:

Wallach crater (4.89°N, 32.27°E) formed within a thin layer of black basaltic lava flows that overlie much brighter anorthositic material. Think of a white cake with chocolate icing. When the asteroid (or comet) impacted this “iced cake”, ejecta from deeper portions (white cake, or rather brighter anorthosite) was thrown out onto the icing (darker basalt) resulting in intermediate tones where the two materials mixed.

The dark streaks seen inside the crater are blocks of the icing (basalt) breaking off and creeping down slope. The fact that the deepest material lands on top of the shallowest material (known as inverted stratigraphy) was first described by Gene Shoemaker from his pioneering observations at Meteor Crater, Arizona. This effect simplifies sampling the local geology in three dimensions. As an astronaut traverses towards the rim of a crater, the rocks underfoot come from deeper and deeper within the crater. The rocks at the rim are from the deepest portions of the crater!

It is especially interesting to use the viewer at the link to see the surrounding terrain, which includes two other craters that are far less distinct.

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Aristarchus Crater on the Moon

9:08 am

Aristarchus Crater

Cool image time! The image on the right, reduced in resolution to post here, shows Aristarchus Crater, one of the more geological intriguing locations on the Moon. This oblique image was taken by Lunar Reconnaissance Orbiter (LRO), still operating in lunar orbit. If you click on the image you can see the full resolution image.

Aristarchus crater is 40 kilometers (25 miles) in diameter and 2700 meters (1.7 miles) deep, with a central peak that rises 300 meters (almost a thousand feet) above the crater floor. When LRO pointed back towards the Sun, LROC was able to capture this magnificent view highlighting subtle differences in albedo (brightness). Some of the albedo contrast is due to maturity (young material is generally brighter than older material) and some reveal true differences in rock type. The central peak shows the complexity of what lies beneath the now hardened impact melt sea that filled the bottom of the crater.

The best part however is the close-up they provided of the crater’s central peaks, posted below.
» Read more

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Scientists finally image SMART-1 lunar impact site

11:00 am

SMART-1 impact site

Eleven years after the European SMART-1 probe was sent crashing onto the Moon’s surface, scientists have finally identified in a Lunar Reconnaissance Orbiter image that crash site.

The image is shown on the right, reduced and cropped to post here.

The images show a linear gouge in the surface, about four metres wide and 20 metres long, cutting across a small pre-existing crater. At the far end, a faint fan of ejecta sprays out to the south. Foing said: “The high resolution LRO images show white ejecta, about seven metres across, from the first contact. A north-south channel has then been carved out by the SMART-1 spacecraft body, before its bouncing ricochet. We can make out three faint but distinct ejecta streams from the impact, about 40 metres long and separated by 20-degree angles.”

Stooke said: “Orbit tracking and the impact flash gave a good estimate of the impact location, and very close to that point was a very unusual small feature. It now seems that impacts of orbiting spacecraft, seen here from SMART-1, and also in the cases from GRAIL and LADEE, will form elongated craters, most of whose rather faint ejecta extends downrange”.

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Frost on the Moon?

10:37 pm

A new analysis of Lunar Reconnaissance Orbiter data suggests that the coldest spots at the Moon’s south pole are also its brightest, even though they are generally in shadow, suggesting that the surface there might have a thin layer of water frost.

These are also the areas where hydrogen has been detected, which strengthens the theory that this is water.

However, the result is not a positive one for future colonists as it suggests that the amount of water on the Moon is far less than hoped. First, there is this:

The icy deposits appear to be patchy and thin, and it’s possible that they are mixed in with the surface layer of soil, dust and small rocks called the regolith. The researchers say they are not seeing expanses of ice similar to a frozen pond or skating rink. Instead, they are seeing signs of surface frost.

Second, they have not detected this same pattern at the north pole, which strongly suggests that the permanently shadowed areas there do not even have frost.

Overall, this result suggests that the Moon might have water on its surface, but not in great quantities.

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LRO hit by meteoriod in 2014

5:35 pm

LRO as it was hit by a meteor

While taking an image in October 2014, Lunar Reconnaissance Orbiter had apparently been hit by some small object, causing it to vibrate and create the zig-zag distortions seen on the image, a cropped section of which is shown on the right.

Clearly there was a brief violent movement of the left NAC [Narrow Angle Camera]. The only logical explanation is that the NAC was hit by a meteoroid! How big was the meteoroid, and where did it hit? The physical properties and vibration modes of the NAC are very well known – during development a detailed computer model was made to ensure the NAC would not fail during the vibrations caused by the launch, which are severe. The computer model was tested before launch by attaching the NAC to a vibration table that simulates launch. The model was solid, both NACs survived the test, and launch.

Most of each NAC is sequestered inside the spacecraft structure, so only the leading edge of the baffle and the radiator are exposed to space, and thus are potential targets for impactors. From the detailed computer model, the LROC team ran simulations to see if we could reproduce the distortions seen the image. Assuming an impact velocity of 7 kilometers per second and a density 2.7 g/cm3, an impacting particle would have been 0.8 mm in diameter (~half the size of a pinhead). If the velocity was faster, then the particle would have been smaller, and if slower then larger.

For comparison, the muzzle velocity of a bullet fired from a rifle is typically 0.5 to 1.0 kilometers per second. So the meteoroid was traveling much faster than a speeding bullet. In this case LROC did not dodge a speeding bullet, but rather survived a speeding bullet!

The image is fascinating because you can see the vibrations slowly disappear as the zig-zags shrink and fade.

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LRO finds lunar impact site for Apollo rocket stage

10:03 pm

Lunar Reconnaissance Orbiter has located the impact site for the Apollo 16 rocket booster that, like four other boosters, had been deliberately crashed on the surface so the Apollo seismometers could use the vibrations to study the Moon’s interior.

The other impact sites had been found already, but Apollo 16 was harder to pin down because contact with the booster had ended prematurely so its location was less well known.

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200 new lunar impact craters discovered

9:18 am

In a paper [pdf] presented this week at a lunar science conference, scientists announced the identification of more than 200 new impact craters on the Moon from Lunar Reconnaissance Orbiter (LRO).

As of 1 May 2015, we have scanned and classified changes in 14,182 NAC temporal pairs using our automated change detection tool leading to the discovery over 200 impact craters ranging in size from 1.5 to 43 m. In addition, we also identified thousands of other surface changes, including about 44,000 low reflectance splotches, 3,500 high reflectance splotches, 850 mixed reflectance splotches, [and] 1 Chinese lander/rover.

They think the splotches are created from impacts too small to see with LRO.

Hat tip James Fincannon.

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Some spectacular oblique images from Lunar Reconnaissance Orbiter have been released.

1:06 pm

Some spectacular oblique images from Lunar Reconnaissance Orbiter (LRO) have been released.

The top three images are all oblique. Make sure you click through to the full caption of each image to get more information.

The Lunar Alps image is especially interesting to those who have ever explored the Moon with a telescope from Earth. The rill shown is well known to amateurs, as are the Montes Alpes, or Alps Mountains, adjacent to it. From Earth that rill definitely looks like a meandering river canyon. This LRO image resolves it into a canyon made up of a series of crater-like depressions, a geological feature quite different from the river canyons of Earth.

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Water on the Moon? The battle continues

2:18 pm

LEND data of lunar south pole

A little over a month ago I reported here on Behind the Black some recent results from the LEND instrument on Lunar Reconnaissance Orbiter (LRO) that had found significantly less water in the permanently shadowed craters at the lunar poles than previously thought. To quote again from that paper’s abstract, which I will henceforth refer to as Sanin, et al:

This means that all [permanently shadowed regions], except those in Shoemaker, Cabeus and Rozhdestvensky U craters, do not contain any significant amount of hydrogen in comparison with sunlit areas around them at the same latitude.

And from the paper’s conclusion:

[E]ven now the data is enough for definite conclusion that [permanently shadowed regions] at both poles are not reservoirs of large deposits of water ice.

Paul Spudis of the Lunar and Planetary Institute in Houston, Texas and one of the world’s top lunar scientists then commented as follows:

You neglect to mention yet another possibility — that this paper and its conclusions are seriously flawed in almost every respect. The veracity of the LRO collimated neutron data [produced by the LEND instrument] have been questioned on serious scientific grounds. Other data sets (spectral, radar) suggest significant amounts of water at both poles, billions of metric tons in total.

Spudis also discussed this scientific dispute at length on his own blog.

When I read Dr. Spudis’s comment I immediately emailed William Boynton of the Lunar and Planetary Laboratory at the University of Arizona, one of the authors of the Sanin et al paper, to get his reaction. Today he sent me the following detailed explanation, describing the basis of the controversy and why he believes the LEND data is valid.
» Read more

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Lunar Reconnaissance Orbiter has published another spectacular oblique image of Tycho crater.

4:51 pm

Tycho Oblique image thumbnail

Lunar Reconnaissance Orbiter has published another spectacular oblique image of Tycho crater.

If you look closely at the slope of the mountain, you can see an avalanche trail at its center and the debris piled up at the mountain’s base.

See the first oblique image, released in June 2011, here. The two images look at the crater from opposite directions.

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Studying the Moon by starlight

10:34 am

The Moon's south pole by starlight

In a paper published today in the Journal for Geophysical Research, Planets, the science team for Lunar Reconnaissance Orbiter describe how they have used starlight to peer into the permanently shadowed craters of the Moon’s north and south poles. Looking only during the lunar night, they measured the dim albedo of the Moon from reflected starlight. From this very weak signal they were able to cull two interesting facts about these very cold and very dark places.

  • The ground at the bottom of these craters is more porous than the surrounding unshadowed terrain.
  • There is evidence in the spectroscopy of 1 to 2% water frost in these craters.

» Read more

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A breathtaking view of the Apollo 15 landing site

2:03 pm

The Lunar Reconnaissance Orbiter team has released a wide angle side view image of the Apollo 15 landing site, showing the lunar module and the areas around Hadley Rille and the Apennine Mountain range that the astronauts explored using their lunar jeep. Below is a cropped close-up, showing the landing site near the top of the image with Hadley Rille near the bottom. Below the fold is a second image showing a wider view that includes the Apennine mountain slope that the astronauts drove their rover up.

Close up of Hadley Rille and Apollo 15 landing site

» Read more

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New images of Apollo landing sites on the Moon

12:45 pm

The Lunar Reconnaissance Orbiter team have released new images of the Apollo 12, 14, and 17 landing sites on the Moon. Below is a cropped image of the Apollo 12 site, showing the trails left by astronauts Pete Conrad and Alan Bean when they walked from their lunar module to Surveyor 3, an unmanned lunar lander that had soft landed there two years earlier. The full image shows some incredible detail.

Apollo 12 landing site

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When dust, pebbles, rocks, and boulders act like liquid

3:35 pm

The science team of Lunar Reconnaissance Orbiter released an intriguing picture yesterday of what scientists call a granular flow down the side of a five mile wide crater on the far side of the moon. Looking at the image, one would swear that the darker material flowing down the slope of the crater rim is a lava flow frozen in place.

lunar granular flow

However, according to the scientists, that is not what it is. Instead, this is merely debris left behind from an avalanche.
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Prime real estate

2:32 pm

The south pole of the moon

Since the 1990s, scientists have suspected that water-ice might be hidden in the forever-dark floors of the polar craters on the Moon. If so, these locations become valuable real estate, as they not only would provide future settlers water for drinking, the water itself can be processed to provide oxygen and fuel.

Moreover, the high points near these craters, including the crater rims, are hoped to be high enough so that the sun would never set or be blocked by other mountains as it made its circuit low along the horizon each day. If such a place existed, solar panels could be mounted there to generate electricity continuously, even during the long 14-day lunar night.

Below the fold is a six minute video, produced from images taken by Lunar Reconnaissance Orbiter (LRO) from February 6, 2010 to February 6, 2011, in an effort to find out if such a place actually exists. It shows how the sunlight hits the south pole across an entire year.
» Read more

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Exploring the floor of Copernicus

9:40 am

thumbnail of index of caves on floor of Copernicus

The Lunar Reconnaissance Orbiter website recently announced a new way to tour the Moon. The website, called QuickMap, allows a user with any home computer to zoom into any spot on the lunar surface and see the high resolution images being taken by Lunar Reconnaissance Orbiter.

Using QuickMap, I spent a few hours this past weekend strolling about on the northern half of the floor of the crater Copernicus. It is in this area, annotated in the image on the right, that NASA engineer James Fincannon has already located a slew of collapse features and possible caves, the images of which I have posted previously on behindtheblack. (Click on the image or here to see a larger version of this updated index map.)

(You also can go sightseeing there if you wish. Go to QuickMap and zoom in on 10.1 latitude and -20.1 longitude to get to the floor of Copernicus. Or pick your own spot on the lunar surface and do some of your own exploring!)

What I found in the northern half of Copernicus’s floor was a plethora of possible caves and collapse features. Literally, the crater floor is littered with what appear to be pits, fissures, rills, and sinks. More significantly, sometimes the cave entrances line up with long straight collapse features, suggesting strongly the existence of extensive underground passages beyond the initial entrance pits.
» Read more

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