Streaks on the Moon

Streaks on the Moon
Click for full image.

Cool image time! The photo to the right, reduced and enhanced to post here, is an oblique view taken by Lunar Reconnaissance Orbiter (LRO) of the rays that were created when four million years ago an object smashed into the Moon’s far side and produced the 13.75 mile-wide Giordano Bruno crater.

Rays are formed as material ejected from an impact event slams into the surface and churns up local material. Rays are bright because they expose fresh material from depth (both the incoming material and locally churned soil). What is fresh material? Over time the lunar surface is impacted by micrometeoroids and bombarded by radiation; both processes work to darken the surface. The dark “mature” layer at the surface is often only about 50 cm (20 inches) thick, so energetic impacts can easily bring up fresh material from the subsurface. Eventually, the bright rays darken and fade into the background as the surface matures.

In this image, you can see where the ejecta blocks from Giordano Bruno hit the surface, creating a secondary crater, which dug up local material and spread that bright material downstream (so to speak).

The image itself is 4.78 miles wide, at its center, and was snapped from an altitude of 66 miles.

Volcano on the Moon

Wide shot of lunar volcano

Close-up of lunar volcano
Click for full image.

Cool image time! The Lunar Reconnaissance Orbiter (LRO) science team today released the oblique image above and in close-up to the right, showing what they call a “silicic volcano.” From the release:

The Mairan T dome is a large silicic volcanic structure with a pronounced summit depression. Remote sensing indicates that the composition of the volcanic material (lava) making up the dome is enriched in silica (SiO2). This rock type would be classified as either rhyolite or dacite on Earth, and the composition starkly contrasts with the dark, iron-rich mare basalts that embay the Mairan T dome. Most of the volcanism on the Moon is basaltic or iron-rich. Still, silicic volcanism also occurred on the Moon. Indeed, bits and pieces of similar materials were found in the Apollo samples; however, all are small fragments delivered to the Apollo sites as material ejected from distant impact events.

One of the great questions for lunar science is how the silicic materials formed. On Earth, specific tectonic settings and higher water contents in the rocks favor the formation of such lavas; however, the Moon lacks plate tectonics and water-rich sediments. NASA is planning a Commercial Lunar Payload Services (CLPS) lander mission to another, larger silicic volcano, one of the Gruithuisen domes, to address this question.

The scientists also note that this volcano formed first, and then was partly covered by the dark flood lava that surrounds it.

Lunar mountains and wrinkle ridges

Montes Recti on the Moon

Cool image time! The photo above, taken by Lunar Reconnaissance Orbiter (LRO), was released today by the orbiter’s science team, and provides us an oblique look at the mountains dubbed Montes Recti (lower right) and the wrinkle ridges near them (lower left). The highest point in this mountain range is about 5,900 feet high.

The image looks west across the northern part of the mare region dubbed Mare Imbrium, the dark area on the Moon’s visible hemisphere near its top. In the distance can be the mountains that form part of mare’s rim. The rounded peak in the top right is Promontorium Laplace (about 8,530 feet high). It is named this because it projects out (a promontory) into the mare a considerable distance from the rim. The crater at top center is Laplace D. As for the wrinkle ridges, the scientists describe them like so:

Tectonic landforms are those formed by forces that act to either contract or pull apart crustal materials. These forces develop faults or breaks in the crustal materials, and movement or slip along the faults form either positive or negative relief landforms. On the Moon, positive relief contractional landforms are the most common. The most significant contractional landforms on the Moon are wrinkle ridges, found exclusively in the dark mare basalts.

Essentially, something caused the ground to contract, which caused it to break at these ridges and be forced upward.

Dawn on the Moon

Dawn on the Moon's far side
Click for full image.

Cool image time! The photo to the right, reduced to post here, was taken on August 25, 2019 by Lunar Reconnaissance Orbiter (LRO). It shows an oblique view looking west just after lunar dawn of an unnamed 13-mile-wide crater in Mare Moscoviense on the far side of the Moon. From the caption:

Mare Moscoviense is one of the few volcanic plains on the farside, which is largely comprised of ancient cratered highland terrain. The fact that the farside was strikingly different from the familiar nearside was a surprise when the Soviet Luna 3 spacecraft returned the first farside images in 1959. The highland crust is thicker on the farside than on the nearside, which is thought to have inhibited magmas from reaching the surface as frequently as they once did on the nearside.

As seen in the image above, Mare Moscoviense lies within a large impact basin, the formation of which thinned the local crust, perhaps making it easier for lavas to erupt that would have otherwise stalled below the surface. But why does this global asymmetry in crustal thickness exist? This is still a mystery, like the origins of the large-scale asymmetries observed on Mars and Mercury, though ideas like a giant impact event that stripped off a portion of the crust or asymmetric overturn of the mantle have been proposed.

Note the dark shadow obscuring the foreground on the left. It appears from the topography in the overhead map at the link that the ridgeline that marks the eastern border of Mare Moscoviense is just high enough at dawn to keep the mare in shadow while allowing the sun’s dawn light to peek over and illuminate the crater’s rim. That ridgeline however only extends so far to the north, thus allowing sunlight to hit the plains on the right sooner.

Apollo 16 on Moon, as visualized by Lunar Reconnaissance Orbiter

In celebration of the fiftieth anniversary of the Apollo 16 mission to the Moon in April 1972, scientists using images from Lunar Reconnaissance Orbiter (LRO) have created a short digital visualization of the lunar surface where astronauts John Young and Charles Duke completed three different excursions across the lunar surface.

I have embedded that video below. The audio is the discussion between John Young and the capcom at mission control during the last excursion. The key moment is when John Young reaches the rim of North Ray crater, and realizes he cannot see its floor because the interior slopes are so steep.
» Read more

The most valuable real estate on the Moon

The most valuable real estate on the Moon
Click for full image.

Cool image time! The photo to the right, reduced and annotated to post here, is an oblique view of the terrain near Shackelton Crater and the Moon’s south pole, taken by Lunar Reconnaissance Orbiter (LRO) and released today.

Shackleton-de Gerlache ridge, about 9 miles long, is considered one of the prime landing sites for both a manned Artemis mission as well as the unmanned Nova-C lander from the commercial company Intuitive Machines. To facilitate planning, scientists have created a very detailed geomorphic map [pdf] of this region. As explained at the first link above,

Going back to time-proven traditions of the Apollo missions, geomorphic maps at a very large scale are needed to effectively guide and inform landing site selection, traverse planning, and in-situ landscape interpretation by rovers and astronauts. We assembled a geomorphic map covering a candidate landing site on the Shackleton-de Gerlache-ridge and the adjacent rim of Shackleton crater. The map was derived from one meter per pixel NAC image mosaics and five meters per pixel digital elevation models (DEM) from Lunar Orbiter Laser Altimeter (LOLA) ranging measurements.

Such geology maps guide planning and exploration, but actual images tell us what the first explorers will see. Below is a close-up overhead view of small area at the intersection of the ridge and the rim of Shackleton.
» Read more

Fiftieth anniversary of Apollo 14 lunar landing

Apollo 14 as seen by LRO
Click for full image.

In honor of the fiftieth anniversary today of the landing of Apollo 14 on the Moon, the Lunar Reconnaissance Orbiter (LRO) science team has used images from the spacecraft to map out what the astronauts did on the surface, as shown in the reduced image to the right. The orange and teal lines indicate the routes followed during the two EVAs, with the pink triangles indicating stopping points along the way.

Unlike Apollo 11 and 12, which focused on engineering goals such as landing precisely on the Moon, Apollo 14 focused on addressing science goals. Antares (lunar module) landed in the Fra Mauro highlands, the original destination of the failed Apollo 13 mission, essentially taking on that mission’s objectives. This was the first crewed landing in the lunar highlands and not in the mare.

The Apollo 14 astronauts who landed on the Moon, Alan Shepard (Commander) and Edgar Mitchell (Lunar Module Pilot), completed two extra-vehicular activities (EVAs) while on the surface. They spent a total of 9 hours and 22 minutes setting up equipment, taking photographs, collecting samples, and exploring.

This was the last mission where the astronauts had to walk. The next three Apollo missions brought a rover with them, so that they could drive to their research sites.

The conjunction of Jupiter and Saturn, as seen from the Moon

Jupiter and Saturn as seen by LRO
Click for full image.

With Jupiter and Saturn closer to each other in the sky than they have been in about 800 years, the science team for Lunar Reconnaissance Orbiter (LRO) decided to aim that lunar orbiter at the two gas giants to get a picture.

The photo to the right, cropped and expanded to post here, was also enhanced by the science team to brighten Saturn so that it would match Jupiter. As they note at the link,

[LRO] captured this view just a few hours after the point of closest separation (0.1°) between the two giant planets. With the sharp focus of the NAC [camera], you can see that the two planets are actually separated by about 10 Jupiter diameters

Both planets however look fuzzy in the image, probably because the camera was not designed to obtain sharp images from this distance. Nonetheless, this is a very cool photo.

LRO snaps picture of Chang’e-5 on Moon

Chang'e-5 on the Moon, taken by LRO
Click for full image.

The science team for Lunar Reconnaissance Orbiter (LRO) late yesterday released an image taken of Chang’e-5 on the surface of the Moon. The image to the right, reduced to post here, is that photo.

China’s Chang’e 5 sample return spacecraft made a safe touchdown on the lunar surface at 10:11 EST (15:11 UTC) 01 December 2020. LRO passed over the site the following day and acquired an off-nadir (13° slew) image showing the lander centered within a triangle of craters.

The LROC team computed the coordinates of the lander to be 43.0576° N, 308.0839°E, –2570 m elevation, with an estimated accuracy of plus-or-minus 20 meters.

If all goes well, the return capsule, which lifted off from the Moon yesterday, will dock with the return vehicle in orbiter later today.

LRO looks at Yutu-2

Yutu-2's travels on the Moon through October 2020
Click for full image.

The new colonial movement: The Lunar Reconnaissance Orbiter (LRO) science team today released an update of the travels of China’s Yutu-2 lunar rover, presently operating on the far side of the Moon.

The photo to the right, reduced and annotated to post here, shows the rover’s present position, having traveled about 1,650 feet to the northwest in the 22 months since landing. The goal, according to Yutu-2’s science team, is to get the rover beyond the present ejecta field of debris thrown from a large impact to the north, and reach a basalt covered region about a mile away. At the pace they are setting, about 100 feet per lunar day, it is going to take them about another three years to get there. Whether the rover will last that long is the question, but I suspect they are hopeful, based on the almost two years of operations so far.

If you go to the link you can also see a short movie showing month-by-month where the rover ended up when it shut down for each long lunar night.

Weird crater on Moon

Strange Ryder Crater on the Moon
Click for full image.

The photo to the right, released today by the science team of Lunar Reconnaissance Orbiter (LRO), takes a overhead view of the unusual crater dubbed Ryder (named after lunar scientist Graham Ryder).

The crater is located on the Moon’s far side, on the edge of the South Pole-Aitken Basin, the Moon’s largest and possibly oldest impact basin. What makes Ryder Crater intriguing is its strange shape, as well as its interior north-south interior ridge.

This crater was featured previously in 2012 in a spectacular oblique image looking east across the crater. Then, the scientists theorized its strange shape was caused by two factors, first that the impact was oblique, and second that it occurred on a steep slope.

Today’s release adds another factor that might explain the interior ridge. The context map below makes that explanation obvious.
» Read more

A lunar landslide

Landslide on the Moon
Click for full image.

Cool image time! The image to the right was posted by the Lunar Reconnaissance Orbiter (LRO) science team on October 9, 2020, and shows a spectacular landslide almost a mile and a half long that had occurred on the interior rim of a crater on the Moon.

The top of the rim is on the left, with the landslide breaking out onto the floor of the crater on the right.

The walls of Kepler crater (30 kilometer diameter) exhibit numerous landslides. In this example, a landslide of dark material begins about 100 meters below the rim from a narrow box canyon. The box canyon is about 50 meters wide and 300 meters long. Overall, the slide is extends some 2300 meters (from the end of the canyon to its base). The base of the slide is on a fault block that lies some 1800 meters below the rim. The wall slope is about 33 degrees.

This slide is actually composed of a series of narrow landslides 20-30 meters wide. Along most of the slope, the individual slides overrun each other forming a band of debris up to about 180 meters wide. At the base of the slope, the individual slides can be recognized as they move apart forming a fan of material. A few individual isolated slides also occur adjacent to the main mass. The overlapping nature of these small slides indicate that the overall feature may have formed over a period of time, rather than all at once.

From above and at this resolution, the landslide looks almost like frozen flowing liquid. It allso looks like it began with a scattering of boulders breaking free at the top all at once that quickly consolidated into a single massive avalanche.

At the link you can zoom in or out to look at the entire image, at full resolution.

A donut on the Moon

A donut crater on the Moon
Click for full image.

In this case the donut is a crater dubbed Bell E Crater, with a second concentric rim in its interior. The photo to the right, reduced to post here, was taken by Lunar Reconnaissance Orbiter (LRO) as part of its high resolution survey of the entire Moon. As noted at the first link:

Craters not only vary in shape but also in complexity. There are simple craters and complex craters with ring structures and mountains at the center. Somewhere in between is Bell E, a small crater located within the larger Bell crater. These donut-shaped formations are commonly known as concentric craters. Many questions remain on the origin of donut craters. While there have been several ideas about their origin, including double impacts, the currently favored hypotheses involve volcanic processes and compositional variations.

The article outlines four hypotheses for explaining this crater’s formation, a perfectly aligned double impact, ripples at impact into thick warm lava, layers of different densities, and later volcanic activity. None do a good job of explaining all of the concentric craters found on the Moon, and thus suggest that these craters might have formed from some combination of more than one theory.

A minor rill on the Moon

Kathleen, a rill on the Moon
Click for full image.

Cool image time! The image above, reduced to post here, is a colorized digital terrain model produced from Lunar Reconnaissance Orbiter (LRO) data. On top of the original mosaic of photos the LRO science team has overlaid the elevation data obtained by LRO’s laser altimeter. It shows a tadpole shaped pit dubbed Kathleen, with its tail trailing off to the southeast. As they note:

Kathleen is a pyroclastic vent with a sinuous rille (colloquially known as Rima Mozart [Not IAU confirmed]) that extends from the southeast end of the vent. Rilles are large channels formed by sustained channelized lava flows. This vent is a great location to investigate ancient volcanism on the Moon.

The elevation data reveals one interesting feature: The lowest part of the vent pit is not at its western end, where one would think at first glance, based on the general dip that produced the rill flowing to the east. That the lowest point is at the widest section of the pit instead suggests that this pit no longer looks as it did when it was venting. In the almost four billion years since it is thought all volcanic activity here ceased, there has been plenty of time for the slow erosion processes on the Moon, caused by radiation, micrometeorites, and the solar wind, to partly fill this pit and round out its cliff walls.

The two overview maps below provide some context.
» Read more

A global map of rockfalls on the Moon

A global map of the rockfalls found on the Moon
Click for full resolution image.

A review of more than two million Lunar Reconnaissance Orbiter (LRO) images of the Moon has allowed scientists to compile the first global map of lunar rockfalls.

The map on the right comes from the paper. From the press release:

The result is a map of the lunar surface between 80 degrees northern and southern latitude that shows 136,610 rockfalls with diameters of more than two and a half meters. “For the first time, this map enables us to systematically analyze the occurrence and causes of rockfalls on another celestial body”, says Dr. Urs Mall from MPS.

Previously, scientists had assumed that lunar quakes in particular were responsible for the displacement of boulders. The new global map of rockfalls indicates that impacts from asteroids may play a much more important role. They are apparently – directly or indirectly – responsible for more than 80 percent of all observed rockfalls.

“Most of the rockfalls are found near crater walls,” says Prof. Dr. Simon Loew of ETH Zurich. Some of the boulders are displaced soon after the impact, others much later. The researchers hypothesize that impacts cause a network of cracks that extend in the underlying bedrock. Parts of the surface can thus become unstable even after very long periods of time.

Though the map suggests vaguely that these rockfalls are more scattered on the lunar farside and more concentrated in the mid-latitudes on the nearside, I suspect this is likely not so. If it is however it reveals something about the Moon that needs to be explained.

Dawn at the Moon’s North Pole

The rim of Aepinus Crater close to the Moon's north pole
Click for full image.

When dawn comes to the airless rough terrain of the Moon’s poles, it comes in fits and spurts. The floors of some craters never see it, while the high crater rims might have only a short time in darkness, their elevation high enough to keep the Sun above the horizon almost continuously. While there appear to be no places at the poles that have eternal daylight, there are places where night is short and infrequent.

The cool image to the right, cropped and reduced to post here, shows one such place close to the Moon’s north pole, the rim of Aepinus Crater. Taken by Lunar Reconnaissance Orbiter (LRO) on March 10, 2020, the illuminated area on this oblique image is about one by four miles in size. With dawn approaching this rim sees the Sun before the rest of the polar region, and remains illuminated long after the surrounding region has returned to darkness.

To get an idea of how small this one illuminated area is, below is a panorama showing the wide region around the rim.
» Read more

Triple impact on Moon

Impact craters Messier and Messier A on the Moon

Cool image time! A new image release from Lunar Reconnaissance Orbiter (LRO) takes a look at the impact process that created the crater Messier and its neighbor crater Messier A. The photo to the right, cropped to post here, shows both craters.

Take a close look at Messier A. It is actually a double crater itself. From the release:

Messier A crater, located in Mare Fecunditatis, presents an interesting puzzle. The main crater is beautifully preserved, with a solidified pond of impact melt resting in its floor. But there is another impact crater beneath and just to the west of Messier A. This more subdued and degraded impact crater clearly formed first.

Did these three craters happen as separate events. According to the data, it appears no. Instead, they might have all been part of a single rain of asteroids, all occurring in seconds.
» Read more

Crash site of Vikram found

Vikram impact point
Click for full image.

Using a mosaic of Lunar Reconnaissance Orbiter (LRO) images, citizen scientist Shanmuga Subramanian located on the Moon the debris and impact point for India’s Vikram lander that crashed there in September, an identification that has since been confirmed by LRO scientists.

The image on the right, reduced to post here, has been modified by the scientists to bring out the features that changed before and after the impact.

After receiving this tip the LROC team confirmed the identification by comparing before and after images. When the images for the first mosaic were acquired the impact point was poorly illuminated and thus not easily identifiable. Two subsequent image sequences were acquired on 14, 15 October and 11 November. The LROC team scoured the surrounding area in these new mosaics and found the impact site (70.8810°S, 22.7840°E, 834 m elevation) and associated debris field. The November mosaic had the best pixel scale (0.7 meter) and lighting conditions (72° incidence angle).

The debris first located by Shanmuga is about 750 meters northwest of the main crash site and was a single bright pixel identification in that first mosaic (1.3 meter pixels, 84° incidence angle). The November mosaic shows best the impact crater, ray and extensive debris field. The three largest pieces of debris are each about 2×2 pixels and cast a one pixel shadow.

No word yet on what this new information reveals about Vikram’s failure.

Lunar Reconnaissance Orbiter locates crashed Chinese orbiter

Before and after images showing Longjiang-2 impact site

Lunar Reconnaissance Orbiter (LRO) has located the Chinese microsat lunar orbiter Longjiang-2, which was sent to impact the Moon in August 2019 after it completed its technology demonstration mission.

The image above shows the before and after of the location, with the satellite’s remains visible as indicated by the arrow.

Through a careful comparison of pre-existing NAC images, the LROC team was able to locate a new impact crater (16.6956°N, 159.5170°E, ±10 meters), a distance of only 328 meters from the estimated site! The crater is 4 meters by 5 meters in diameter, with the long axis oriented southwest to northeast. Based on proximity to estimated crash coordinates and the crater size, we are fairly confident that this new crater formed as a result of the Longjiang-2 impact.

The picture of the impact site might not be very impressive, but remember, this satellite only weighed about a hundred pounds. The engineering however is impressive, on all counts. First, the Chinese built a tiny cubesat that reached lunar orbit and operated there for more than a year, during which it even took a picture of the Earth. Second, the engineering team of LRO was able to find this tiny impact site for such small spacecraft in less than four months.

Bhabha Crater at dawn

Central peaks of Bhabha Crater at dawn

Cool image time! The Lunar Reconnaissance Orbiter (LRO) science team have released a beautiful oblique image of Bhabha Crater, located on the Moon’s far side, taken just as dawn was breaking over the crater’s central peaks.

The image to the right is a section of that picture, showing the central peaks near the bottom with the western rim of the 50-mile-wide crater at the top. The giant shadows of those central peaks can be seen extending across the floor of the crater and against that western rim. The photograph was taken on August 28, 2019 from an altitude of about 45 miles. The area of the central peaks in daylight is estimated to be about nine miles across.

The LRO science team releases a new press release image about once every two weeks. I suspect that they hoped this release would have shown the location of India’s Vikram lander. As they are as yet unable to find it, they instead provided us this cool image instead.

If you go to the link you can use their viewer to view and explore this very very large image. For example, if you zoom into those central peaks you can actually see small boulders scattered across their rounded tops.

LRO’s 2nd attempt to find Vikram comes up empty

In their second attempt to find India’s failed lunar lander Vikram, the science team of Lunar Reconnaissance Orbiter (LRO) were unsuccessful in spotting it.

A project scientist of Nasa’s LRO mission confirmed that the space agency’s second attempt to locate Vikram had come up empty. “The Lunar Reconnaissance Orbiter imaged the area of the targeted Chandrayaan-2 Vikram landing site on October 14 but did not observe any evidence of the lander,” Noah Edward Petro, the project scientist told news agency PTI.

Petro explained that Nasa compared the images shot by the LRO on October 14 with an image of the same area before Vikram’s landing. Nasa used a technique that would help it spot any signs of impact on the lunar surface indicating Vikram’s possible location. However, the images revealed nothing.

“It is possible that Vikram is located in a shadow or outside of the search area. Because of the low latitude, approximately 70 degrees south, the area is never completely free of shadows,” John Keller, deputy project scientist of Nasa’s LRO mission, explained while speaking to news agency PTI.

Based on the data obtained during the landing attempt, it appeared that Vikram should have crashed within a relatively small target area. That they haven’t seen it yet suggests that it landed within a shadowed area that will take time for the Sun to reach, if ever, or that it is farther away that expected, which implies that during landing much more went wrong than presently believed.

LRO scientists release image of Vikram landing site

Overview of Vikram landing area
Click for full image.

The Lunar Reconnaissance Orbiter (LRO) science team yesterday released their high resolution image taken of the area where it is believed India’s lunar lander Vikram crashed.

The image to the right is not that image, but an oblique overview showing where that landing region is, the center of which is indicated by the white cross. Vikram was aiming for this flat region between the Simpelius N and Manzinus C craters.

In releasing the image, the scientists explained what they thought were the reasons they have so far failed to find Vikram.

We note that it was dusk when the landing area was imaged and thus large shadows covered much of the terrain, perhaps the Vikram lander is hiding in a shadow. The lighting will be favorable when LRO passes over the site in October and LROC will attempt to image the lander at that time.

You can explore the actual image at the link. It is quite large, though their viewer there allows you to zoom in and move about, inspecting each grid area very closely. As they note, there are a lot of shadowed areas.

LRO’s high resolution camera can see objects as small as Vikram, even if broke up somewhat on landing. The key for discovery will be timing. LRO will have to pass over at a time when the lander is not in shadow.

UPDATE: Below the fold is a side-by-side comparison of this region, with mid-day on the left and the dusk LRO image on the right, created by Rex Ridenoure of Ecliptic Enterprises.and graciously provided to me.
» Read more

LRO fails to spot Vikram on Moon

Despite successfully taking high resolution images of the area on the Moon where it is thought India’s Vikram crash-landed two weeks ago, the Lunar Reconnaissance Orbiter (LRO) science team has been unable to identify it in those images.

LRO’s Lunar Reconnaissance Orbiter Camera instrument, or LROC, imaged the intended south pole touchdown site for the lander, which is called Vikram, as planned yesterday (Sept. 17), Aviation Week’s Mark Carreau reported. But “long shadows in the area may be obscuring the silent lunar explorer,” Carreau wrote.

“It was near dusk as the region prepares to transition from a two-week lunar day to an equally long lunar night, so shadows covered much of the region, and Vikram may not be in the LROC’s field of view,” Carreau wrote, citing a NASA statement.

This means that they will simply have to try again during a later orbit. Eventually the lighting conditions will be right, and LRO will photograph Vikram.

LRO to image Vikram landing site next week

The Lunar Reconnaissance Orbiter (LRO) science team plans to take high resolution images of the Vikram landing site when the orbiter flies over that site on September 17, thus allowing them to release before and after images.

Noah Petro, LRO’s project scientist at NASA’s Goddard Space Flight Center, said that the orbiter is due to fly over the Vikram landing site Tuesday, Sept. 17. “Per NASA policy, all LRO data are publicly available,” Petro wrote in an email. “NASA will share any before and after flyover imagery of the area around the targeted Chandrayaan 2 Vikram lander landing site to support analysis by the Indian Space Research Organization.”

Officials with India’s space agency ISRO have said they have photographed Vikram with their orbiter, Chandrayaan-2, but they have not released these images as yet. Their have also been reports from India stating that their images suggest the lander is still in one piece, but these reports are not confirmed.

LRO’s images should clarify the situation. The images should also help tell us what exactly happened after Indian engineers lost contact with Vikram shortly before landing.

Golfing with boulders on the Moon

Boulder tracks on the Moon
Click for full resolution image.

Cool image time! The Lunar Reconnaissance Orbiter team this week released a beautiful image of boulder tracks rolling down the inside slope of 85-mile-wided Antoniadi crater on the far side of the Moon. The image above, cropped, reduced, and annotated to post here, shows these tracks.

The most obvious track is cool because the boulder almost made, as the scientists note, “a hole-in-one.”

Running from the outcrops to the rim of the partially buried crater is a track etched by a rolling boulder bigger than a bus. Perhaps a moonquake shook it loose. The boulder bounced and rolled toward the partially buried crater, plowing a path that is still visible through the loose material of the slope. When it reached the rim of the partially erased crater, its path curved and it slowed to a stop.

…Had it rolled just 75 meters more, the boulder might have plopped neatly into a 30-meter-diameter young impact crater on the floor of the partially erased crater.

The arrows I have added indicate two more less obvious boulder tracks. If you click on the full resolution image and zoom in you can also see another series of impressions in the middle of the photograph that look like a dotted line, suggesting they were left by a boulder bouncing down the slope.

The scattered of boulders in the floor of the small crater all likely came from the top of the big crater’s rim, which I show in the wider image below.

Wider image showing entire crater slope

The box indicates the location of the image above.

While many things over the eons could caused these boulders to roll (moonquakes, erosion from the solar wind, other nearby impacts), a close look at the ground surrounding them does not show tracks emanating from most, suggesting they have been there a very long time, long enough for the surface reworking caused by the solar wind to have smoothed those tracks out.

The Moon is airless and mostly dead. The solar wind is incredibly weak. Any changes caused by it will take a lot of time. Consider the time required to smooth out those tracks. The mind boggles.

Jackson Crater on the Moon’s far side

Jackson Crater

Central peaks of Jackson Crater

In celebration of the 50th anniversary of the Apollo 11 mission, let’s look at another cool Moon photograph. The Lunar Reconnaissance Orbiter (LRO) science team on July 19 released a new breath-taking oblique image of Jackson crater, located on the Moon’s far side. The image above, reduced significantly to post here, shows that photograph and the crater’s cluster of near-center peaks. From the caption:

East-to-west view of Jackson crater (44 miles diameter). Image was acquired when LRO was at an altitude of [69 miles] and the Sun was to the west of the crater (LROC was facing somewhat towards the Sun; phase angle 114 degrees). The central peak rises about [5900 feet] above the crater floor and the top of the crater rim in the background has more than [13,000 feet] relief relative to the floor. Image width is about [40 miles] and north is to the right

The white box indicates the area covered by the close-up to the right. From the article:

What is the composition of the crust from top to bottom? It is relatively easy to measure the surface, but what lies beneath the surface? On the Earth geologists can dig and drill deep into the crust. We do not have that luxury on the Moon, at least not yet! However, we can take advantage of natural drill holes in the crust – impact craters! When impacts occur they dig into the crust and the central peaks expose the deepest material. Jackson crater formed on what was rather uneven terrain: to the east of the crater the elevation is about +6000 meters and to the west about +3000 meters. The bottom of the crater sits at +1000 meters, and the material exposed in the central peak comes from more than 1000 meters deeper still. By studying the rocks exposed in the central peak we can get a glimpse of materials that have come up from five or more kilometers below the surface (>3 miles).

The black pile of giant boulders near the top of the close-up suggests molten material dredged up from deep below the surface. So do the many black boulders on the nearer mountain slopes.

Why this dark material does not cover the entire surface is not clear. The lighter and darker material indicates different materials and ages, but the specifics are not known, as yet.

The Untouched Moon

Montes Carpatus
Click for full image.

In celebration of Apollo 11: Continuing the theme of yesterday’s cool image, where I noted how little of the Moon we have really seen, today’s cool image gives us a breath-taking glimpse of one such untouched region, the Montes Carpatus region.

The photograph to the right, reduced to post here, was released by the Lunar Reconnaissance Orbiter (LRO) science team in March 2018. From the release:

Volcanic rocks are our best window to the deep interior of the Moon, and the Montes Carpatus has no shortage of volcanic landforms: lava flows, pyroclatic deposits, rilles, and more! Lavas are formed as the mantle begins to melt, so by sampling volcanic rocks of various ages from regions across the Moon scientists can reconstruct the range of compositions and processes over time. The Montes Carpatus formed as a result of the giant impact that formed the mighty Imbrium basin, the mountains are actually the raised rim of the basin.

Today is the 50th anniversary of the Apollo 11 landing. If you had told anyone involved in that mission that fifty years later no significant further manned exploration of the Moon had yet occurred, they would have scoffed.

It is a terrible condemnation of my generation, the generation that followed Apollo 11, that we did nothing grand like this. I challenge the generations today to reach higher, and do better.

The Taurus-Littrow valley

Taurus-Littrow Valley
Click for full image.

It might not be Apollo 11, but during this 50th anniversary week of that mission, why not look at where the last Apollo 17 crew landed, in the middle of the Taurus-Littrow valley, as shown on the right in a Lunar Reconnaissance Orbiter (LR) image released by the LRO science team in 2018.

The image illustrates how ambitious NASA had become by this last Apollo mission. The Apollo 11 site was chosen because it was flat with as few risks as possible. By Apollo 17, the Apollo engineers and astronauts were quite willing to drop the LM down into this valley between gigantic mountains. Granted, the valley was more than 400 miles wide, but considering the risks of every Apollo flight, the choice was daring to say the least.

Taurus-Littrow also has a cluster of craters believed to have been formed by material flung out from the formation of 86-kilometer-wide Tycho crater about 100 million years ago. Tycho is 2250 kilometers from Taurus-Littrow, but the impact that formed it was violent enough that it cast material far across the Moon.

Nor is this location the most spectacular on the Moon. In fact, considering that all the manned and unmanned missions in total have probably covered less ground than a New York cab driver does in a single day, we have seen almost nothing there.

A wave on the Moon

A lunar ejector blanket

Continuing this week’s celebration of the 50th anniversary of the Apollo 11 mission means we get to look at another cool image from the Moon. The photograph on the right, reduced to post here, was released by the Lunar Reconnaissance Orbiter (LRO) science team in 2016.

What are we looking at? At first glance it looks like a black & white photograph of The Wave in northern Arizona. What it is instead is the pattern of ejecta laid down across the surrounding terrain immediately after the impact that created relatively fresh Chaplygin Crater. From the website:

The delicate patterns of flow across, over, and down local topography clearly show that ejecta traveled as a ground hugging flow for great distances, rather than simply being tossed out on a ballistic trajectory. Very near the rim lies a dark, lacy, discontinuous crust of now frozen impact melt. Clearly this dark material is on top of the bright material so it was the very last material ejected from the crater.

Below the fold is a wider shot of the entire crater and its surrounding terrain, with the rectangle indicating the region covered by the close-up above The dark crust near the rim mentioned in the quote can clearly be seen.
» Read more

Weird lunar crater

Concentric crater in Apollo Basin on the Moon

In celebration of the 50th anniversary of the Apollo 11 mission, it is time for another cool image from the Moon. The photograph on the right, reduced to post here, was taken by Lunar Reconnaissance Orbiter (LRO) in 2013. It shows a weird crater with concentric features that is found within Apollo Basin, a large 334-mile-wide double-ringed impact feature in the southern hemisphere of the Moon’s far side.

Concentric craters have an inner rim whose formation mechanism is not yet entirely understood, but the concentric mounds may indicate that there is a discontinuity, such as layers with different strengths, in the subsurface excavated by the impact.

Or to put it more bluntly, they really have no idea why this crater ended up looking as it does.

1 2 3