Soaring over the Apennines

This is another LROC NAC mosaic viewers may really want to see using the "see all sizes" download option that accompany slideshow images in Flickr. An oblique view, looking west over the Apennine Mountains toward Hadley Rille (above -north is to the right).  The morning shadows are much as they were July 30, 1971, when Dave Scott and Jim Irwin flew on their backs over range at bottom, flipped forward and landed on the broad plain between those hills and Rima Hadley. Hadley Base, their landing site, and the descent stage of the Apollo 15 lunar module Falcon is right where they left it, just within the resolution of full scale reproductions of this image. 

Notable features in a thumbnail of LROC NAC oblique mosaic M1123519889LR, LRO orbit 17751, May 18, 2013; spacecraft and cameras slew 55.22° from orbital nadir, 76.87° incidence angle, average resolution 2.87 meters from 130.27 km over 26.11°N, 11.75°E [NASA/GSFC/Arizona State University].

J. Stopar

LROC News System

Apollo mission planners selected an adventurous landing site for Apollo 15 (26.132219°N, 3.633861°E), on a relatively small patch of lava plains (mare). 

This site is nestled between the towering Apennine mountains to the east, attaining heights of 3-5 km, and the 200 meter deep, v-shaped valley of Hadley Rille to the west.

The experience gained from the successful landings of the preceding Apollo missions afforded mission controllers confidence that a landing descending through a mountain range was possible, though it required a steeper descent angle (25° rather than 14°).

The landing site of Apollo 15 (direct center), on Hadley Rille Delta between the Apennine mountain range on the southeast periphery of Mare Imbrium and Rima Hadley, winding through the distinctly darker mare material of Palus Putredinis. LROC WAC GLD100 elevation overlain atop LROC 100 meter global mosaic. The peaks of the Apennine Mountains rise more than 5 km over the interior of the Imbrium basin [NASA/GSFC/Arizona State University].

A captioned video of the descent of Apollo 15 conveys the excitement of astronauts David Scott and James Irwin as they set down near Hadley Rille. The Hadley Rille landing site also presented an opportunity to test the capabilities of the new lunar roving vehicle (LRV).

"Down on the plain at Hadley." Newly realigned video (3:37) of the landing of Apollo 15, July 30, 1971. [LunarModule5].

The Apennine Mountain Range formed during the Imbrium basin-forming event, and it was hoped these mountains contained materials from very early in the Moon's history (which they did!). As astronauts Irwin and Scott descended over the Apennines, they reported a floating sensation that resulted from glimpsing mountain peaks passing by the windows of the Lunar Module (LM). The descent was a complete success, and the LM set down near the planned site! Although, the astronauts were a little surprised to land with one foot-pad in a small crater, placing the vehicle on a slant.

Cmdr. Dave Scott captured this view of the Apollo 15 lunar module Falcon where it came to rest tilting toward the Apennine mountains beyond, while Jim Irwin checked out the first of the three Apollo "J mission" lunar rovers. See full-size mosaic of two color images from the panorama (AS15-86-11600 and 11601) HERE [NASA/JSC/ALSJ].

Three EVAs (or traverses) were planned for Apollo 15 using the LRV, two of which allowed sampling part of the Apennine Mountain Range to the south and southeast and required long (multi-kilometer) traverses.

Thumbnail of a mosaic of black and white images from Science Station 6, during the second EVA of the Apollo 15 expedition, on the slopes of the "Apennine Front." In the full-size panorama, HERE, the lunar module Falcon is visible, several kilometers away, between Hadley rille on the far left and Mt. Hadley, dominating the center of this mosaic [AS15-85-11481-11492, NASA/JSC/ALSJ].

Astronauts Scott and Irwin were accomplished field geologists; listen HERE as Commander Scott recently reflected on his Apollo 15 experience, including the importance of field-geology training.

The tiny arrow marks the location of the LM, just barely within the resolution of the LROC NAC mosaic (at full-scale), while LRO orbited over a spot 130 km away. Of course, the landing zone has been documented with remarkable detail from LRO, from better vantages [NASA/GSFC/Arizona State University].

Related Posts:

Man's first wheels on the Moon at 41 years

Retracing the Steps of Apollo 15: Constellation Region of Interest

Apollo 15 Lunar Laser Ranging Retroreflector - A Fundamental Point on the Moon

Layers near Apollo 15 Landing Site

Hadley Rille and the Mountains of the Moon

Kaguya captures Hadley Rille and Apollo 15

The complex case at Lassell K

An early morning view looking east-to-west from an altitude of 86 km across the southern portion of the Lassell Massif, an irregularly shaped series of hills and steep-walled depressions. North is to the right in this LROC NAC oblique mosaic M1108311369LR, LRO orbit 15611, November 23, 2012; 71.73° incidence angle, spacecraft and camera slew 56.64° from orbital nadir, resolution above 2 meters from 85.65 km over 14.63°S, 355.69°E [NASA/GSFC/Arizona State University].

J. Stopar

LROC News System

The Lassell Massif is a complex area of rugged terrain located in northeastern Mare Nubium (14.7°S, 351.0°E). This undulating terrain of hills and steep-walled depressions is 45 km across from north to south and 25 km across from east to west.

The southern portion of the massif comprises several prominent elongate depressions (like Lassell K and Lassell G, seen below) that are clustered together.

The Lassell Massif in Mare Nubium; north is to the right. Prominent features of the Lassell Massif region include Lassell C, K, and G [NASA/GSFC/Arizona State University].

The clustering and irregular shape of these negative-relief features is reminiscent of volcanic calderas on Earth and other terrestrial planets, including Mars. Calderas generally form through collapse as magma retreats from the vent area. Overlapping collapse features suggest multiple episodes of magma advance and retreat over time. Lassell K and G may be part of a volcanic caldera!

Lassell K and G could, however, instead represent a series of clustered impact craters, which are relatively common on the Moon.

Remote sensing data displayed in eight diverse views of the 1000 meter-high profile of Lassell massif, collected by four spacecraft (all of them post-Apollo) presented in an overlapping 40.2 km-wide field of view, visible throughout both day and night. The largest crater at center-left is Lassell C (8.74 km; 14.67°S, 350.64°E) [Clementine, LRO, Chandrayaan-1 and Chang'e-2].

Lassell K (left) and portion of Lassell G (right). The upper walls of these steep-walled depressions have dark, low-reflectance, boulders and downslope streamers (arrows), where a thin layer of dark material, possibly pyroclastic, has eroded out of the wall [NASA/GSFC/Arizona State University].

Looking closely at this region, we see other features that are typical of volcanic eruptions including: dark mantling layers interpreted as possible pyroclastics, a subdued or mantled terrain, and even a possible volcanic cone.

Taken together, these features suggest a complex volcanic history for this region. If the Lassell Massif is constructed from a series of volcanic extrusions, it may represent an unusual type of silicic volcanism on the Moon (perhaps similar in composition to rhyolite).

Read more about the Lassell massif and its unusual style of volcanism in a study presented by members of the Lunar Reconnaissance Orbiter Camera team and colleagues to the 44th Lunar and Planetary Science Conference (2013): "The Lassell Massif, Evidence for Complex Volcanism on the Moon," #2504.

The full oblique image (below) along with other images and compositional data sets may reveal more clues to the timing and nature of volcanism in the Lassell region. However, returning rock samples to Earth and exploring the slopes of this structure from the surface may be the only way to confirm its origins.

View assorted sizes of an unlabeled sample of a mosaic from the LROC observation above, HERE.

View oblique in full-window, HERE.

Related LROC Featured Images:

New Views of the Gruithuisen Domes

Lassell D Ejecta

The Fourth Mairan Dome

Farside Highlands Volcanism

Up From the Depths

Aristarchus Spectacular

A splendid oblique view of Larmor Q

LROC NAC view of the south wall and rim of splendiferous Larmor Q crater, looking obliquely east-to-west; LROC NAC oblique mosaic M174081337LR, LRO orbit 10788, October 24, 2011; 44.93° incidence angle, resolution roughly 2.3 meters, spacecraft and camera suite slewed 67° from orbital nadir, 59.44 km over 28.84°N, 211.72°E [NASA/GSFC/Arizona State University].

J. Stopar

LROC News System

Larmor Q (28.674°N, 176.32°E) is sub-circular crater, whose  23 km diameter is measured north to south and 19 km measured east to west.

But Larmor Q is not just another stunning crater; it is also scientifically interesting.  Oblique images, like the one below, provide a unique vantage point that can help with geologic interpretation.

Oblique view (reduced for web-browsing) of Larmor Q crater, looking east-to-west. The crater is wider in the north-south direction than in the east-west direction. Click for larger image [NASA/GSFC/Arizona State University].

One of the most obvious features of Larmor Q is the large accumulation of slumped wall materials inside the crater. This crater is a transitional morphology between smaller simple craters like this one, HERE, and larger, complex craters like Tycho or Copernicus.

The crater Giordano Bruno (21 km in diameter) is another example of a transitional crater. Wall slumping in transitional craters affects the final crater shape. When the northern wall of Larmor Q failed, the northern rim crest of the crater moved outward, contributing to the larger crater diameter in the north-south direction.

Prominent features of Larmor Q include slumped wall material and impact melt deposits; located at 176.313°E, 28.634°N [NASA/GSFC/Arizona State University].

This oblique image of Larmor Q is also useful for studying the distribution of impact melt, which, in turn, can tell us how impact melt is generated and interacts with the forming crater. In Larmor Q, most of the impact melt rock is located inside the crater opposite the largest slumped materials.

View of impact melt deposits inside Larmor Q. The melt has splashed up the southern wall (left) and ponded in the floor of the crater (center of image)[NASA/GSFC/Arizona State University].

Flows of impact melt on the rim of Larmor Q crater now solidified into lobate deposits [NASA/GSFC/Arizona State University].

There are also several relatively small deposits (flows) of impact melt rock on the crater rim. Because the largest concentration of impact melt occurs opposite the largest slumped materials, we infer that the melt “splashed” up on the southern wall primarily as a result of the slumped material impinging on the crater floor.

LROC Wide Angle Camera (WAC) image of the 18.3 km diameter crater Larmor Q. Slumping of the crater walls has not yet covered all the impact melt on its floor. LROC WAC monochrome (604 nm) observation M136389155C, LRO orbit 5233, August 14, 2010; 54.83° angle of incidence, resolution 82 meters from 58.4 km [NASA/GSFC/Arizona State University].

NASA ILIADS application simulated orbital view (not too dissimilar to the oblique perspective of the LROC Featured Image released May 13, 2014) shows the region of the lunar farside highland terrain between Larmor Q (23 x 19 km; 28.674°N, 176.32°E, bottom center) and Mare Moscoviense (275 km; 27.28°N, 148.1°E), perhaps the most immediately eye-catching feature of the Moon's opposing hemisphere, 750 km away and 1000 meters higher in average elevation above global mean. LROC WAC 100 meter global mosaic imagery applied to LRO LOLA laser altimeter-based digital elevation model [NASA/MSFC].

The full resolution oblique view of Larmor Q crater contains more fascinating clues of the impact cratering process, HERE.

Related LROC Featured Images:

Dense Fractures on the Floor of Larmor Q

The View Inside of a Tilted Crater

Very Oblique View of Giordano Bruno

Ryder Spectacular!

Sunset Over Giordano Bruno

Necho's Jumbled Floor

View from the Other Side

Earthrise!

LROC Wide Angle Camera (WAC) observation M1145896768C, LRO orbit 20898, February 1, 2014; spacecraft and camera slew 63.8° from orbital nadir. LROC Featured Image, May 7, 2014 [NASA/GSFC/Arizona State University].

Mark Robinson
Principal Investigator
Lunar Reconnaissance Orbiter Camera
Arizona State University

LRO experiences twelve earthrises every day, however LROC is almost always busy imaging the lunar surface so only rarely does an opportunity arise such that LROC can capture a view of the Earth. On the first of February of this year LRO pitched forward while approaching the north pole allowing the LROC WAC to capture the Earth rising above Rozhdestvenskiy crater (181 km; 85°N, 202.1°E).

The LROC Wide Angle Camera (WAC) is very different than most digital cameras. Typically resolution is reported as the number pixels in a single image, a cell phone camera today has more than 5 million pixels (5 megapixels). A single WAC frame has only 9856 pixels, however the WAC builds up a much larger image by exposing a series of images (or frames) as LRO progresses in its orbit; this type of imaging is called "push-frame". Over a full month as the LRO orbit track progresses around the Moon the WAC builds up a collection of images that covers the entire globe.

Occasionally LRO points off into space to acquire observations of the exosphere and perform instrument calibration measurements. During these slews sometimes the Earth (and other planets) pass through the WAC's field of view and dramatic images such as the one shown here are acquired. In the opening image the Moon is a grayscale composite of the first six frames of the WAC observation (while the spacecraft was still actively slewing), using visible bands 604 nm, 643 nm, and 689 nm. The Earth is a color composite of later frames, using  the 415 nm, 566 nm, and 604 nm bands as blue, green, and red, respectively. These wavelengths were picked as they match well the response of the human eye, so the colors are very close to true, that is what the average person might see. Also, in this image the relative brightness between the Earth and the Moon is correct, note how much brighter the Earth is relative to the Moon.

LROC WAC Earthrise [NASA/GSFC/Arizona State University].

In the video the "venetian blind" banding demonstrates how a WAC image is built up frame-by-frame. The gaps between the frames are due to the real separation of the WAC filters on the CCD. The longest wavelength (689 nm) band is at the bottom of the scene, and the shortest (415 nm) is at the top; note how the Earth is brighter when it enters the top band due to the blue from the ocean. The frames were acquired at two second intervals, so the total time to collect the sequence was 5 minutes. The video is faster than reality by a factor of ~20.

Related Posts:
In the Shadow of the Moon
Americas from the Moon
Earth from the Moon

Taking a peek at Icarus

The central peak of Icarus crater rising out of the shadows to greet a new lunar day! Image field of view approximately 10 km (north is at right. LROC NAC oblique mosaic M1124685518LR, LRO orbit 17914, June 1, 2013; spacecraft and camera slew 62.84° from nadir, resolution 3.3 meters per pixel and captured from 106.53 km over 5.58°S, 193.85°E [NASA/GSFC/Arizona State University].

H. Meyer
LROC News System

Icarus crater is one of a kind on the Moon; its central peak rises higher than about half its rim. Most central peaks rise only about halfway to the crater rim. Icarus' large, rounded central peak resembles that of Alpetragius on the eastern limb of Mare Nubium.

The disproportionate size of the central peak may be because both Icarus and Alpetragius are close in diameter to the transition between central peaks and peak rings.

A reduced resolution image of the full NAC oblique looking from east to west across Icarus crater (5.348°S, 186.579°E). Notice the gentle slopes of the terraces on the crater wall and many superposed craters that suggest that Icarus is quite old. Icarus is approximately 94 km in diameter . LROC NAC oblique mosaic M1124685518LR  [NASA/GSFC/Arizona State University].

Icarus is located just west of Korolev crater on the lunar farside. Like the floor of Korolev, the floor of Icarus is covered with relatively smooth light plains material that can be seen outside the crater as well, filling not only crater floors but also the surface between craters in the highlands (See WAC context image below).

LRO WAC image of Icarus crater and vicinity (5.49°S, 186.74°E) in the lunar highlands. Image field of view approximately 365 km, Korolev crater and the Orientale basin are both east of this site [NASA/GSFC/Arizona State University].

A "bonus" oblique assembly of Icarus crater, from a 100 km orbit, looking south, from the Planetary Camera collection from Japan's lunar orbiter SELENE-1 (Kaguya) [JAXA/SELENE].

These light plains were deposited during the formation of the Orientale basin, which is located over 1500 km away! The specific mechanism by which the light plains were emplaced is still under investigation, but the plains are likely made of ejecta produced during the formation of the Orientale basin.

See the full size NAC oblique HERE.

Related LROC Posts:
Stopped In Its Tracks
Overprinting Orientale
Crater Mendeleev

Offset floor of Buys-Ballot crater

LROC Featured Image, released December 5, 2013: Lobate scarp ridge along the east floor of Buys-Ballot crater. LROC NAC image centered on 21.321°N, 175.152°E, field of view 1.41 km. Sunset illumination (angle of incidence 82.35°), LROC NAC observation M1095343282LR, LRO orbit 13796, June 26, 2012; mean resolution 1.4 meters per pixel, spacecraft and camera slew 2.31° off nadir, captured from 139.75 km over 20.94°N, 175.0°E [NASA/GSFC/Arizona State University].

Hiroyuki Sato
LROC News System

The opening image is of the eastern edge of the floor of the farside crater Buys-Ballot (66.4 km in diameter). The shape of this crater is elongated from the northwest to southeast (see next WAC context image), likely due to a low impact angle. The floor is partially resurfaced by basaltic lava, leaving a relatively flat area around the linearly aligned central peaks.

The topographic ridge from upper-left to lower-right of the opening image is offset along a lobate scarp that extends about ~60 km along the contact of the flat floor and eastern crater wall. The late afternoon illumination from the left side of this image (incidence angle is 82.4°) highlights the fault scarp and the up thrown lava (lower left half of the image). The scarps extend out of the crater in the south, but segments there are not as well developed as those inside the crater and gradually disappear.

Full 15.3 km-wide field of view centered on area shown at 1.41 meters per pixel resolution in the LROC Featured Image, above, released December 5, 2013. LROC NAC mosaic M1095343282LR [NASA/GSFC/Arizona State University].

The lobate scarp is located in mare basalts and extends up and out of the crater into the surrounding highlands, somewhat similar to the famous Lee Lincoln scarp near the Apollo 17 landing site. Although formed in mare, the fault scarp does not have the distinctive morphology typical of wrinkle ridges that are found exclusively in mare basalts (see Wrinkles in Mare Frigoris, The Ghosts of Mare Fecunditatis & Boulder Clusters on a Ridge Crest).

Lobate scarps are formed by thrust faults caused by global contraction of the Moon as its interior cools. Sometimes these young thrust faults crosscut highland craters like Buys-Ballot crater and Seares crater, resulting in fascinating sharp morphologies on top of the featureless flat basaltic plain.

Context view of Buys-Ballot crater (LROC Wide Angle Camera monochrome mosaic, resolution standard global 100 meter per pixel), field of view centered on 20.86°N, 175.15°E. The LROC NAC mosaic footprint (blue rectangle) and location of LROC Featured Image (yellow arrow) noted [NASA/GSFC/Arizona State University].

Explore the low-sun picture of the lobate scarps inside Buys-Ballot crater, HERE.

Related Posts:
Squished Crater
Taurus Littrow Valley, West-To-East
Not Your Average Scarp
Lobate Scarp or Fluidized Ejecta?
Tectonics in Mare Frigoris
Scarps in Schrödinger
Lunar Lobate Scarp
Right Angle
Slipher Crater: Fractured Moon in 3-D
Aitken Crater Constellation Program Region of Interest
The Moon in 3D

Bonus image: an oblique view of the south interior of the Buy-Ballot formation. LROC Narrow Angle Camera (NAC) mosaic M167091099LR, LRO orbit 9758, August 4, 2011; angle of incidence 58.6°, camera and spacecraft slew from nadir 64.7° - mean resolution 3.9 meters per pixel, from 60.35 km over 20.37°N, 169.9°E, 140 km east of field of view (mechanics of observation below) [NASA/GSFC/Arizona State University].

Mechanics of 'Bonus' image, above; highly slewed LROC NAC oblique observation M167091099LR, a slewed view of the southern interior of the Buys-Ballot formation [Google Earth].

Tsiolkovskiy's Central Peak

LROC Narrow Angle Camera (NAC) oblique mosaic M1098059280LR (orbit 14176, July 27, 2012; angle of incidence 60.08°), the central peak of farside landmark Tsiolkovskiy crater. The image field of view is approximately 25 km across, the central peak rises 3.4 km above the mare-inundated crater floor.  Spacecraft and camera slewed 64° far east of nadir, capturing the dramatic scene from 87.66 km over 20.44°S, 121.42°E [NASA/GSFC/Arizona State University].

Raquel Nuno
LROC News System

Today's Featured Image is a spectacular LROC NAC oblique view looking East at the central peak of Tsiolkovskiy crater. This large impact crater, with a diameter of 185 km, is located on the farside at 20.38°S latitude and 128.97°E longitude.

It is classified as a complex crater because of its terraced walls, scalloped rim, and central peak, which rises over 3400 m (11,150 ft) from the crater floor.

Central peaks of craters form in a matter of seconds from very energetic impact events. The tremendous pressure imparted from the impactor on to the target rock causes it to behave like a plastic for a few brief seconds. An imperfect analogy is a water droplet splashing into water, at first which produces a central jet, the fluid-like behavior of rock after the impact causes it to rebound upwards. Another factor assisting in the uplift of a central peak is the gravitational collapse of the crater walls which pushes material in the center upwards.

LROC interferometry and LOLA (laser altimeter) data, a brief tour of an advanced lunar Digital Elevation Model (DEM), in the vicinity of Tsiolkovskiy crater. "Tour of the Moon, Additional Footage," Science Visualization Studio [NASA/GSFC/SVS/ASU].

The floor of Tsiolkovskiy crater is partially flooded by mare basalt, which is the low reflectance smooth material seen in both the Featured Image above and the WAC context image below. The mare basalt on the floor of Tsiolkovskiy crater formed from basaltic lava that erupted after the crater formed and pooled. Mare basalts are predominantly seen on the lunar nearside; they make up the dark plains we are familiar with when we look at the Moon. This uneven distribution of mare basalts is thought to be due to the difference between the crustal thickness on the nearside and farside. The nearside crust is thinner, allowing easier access for basalt to flow up to the surface, whereas the thicker crust on the farside makes it so that only large impacts, like the one that formed Tsiolkovskiy crater, have enough energy to excavate deep enough into the crust to allow the release of basaltic lava.

Nearly every feature visible in the NAC oblique mosaic above is visible in this 50 km wide field of view captured from almost directly overhead. LROC Wide Angle Camera (WAC) monochrome (643 nm) observation M49675737CE, spacecraft orbit 7191, January 14, 2011; angle of incidence 74° at 78.4 meters per pixel resolution, from 57.15 km [NASA/GSFC/Arizona State University].

Deeper context from a mosaic of orbital passes, as the Moon rotated under the polar orbit of LRO shows the peaks emerging from it's distinctive (for the farside) mare-flooded floor. Terraced walls, slump and hummock of the complex crater come into view in this 145 km-wide field of view [NASA/GSFC/Arizona State University].

It's difficult to step back far enough to grasp the area affected by this super-positioned impact in the farside southern highlands. This context image originally helped illustrate "Tsiolkovskiy central peaks at sunset," July 3, 2013 [NASA/GSFC/Arizona State University].

On the left, LROC WAC monochrome mosaic centered at 120 degrees East longitude. On the right, LROC WAC context image of Tsiolkovskiy crater [NASA/GSFC/Arizona State University].

Tsiolkovskiy easily stood out, a rare dark spot highlighting the surprising differences between the Moon's near and its farside when it was first photographed by the Soviet Union's Luna 3 in 1959. This LROC WAC mosaic, centered on 180° and the equator, was among the first LROC Wide Angle Camera images released. Tsiolkovskiy is marked by the arrow [NASA/GSFC/Arizona State University].

The Tsiolkovskiy Crater was a Constellation Program region of interest because of the possibility to study the central peak, where astronauts could sample rocks that came from deep beneath the lunar surface.

Explore Tsiolkovskiy's central peak from an orbiting astronaut's perspective, HERE.

Related Posts:

Tsiolkovskiy central peaks at sunset (July 3, 2013)

Bullialdus Central Peak Oblique (January 23, 2013)

New oblique view of Tsiolkovskiy central peaks (December 26, 2012)
The Old and the Young at Tsiolkovskiy (October 31, 2012)

Sampling a Central Peak (August 9, 2012)
Weaving boulder trails on the Moon (July 11, 2012)
Bulging wrinkles at Tsiolkovskiy (January 11, 2010)
Regolith on Basalt (January 10, 2012)
Follow the highlands-mare boundary in Tsiolkovskiy (September 29, 2011)
The Hummocks of Tsiolkovskiy (August 26, 2010)
More of Tsiolkovskiy's boulders and boundaries (August 26, 2010)
Small fractures in the mare floor of Tsiolkovskiy (August 25, 2010)
Tsiolkovskiy - Constellation Region of Interest (May 1, 2010)
Uplift, Boulders of Tsiolkovskiy (September 1, 2009)

Oblique look deep into the heart of Lowell crater

Oblique LROC Narrow Angle Camera (NAC) mosaic of Lowell crater (62.65 km - 12.96°S, 256.58°E), super-positioned (or is it?) on the northeast quadrant of the Orientale basin. LROC NAC observations M1108918822R & L, spacecraft orbit 15696, November 30, 2012; angle of incidence 80.52° averaging 3 meters per pixel resolution (spacecraft and camera slew -62.35° from 91.55 km over 12.81°S, 262.88°) [NASA/GSFC/Arizona State University].

Named for the one and only Percival Lawrence Lowell (March 13, 1855 – November 12, 1916), popularizer of Mars lore in the late 19th century, and celebrated in part also by Clyde Tombaugh when he chose a name for "Pluto" in 1930, in the first two letters of that now "former planet's" Olympian moniker.

Looking north over Lowell and the northwest Orientale basin. LROC Wide Angle Camera (WAC) global mosaic draped on LOLA laser altimetry using NASA ILIADS application [NASA/GSFC/MSFC/ASU].

Related Posts:
Oblique views of Moon's highest and lowest places (October 3, 2012)

Impact melt lobes (April 12, 2012)

Orientale Sculpture

An oblique view of ejecta over 400 km south of the Orientale basin rim, a scene approximately 5 km across, centered at 51.8°S, 264.8°E, LROC Narrow Angle Camera (NAC) mosaic M1127819355LR, LRO orbit 18355, July 7, 2013; native resolution 1.9 meters per pixel [NASA/GSFC/Arizona State University].

Brett Denevi
LROC News System

Today's featured image is located near the center of the ancient 600-km Mendel-Rydberg basin. Its degraded state means Mendel-Rydberg's presence is not obvious in the WAC context image below (in fact, its existence was only confirmed with Clementine (1994) topography data), but its western rim is near the crater Mendel, and Rydberg and Guthnick craters are near the center of the basin.

However, it was not the Mendel-Rydberg impact that was responsible for the ups and downs in the hummocky deposits seen in today's Featured Image, but the Orientale impact event, hundreds of kilometers away to the north.

Ejecta from impact basins is both erosional, gouging out long valleys and leaving strings of large secondary craters (along the arrows in the image below), and depositional, blanketing even distant terrain with material excavated from the impact site. Basin ejecta plays such a large role shaping the lunar surface that these ups and downs are often referred to as "basin sculpture," and the ejecta from Orientale certainly sculpted the terrain in today's image.

LROC Wide Angle Camera (WAC) mosaic context views of the southern Orientale region. The blue box in the image at bottom shows the field of view at top, where a yellow box shows the approximate field of view shown in the LROC Featured Image. Click to enlarge [NASA/GSFC/Arizona State University].

The hummocky deposits that cover low-lying areas in the top image, and the image below, are likely ejecta from the Orientale basin. These low-lying regions may have once been exposures of smooth mare basalt, some of which is still exposed on the surface in nearby regions, but are now hidden under a blanket of debris from Orientale. Buried volcanic deposits such as these are known as "cryptomare" and tracking down the locations of these ancient sites of volcanic activity is key for understanding the extent of early volcanism on the Moon.

A wider (and reduced-resolution) view of the LROC NAC mosaic from which the LROC Featured Image within the Mendel-Rydberg basin was cropped. LROC NAC M1127819355LR [NASA/GSFC/Arizona State University].

You may also note that the hills in the southern portion (right side) of the image above have a lumpy texture, also visible in the WAC context image. This is also likely due to Orientale's influence - the result of a massive ground hugging flow of ejecta that piled up on the sloped terrain. This oblique view of the region gives a great perspective on its complex history that would have been compelling enough with just the ancient Mendel-Rydberg basin and early lunar volcanism, but the spectacular basin ejecta flows captured here are just icing on the cake (so to speak).

Click HERE to see the full-resolution view.

Related LROC Featured Images:
Amazing Orientale Peaks and Valleys
Regolith Patterns in Mendel-Rydberg
Window to the Farside Mantle
Two-toned Impact Crater in Balmer Basin: A reflection of the Target?
Dark Craters on a Bright Ejecta Blanket

The View Inside a Tilted Crater

Oblique view of the chaotic interior of 30-km Wiener F crater. LROC Narrow Angle Camera (NAC) mosaic M1113262343LR; LRO orbit 16307, January 19, 2013, spacecraft and camera slewed 52° west from 160.39 km over 41.84°N, 140.28°E, subsampled from a scaled 2.78 meter per pixel resolution. Scene width approximately 13 kilometers from left to right, centered at 41.1°N, 150.0°E. [NASA/GSFC/Arizona State University].

Brett Denevi
LROC News System

Impact melt is commonly found in and around fresh lunar craters and can be spotted as ponds, flows, and ejecta.

This oblique view of the farside crater Wiener F highlights one of the more spectacular examples of what happens to the melt when a crater forms on a slope.

In the image above, you have a great perspective view of the chaotic crater interior, where material slumping into the crater interacted with the fluid melt, creating rough, hummocky mixtures in some regions and smoother pools of melt in others. But what is really interesting about this crater becomes clear when you zoom out to the full width of the image, below.

Thumbnail view of LROC NAC mosaic M1113262343LR, looking from west to east into Wiener F crater. For the full-resolution, zoomable view click HERE [NASA/GSFC/Arizona State University].

Wiener F formed atop a larger, older crater, so its northern rim, on the left in the picture above, ended up substantially lower than the southern rim. A profile across the crater, taken from the GLD100, shows the northern rim of the crater is over 2 km lower in elevation than the southern rim!

A profile from south to north across crater Wiener F, taken from LROC WAC-derived topography data [NASA/GSFC/Arizona State University].

So tilting the crater like this is like tilting a glass of water - it spills. In this case, the hot impact melt that would normally stay within the crater poured out, spilling over the northern rim and pooling outside the crater. Click on the image below to see this spectacular flood. You can find individual flows and places where the melt was still moving even as a crust of hard rock formed on top, resulting in cracks and wrinkles in the top layer.

View of the impact melt that escaped Wiener F, pooling outside the northern crater rim. Image subsampled from the original resolution [NASA/GSFC/Arizona State University].

Impact melt is a favorite target for LROC imaging because of its often complicated and bizarre features, and because of what it tells us about the impact process. The volume of melt can give clues as to how fast an impactor hit the surface (higher velocities mean higher shock pressures and more heat to melt rock), at what angle it impacted (melt is often thrown downrange of an impact), and how long ago the impact occurred (by observing how well preserved the melt morphology is, or by age-dating a sample of melt). Impact melt can also give insights into how portions of the crater moved and settled as the crater formed (for example, how did melt get up HERE?).

LROC Wide Angle Camera (WAC) contextual view of Wiener F crater, nested in the Farside Highlands [NASA/GSFC/Arizona State University].

Wiener F is another piece of that puzzle, showing what a dynamic environment an impact crater is shortly after formation. Click HERE for the full-resolution view of Wiener F.

Other Spectacular
Impact Melt Favorites:
Rumker E Impact Melt
Dynamics of Molten Rock
La Pérouse A Impact Melt
Rippled Pond
Breached Levee
Secondary Melt on the rim of Wiener F
Getting cracked in Wiener F
Giordano Bruno Whorl