Tag: Shackleton Crater

Scientists: No obvious ice in the permanently-shadowed interior of Shackleton Crater

10:59 am

Shadowcam-LRO mosaic
Click for original image.

Using the low-light image produced by the American Shadowcam instrument on South Korea’s lunar orbiter Danuri, scientists now belief that there are no thick obvious deposits of water ice in in the permanently-shadowed interior of Shackleton Crater at the Moon’s south pole.

The image to the right combines pictures taken by Lunar Reconnaissance Orbiter (LRO) of the region around Shackleton with pictures produced by Shadowcam of its permanently-shadowed interior. From their paper’s conclusion:

The trailing (right) side of Shackleton’s interior is warmer owing to the secondary illumination asymmetry and floor topography. Illumination at the floor of Shackleton is patchy and possibly indicates a similar patchy (50 m scale) temperature distribution, which could mean a spatially irregular concentration of cold-trapped volatiles at the subsurface or mixed with regolith.

According to our Shackleton crater interior mapping from ShadowCam images, there is no observed evidence of thick ice deposits or surface ice that could be easily recognized by any relative brightness features observed in multiple illumination geometries. However, this analysis did not include the estimation of reflectance, nor did it involve reviewing all of the images of Shackleton in this preliminary study. Our hypothesis, in the context of water frost detections in Shackleton, is that if ice or frost is present in Shackleton’s interior, then the concentrations are either below the threshold that results in an observable signature in ShadowCam images, or might be mixed with the regolith at the detected areas. At other places where surface temperatures are below 110K, water frost could be hidden in subsurface layers.

The paper’s main purpose was to identify the dim lighting sources within the crater, all of which come from light bouncing off other surfaces. In the process the scientists obtained a better understanding of the surface itself.

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Image released of permanently shadowed floor of Shackleton Crater

11:01 am

Shadowcam-LRO mosaic
Click for original image.

NASA today released a mosaic combining images from Lunar Reconnaissance Orbiter’s high resolution camera LROC and the Shadowcam camera on South Korea’s Danuri lunar orbiter that shows for the first time the entire permanently shadowed floor of Shackleton Crater at the Moon’s south pole.

That mosaic, cropped, reduced, and sharpened to post here, is to the right. I have added the black cross to mark the location of the south pole, just inside Shackleton, the large crater on the right. The inset shows the floor of the crater at higher resolution.

LROC can capture detailed images of the lunar surface but has limited ability to photograph shadowed parts of the Moon that never receive direct sunlight, known as permanently shadowed regions. ShadowCam is 200-times more light-sensitive than LROC and can operate successfully in these extremely low-light conditions, revealing features and terrain details that are not visible to LROC. ShadowCam relies on sunlight reflected off lunar geologic features or the Earth to capture images in the shadows.

Thus, in the mosaic to the right the interior of Shackleton was imaged by Shadowcam, and then placed on a mosaic of LROC pictures.

If you click on the full image at high resolution and look closely at the crater floor, it is difficult to determine if there is any ice there. There are several mounds that could be ice, but could also be accumulated dirt and debris. What is most significant however is the smooth interior walls of the crater. It appears it will very possible for a rover to drive down those walls and into Shackleton.

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The most valuable real estate on the Moon

10:09 am

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.
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Future lunar colonies at Shackleton Crater at the Moon’s south pole

9:52 am

The rim of Shackleton Crater
Click for full image.

The Lunar Reconnaissance Orbiter (LRO) science team has released a new image of the rim of Shackleton Crater, reduced slightly in resolution to post here on the right. The Moon’s south pole is located on the crater’s rim near the top right of this image. As they note at the link, the interior of Shackleton never gets any sunlight, making it what scientists call a Permanently Shadowed Region (PSR), while a ridgeline running south to de Gerlache Crater gets sunlight 90% of the time.

An elevated ridge runs roughly between Shackleton and de Gerlache craters, and the relatively high elevation of this landscape means that some portions are illuminated up to 90% of the time, but nowhere is permanently illuminated. Future explorers could take advantage of this persistent illumination by setting up solar panels in several closely spaced locations providing nearly constant solar generated electricity.

The proximity to Permanently Shadowed Regions in and around Shackleton crater adds scientific value to this destination, as PSRs are often home to compounds such as water ice that are not found elsewhere on the Moon, but which contain clues to the history of of inner Solar System water and other volatile elements. A nearby, ready source of water-ice would also be of benefit to human surface activities, either as a consumable (air or water) or as spacecraft fuel.

Below is a more detailed map they provide showing this area, with the permanently shadowed regions shaded in blue. The green dot indicates the location of the south pole. The green arrows indicate regions in sunlight in the full image.

The region around Shackleton

Sadly, I expect we are looking at the locations of future Chinese and Indian lunar bases. Though the U.S. has done all the proper legwork to find out the exact locations to build a lunar base at Shackleton, our government has decided we will instead twiddle our thumbs in lunar orbit while other countries use our legwork to land and establish bases on the Moon itself.

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Water Ice in Shackleton Crater?

9:58 am

Ice in Shackleton?

New results from the radar instrument on Lunar Reconnaissance Orbiter (LRO) has found evidence of water-ice on the slopes of Shackleton Crater, located at the Moon’s south pole. The paper, published on Saturday in Geophysical Research Letters – Planets, suggested that about 5 to 10 percent of the weight of the material on the slopes of the crater is comprised of water ice, to depths of 6 to 10 feet.

The box on the upper left in the image to the right shows the data from a radar sweep of the crater taken on April 18, 2010, and compares that to five computer models. As you can see, the data here most closely matches the 5% ice model. Two other sweeps showed similar results.

The water-ice, if there, is not in slabs of ice, as sometimes portrayed in the press, but would be mixed into the Moon’s regolith, or “topsoil”, and would have to be processed out like ore to be useful. Or to quote the paper’s conclusion:

The fundamental conclusions made with high resolution, ground based radar of Shackleton remain unaltered — that no large-scale, meters thick ice deposits are evident within the crater. Rather, Mini-RF data are consistent with roughness effects or with a small percentage of water-ice deposits admixed into the uppermost 1-2 meters of silicate regolith within Shackleton, possibly accounting for the observations made by the Clementine bistatic experiment.

Several points:
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According to this article, the water-ice discovered at Shackleton Crater is insufficient for human settlement.

8:44 am

The uncertainty of science: According to this article, the water-ice discovery announced yesterday at Shackleton Crater is insufficient for human settlement.

The latest LRO data indicate “that water is not there … in a way that would facilitate human exploration,” says planetary scientist Maria Zuber, who led the team analyzing the data.

If the signatures the team saw in the soils on the crater floor do indicate water, how much water might there be? Roughly 100 gallons – enough to fill two or three residential rain barrels – spread over a surface of about 133 square miles. Leave the swim-suit at home. “This is not like Mars,” says Dr. Zuber, a professor at the Massachusetts Institute of Technology in Cambridge, in an interview. On the red planet, explorers would find thick layers of icy soil in many locations just by turning over a shovelful or two of topsoil. [emphasis mine]

This story seems to answer my question about Zuber’s participation in the water in Shackleton paper as well as the previous paper saying there is much less water on the Moon than previously believed. It also raises questions about the journalism work of many of the other stories published in the past few days, which heavily touted the possibility of water in Shackleton.

I intend to dig into this story a bit more. Stay tuned.

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New data from Lunar Reconnaissance Orbiter suggests that ice may make up as much as 22 percent of the surface material in Shackleton Crater, located on the moon’s south pole. The uncertainty of science: New data from Lunar Reconnaissance Orbiter suggests that ice may make up as much as 22 percent of the surface material in Shackleton Crater, located on the moon’s south pole.

11:01 am

The uncertainty of science: New data from Lunar Reconnaissance Orbiter suggests that ice may make up as much as 22 percent of the surface material in Shackleton Crater.

What I find most interesting about this result is that the team leader of this paper, Maria Zuber, was also one of the co-authors of the paper I wrote about two days ago that said there was no water in Shackleton Crater.

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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.
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