. Landing on the Schrödinger basin,  the second youngest basin on the Moon

A study of A. L. Souchon and al. - 42nd Lunar and Planetary Science Conference (2011)

About the video: On 15 January 2012 the Lunar Reconnaissance Orbiter slewed 64.5 degrees to the east to capture this astonishing view of the floor and central peak of Tycho crater. In June of 2011, LRO captured a view looking to the west. Check it out: http://www.youtube.com/watch?v=361YcacQZjg More amazing LROC images can be found at http://lroc.sese.asu.edu.

 
 

The Schrödinger basin - 135°E, 75°S

The lunar farside — that mysterious face of the Moon hidden from Earth – contains a cache of clues about how the Earth formed, how planets evolved, and how volcanic and impact cratering processes reshaped the Solar System. The farside of the Moon holds the key to the earliest bombardment of the Earth and whether impact cratering processes were involved in the origin and earliest evolution of life on Earth.

The oldest and largest impact basin on the Moon is nearly 2,500 kilometers in diameter and stretches from the South Pole to a tiny crater called Aitken. This South Pole-Aitken basin (also called SPA basin) is one of the leading targets for human and human-assisted robotic exploration. A particularly rich scientific and exploration target within that basin is the Schrödinger basin, about 320 kilometers in diameter, and located towards the south polar end of the South Pole-Aitken basin.

Scientists and engineers are already designing the methods for a mission to Schrödinger that collects samples and brings their extraordinary secrets back to Earth for study. To give you a perspective of this mission, we have created a video and soundtrack that carries you to the Moon, around the South Pole-Aitken basin, and to a first landing site within the Schrödinger basin. We hope this is the first step in an exhilarating mission of discovery.

 

Credit: This flyover was conceptualized and produced by Dr. David A. Kring. The Lunar Reconnaissance Orbiter Camera data was assembled and rendered by Dr. Debra M. Hurwitz. Modeling and animation were implemented by John Blackwell. The music on the sound track is Darkest Night by Pond5 and used with permission. / Lunar and Planetary Institute

 

Second youngest large basin on the Moon, the Schrödinger impact basin include variety of geologic features available that could be interesting for future exploration. Often, boulders in Schrödinger come from regions that are not easily accessible by robotic equipment or humans. The above image highlights a distribution of boulders near the base of a part of the central peak ring, located at 77.196°S and 133.178°E.

Boulders >1 m across, and a few trails, surround the base of a mountain in the Schrödinger central peak ring. Boulder in lower left is ~55 m across. Image NAC M187340587LR is width of 732 m. [NASA/GSFC/Arizona State University].

Boulders rolled down an incline on a terrace near the Schrödinger basin rim. Boulders are ~20 to 30 m in size. The LROC NAC M159017963R image is width of ~1.2 km, and is showing in down slope direction to upper left. [NASA/GSFC/Arizona State University].

When scientists and engineers brainstorm landing site locations for future lunar missions - robotic or human - they must consider numerous factors as the technology and equipment that will land the mission on the Moon and the scientific and resource interest of a location.

LROC images, as well as the data from other instruments aboard LRO, provide scientists and engineers the means to study the lunar surface at high-resolution. Future missions can then take truly advantage of the rich geology of the Moon.

When Schrödinger has impacted into the South-Pole Aitken (SPA) rim material, it may have sampled some of the deep lunar crust excavated by its host impact. Schrödinger basin is located on the rim of the SPA basin at 79.13°S and 140.60°E. If it is true, the smooth deposits on the basin floor may be a combination of both impact melt and volcanic material. There are also several pyroclastic vents located within the basin, suggesting that at least some episodes of volcanic activity in the basin had high volatile contents.

On the left image, a portion of eroding basin wall terrace material is showing. Several boulders around 30 m in diameter rolled downhill from a boulder cluster. Their original locations may be derived using the prominent boulder trails left behind during their downhill descent. Sampling these boulders would be particularly useful during a future mission because they represent material from the basin rim and do not require an astronaut or rover to traverse to the higher elevations.

Schrödinger boulders

Schrödinger basin rim

Ejecta blancket features.

Scrödinger impact crater

Dozens of boulders, ranging from 10 m to more than 30 m in diameter, are distributed within an ejecta ray close to the crater rim (lower right). These boulders represent the deepest material excavated during crater formation. LROC NAC M159013302LR, image width is ~850 m [NASA/GSFC/Arizona State University].

NASA’s Vision for the Space Exploration [1] aims to locate landing sites where key planetary processes can be studied through the diversity of crustal rocks.

Five Science Goals were devised to guide that study: (i) determine the extent and composition of the primary feldspathic crust, KREEP layer, and other products of differentiation; (ii) inventory the variety, age, distribution, and origin of lunar rock types; (iii) determine the composition of the lower crust and bulk Moon; (iv) quantify the local and regional complexity of the current lunar crust; and (v) determine the vertical extent and structure of the megaregolith.

We surveyed the lunar surface to identify suitable landing sites and found hundreds of sites that address individual Science Goals [2, 3, 4, 5], but only a few that will maximize the science return relevant to multiple Goals within Concept 3: Key Planetary Processes are Manifested in the
Diversity of Lunar Crustal Rocks (Ref.  A Global Lunar Landing Site Study to Provide the
Scientific Context for Exploration of the Moon - Edited by David A. Kring and Daniel D. Durda, LPI-JSC Center for Lunar Science and Exploration, Copyright  2012)

The Schrödinger basin - 135°E, 75°S

To studying the key planetary processes on the Moon

The Schrödinger basin, being the second youngest basin on the Moon, will provide some of the best preserved basin features on the lunar surface for scientific study, and will offer a glimpse into the still enigmatic region of the South Pole-Aitken basin. This terrane has never been directly sampled, and any meteoritic clasts from this region remain uncertain.  Differentiation products:  Schrödinger provides access to nearly every key depth in planetary differentiation models. The large basin lies within the thin crust of the SPAT, and its large size implies that it will likely have incorporated mantle material in its melt. Mantle material, the crust-mantle boundary, and lithologies produced by the SPA event may also be exposed within the stratigraphic uplift of the peak ring. Schrödinger is also uniquely positioned to determine how the SPA basin-forming event modified the crust over most of the Moon’s southern hemisphere, where it may, for example, have consumed any urKREEP residual layer from the Magma Ocean.

Rock types variety:  Detections by [7, 8] of pure anorthosite (PAN) are located within the peak ring of Schrödinger (Fig. 1), making these uplifted regions particularly of interest. Other rock types also appear to be pervasive within Schrödinger basin. Pyroclastic deposits are located in the southeast region, positioned near a peak ring outcrop [9] (Fig. 1). Mg-suite rocks may be sampled as well, as spectral analysis of plutonic rocks (such as gabbro, norite, troctolite, gabbronorite, anorthositic troctolite, anorthositic gabbro) by [10] suggests the possibility of exposure. However, care must be taken in interpreting the results analysis, as such findings could correspond also to lower crust material. Multiple sources of olivine in the ejecta of craters that penetrate into the peak ring have been recently detected [11] (Fig. 1). Assuming that such detections could be invasive throughout the entirety of the peak ring structures, locations that can expose fresh parts of the peak ring appear to be of high scientific interest.

Lunar crust complexity:  Schrödinger basin is a Type I gravity anomaly [12, 13], in which the magnitude of the free-air and Bouguer anomalies are the same, thus categorizing it as a good location for setting up geophysical instruments such as seismometers. In addition, the complex terrain can offer clues into the unique lithology and regional complexity of the SPAT. The placement of seismometers will also help determine the extent of the megaregolith in the region [2]. 


 

Today's Featured Image highlights a portion of eroding basin wall terrace material. Several boulders around 30 m in diameter - roughly the distance between bases in a baseball field or about two semi-trailer trucks - rolled downhill from a boulder cluster. Their original locations may be derived using the prominent boulder trails left behind during their downhill descent. Sampling these boulders would be particularly useful during a future mission because they represent material from the basin rim and do not require an astronaut or rover to traverse to the higher elevations.

 
 

Boulders rolled down an incline on a terrace near the Schrödinger basin rim. Boulders are ~20 to 30 m in size. Image width is ~1.2 km, downslope direction to upper left, LROC NAC M159017963R [NASA/GSFC/Arizona State University].

The First site is located in the southeast part of the basin, near a peak ring outcrop that lies within a field of pyroclastic deposits. Here astronauts may sample volcanic glass from the deposits, as well as PAN and olivine detected around a nearby crater that penetrated the peak ring. There are also possible bedrock exposures within the slopes of the peak ring. Four stations within a 10 km radius of the landing site are suggested. Station 1 is located at a rille, where samples should be taken, and the collapsed rille walls should be analyzed for any exposed layering structures. In addition, as this is a volcanic feature, one should look for unique volcanic lithologies that might occur here. Stations 2 and 3 are located at the base of peak ring massifs. Optimally, samples should be taken on a traverse from one station to the next, to determine how material may differ on a small scale. In particular, outcroppings and possible exposures should explicitly be sampled. Station 4 lies within a large field of pyroclastic deposits, where samples of volcanic rocks and regolith should be taken for comparison with other samples.

The Second site lies on the peak ring in the northern part of Schrödinger basin. A fresh crater (about 7 km in diameter) occurs directly on the ring and is believed to expose bedrock and possible layering within the crater walls. As the peak ring is thought to have uplifted mantle material, possible urKREEP, and both lower and upper crust, this preserved exposure could provide a plethora of useful information with regard to NRC’s Concept 3. This crater is also a site of olivine detections , and nearby PAN detections. 

This particular site may sample volcanic glass from the deposits, as well as PAN and olivine detected from the nearby crater which has penetrated into the peak ring. There is a possibility of outcropping and bedrock exposure within the walls of the peak rings; however, this region may be covered with a thicker layer of regolith than the second proposed site.