The Lunar Orbiter Laser Altimeter (LOLA)

Landing sites: Pit crater/lava tubesPolar RegionsSouth Pole - Aitken BasinMarius Hills




The Lunar Orbiter Laser Altimeter (LOLA)

For the future Moon's missions, landing sites selection will be a critical matter. Many companies have already chooses their sites, but other not. Here, we propose some locations that will be profitable to uses because they are  relevant in resources and safe to land. We know that, in big part, by the work of LOLA.
One of the main goal of the Lunar Orbiter Laser Altimeter (LOLA) is to provide a precise global lunar topographic model and geodetic grid that serve as the foundation of essential lunar understanding. 
 The topographical data given by LOLA helps future missions manager to choose a safe landing   site and enhance exploration-driven mobility on the Moon.
To be able to do this, the Orbiter completes 3 full LRO measurement objectives and addresses 2 other. By providing all the data necessary to select intriguing, safe landing sites, LOLA give the reference system needed to navigate into those sites.
LOLA builds on extensive spaceflight heritage, including the Mercury Laser Altimeter (MLA) and the Mars Orbiter Laser Altimeter (MOLA). The LOLA measurement team has 15 years of altimetry experience that includes providing MOLA data to the Mars Exploration Rover site-selection teams.

Located along the northeastern limb of the Moon, centered at 56.8 N & 81.5 E, the Humboldtianum Basin is a region of interest for NASA's former Constellation Program. LOLA data shows that the 650 km diameter basin is more than 4.5 km deep. The basin is estimated to have been formed during the Moon's Nectarian Period, approximately 3.92-3.85 billion years ago.

The Goddard Crater is located along the Moon's eastern limb  at 14.8 N & 89.0 E. LOLA data shows a floor-crater of 90 km diameter relatively flat and smooth.

The Schrödinger impact basin, centered at 75.0 S &  132.4 E, is located on the lunar far side within the South Pole-Aitken Basin. The basin is believed to be the second youngest impact basin on the Moon, after the Orientale basin. LOLA data reveals that the basin has approximately 3.3 km of relief from the rim to the floor.

The Reiner Gamma region on the lunar nearside, located at about 7.5 N & 301.4 E, has an unusual surface feature called a "lunar swirl." Visible in the Clementine 750-nm mosaic image shown above, it resembles a swirl of cream in a mug of hot chocolate. Lunar swirls have a higher albedo than the surrounding lunar surface. The formation of lunar swirls, especially the Reiner Gamma swirl, is a mystery. 
LOLA works by propagating a single laser pulse through a Diffractive Optical Element (DOE) that splits it into 5 beams. These beams then strike and are backscattered from the lunar surface. For each beam, LOLA measures time of flight (range), pulse spreading (surface roughness), and the transmission and the return of energy (surface reflectance). With its two-dimensional spot pattern, LOLA unambiguously determines slopes along-track and across-track.
In a 50 km polar orbit, pulsing the laser at 28 Hz creates a ~50 m-wide swatch of 5 topographic profiles. Swaths will have 1.25 km separation at the Equator, with  a complete polar coverage beyond +/-86 degrees latitude. Raw measurements are transmitted to Earth for analysis.
LOLA gives ample reserve to accommodate uncertainties in lunar surface roughness and albedo. This is the reason why the LRO spacecraft is so flexible in its mission.

Projection surface

LROC WAC Global Mosaic and DTM
The WAC 100 m/pixel global mosaic is comprised of over 15,000 images acquired between November 2009 and February 2011. The WAC 100 m/pixel global DTM was derived from over 44,000 WAC stereo models from primary phase. The highest elevation (white) is 10,760 m, and the lowest elevation (purple) is -9150 m.

Pit crater/lava tubes - 33.22°E, 8.336°N - Mare Tranquillitatis

Lunar pit craters are small, steep-walled collapse features that suggest subsurface voids. Over 200 pit craters are located in impact melt and are relatively shallow, at about 10 m. However, 10 pits are located in mare highland units and are much deeper, in a range of about 10 to 40 m. These pits may have lava tubes of unknown lateral extent. For those in non-mare impact melt, they may have networks of sub-lunar tubes. 

At the left: Five of many LROC Narrow Angle Camera (NAC) show an high resolution of the increasingly Mare Pit Crater, in the Sea of Tranquillitatis.
Pit craters within impact melt deposits provide access to unique impact-related units that have not been exposed to space weathering, allowing for extremely precise dating of impact events. This is the case for the lunar volcanic stratigraphy through time, as well as the physical, chemical and thermal nature of effusive lava flows. Here, the study of trapped regolith could give insight to how the Sun has evolved by the evaluation of solar wind implanted species.
Studying the impact melt on the surface and subsurface will provide important insight into crater formation processes as well as the crater evolution.
The exploration of pit crater/lava tubes interiors may lead to the discovery of water ice deposits within cold, shadowed subsurface voids.

Credit: NASA
Quantifying the radiation at the surface and within the interiors will give a good insight as to where a persistent habitat could be placed to protect Humans.
For this purpose, it is necessary to develop new technologies designed to access difficult areas with steep slopes and persistent shadows resulting from cold temperatures.  
Thus, in an exploration mission scenario, instruments can be deployed to investigate the interior structure and composition of a pit crater. One of the main goal will be to answer the question - How can a sublunar cavern be advantageous for Humans' habitat? 

Marius Hills - 53°W, 13°N

The Marius Hills are a volcanic province on a broad shield structure that may have experience long-lived volcanism. In addition, the lunar magnetic anomaly Reiner Gamma crosses the site, and a lava pit occurs at the site. (see image at right)
The Marius Hills provide an opportunity to study the temporal evolution of volcanic volatiles.
A long-lived rover capable of traversing slopes 10-15° (>20° capabilities desired) could sample several key volcanic land forms including mare, flows, cones, rilles, and shields.

Image Credit: NASA/Goddard/Arizona State University
LRO has now collected the most detailed images yet of at least two lunar pits, quite literally giant holes in the moon. Scientists believe these holes are actually skylights that form when the ceiling of a subterranean lava tube collapses, possibly due to a meteorite impact punching its way through. One of these skylights, the Marius Hills pit, was observed multiple times by the Japanese SELENE/Kaguya research team. With a diameter of about 213 feet (65 meters) and an estimated depth of 260 to 290 feet (80 to 88 meters) it's a pit big enough to fit the White House completely inside. The image featured here is the Mare Ingenii pit. This hole is almost twice the size of the one in the Marius Hills and most surprisingly is found in an area with relatively few volcanic features.

South Pole - Aitken Basin - 170°W, 53°S

The South Pole-Aitken Basin (SPA) is the oldest, deepest, and largest impact basin on the Moon and it has longtime been recognized as a high-priority location for scientific studies and exploration.  
SPA is located on the farside between Aitken crater and the South Pole, and has a diameter of ~2600 km. It contains an ancient impact melt, basalts, excavated substrate materials (pre-SPA materials such as lower crustal/mantle materials), and swirls.
The SPA impact event is likely to have excavated deeply enough to contain exposures of lower crustal and/or mantle materials.
By sampling it, it will be possible to know the evolution, not just of the Moon, but also ofthe Solar System.
The age of SPA would anchor the lunar impact-basin chronology. If the SPA Basin formation age proves to be relatively close to 4 Ga, then a cataclysm or spike in the heavy impact bombardment at that time is supported.
So, understanding the source and distribution of heat-producing elements, such the thorium, in the basin will give insight about lunar differentiation and its thermal evolution.  
The SPA-forming impact may have excavated deeply enough to contain exposures of lower crustal and/or mantle materials. Sampling these materials would provide direct knowledge of rock types, crystallization ages, and depth constraints, therefore unraveling the nature of the Moon’s lower crust and mantle.

Apollo's astronauts and the sample-return vehicle Luna bring back samples from the near side of the Moon. By taken samples from SPA's basalts on the far side, that will give a different insight about ages and compositions of mantle source regions.
Portions of SPA are relatively smooth, indicating that basalts may lie beneath the observed surface materials in the form of cryptomare. Determining the composition of that resource is necessary to understand what materials are present within the basin interior.
SPA holds the key to understanding the formation and structure of large basins. The basin contains impact melt deposits that likely contain lower crustal or upper mantle components.

At the left:Near South Pole - Aitken basin

A robotic sampling, handling and storage mission on the surface could analyse the resource potential and the preservation of volatiles components that has been occurred untl today.
A humans mission will give insight about how living and working on the lunar surface. Astronauts will excavate, make sortie, refine materials and store it, as well as take measures of landing conditions to assess the effects of rocket exhaust on the surface, which beneath directly the lander. 
Sampling regolith or sieved rock fragments by an automated rover, and return it to Earth, will be possible by a static lander mission. For this proposed mission, many potential landing sites in the center of the basin or in the transient crater rim are very interesting candidates.

Polar Regions - 0.0°E, 89.9°S -Shackleton Crater

North Pole

Credit: LRO/NASA

South Pole

Credit: LRO/NASA

Previous missions, like Clementine and LCROSS, have revealed the existence of water in lunar polar regions. The vast majority of this water resides in some Permanently Shaded Regions (PSRs) on floor and wall craters. Obtaining these data from different PSRs and knowing the amount, the form as well as the composition of polar volatiles, are critical for scientific, exploration and commercial communities.
For now, what is known is that, hydrogen deposits can be found at the Peak crater and at the NE of Hevesy crater of the North Pole. The spacecrafts have also discovered hydrogen at Cabeus, Shoemaker, Faustini, Nobile, and Shackleton craters, all in the South Pole. 
At the North and South Poles, large volume of volatiles are available for future uses. This is interesting for scientific or commercial purposes.
Then, knowing the precise locations, characteristics, and types of volatiles would surely allow the private commercial sector to develop business plans and future mission scenarios.
These resource potential can be extracted by technologies-related and these operations may be overseen by humans in-situ analysis. However, these activities will most likely stir up a significant amount of dust.  So, the impact of dust on crews during surface activities is an important endeavor to understand.

Because of the resources' proximity  at the Poles, mining operations and habitats must be established in these areas. Working there or on the lunar surface will improve methods of resource production in real-time and the mobility. For habitats, experiments of radiation shielding for astronauts-workers, and life support systems will be useful for next missions.

One exploration scenario suggested will be to  deploy assets with a rover, to explore polar PSRs to characterize volatiles and the resistance of mechanical devices in cold traps.
Another exploration scenario could be the collection and thereturn of samples to Earth to better analyze volatile species present at these poles.



Learn more about other Landing sites

The Nectarian-aged multi-ring impact basin Moscoviense is situated on the Far Side of the Moon and it has been formed 3.85-2.92 Ga ago. The basin contains an elongated floor with non-concentric basin rings, and have some of the thinnest crust on the Moon, although it is located in the relatively thicker crust of the lunar highlands.
Rima Bode is a spatially extensive (~7000 km2) dark mantling deposit produced by fire fountaining, possibly composed of black glass, as indicated by its very low albedo.

Aristarchus crater is located on the edge of the Aristarchus Plateau, one of the most geologically interesting regions of the Moon.

Gruithuisen Domes (inthe right-below)

.The Gruithuisen Domes are located on the western edge of the Mare Imbrium in the northwestern portion of the Procellarum KREEP terrane.
Their unique morphological surface suggests that the lava flows that produced the domes were highly viscous.
Aristarchus crater floor