The Acceleration of the Human Exploration of the Solar System with Space Elevators (original) (raw)

2007

All astronauts who walked on the Moon reported difficulties with lunar dust. These problems were likely worsened by the fact that the dust was electrically charged, which enhanced its adhesive properties. In order to develop strategies to tackle these issues it will be necessary to advance our theoretical understanding of the lunar dust-plasma environment, as well as comprehensively characterize it with in-situ measurements. Summarized here are the relevant properties of lunar dust and its impact on astronauts, together with a discussion of the three main problem areas: (1) Dust Adhesion and Abrasion, (2) Surface Electric Fields and (3) Dust Transport. Also discussed are recent calculations relating to some of the Apolloera observations, together with necessary future in-situ measurements and suggested mission strategies.

Scientific Return of a Lunar Elevator

The concept of a space elevator dates back to Tsilokovsky, but they are not commonly considered in near-term plans for space exploration, perhaps because a terrestrial elevator would not be possible without considerable improvements in tether material. A Lunar Space Elevator (LSE), however, can be built with current technology using commercially available tether polymers. This paper considers missions leading to infrastructure capable of shortening the time, lowering the cost and enhancing the capabilities of robotic and human explorers. These missions use planetary scale tethers, strings many thousands of kilometers long stabilized either by rotation or by gravitational gradients. These systems promise major reduction in transport costs versus chemical rockets, in a rapid timeframe, for a modest investment. Science will thus benefit as well as commercial activities.

The lunar dust environment

Planetary and Space Science, 2011

Each year the Moon is bombarded by about 10 6 kg of interplanetary micrometeoroids of cometary and asteroidal origin. Most of these projectiles range from 10 nm to about 1 mm in size and impact the Moon at 10-72 km/s speed. They excavate lunar soil about 1000 times their own mass. These impacts leave a crater record on the surface from which the micrometeoroid size distribution has been deciphered. Much of the excavated mass returns to the lunar surface and blankets the lunar crust with a highly pulverized and ''impact gardened'' regolith of about 10 m thickness. Micron and sub-micron sized secondary particles that are ejected at speeds up to the escape speed of 2300 m/s form a perpetual dust cloud around the Moon and, upon re-impact, leave a record in the microcrater distribution. Such tenuous clouds have been observed by the Galileo spacecraft around all lunar-sized Galilean satellites at Jupiter. The highly sensitive Lunar Dust Experiment (LDEX) onboard the LADEE mission will shed new light on the lunar dust environment. LADEE is expected to be launched in early 2013. Another dust related phenomenon is the possible electrostatic mobilization of lunar dust. Images taken by the television cameras on Surveyors 5, 6, and 7 showed a distinct glow just above the lunar horizon referred to as horizon glow (HG). This light was interpreted to be forward-scattered sunlight from a cloud of dust particles above the surface near the terminator. A photometer onboard the Lunokhod-2 rover also reported excess brightness, most likely due to HG. From the lunar orbit during sunrise the Apollo astronauts reported bright streamers high above the lunar surface, which were interpreted as dust phenomena. The Lunar Ejecta and Meteorites (LEAM) Experiment was deployed on the lunar surface by the Apollo 17 astronauts in order to characterize the lunar dust environment. Instead of the expected low impact rate from interplanetary and interstellar dust, LEAM registered hundreds of signals associated with the passage of the terminator, which swamped any signature of primary impactors of interplanetary origin. It was suggested that the LEAM events are consistent with the sunrise/sunset-triggered levitation and transport of charged lunar dust particles. Currently no theoretical model explains the formation of a dust cloud above the lunar surface but recent laboratory experiments indicate that the interaction of dust on the lunar surface with solar UV and plasma is more complex than previously thought.

Theoretical and Experimental Study of Lunar Dust Dynamics

HAL (Le Centre pour la Communication Scientifique Directe), 2014

One of the most important problems on the Moon, reported during the Apollo missions, is lunar dust. Its surface is covered with a layer of very fine grains (20 µm and less), very abrasive which tend to stick on any surface, producing malfunction of devices, degradation of thermal control coatings or bad accuracy of measurements. These dusts were also observed to levitate above the lunar surface by astronauts and, thereby, generated a reduced visibility. It is therefore necessary to understand the physical mechanisms that govern this dynamics on the Moon and on asteroids by providing a physical model taking into account electrostatic charge phenomena, transport and adhesion of dust, stemming from interactions with the space environment and materials of interest for exploration systems. Consequently, it is required to know the environmental conditions favoring transport of particles to set up experiments. In this article, semi-analytical models of charged dust dynamics will be presented, based on literature data of the conditions over the Moon surface. We also present experimental investigations conducted in ONERA vacuum chamber in Toulouse. The main objective of this experimental study is to observe the levitation of dust grains as a function of key parameters: electric field, dust radius distribution, charging environments.

Proceedings, Global Space Exploration Conference 2012

Space Elevators are not a new idea, the original concept dating back to Tsilokovsky, but are not commonly considered in near-term plans for space exploration. While a Terrestrial elevator would require substantial improvements in tether material, a Martian Space Elevator (MSE) or a Lunar Space Elevator (LSE) would not, and there are currently possible elevator missions that would enhance the exploration of the solar system. This paper considers two proposed missions leading to a infrastructure capable of supporting human exploration, shortening the time and lowering the cost required for exploration and enhancing the capabilities of robotic and human explorers. Both missions use planetary scale tethers, strings many thousands of kilometers long stabilized either by rotation or by gravitational gradients.

The Lunar Atmosphere and Dust Environment Explorer Mission

2008

The Lunar Atmosphere and Dust Environment Explorer (LADEE) is a Lunar science orbiter mission currently under development to address the goals of the National Research Council decadal surveys and the recent "Scientific Context for Exploration of the Moon" (SCEM) [1] report to study the pristine state of the lunar atmosphere and dust environment prior to significant human activities. 12 LADEE will determine the composition of the lunar atmosphere and investigate the processes that control its distribution and variability, including sources, sinks, and surface interactions. LADEE will also determine whether dust is present in the lunar exosphere, and reveal the processes that contribute to its sources and variability. These investigations are relevant to our understanding of surface boundary exospheres and dust processes throughout the solar system, address questions regarding the origin and evolution of lunar volatiles, and have potential implications for future exploration activities. The LADEE science instruments include a neutral mass spectrometer, ultraviolet spectrometer, and dust sensor. LADEE will also fly a laser communications system technology demonstration that could provide a building block for future space communications architectures. LADEE is an important component in NASA's portfolio of near-term lunar missions, addressing objectives that are currently not covered by other U.S. or international efforts, and whose observations must be conducted before large-scale human or robotic activities irrevocably perturb the tenuous and fragile lunar atmosphere. LADEE will also demonstrate the effectiveness of a low-cost, rapid-development program utilizing a modular bus design launched on the new Minotaur V launch vehicle. Once proven, this capability could enable future lunar missions in a highly cost constrained environment. This paper describes the LADEE objectives, mission design, and technical approach.

Review of research on lunar dust dynamics

Astrophysics and Space Science

Lunar dust particles are generated by hypervelocity impacts of interplanetary micron-meteoroids onto the surface of the Moon, which seriously threatens the security of explorations. Studying the lunar dust dynamics helps to understand the origin and migration mechanism of lunar dust, and to provide the theoretical guidelines for the orbital design of lunar space missions. This paper reviews previous research on the lunar dust dynamics, including the interplanetary impactor environment at the Earth-Moon system, the mass production rate, the initial mass, speed and ejecta angle distributions, the related space exploration missions, the dynamical model and spatial distribution of dust particles originating from the lunar surface in the whole Earth-Moon system.

Lunar exploration: opening a window into the history and evolution of the inner Solar System

Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2014

The lunar geological record contains a rich archive of the history of the inner Solar System, including information relevant to understanding the origin and evolution of the Earth–Moon system, the geological evolution of rocky planets, and our local cosmic environment. This paper provides a brief review of lunar exploration to-date and describes how future exploration initiatives will further advance our understanding of the origin and evolution of the Moon, the Earth–Moon system and of the Solar System more generally. It is concluded that further advances will require the placing of new scientific instruments on, and the return of additional samples from, the lunar surface. Some of these scientific objectives can be achieved robotically, for example by in situ geochemical and geophysical measurements and through carefully targeted sample return missions. However, in the longer term, we argue that lunar science would greatly benefit from renewed human operations on the surface of th...