posted on Dec, 16 2007 @ 02:42 AM
2,0 LUNAR DUST CHARACTERISTICS
The characterization of the lunar dust is the first step in the search for the solution to the dust adhesion problem. The energy required to break the
adhesive bond of the dust to various surfaces is dependent on the dust properties as well as those of the surfaces to which the dust adheres.
3,0 ALTERNATIVE DESIGNS
All support equipment for moon base which has the possibility of being exposed to the lunar environment, directly or indirectly, must consider the
existence of the lunar dust in its design. Although removal may not be required in some cases, the cleaning task will play a major role
in the allocation of crew time and equipment maintenance if prevention measures are not taken.
3.1.2 Prevention Alternatives
Prevention alternatives exist in both hardware and operation design for all systems exposed to the lunar dust. Areas of particular interest are:
• Large surface areas (solar arrays, thermal radiators)
• Optical Equipment (windows, lenses, mirrors)
• Extravehicular Mobility Unit (spacesuit, portable life support)
• Mechanical Systems (lunar rovers, robotics)
• Interfaces (tools, connectors)
22.214.171.124 Large Surface Areas
Large areas such as solar arrays and thermal radiators present a
large and possibly critical problem for lunar dust removal.
126.96.36.199 Optical Surfaces
Surfaces such as mirrors, windows, and lenses pose a unique
problem for lunar dust removal due to the delicate surface finish which
must be preserved.
188.8.131.52 Extravehicular Mobility Unit (EMU)
The EMU consists of the spacesuit, portable life support system, and
any associated support equipment. Primarily, the cleaning difficulty of the
EMU is determined by the contamination requirements of the lunar habitat.
This results from the need for the astronaut and any associated equipment
to pass through the airlock.
184.108.40.206 Mechanical Systems
A variety of mechanical systems will be exposed to the lunar dust
environment. Equipment such as manned and autonomous lunar rovers
and robotic systems will present the difficulty of keeping lunar dust from
abrading critical moving parts. Fortunately, mechanical systems have been
tested in previous lunar experience; for instance, the Apollo lunar rover.
A primary source of mechanical interfaces is derived from the
maintenance of systems outside the lunar habitat.
3.1.3 Prevention of Dust Accumulation on Lenses
In this section, a concept for preventing dust accumulation on the
surface of lenses is explored. The concept is based on the lens cleaning
problem associated with cameras and vision systems. Two of the ideas
from the previous section discussing the prevention of dust on lenses are
used; the automated iris and sacrificial surfaces.
The system is proposed to operate either autonomously, by
crewmember at a control station, or by an astronaut conducting an EVA.
220.127.116.11 Autonomous Contamination Detection
Contamination detection for lenses and optical surfaces is an area of
intensive study for missions such as the Hubble Space Telescope and Space
System maintenance is performed by direct removal and replacement
of the dust prevention cartridge.
3.1.4 Prevention Summary
In many cases, lunar operations may require the use of
contamination prevention; however, the use of contamination prevention
on optical lenses has some distinct disadvantages. Primarily these are,
added weight and system complexity, as well as a probable reduction in
3.2.1 Electrostatic Solutions
18.104.22.168 Transportation of Dust by Electrostatics
The following has been taken from pdf. page 24 - 27 .... please read the complete pages if interested in this topic ... no conspiracy
There are many theories that explain the transportation of dust
particles, but the transportation or erosion of dust by electrostatics seems to explain it best and satisfies all conditions. Erosion is assumed to be
carried out in two step liberation of the particle in the transportation phase and actual transportation of the particles by the transportation
Initially, the particles are not readily moved but when the particles
are disturbed then they can be easily transported by the transportation
mechanism. Only a small amount of particles are put in the transportation
phase to be carried away; this mechanism of carrying only few dust
particles is best explained by the electrostatic theory.
Many actions are considered responsible for the transportation of
material from the lunar surface such as thermal variations,radiation
pressure, forces arising from traces of gas and cycles of evaporation and
condensation; but all these are considered inferior and unimportant when
electrostatic phenomena is explained.
The transported dust is small in size because of degradation by
meteoritic impact. The dust is also characterised by low thermal
conductivity and low volumetric specific heat.
Light, X-ray radiations and particle bombardment from the sun all
cause emission of secondary electrons on the surface.
The emitted electrons form a thin layer near the lunar surface and are referred to as a plasma sheath. This sheath is carded away to the dark
side of moon by solar wind thus forming a potential difference on the lunar surface between the sunlit and dark side.
There are two reasons for differential charging of the dust particles.
First, size variations within the particles result in varying charges in the
dust due to emission of electrons from the outermost orbit. This sets up
strong electric fields and causes dust movement. When bombarded with
electrons of sufficient energy in the form of radiation, solar radiation, the
outermost orbit of an atom in an insulator can be removed, thus making the atom positively charged. When many atoms give out electrons from the
outermost orbit the body overall becomes positively charged.
Similarly when different particles on the lunar surface, in the same vicinity, emit varying numbers of electrons, the particles have different
charges. A typical value of the energy to remove electron from the outermost orbit is about 300V. This is one of the reasons for differential
charging. This electron emission sets up differential charges on the individual dust particles.
[edit on 16-12-2007 by frozen_snowman]