Table Of Contentu98-1G900
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Glass and Ceramics
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Larry A. Haskin
A variety of glasses and ceramics lunar material or close simulants,
can be produced from bulk lunar so properties are not known in
materials or from separated detail; however, common glass
components. Many glassy technologies such as molding and
materials have been described in spinning seem feasible (fig. 7).
previous studies (Mackenzie and Uses of glass include structural
Claridge 1979, Criswell 1980). applications (bricks, slabs, beams,
They include sintered (heated and windows) and specialty applications
pressed) regolith, quenched molten (fiber strengtheners, insulation,
basalt, and transparent glass heat shields, cables, light pipes).
formed from fused plagioclase. No See figures 8 and 9.
research has been carried out on
Finished
Empty mold Loaded mold Glass pressed piece
(a) Block mold
Figure 7
Finishe_d
Glass Forming
Empty mold Loaded mold Glass pressed piece The materia/ on the lunar surface has
a high sificate content. Some of
(b) Split mold
these silicate materials could be the
constituents of transparent glasses, which
could have a variety of uses at a lunar
base. Various processes are available
for fabricating objects from glass. Here,
molds are usecl for glass Dressing. The
fiquid glass is poured into the mold,
which is compressed. When the glass
has cooled, the object is extracted from
Untrimmed Finished the mold.
Empty mold Loaded mold Glass presseo piece piece From Shand 1958, p. 164.
(c) Font mold
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Continuous
filaments
Figure 8
Sapizpinliegd
Glass Drawing Strand
When silicate glasses are me/ted, they
are viscous and thus can readily be
drawn by special machines into fibers Winding
or rods or tubes. Glass fiber textiles tube
and mats, which are commonly used
terrestrially as thermal and electrical
insulators, could be used as
construction materials in a space
facili_/.
From Shand 1958, p. 385.
arbles
:: :2e221:Ee?us'2:o
Figure 9
Fiberglass / __High-pressuresteamjetsattenuate
Another product that could be formed '_/1:_ _ molten streams into fine fibers
from lunar soil is fiberglass, which _/I/_}_,_k I Mat Bonded in drying oven
might find use as a structural material,
perhaps combined with organic or
metallic materials. On Earth, fiberglass
tanks are commonly used for storage of
fluids, such as in standard water
Fibers laidin thin _,
heaters.
web-like mat on Binder
From Shand 1958, p. 384. conveyor belt applied
292
Among the high-leverage uses and microwave heating. Direct use
of fused silicate materials in of waste heat from nuclear
the proposed utilization of reactors used in space or on the
nonterrestrial resources are the Moon may also be practical but
fabrication of heat shields for might require complex heat
orbital transfer vehicles traveling exchangers, heat pipes, and other
from the Moon to Earth and the devices for thermal control. The
use of sintered or melted and microwave heating concept is
sand-cast soil for structural support described in more detail in the first
in unpressurized lunar shelters. appendix to this part. It offers an
The work of Blacic (1985) indicates efficient means of converting
that lunar glasses made under electrical energy into heat,
the anhydrous, hard-vacuum delivered locally and in a controlled
conditions on the Moon could have manner to the target to be heated.
very high strengths and thus be Additional work is necessary to
quite applicable to structures in define optimum thermal processing
space. Prestressed beams made systems for glass and ceramic
with sintered bricks, using products and the properties of the
fiberglass or iron bars as tendons, heated lunar material. It will be
may find early application as desirable to have access to good
structural members. simulants of lunar regolith or
increased quantities of real lunar
Ceramics like those used on Earth soil to further such necessary
could be produced by chemical research.
processing of raw lunar material;
for example, fractional volatilization The production of more complex
of plagioclase could lead to melts ceramics, composites, and even
for ceramic applications. The semiconductors may prove
recombination of plagioclase desirable at some point during the
with the residue of the ilmenite development of a lunar base.
reduction process (metallic iron Although perhaps not within the
and titanium dioxide) could yield scope of most easily obtainable
cermets with interesting properties. materfals, semiconductors
Ceramics might find uses similar to produced from lunar materials
those of glasses. could have a major effect on
the means of producing electricity
Alternative means of preparing on the Moon. Silicon-based
glasses and ceramics appear to photovoltaic devices could be
be direct heating using solar constructed using silicon reduced
concentrators (Ho and Sobon from silicate minerals, covered with
1979), electrical resistive heating, thin glass layers made from silicon
293
dioxide, supported by iron,
aluminum, or glass structures, and
supplied with iron wires to conduct
currents. Lunar ilmenite has
interesting semiconductor
properties (see fig. 10) and might
be usable in converting sunlight to
electricity. The preparation of
photovoltaic devices is now well
known on Earth; however, adapting
these processes to alunar
environment would be quite
challenging.
Figure 10
Semiconductors
Lunarilmenite is a natural semiconductor.
Here, a "boule" of ilmenite of lunar
composition has been fabricated in a
furnace as a single crystal. Cut into
thinwafers, provided withelectrical
leads, and exposed tothe Sun, this
semiconductor would cause an electrical
current toflow. A/though rather low in its
efficiency of converting light to electricity,
ilmenite is so abundant on the Moon
that itmay be anattractive alternative to
photovoltaic devices brought from Earth.
Courtesy of R. K.Pandey, Electronic
Materials Laboratory, Texas A&M
University, College Station, TX
O,r__IL__I,_1./,-_I,. PA_,_,_
EtLACK AND WHJTE PHOTOGRAPH
294
