Lunar
Exploration Science |
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"They view the great vault above.
They ponder shifting planets, eerie comets, the fixity
of the stars - at first with wonder, then with
speculation, and finally determination. They
measure, weigh, calculate, analyze; and because of
the inner nature of them...They finally go."
-Jeff
Sutton, (Apollo at Go)
After the Apollo Program NASA
had other plans to explore the moon. The Integrated
Manned Space Flight Program planned for 1970-1980,
was presented in 1969. It considered some following
options for the post-Apollo U.S. space program. |
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The proposal included
six new Apollo-type lunar expeditions followed by
a space workshop (later called Skylab), two additional
lunar expeditions and then a series of extended lunar
missions (XLM) lasting several days. Shortly
thereafter, a new Space Tug called the Lunar Module-B
(LM-B) would launch. The LM-B could support
a crew of three on the moon for a month, while the
Space Tug would house six men in space for a week.
By 1975, a space station with a dozen astronauts would
begin Mars flight simulations. The first reusable
shuttle would begin flying soon after. The design
for the shuttle included orbital flights of up to
30 days. |
A "Lunar
Orbital Space Station (LOSS) Design Reference Mission,
developed in 1970 by North American Rockwell had
Saturn V-B rockets launching crews of six to eight
to a lunar orbiting space station in polar orbit.
The 3-year mission plan included six month-long
lunar surface expeditions each year.
Scientific
objectives for these missions included locating a
site for a future lunar base and analysis of lunar
resources. |
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Congress
and the American public seemed to have lost interest
in the moon flights by the time of Apollo 16.
The race was won!
The last
three scheduled Apollo missions (18-20) were eventually
cancelled (although their Saturn
V rockets had already been built). However,
lunar science was still in its infancy. Although
we learned many things about the moon, we had only
landed in a small number of locations.
Experiments
left on the moon lasted for several years but were
then powered down due to congressional funding cuts.
Skylab
and the (non-nuclear) Space Shuttle were the only
two projects that escaped unscathed by congressional
budget cuts in the 1970's. But many unanswered
questions about the moon still exist! |
Since
then, scientists have studied moon
rocks and the other results of experiments we
left on the moon, but are very adamant that we must
return. It would be as if you landed in six places
on the Earth, brought back some samples, and then
decided you knew EVERYTHING there was to know about
the Earth.
Recent
missions to the moon, Clementine
and Lunar
Prospector have taught scientists more about
the global surface composition of the moon, its
topography, internal structure and about the poles.
The findings, however, leave more questions answered.
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For example, we now know
that the moon's
crust is highly enriched in aluminum (supporting
it's origin by early global melting), but the mare
basalts high in titanium returned in abundance by
the astronauts on Apollo 11 and 17 are actually
quite rare.
Magnesium
and iron rich zones found in the lunar highlands
are usually associated with large impact basins,
not highland terrain. While we know that the
subsurface mass concentrations ('mascons') inside
the moon cause a lumpy gravitational field (requiring
constant adjustments for orbiting spacecraft), we
can only speculate that the mascons found beneath
the floors of large impact basins may represent
dense uplifted rocks from the lunar mantle.
The areas found near the lunar
poles in permanent darkness may contain water
ice (from impacting comets).
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Dr. Paul
Spudis, a lunar scientist and author of The Once
and Future Moon believes that NASA must return to
the moon for a variety of reasons. Not only
would it be cheaper than going to Mars, he believes
that it is a good place to begin to learn how to
live and work in space.
In
addition, Spudis has written about the potential in
terms of science to be learned on the moon.
Not only in astronomy, but also in the fields of physics,
life sciences and geoscience. The trip to the
moon only needs as much fuel as the launch of a satellite
to the higher geosynchronous orbit. |
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other plans to return to the moon include the development
of a lunar telescope, a permanent lunar base for testing
long duration spaceflight systems (life support, suits
and tools, rovers and laboratories), mining of lunar
resources for use on Earth, and the development of
manufacturing plants to produce hydrogen-oxygen chemical
rocket propellants. |
Lunar Telescope design
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Many applications both scientific and industrial
have been suggested for the moon including:
- a scientific laboratory complex
- an astrophysical observatory
- an industrial complex to support space-based
manufacturing
- a "fueling station" for spacecraft
- a training site and assembly point for human
expeditions to Mars
- a nuclear waste repository
- a response complex to protect the Earth from
short-warning comets and asteroids
- a studio for extraterrestrial entertainment
using virtual reality and telepresence
Science
facilities on the moon will take advantage of the
moon's unique environment to support astronomical,
solar and space science observations. Special
characteristics include the 1/6th gravity of the
moon, its high vacuum, seismic stability, low temperatures
and a low radio noise environment on the far side.
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The far side of the moon is permanently
shielded from direct radio transmission from Earth.
This uniquely quiet lunar environment may be the only
location in space where radio
telescopes can be used to their full advantage.
The solid, seismically stable, low gravity high vacuum
platform will allow scientists to search for extrasolar
planets using precise interferometric techniques.
A fully equipped lunar science
base also provides life scientists with the opportunity
to extensively study biological processes in reduced
gravity and in low magnetic fields. Genetic
engineers for example can conduct their experiments
in facilities that are isolated from the Earth's biosphere.
Genetically
engineered lunar plants could become a major food
source and supplement the life support system of the
base. Areas near the South Pole that are permanently
shadowed also have locations that are nearly always
in sunlight providing unlimited solar energy resources
for lunar facilities. |
The first
lunar researchers to live and work on the moon will
perform the scientific and engineering studies needed
to confirm the specific role the Moon will play
in our exploration of the solar system. The confirmation
and harvesting of the Moon's ice reservoirs in the
polar regions could significantly impact the development
of future lunar bases.
Discoveries
originating in lunar laboratories would be channeled
directly into appropriate sectors on the Earth as
new ideas and techniques, similar to the way the
International
Space Station laboratories will in the future.
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South pole of the moon |
The ability
to provide useful products from native lunar materials
will have an influence on the growth of lunar civilizations.
These products could support overall space commercialization. They
include:
- The production of oxygen for use as
a propellant of orbital transfer vehicles.
- The use of raw lunar
soil and rock (regolith) for radiation shielding
on space stations, space settlements and transport
vehicles.
- The production of ceramic and metal products
to support the construction of structures and
habitats in space.
- Hydrogen and water harvested from lunar
ice.
An initial
lunar base will include the extraction of lunar resources
and operation of factories to provide products for
use on the moon and in space. From Apollo, we
know that the moon has large supplies of silicon,
iron, aluminum, calcium, magnesium, titanium and oxygen.
Lunar soil and rock can be melted to make glass fibers,
slabs, tubes and rods. Sintering (heating materials
so they coalesce) can produce lunar bricks and other
ceramic products. Iron metal can be melted or cast
into shapes using powder metallurgy. Lunar products
could find a market as shielding materials, in habitat
construction, in the construction of large space facilities,
and in electrical power generation and transmission
systems.
Many space visionaries envision
a day when the moon will become the chief source of
materials for space based industry. |
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| Telescopes
The first,
and so far only, lunar astronomical
observatory was deployed by the Apollo
16 crew in 1972. The Far
Ultraviolet Camera/Spectrograph
used a 3-inch diameter Schmidt telescope
to photograph the Earth, nebulae, star
clusters, and the Large Magellanic Cloud.
The tripod mounted astronomical equipment
was placed in the shadow of the Lunar
Module so it would not overheat.
The Far Ultraviolet Camera took pictures
in ultraviolet light which would normally
be blocked by the Earth's atmosphere.
It had a field of view of twenty degrees,
and could detect stars having visual
magnitude brighter than eleven. 178
images were recorded in a film cartridge
returned to Earth. The observatory still
stands on the Moon today.
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Astronaut John Young and the Apollo Lunar
Telescope |
Why
is the moon such a good place for astronomy?
First of all, the moon has no atmosphere.
The sky is perfectly black and the stars
do not twinkle. Stars and galaxies can
be observed at all wavelengths including
x-ray, ultraviolet, visible, infrared,
and radio.
In
contrast, the Earth's atmosphere absorbs
light, causes distortion, and totally
blocks the x ray, ultraviolet and certain
infrared and low frequency radio signals.
These limitations prevent scientists from
studying many important phenomena in stars,
galaxies, and black holes. |
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In addition, night
time on the Moon lasts about 350 hours.
This would permit scientists to watch
deep space objects for very long periods,
or to accumulate signals on very faint
sources such as dim stars, galaxies, or
planets around other stars.
In contrast, the Hubble
Space Telescope, NASA's current premier
telescope for space research, is in a
low earth orbit some 350 km high (the
moon is 450,000 km away). Sunrise and
sunset are only 90 minutes apart on the
HST, meaning that the dark time (the time
HST is in Earth shadow) is only 45 minutes
long which is a major constraint for astronomers. |
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Unlike
orbiting spacecraft, the moon is a very
large and ultra-stable platform for telescopes
of any kind and has no seismic activity
unless there is meteoric impact. Average
ground motion on the surface is estimated
to be less than 1 micron (one millionth
of a meter, or about the thickness of
a hair). |
This stability
is crucial for 'optical
interferometers', instruments needed
to carry out a systematic search of
planets around other stars within our
own galaxy. An interferometer
is an array of several telescopes that
work together to increase magnification
ability. (Other galaxies are too
far away for visual or radio detection
of alien civilizations.)
The
Moon is very near to the Earth relative
to other planets. Round trip light travel
time is about 2.5 seconds. This means
a telescope on the Moon can be controlled
from ground station with a nearly instantaneous
response. (This goes for all kinds of
remotely controlled operations, not just
telescopes). Except for rare meteoric
hits, a lunar telescope could last almost
indefinitely as there is no weather on
the moon. The retro-reflectors left on
the moon by the Apollo astronauts, for
example, are still in operation after
more than thirty years.
A telescope on
the moon will remain productive for many
decades at low cost. The purpose of the
NASA
Lunar Telescope Deployment task is
to develop and demonstrate telerobotic
technologies that enable an unmanned lunar
observatory that is constructed and operated
from Earth. Specifically, the task is
to study an optical interferometric telescope
for the moon. |
A
telescope on the moon could also be used
for educational purposes. Wendell
Mendell, a NASA scientist working in the
Exploration Office, supports a lunar telescope
for student access. |
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Optical
telescopes can be on either the nearside
or the farside of the Moon. (The term
'darkside' is not correct because it implies
that the Sun doesn't shine there, but,
in fact, the Sun shines on both sides
equally.) There is very little atmosphere
to scatter light from the Sun or Earth,
so you could use an optical telescope
even during the day. |
Radio telescopes
are best placed on the farside, to block
out the radio noise of Earth and its
increasingly noisy fleet of satellites.
Radio bends around small obstacles so
it is harder to block out. Half a mile
from the point where you can no longer
see any of Earth would not be enough.
Data
communications from the lunar observatory
to Earth would be done by laser through
a lunar satellite to further avoid noise.
Astronomers could control the telescopes
through the international computer networks
from their own offices on Earth.
A
one-meter transit telescope is mounted
to a robotic lunar lander on the surface
of the Moon. The Moon is a uniquely suitable
platform for astronomy, which could include
extreme ultraviolet images of Earth's
magnetosphere (permitting study of solar
wind interaction), the first far ultraviolet
sky survey, and first-generation optical
interferometers and very long wavelength
radio telescopes.
The instrument
illustrated above is a Lunar Ultraviolet
Telescope Experiment (LUTE), which takes
advantage of the stable and atmosphere-free
lunar surface, and uses the Moon's rotation
to survey the ultraviolet sky. The lander
is an "Artemis" - class lander capable
of delivering up to 200 kilograms to the
lunar surface. The "Artemis" robotic lunar
lander is designed for cost-effective
delivery of payloads to the Moon to study
lunar geology, astronomy, and as a precursor
to human lunar expeditions. |
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Some
scientists feel that the lunar far side:
quiet, seismically stable and shielded
from Earth's electronic noise, may be
the solar system's best location for such
an observatory. The facility would consist
of optical telescope arrays, stellar monitoring
telescopes and radio telescopes allowing
nearly complete coverage of the radio
and optical spectra.
The
observatory would also serve as a base
for geologic exploration and for a modest
life sciences laboratory. In the left
foreground, a large fixed radio telescope
is mounted on a crater. The telescope
focuses signals into a centrally located
collector, which is shown suspended above
the crater. The lander in which the crew
would live can be seen in the distance
on the left. Two steerable radio telescopes
are placed on the right; the instrument
in the foreground is being serviced by
scientists. The other astronaut is about
to replace a small optical telescope that
has been damaged by a micrometeorite.
A very large baseline optical interferometer
system can be seen in the right far background.
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Questions
to think about:
- If you were an astronomer on the
moon which type of telescope would
you enjoy working on?
- Which telescope should we consider
putting on the moon first? Why?
- If you discovered an Earth-like
planet around another star using an
interferometer array how would you
write the press release?
Next..Lunar Mission Scenarios (pg 5 of
9) |
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