Tests have been carried out on ground penetrating missiles using 'bunker buster' technology that could be fired into the depths of dark lunar craters to look for ice.
The proposed mission is called Polar Night, a lunar orbiter that would fire instrumented missiles towards the surface of the Moon.
Tests performed recently in New Mexico have shown that scientific equipment could survive the rapid deceleration of striking the ground and being buried a few metres beneath the surface of the Moon.
The researchers hope that Nasa will approve their mission early next year for a 2007 launch.
Shock testing
The impetus behind these tests is that for many decades scientists
have speculated about the possibility of ice at the lunar poles having
accumulated there over geologically long periods of time.
Into the plywood
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The ice would be from impacting comets. If some of the ice from the
comets found its way into dark lunar polar craters where the Sun never
reaches, it could be trapped for billions of years.
The lunar polar ice hypothesis was finally confirmed by observations
made by the Lunar Prospector spacecraft in 1998.
Technically, the Lunar Prospector data is compelling evidence for the
presence of hydrogen. However, most scientists are convinced a small
amount of water ice is present at the lunar poles, though other
hypotheses exist.
Because of the scientific attraction of lunar polar exploration the
University of Hawaii, with engineers and scientists from the US Naval
Research Laboratory, Utah State University, the Jet Propulsion
Laboratory, Los Alamos National Laboratory, and Sandia National
Laboratory are proposing an adventurous mission called Polar Night.
"Polar Night would conduct a highly detailed remote sensing survey of
the poles to refine our understanding of the temperatures and
distribution of hydrogen, then directly sample the polar ice with three
hard-landing probes," Professor Paul Lucey of the University of Hawaii
told BBC News Online.
"The probes are based on bunker-buster penetrators, but instead of
explosives, would carry sophisticated scientific instruments hardened
against the shock of striking the lunar surface."
"The instruments were recently shock tested in the New Mexico desert
by firing them at high speed into 2 metres (6 feet) of plywood, where
they experienced 1200 G's of shock and worked perfectly afterwards."
New questions
According to Professor Lucey the existence of lunar polar ice raises
a new set of questions.
- What is the nature of the deposit?
- What is the source of the water?
- Are other ices besides water ice present?
- Is the hydrogen actually in the form of water ice, or is it
hydrogen from the solar wind?
He told BBC News Online, "The lunar poles are a potential science
bonanza, possibly having recorded the volatile history of the solar
system for 2 billion years."
"That potential has an analogy with the poles of the Earth, where
meteorites are routinely preserved by the Antarctic icecap and collected
by scientists. There is a nice symmetry here: on the Earth, the ice of
the poles collects rocks from space, while on the Moon, the rocks of the
poles collect ices from space."
Easily collectable ice at the lunar poles could also transform the
economics of space exploration.
Professor Paul Lucey
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"For resources for future space travel the chemical form and
concentration are clearly relevant to the economic value of these
deposits, regardless of our current ignorance of the economics of the
future," says Professor Lucey.
The scientists hope the mission will be funded by Nasa's Discovery
program of moderate cost planetary science missions.
Lunar Prospector was a mission in this series, and the current
missions in flight are Genesis, returning a sample of the solar wind,
and Stardust to return cometary and interstellar dust.
The proposals for the next round of the Discovery Missions Program
are due later this year with the selection of the 3-5 finalists taking
place a few months later.
If Polar Night survives the proposal process, the first impacts would
occur in 2007.
