NEWS: The allure of an outpost on the Moon

The Allure of an Outpost on the Moon
By KENNETH CHANG

Published: January 13, 2004 NY TIMES


For some, it is the steppingstone of the Moon, not the distant goal of Mars,
that is the irresistible destination in the human venture into space that
President Bush will propose tomorrow.

For geologists, Moon rocks could tell much about the first billion years of
Earth's history. For astronomers, the Moon would be a cold, dark place ideal
for a telescope staring deep into the cosmos.

"There's a lot we could get out of the Moon," said Dr. Allan H. Treiman, a
scientist at the Lunar and Planetary Institute in Houston. But he added,
"It's not grab-the-public-by-the-throat science."

After the climactic triumph of Apollo, the public lost interest in continued
human exploration of the Moon, and the Nixon administration cut deeply into
NASA's budget. In the three decades since, NASA has focused robotic missions
on more distant, more mysterious worlds like Mars and Jupiter and sent only
two small orbiting spacecraft to the Moon. Clementine, a joint effort with
the Department of Defense, found signs of frozen water at the lunar south
pole in 1994. In 1998 and 1999, the space-on-a-budget Lunar Prospector
mission, which cost $63 million, found even stronger evidence of ice and
mapped out the Moon's gravitational and magnetic fields.

The primary reason to return and establish a permanent base on the Moon
would be to assist a mission to Mars. Because the Moon's gravity is
one-sixth of Earth's, gathering raw materials there - everything from metal
for the spaceship to water for the astronauts to drink - would be much
cheaper than hauling them up from Earth. So the cost and difficulty of
traveling to Mars would be reduced.

The Moon base would also serve as a proving ground for new technologies
developed for a Mars mission.

"If we learned to do that nearby, it might be a lot easier," Dr. Treiman
said. "That's one of the big deals of using the Moon as a way station. We
could learn how to live on Mars by living on the Moon."

But the Moon has its own appeal. About 4.45 billion years ago, a planetary
interloper the size of Mars slammed into the infant Earth, tossing a blob of
rock into space that became the Moon. With only one-eightieth Earth's mass,
the Moon long ago cooled to the core, leaving it geologically dead. It is
also too small to hold on to an atmosphere.

It is just this deadness that excites geologists. They see it as a museum of
the history of the solar system. "To learn about the Moon is going to tell
how the Earth formed," Dr. Treiman said.

On Earth, the continuous march of plate tectonics has destroyed almost all
of the surface rocks from its first billion years. On the Moon, those rocks
are still on the surface. The youngest rocks on the Moon are as old as some
of the oldest rocks found on Earth: 3.2 billion years.

The craters on the Moon also preserve a record of the early bombardment of
meteors. "The moon is a great place to study geological processes and it
nicely complements the missing geological record on the Earth," said Dr.
Paul D. Spudis, a planetary scientist at Johns Hopkins's Applied Physics
Laboratory.

The 843 pounds of rocks brought back by Apollo astronauts revolutionized
scientists' understanding of the Moon. The similar mix of oxygen atoms in
the rocks of the Moon and Earth showed the two had a common ancestry instead
of the Moon's forming elsewhere and then being captured by Earth's gravity.
The chemical composition also showed there had never been significant
amounts of water in most areas, except possibly the polar regions.

But the rocks came from just the six Apollo landing sites, leaving the rest
of the surface, the size of Africa, unexplored. Dr. David S. McKay, a
scientist at NASA's Johnson Space Center, would like the agency to go to
other locations and dig trenches perhaps 100 yards deep to examine in detail
the top layer of crushed rock and dust, known as the regolith.

"I think there is a lot of data hidden away on the Moon that remains to be
unraveled," Dr. McKay said. "The lunar regolith is like a giant tape
recorder that has been running for billions of years."

As astronomers try to look farther into the universe, they need a large
telescope that can stay focused on a single patch of sky for weeks or
months. Near absolute-zero temperatures and an airless environment are
needed to prevent blurring. A nearby Moon base would allow easy repairs and
upgrades.

"The Moon is a place that has been thought about a lot that has a lot of
what you want," said Dr. J. Roger P. Angel, a professor of astronomy at the
University of Arizona. He has proposed putting a large infrared telescope in
a deep crater at the Moon's south pole.

At a Senate hearing on lunar exploration in November, Dr. Angel suggested
that the mirror of such a telescope might consist of a round dish, 20 yards
wide, with a reflecting liquid that spun at a rate of two revolutions a
minute. The centrifugal force, coupled with the Moon's gravitational force,
would push the liquid toward the outer edges of the dish to form a perfectly
curved surface for gathering starlight.

Not only will a lunar telescope be more sensitive than the Hubble Space
Telescope, but it should be able detect galaxies and stars far fainter than
will be seen by Hubble's planned replacement. It may even pick up light from
the very first stars of the universe half a billion years after the Big
Bang. "That's something you could do brilliantly from the Moon," Dr. Angel
said.