Space
scientists are evaluating use of Moon-based instruments to study the Earth.
Lunar situated sensors at an Earth Observatory could yield distinctive
observations of our home world, its vegetation, polar caps, as well as monitor
Sun/Earth interactions.
One
early prospect is to inspect the Earth from the Moon to appraise sensitive gear
and procedures helpful in spotting Earth-like planets circling other stars.
Planting
Earth-looking science instruments on the Moon is not a new idea.
Back
in 1972, Apollo 16 was the fifth mission to land men on the Moon and return
them back here to terra firma. While bounding about the lunar landscape,
astronauts snagged rock and soil samples, took pictures and performed research
tasks that included use of an ultraviolet camera/spectrograph - the first
astronomical and Earth observations taken from the Moon's surface.
But
more recently, a NASA Advisory Council subcommittee has taken on the task to
consider the merit of gazing at the Earth from the Moon. That review has been
spurred by the space agency's big picture plan for returning humans to the Moon
by 2020 - one element of the Vision for Space Exploration set in motion by U.S.
President George W. Bush in early 2004.
Whole Earth cataloging
Late
last year, a sub-panel group of the NASA Advisory Council (NAC) reviewed and
consolidated a list of Earth Science objectives that could be carried out from
the Moon's surface. In their down-to-earth view, Moon-based spectrometers of varying
resolution operating over a wide range of wavelengths could perform valuable
work.
"A
general Earth Observatory on the Moon would be of considerable value. This
Earth Observatory would have specific technological and energy requirements,
and require significant investments in new technology, which NASA would need to
determine in consultation with the Earth Science community," the NAC study
group reported.
NAC
members are also discussing a Moon-based Earth Observatory that is Internet
accessible to the scientific community as well as the public. That Internet
link would offer a continuously monitored, hyper-spectral, single frame sight
of the whole Earth.
Furthermore,
by making use of data fusion technology, Earth imagery from Moon could be instantly
integrated with real-time heliophysics and aeronomical data. Potentially, this
mixing of information sets could lend a hand in deciphering the complex
interactions of space phenomena with Earth weather processes.
There's
also NAC member opinion about inspecting Earth's photometric signature of plant
life from the Moon. By studying the biologically altered reflected light from
the Earth, such looks may be helpful in fine-tuning skills in the search for
Earth-like, extrasolar planets.
Durability of equipment
The
Moon presents a useful and stable platform for obtaining unique, simultaneous
views of the Earth and Sun explained Jay Herman, a project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Still, setting up
science gear on the lunar surface, powering them, and protecting hardware from
the Moon's vicious day/night temperature swings is no piece of cake, he told SPACE.com.
Herman
said that lunar dust is also a troublesome issue. "It's quite abrasive. So
keeping it out of movable joints...it'll damage equipment very quickly. That's a
major problem," he advised.
The
real question in placing precision optical paraphernalia on the Moon is the
durability of that equipment, Herman suggested. Also, just how much attention
such gear would need from space suited moonwalkers needs to be addressed, be it
for initial deployment and setup to instrument pointing and final checkout.
Engineering
around such problems would seem doable, Herman said.
Suitcase science
Equipment
on the Moon could address the relationship between solar activity and the
structure and dynamics of Earth's atmosphere from the surface to the
thermosphere-ionosphere, for a range of seasons, solar radiation and energetic
particle inputs, Herman explained.
At
the same time, Sun-scanning instruments could independently provide new
information on the processes governing solar activity using wavelengths from
the visible to soft x-rays.
Indeed,
the output from such science observations from the Moon, Herman added, could help
piece together the saga behind Sun-Earth weather relationships and long-term
climate factors.
But
to get a better handle on the types of science equipment that might be
stationed on the Moon, Herman suggested first installing relatively inexpensive
suitcase-sized instruments on the lunar surface.
"That
would be sort of the first step toward seeing whether the Moon is actually a
suitable place for instrumentation...say for larger telescopes," Herman said.
"These would be small, economical instruments to observe the Earth or the Sun,
or both."
advertisement
