From: Spudboy100@aol.com
Date: Thu Mar 06 2003 - 01:33:54 MST
http://www.sfgate.com/cgi-bin/article.cgi?f=/news/archive/2003/03/05/state0320E
ST0003.DTL&type=science
<<(03-05) 00:20 PST TUSTIN, Calif. (AP) --
A plan by a Texas company to send a spacecraft sailing to the stars on the
gentle push of the sun's rays has caught the interest of the National Oceanic
and Atmospheric Administration, which is exploring the technology for use
closer to home.
Team Encounter wants to test a spacecraft with a solar sail by late 2004,
sending it into Earth orbit with messages and photographs tucked aboard by
paying customers.
Once in space, the craft would unfurl an enormous, gossamer sail to catch the
sun's rays, harnessing the gentle -- but constant and cumulative -- pressure
of particles of light to propel it through space.
The sail would be made of Mylar, coated with aluminum and chromium. It would
be 76 times thinner than a human hair and cover a football field-size area --
but able to fit in a package the size of a bread box.
"From everything we've seen so far, it's possible. There are no show
stoppers," said Costas Cassapakis, president of L'Garde Inc., the Tustin
company developing the 62,000-square-foot sail and the 164-foot inflatable
booms that would deploy it.
If the orbital mission succeeds, a second spacecraft would be sent out to the
stars with a payload of messages and DNA samples.
While NOAA wants no part of that mission, the technology intrigues it.
"The mission was far out, but the way they were getting at it wasn't," said
Patricia Mulligan, a NOAA mission planner.
NOAA has paid a small amount to examine Team Encounter's engineering data. It
also wants the Houston-based company to point its craft toward a part of
space the agency wants to exploit for future satellite missions, Mulligan
said.
Solar sails could enable satellites to loiter in space at spots called
Lagrange points, where the gravitational pulls of the Earth and the sun
cancel each other.
A Lagrange-based craft has a stable vantage point above Earth that
traditional orbiting satellites lack. But it also requires constant
adjustment. That can be fuel-intensive for chemically powered spacecraft but
a solar sail doesn't have that problem.
"It relies on the virtually inexhaustible supply of energy from the sun,"
said Charles Chafer, Team Encounter's president and chief executive officer.
NOAA has preliminary plans for two types of solar sail craft that would park
in Lagrange orbits. One, called Geostorm, would sit part way to the sun and
provide early warning of solar storms before they reach Earth. The storms --
waves of charged particles from solar flares -- can disrupt communications
networks and power grids.
Another craft, called a polesitter, would linger either above or below the
ecliptic, the plane in which the planets orbit the sun. That would enable it
to stare down on either of the Earth's poles.
Those spacecraft could provide a dedicated communication link for scientists
in the Antarctic, who now must contend with spotty connections to polar
orbiting satellites that pass overhead once every 90 minutes, Mulligan said.
Team Encounter is considering NOAA's request to fly a solar sail spacecraft
into a polesitting orbit. NOAA has provided $50,000 to explore if such a
mission would be feasible, Mulligan said.
It isn't the only private developer of a solar sail mission, an idea that's
been knocked around for decades. The Planetary Society, a Pasadena-based
space exploration advocacy group, also is working on such a spacecraft.
The group hopes to launch an eight-petaled solar sail into orbit as early as
August, Executive Director Louis Friedman said.
Project members, who include Ann Druyan, the widow of astronomer Carl Sagan,
hope the craft will move out from the Earth and become the first to be
propelled by sunlight.
"If it spirals outward a few centimeters and we can measure it, then we can
declare victory," Friedman said.
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