NAVSPASUR Upgrade
From: Allen Thomson (thomsona_at_flash.net)
Date: 02/21/05
- Next message: Joe Strout: "Re: Space Tourist Spacesuits"
- Previous message: Ed Kyle: "Re: Rocket design up in air, says Marshall chief"
- Messages sorted by: [ date ] [ thread ]
Date: 21 Feb 2005 13:40:12 -0800
http://www.tuscaloosanews.com/apps/pbcs.dll/article?AID=/20050221/APN/502210732
Rural site part of America's oldest satellite-
tracking system
By DAVID WHITE
February 21, 2005
The Air Force Space Command's Jordan Lake
Field Site, part of America's oldest satellite-
tracking system, tries to blend into quiet,
rural Elmore County.
The barbed wire fence that surrounds the 11-acre
site has bluebird houses attached here and there.
Eight gourds for purple martins hang near the main
building.
The site's 10 employees will phone if a cow
gets loose from Billy and Sarah Matthews' 500-acre farm.
"They're good neighbors," Sarah Matthews said.
But those workers also run a 1,032-foot-long radio
antenna array that, among other things, helps keep
the International Space Station out of harm's way.
The gray aluminum structure looks a bit like a
grilled walk way raised about 12 feet in the air by
hundreds of poles.
Atop the walkway, which is really a radiation
groundscreen, stand 256 antennas in a straight line,
each shaped like an arrow head. Each antenna
produces 150 watts of power and radiates radio waves
at a frequency of 216.99 megahertz, just higher than
the frequencies reserved for television stations that
broadcast on channel 13. They beam their energy
straight up into space.
At almost a fifth of a mile long, the antenna array
does stick out amid the pastures, hardwoods and
houses on Jones Corner Road. But site manager Frank
Bullard said that, before a new Space Command sign
went up, some folks thought the array and its many
amplifiers and power supplies were something run
by Alabama Power Co. or a water treatment plant.
"It's like we don't even exist over here," he said.
Addie Stubbs, who lives with her husband, Jimmy,
near the Jordan Lake site, said, "It's never
bothered us. It's been there for years."
The site makes a bigger impression in space. Along
with transmitter sites in Texas and Arizona, it
creates an invisible fence of radio waves that
extends east-to-west across America at about the
33rd parallel. Orbiting satellites and other
objects that cross the fence reflect radio waves
back to earth, where they're collected at six
receiver stations. The receivers are sensitive
enough to detect objects as small as a basketball
orbiting as far as 15,000 nautical miles, or 17,200
land miles, above the earth's surface, Bullard said.
The receiver stations, in Georgia, Mississippi,
Arkansas, New Mexico and California, record more
than 5 million detections each month, according to
the Air Force Space Command.
The stations send the information to the Alternate
Space Control Center at a Navy base in Dahlgren,
Va. A computer system there uses the information to
update a catalog of more than 10,500 orbiting
objects. Only about 500 are working satellites,
according to the Space Command. The rest are dead
satellites, rocket parts and other debris.
The fence of radio waves can detect about 60
percent of the orbiting object catalog. It can't
see objects if they don't cross America at about
the 33rd parallel, said Air Force Master Sgt.
Robert Pascal.
He oversees the three transmitter and six receiver
sites. Together, they're formally known as the Air
Force Space Surveillance System. Informally,
they're called the "Fence."
The Fence can tell when a Russian spy satellite will
orbit over sensitive areas. It can tell when a
satellite or other catalogued object breaks up. It
can report a new object, and by its path tell if it
likely came from a Russian, European, Chinese or
other launch site, Pascal said. A new object then
can be tracked by other sensors, such as telescopes
and advanced phased array radars that, along with the
Fence, are part of the worldwide Space Surveillance
Network directed by the U.S. Strategic Command.
The Fence also can tell if a catalogued object
crosses later than expected. Then observers at
Dahlgren or the Space Control Center at Cheyenne
Mountain, Colo., can plot the decaying orbit and
predict when the object will re-enter the atmosphere.
"We have an agreement with the Russians that
anything that re-enters over their land mass, we have
to report it to them, whether it's their junk, our
junk or some other country's, so they don't think
we're launching an attack against them," Pascal
said. "It builds confidence."
He said the Fence also has warned the
International Space Station about two dozen times
to fire its thrusters to avoid collisions with
satellites or debris, and it warns the space
shuttle of dangerous objects.
Pascal said the Fence and related Dahlgren
computer center, which are staffed by 188 people,
will cost an estimated $167 million to run for
five years, this year through 2009.
"For the buck, this system is relatively cheap
to run," he said. "It's a very basic system, but
it's very effective."
The military has had a satellite-detection
transmitter in northwest Elmore County since the
summer of 1958. The Naval Research Laboratory
built it about 10 months after the Russians
launched Sputnik. The current site, across Jones
Corner Road from the old one, has been running
since 1965 near Mt. Pisgah Missionary Baptist Church.
The Navy operated the Jordan Lake site and the rest
of the Fence until the Air Force took them over
Oct. 1. Bullard said little has changed, other than
the sign.
"We're on seven days a week, 24 hours a day,
emitting energy out into space," he said.
- Next message: Joe Strout: "Re: Space Tourist Spacesuits"
- Previous message: Ed Kyle: "Re: Rocket design up in air, says Marshall chief"
- Messages sorted by: [ date ] [ thread ]
Relevant Pages
|
