THE VIRGINIAN-PILOT Copyright (c) 1994, Landmark Communications, Inc. DATE: Sunday, September 18, 1994 TAG: 9409180067 SECTION: LOCAL PAGE: B1 EDITION: FINAL SOURCE: BY JAMES SCHULTZ, STAFF WRITER DATELINE: WALLOPS ISLAND LENGTH: Long : 105 lines
Bugs, bats and a handful of invited passengers might have been the only witnesses to the eerie sight. About 8:30 Friday night, a pinky-finger-sized pulse of brilliant emerald light was fired from the top of a parked airplane, seeming to spear the balmy night skies.
This was no otherworldly encounter, but a preflight test at NASA Wallops Flight Facility of a sophisticated, $1 million-plus laser system developed in Hampton at NASA Langley Research Center. The plane, a Lockheed Electra turboprop modified into a flying laboratory, soon would hunt for the orbiting space shuttle Discovery.
The mission: To catch and briefly shadow the shuttle's orbit. Discovery, scheduled to land Monday afternoon, is carrying another Langley-designed laser system that could revolutionize the study of weather and climate.
The instruments aboard Discovery are collectively known as LITE, which stands for Lidar In-Space Technology Experiment. Lidar, short for light detection and ranging, is the optical equivalent of radar. During the past week, LITE has sent millions of laser bursts through Earth's atmosphere, taking what amounts to miles-long core samples of air.
``We're able to see things that are totally invisible to a person looking up or down from an aircraft, or invisible to a satellite - things like cirrus clouds (that are) important to climate,'' said Edward V. Browell, head of the Langley's Lidar Applications Group. ``We can study processes that are global in nature.''
The processes in question involve molecule-size particles called aerosols, which influence the formation of clouds, affect global temperatures, and can determine where and how much rain will fall. Airborne residue from forest fires, agricultural burning, wind erosion, volcanic eruptions and automobile exhaust all can be classified as aerosols.
So a five-member research contingent came from Hampton on Friday night to double-check the results from the LITE shuttle experiment. The laser configuration on board the Electra essentially was the same as that on board Discovery. But the Electra's lasers could ``see'' the atmosphere with a higher resolution because of the smaller distance the airplane's laser signals traveled.
To a bird in flight, the Electra would have seemed a bizarre sight as it rumbled through the night, heading on a beeline northwest at 300 miles per hour at an altitude of 22,000 feet, toward Cleveland and then doubling back to the shuttle rendezvous point near Dulles International Airport in Northern Virginia.
An emerald spear protruded in two directions, up into the atmosphere and down to the ground, through a pair of quartz windows mounted in the roof and belly of the aircraft.
At 10:30 p.m. the laser was pulsating away. Scientists were beginning to review the results of their labors, produced by an onboard laser printer in vibrant violets, purples, blues, yellows, oranges and reds.
Clouds were seen. Pollutant plumes from industrial plants in the Midwest showed up. Also in evidence were remnants from the 1991 Mount Pinatubo eruption in the Philippines, which temporarily cooled global climate.
``I see these missions as a fishing expedition,'' said William B. Grant, a senior atmospheric research scientist at Langley, speaking over the constant thrumming of the Electra's engines.
``Occasionally you catch a big fish. You look for things you can't predict.''
Using an earlier version of the same laser system, Grant and his colleagues mapped an unexpected post-Pinatubo decrease in the protective ozone layer in the tropics and middle latitudes.
Coffee, sodas, cookies and popcorn kept the watchers alert as the minutes blurred into hours. Then came the shuttle intersection point, at six minutes past midnight Saturday.
There was no raucous celebration as the plane droned on.
The laser continued to pulse until shortly before 2:30 a.m., when technicians powered down the equipment and strapped in for landing.
``It's a great data set,'' said a still-chipper Arlen Carter, science mission director.
``It's been a lot of fun. I'm an engineer; I like technical subjects. For me to be along on this - what could be more fun?''
During the past week, the LITE experiment has involved an estimated 200 researchers worldwide and Electra-like aircraft flights over the Pacific Ocean and in Canada, Europe, Russia and Japan.
If experimental results bear up as expected, the next step could be design of a network of orbiting lidar satellites that would monitor the world's atmosphere minute-by-minute.
Such a network could be built in as little as three years. Langley likely would lead the effort, perhaps becoming an international nerve center for lidar and lidar-like technology.
``This (shuttle experiment) is going to be a treasure trove of information for a lot of people to study for a long time to come,'' said M. Patrick McCormick, LITE project scientist.
``It's worked. I'm riding pretty high right now.'' ILLUSTRATION: Graphic
JANET SHAUGHNESSY\ Staff
LIDAR IN-SPACE TECHNOLOGY EXPERIMENT (LITE)
SOURCE: NASA Langley Research Center
[For complete graphic, please see microfilm]
Photo
KENNETH SILVER/ASSOCIATED PRESS
In a preflight test, a pulse of laser light is emitted Friday night
from NASA Langley's flying laboratory: a Lockheed Electra turboprop.
The plane later linked up with the orbiting space shuttle
Discovery, testing a laser system that could be used to better
forecast global weather and climate.
by CNB