NASA Rockets to Explore Northern Lights Next Week
for National Geographic Today
|February 13, 2003|
Even in the wake of the Columbia space shuttle tragedy, long-planned NASA missions continue. The first post-Columbia flight, an unmanned rocket, lifted off last Thursday from White Sands, New Mexico.
As early as next week, at the Poker Flat Research Range, 30 miles (50 kilometers) northeast of Fairbanks, Alaska, NASA will send an unmanned rocket to probe the shimmering spectacle of the northern lights, or aurora borealis. The rocket's five-minute streak across the heavens will help measure how solar winds and the resultant aurora affect earthly communications and navigation.
On Tuesday, a NASA team arrived at Poker Flat to prepare for the two-rocket "Horizontal E-region Experiment," or HEX.
By coincidence, Poker Flat hosted NASA's first rocket launch after the 1986 Challenger shuttle disaster. Post-Challenger safety precautions still apply at the range.
"We've got recreation near us, we've got homeowners near us, we've got calving grounds and bird nesting areas near us," said Poker Flat operations controller Kathe Rich. "We need to pay attention to things like that."
The first HEX rocket, slated to soar about 100 miles (160 kilometers) up, follows a program that angles it in mid-flight to enter the aurora horizontally. If the steering mechanism fails, a built-in "flight termination system"an explosive devicedestroys the third-stage booster.
The new mission could blast off between Feb. 18 and March 8, depending on clear skies and the right conditions. Probing the aurora is "like hitting a moving target," said HEX project director Mark Conde, a physicist and assistant professor at the University of Alaska-Fairbanks.
Timing the Launch
In aurora research, timing is everything. Aurora watchers know that the display can fill the sky for hours or disappear in an instant.
Conde's responsibility is to signal the launch when he senses that the curtain of lights will remain stable for the duration of the rocket's brief flight.
Conde must eyeball the right momentliterally. He has long been going out at night with binoculars to get the cues he needs. "Every night," he said, "I watch the sky and say, 'Could I launch now?"'
The northern lights are powered by so-called solar wind, high-energy ionized particles emitted by the sun that form an electric field around the Earth. This field accelerates electrons, which then bombard gases in the Earth's upper atmosphere and cause them to produce a light show of colors.
Viewers at high latitudes are likeliest to see the effectknown as aurora borealis in the northern hemisphere and aurora australis in the southernbecause the Earth's magnetic field draws the solar-charged particles toward the poles.
The same solar weather that triggers the aurora can also play havoc with radio and satellite transmissions as well as power grids. But scientists cannot predict the extent of the disruptions. The clues, they feel, lie in the upper atmospherethe realm of "sounding" rockets.
NASA's sounding rockets range in size from single-stage Super Arcas at about 7 feet (2.1 meters) tall to the 65-foot (19.8 meters), four-stage Black Brant XII. The primary HEX rocket is 57 feet (17.3) tall.
Revitalizing the Rocket Program
At Poker Flat on Jan. 27, NASA launched the High Bandwidth Auroral Rocket, HIBAR, a sounding rocket, to measure high-frequency wave signals in the aurora.
"The speed at which data was required was higher than could be done by a satellite passing the same way," said Roger Smith, director of the University of Alaska Geophysical Institute, which owns and operates Poker Flat. "Also, with a satellite you could not choose when it could pass. Many of the experiments with rockets are designed to be done in exactly the right place at the right time."
A 2002 report by the National Academy of Sciences champions suborbital explorers like sounding rockets as "critically important for the next generation of solar and space physics research." NASA should "revitalize" its suborbital program and "aggressively support development of a range of low-cost vehicles capable of launching payloads for scientific research," the report said.
At Poker Flat, Conde is scanning the skies for the moment to start the countdown. The HEX rockets are prepared to accumulate an enormous amount of data in their brief arc across the sky.
"We spent two years and $3 to $5 million, and the rocket will be in the air five minutes," Conde said. "I can't really think of anything else in science where people have so much riding on one moment."
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