A grandspectacle in the evening sky created by a spacebound rocket delightedstargazers and frightened the uninformed across hundreds of miles in thesouthwestern United States on Thursday.
The six-story Minotaurrocket soared off its launch pad at 7:24:29 p.m. PDT (10:24:29 p.m. EDT;0224:29 GMT) from Vandenberg Air Force Base in California carrying anexperimental military spacecraft.
Billed before launch as apotentially stunning blastoff, the mission delivered with a fast-growing cloudof colors painted in the darkening sky. Residents throughout central andsouthern California were treated to ringside seats, but folks as far away asUtah, Nevada and Arizona witnessed the incredible sight. Television stationsand local authorities reported being flooded with calls wondering what hadhappened.
The Minotaur's ascent toreach the desired orbit around Earth was timed perfectly to produce aspectacular "twilight phenomenon" that occurs when rockets or missilesare launched just before sunrise or shortly after sunset. Unburned fuelparticles and water drops in the rocket's contrail freeze in the less denseupper atmosphere and get reflected by sunlight at high altitudes to generatesuch breath-taking scenes. The winds aloft twist the exhaust cloud, giving it acorkscrew effect.
Vandenberg Air Force Base,positioned along the Pacific coastline 140 miles northwest of Los Angeles, hashosted more than 1,700 launches since December 1958. But only a fraction of theflights have displayed such a spectacle.
The rarity prompted manyspace enthusiasts to plan ahead for Thursday's launch, scouting out primeviewing spots to observe the moment. It was the first such twilight launch inseveral years, and weather conditions didn't spoil the show.
The OrbitalSciences-managed Minotaur rocket uses decommissioned first and second stagesfrom a Minuteman 2 ICBM missile and solid-propellant motors from the commercialPegasus rocket program for its third and fourth stages. The vehicle is designedto provide the U.S. government with reliable access to space for smallsatellites.
The $20 million Minotaurdeployed into a sun-synchronous orbit around the planet's poles the Space TestProgram-R1 mission's Streak satellite. Built by General Dynamics C4Systems/Spectrum Astro Space Systems in Gilbert, Arizona, the craft will beoperated by the Defense Advanced Research Projects Agency.
"Streakis a technology demonstrator whose objective is to demonstrate rapid response,short mission life, low Earth orbit space technologies and gather informationabout the low Earth orbit environment," a DARPA spokesperson said.
Information released byDARPA indicates Streak is fitted with two instruments -- an ion gauge and anatomic oxygen sensor.
"The vehicle willcharacterize the orbital regime, demonstrate operational feasibility from acommand and control standpoint and also from a platform perspective for futureDoD missions," the spokesperson added.
DARPA is the DefenseDepartment organization whose mission is "to maintain the technologicalsuperiority of the U.S. military and prevent technological surprise fromharming our national security by sponsoring revolutionary, high-payoff researchthat bridges the gap between fundamental discoveries and their militaryuse."
Streak's price tag isclassified.
This was the fourthMinotaur launch. The Air Force says another is planned on December 18 fromVandenberg to loft a cluster of tiny satellites for a joint Taiwan-U.S.project, called COSMIC, to study the atmosphere.
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