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Apr. 14, 1999: Last Sunday in Huntsville, Ala., a weather
balloon was launched amid the golden light and stretching shadows
of late afternoon. The whipping wind quickly carried the balloon
aloft at 6:47 p.m. CDT, encouraged by the enthusiastic cheers
of the launchers. Their eyes followed the balloon until it disappeared
into the expansive blue sky, then they quickly huddled around
tiny TV monitors to watch scenic video filmed from the balloons
payload.
"Local resident Chet Hale offered to drive them back across a cow pasture and through some gates until they saw the strobe light and heard the Sonalert beeper," says Bill Brown, a balloon launch volunteer. "Although the chase team woke him up in order to roam about on his property, Mr. Hale was quite thrilled about chasing the payload in the middle of the night." The payload was eventually found at the top of a 15-ft. tree. The xerogel samples will be sent back to the NASA Marshall Space Flight Center to be analyzed and compared with the samples taken during the Leonids weather balloon flight last November. "Last November's experiment went very well," says Dr. John Horack, a scientist at NASA Marshall. "After we recovered the payload we looked at these xerogel collectors with an electron microscope -- there were lots of tiny craters caused by impactors measuring 20 to 50 um. We caught something, but the question is, What did we catch - meteoroids, or something else?" Sundays flight was intended to help answer that question. Unlike last year's flight, which took place during the most intense meteor shower since 1966, this mission coincided with an annual lull in meteor activity. Because meteor activity is greatest near dawn, Sundays launch was scheduled at dusk. "We're launching the balloon near sunset so the body of the earth will act as a shield, or a barrier, between the balloon and most incoming meteoroids," says Dr. Tony Phillips, a scientist with NASA/Marshall. "The low flux of meteoroids will make this flight serve as a control experiment for the 1998 Leonids flight." Above:The rate of meteor activity
is greatest near dawn because the earth's orbital motion is in
the direction of the dawn terminator. Earth scoops up meteoroids
on the dawn side of the planet and outruns them on the dusk side.
"Even my wife seemed to enjoy watching this, and after half-an-hour or so, we had lots of curious neighbors stopping by to watch too. The cookout turned into a mini block party with ATV supplying the entertainment," Rayburn e-mailed. "We continued to watch a beautiful sunset from high above the earth and were amazed at just how much fun ATV is. In a word, I'm excited and had a ball." NASA will launch two more weather balloons this year to capture meteoroid samples. In August, xerogel will be used to take samples of the Perseid meteoroid shower. This November, the Leonid shower is predicted to be an even better show than the much-hyped 1998 Leonid shower, and a balloon will be there to see if this prediction is correct. Both balloons will be equipped with a video camera just as in Sundays launch. |
Web Links | |
NASA/Ames Leonids MAC Workshop - April 12 - 15, 1999 Leonids' Particle Analyses from Stratospheric Balloon Collection on Xerogel Surfaces - conference abstract Leonids Live! -site of the live webcast of the 1998 Leonids Related Stories: |
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