SPRITES DETECTION

The primary focus of the SPRITES'99 campaign was to support a series of stratospheric balloon missions over and near transients electromagnetic events generating storms in conjunction with coordinated ground-based measurements in several distant points.

The instrumentation package -designed and developed by the University of Houston- included a three axis broad band electric field and magnetic field detector with sufficient dynamic range and bandwidth to resolve the expected sprite excitation field and to distinguish between ac and dc excitation mechanisms.

A gamma ray spectrometer consisting of a scintillation counter and a pulse height analyzer was also flown.

On board memory was sufficient to record over a thousand bursts, with 160 ms sampling times and a 40 ms pre-trigger period.

Launch site: Ottumwa Industrial Airport, Iowa, US  
Balloon launched by: National Scientific Balloon Facility (NSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon 1.500.000 cuft
Balloon serial number: SF3-1.507-.8/0-NHR
Flight identification number: ABT#18
Campaign: SPRITES 99  

The flight was aborted due to the balloon burst at the time of the launching but before the payload release.

The balloon required just over one hour to reach its ceiling (around 33 km) after which it was expected to float generally westerly at 20-30 kts. In order to prepare for launch, a decision was required several hours before sprites were expected to begin. As a further complication, the balloon was expected only to fly near the target storm, but not over it. Such overflights are now disallowed given the 1989 uncommanded payload release over Dallas, Texas.

During much of the experimental period, adverse weather at the launch site (rain and/or high surface winds) severely limited the launch opportunities.

This was the intended second launch of the campaign. A superstorm was extremely well forecasted and the payload was prepared for lift off when an inflation accident scrubbed the mission.

• Sprites 99 Balloon Campaign Space Physics Group, University of Houston