Description of the payload

The gondola carried a complement of Hard X-Ray and Gamma Ray detectors, including both liquid nitrogen cooled Germanium detectors for high resolution and large area phoswich scincillation for high sensitivity for observations of microflares and flares of the Sun.

Details of the balloon flight and scientific outcome

 

Launch site: Australian Balloon Launching Station, Alice Springs, Australia  
Balloon launched by: National Scientific Balloon Facility (NSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon 792.000 m3 - (RACOON)
Flight identification number: 213N
Payload weight: 2100 lbs

The balloon was launched at 21.00 utc on February 9, 1987. Due to a malfunction of the ballast control system all 900 lbs of ballast were dropped at launch. The balloon thus flew unballasted for the entire flight.

With the loss of ballast the ascent was extremely rapid (~ 1500 ft/min) and the balloon reached a float altitude of ~132.000 ft (~2000 ft more than normal). Some of the hleium was vented and perhaps some leaks developed from the stress of the fast ascent.

The daytime float altitude generally decreased troughout the flight. Preliminary analysis indicates that helium was lost at a rate of ~l-2% per day, possibly from a Small leak.
The gas temperature and therefore the float altitude. are determined primarily by the radiation the balloon receives from the sun and the earth. Cold storm clouds below the balloon were
apparently responsible for the unusual deep drops in altitude.

The balloon started westward at an average rate of ~ 30° longitude per day
( ~130 km/hour), but slowed down as the balloon altitude decreased.

Finally after 12 days of flight crossing the entire Indian Ocean, Africa and the Atlantic Ocean the payload was commanded to cut down over Brazil, and was recovered with relatively
minor damage. All the detectors, the experiment data system, and electronics functioned
perfectly.

The payload was launched at 21.00 UTC on February 9, 1987. Due to a malfunction of the ballast control system all 900 lbs of ballast were dropped at launch. The balloon thus flew unballasted for the entire flight.

With the loss of ballast the ascent was extremely rapid (~ 1500 ft/min) and the balloon reached a float altitude of ~132.000 ft (~2000 ft more than normal). Some of the hleium was vented and perhaps some leaks developed from the stress of the fast ascent.

The daytime float altitude generally decreased troughout the flight. Preliminary analysis indicates that helium was lost at a rate of 1-2% per day, possibly from a Small leak. The gas temperature and therefore the float altitude. are determined primarily by the radiation the balloon receives from the sun and the earth. Cold storm clouds below the balloon were apparently responsible for the unusual deep drops in altitude.

The balloon started westward at an average rate of ~ 30° longitude per day ( ~130 km/hour), but slowed down as the balloon altitude decreased. Finally after 12 days of flight crossing the entire Indian Ocean, Africa and the Atlantic Ocean the payload was commanded to cut down over Brazil, and was recovered with relatively minor damage in the Palotina municipality in Parana state. All the detectors, the experiment data system, and electronics functioned perfectly.

External references and bibliographical sources