Purpose of the flight and payload description

A balloon-borne detector for solar neutrons, based on n-p scattering between two large-area (1 m2) plastic scintillators.

The instrument was designed to take advantage of the RACOON (Radiation COntrolled balloON) technique to measure solar flare neutrons in the energy range 20 to 150 MeV.

It consisted of two scintillators separated by a 1m time-of-flight (TOF) path. Neutrons incident on the detector produce protons via n-p scatterings and C(n,px) interactions in the lower scintillator.

Since the gondola orientation and the position of the Sun are known, the incident neutron energy can be determined from the measured proton energy by simple scattering kinematics.

Data were processed on an event by event basis by an on-board microcomputer based on an M6800 microprocessor. The microcomputer also performed a high degree of data compression which was necessary before telemetry transmission through the GOES and METEOSAT satellites.

The experiment operated for 22 days until the payload was lost due to a balloon failure over the Indian ocean.

Ironically, although the flight was preceded by several large solar flares, the solar activity during the flight was the quietest on record.

Details of the balloon flight

Balloon launched on: 1/19/1983 at 20:41
Launch site: Australian Balloon Launching Station, Alice Springs, Australia  
Balloon launched by: RAAF (FFAA Australia)
Balloon manufacturer/size/composition: Zero Pressure Balloon 440.000 m3 - (RACOON)
Balloon serial number: 344.06-0.5-NSCH-0.5-(2)-Caps-15
End of flight (L for landing time, W for last contact, otherwise termination time): 2/10/1983
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 22 d
Landing site: Lost over the Indian Ocean
Payload weight: 1.700 lbs

The instrument was launched at 2040 UTC on January 19, 1983 on a 440.000 m3 zero pressure polyethylene balloon.

The flight was scheduled to take advantage of the zonal winds which are characteristically uniform, both in bearing and velocity, during the three summer months at mid-latitudes.

The balloon drifted westwards at ~ 1200 nautical miles per day and remained within latitudes of +7 -0 degrees of the launch site.

The flight trajectory is shown at left.

Processed data were telemetered to the ground through the METEOSAT and GOES satellites and the position of the balloon continuously monitored by the ARGOS satellites.

After circumnavigating the globe, an attempt was made to terminate the flight as it passed over Australia. The initial attempts to do so failed and termination was not achieved until it was out over the Indian Ocean were the payload was lost.

External references

Images of the mission


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