Purpose of the flight and payload description

This flight was part of a balloon expedition to study cosmic rays in the vicinity of the equator during the International Quiet Sun Year (IQSY) organized and managed by the National Center for Atmospheric Research as a joint United States - India activity. The program was conducted in Hyderabad, India during the late winter and early spring of 1965.

The main objective of the flight was to launch a X-Ray Telescope developed at the Southwest Center for Advanced Studies in Dallas, Texas. The experiment studied the energy spectrum of the cosmic radiation in the energy range 15 to 40 Bev, which was a portion of the spectrum little known at the time.

As additional payloads were also included:

A package of nuclear research emulsions with various sensitivities and having a large horizontal area provided by the U.S. Naval Research Laboratory, Washington, DC. The mission called for the detector to reach reach a pressure altitude of approximately 3 mb and stay there for 10 to 12 hr. That would make possible for the first time to obtain a charge spectrum for primary heavy nuclei with an almost negligible correction for fragmentation in the overlying atmosphere near the earth's magnetic equator. These data, in combination with data obtained from similar exposures during IQSY at Ft. Churchill and Minnesota, would make possible the comparison of spectra, fluxes and ratios of light to medium to heavy groupings for primary cosmic ray nuclei with Z > 3 over a wide range of energies. The combined data could then be used to study various mechanisms which may play a role in the propagation of the cosmic radiation through interstellar space.

An experiment to study the effects of Cosmic Rays on Seedlings provided by Osmania University, Hyderabad, India

Details of the balloon flight

Balloon launched on: 3/18/1965 at 6:15 ist
Launch site: Osmania University Campus, Hyderabad, India  
Balloon launched by: Raven Industries Inc.
Balloon manufacturer/size/composition: Zero Pressure Balloon Winzen 2.940.000 cuft (0.7 Mil. Stratofilm)
Balloon serial number: SF-199.78-070-NS-01 S/N 154
End of flight (L for landing time, W for last contact, otherwise termination time): 3/18/1965
Landing site: Aborted flight due to balloon failure during ascent.
Campaign: No Data IQSY-EQEX
Payload weight: 363 lbs

The Southwest Center for Advanced Studies counter telescope presented several problems when incorporated into the ballooning system. The experiment required scanning 360º horizontally at 23° from the vertical. The system was best positioned at the bottom of the flight train since it was equipped with a rather large and fragile antenna. After arranging the various components of the train in a line with the necessary clearance, it became evident that the system was awkward and extremely long. It was possible to eliminate a cross bar suspension by allowing the expended ballast to fall on the counter telescope. The telescope was covered with a layer of polyethylene to keep ballast out of the circuitry. By relocating the ballast near the center line, the length of the flight train was considerably reduced. A flight suspension system in which several packages of different weights are arranged in tandem, often sustains considerable damage from oscillation during descent. To minimize this oscillation, a 38-ft diameter, lightweight chute was used. To further enhance the stability of the system, the rotator and all equipment above the telescope were suspended from two points on a plate attached to the balloon end fitting. This method provided a more rigid linkage between the balloon and the
rotor and helped achieve a consistent scanning rate with little oscillation.

The 285-ft DF and altitude telemetry antenna was attached to the outer end of a 10-ft bamboo pole to prevent it from fouling the scientific data telemetry antenna. After the balloon was ascending and vertical, the antenna was deployed by radio command. The first flight of this system was scheduled for 18 March. The surface wind was calm and inflation was completed by 6:15. As the balloon was released, it rose over the instrument package, lifting it gently to about 20 ft until the telescope telemetry antenna was just off the ground, at which time the anchor line was released.
Seconds later, the balloon descended and the telescope began to drag. Efforts to restrain the balloon failed and the balloon and flight train finally came down in the University Botanical Garden about 1 mile from the launch site. Inspection of the balloon was not possible since it had been badly damaged and was lying on top of the trees. The telescope was suspended 10 ft above the ground in an Australian wattle tree.

Examination of the apparatus disclosed a damaged framework and some minor circuitry damage. A phototube was ruined but this component damage was not critical. The failure was obviously due to insufficient lift at the time of release.

External references

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