ALFAN I (Airborne Measurement of Low Frequency Atmospheric Noise)

Developed by Rome Air Development Center

Balloon launched on 8/4/1986, from Roswell Industrial Air Center, New Mexico, US

Purpose of the flight and payload description

This flight was part of a project started in late 80's by the Propagation Branch of Rome Air Development Center, in a joint program with the Defense Nuclear Agency and the Air Force Electronic System Division. It was aimed to obtain measurements of Transverse Magnetic (TM) and Transverse Electric (TE) polarization atmospheric noise. The program, named ALFAN (Airborne Low Frequency Atmospheric Noise), was designed to obtain data at high altitudes, using a stratospheric balloon to provide an electrically-quiet platform for the experiments.

The ALFAN measurement system consisted of three identical low frequency receivers and an octahedron-shaped antenna arrangement, made up of three loop antennas, orthogonal to each other. Each of the loop antennas were 1.73 meters on a side. In level flight two vertical loop antennas respond to horizontal magnetic fields, while a horizontal loop antenna responds to vertical magnetic fields.

The signal receiver was integrated with a digital sampling system and a down-link data telemetry system. In addition, an up-link command system was employed to allow various parameters of the receiver (including the frequency to be monitored) to be changed during flight, via commands from the ground. The receiver, control and telemetry systems and the battery power supply were mounted on a horizontal "load-bar", with the antenna system suspended beneath the bar.

The payload (including antennas) weighted about 386 kg, and was connected to a recovery parachute having a diameter of about 18.3 meters. This was, in turn, connected to the free-floating balloon, which had a capacity of about 10,000 cubic meters.

Details of the balloon flight

Balloon launched on: 8/4/1986 at 7:30 local (13:30 utc)
Launch site: Roswell Industrial Air Center, New Mexico, US  
Balloon launched by: Air Force Geophysics Laboratory (AFGL)
Balloon manufacturer/size/composition: Zero Pressure Balloon Raven LTV-018 - 355.000 cuft
Flight identification number: H86-11
End of flight (L for landing time, W for last contact, otherwise termination time): 8/4/1986 at 12:45 local (18:45 utc)
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 5 h 15 m
Landing site: Near Alamogordo, New Mexico, US
 Payload weight: 918 lbs

External references

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