For AESOP (Anti-Electron Sub Orbital Payload)

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Launch site:European Space Range, Kiruna, Sweden  
Launch team: Columbia Scientific Balloon Facility (CSBF)
Balloon: Open balloon (zero pressure)
Volume: Winzen - 39.570.000 cuft (0.8 mil)
Serial number: W 39.57-2-48
Flight identification number: 554N
Campaign: - 
Payload weight: 1905 lbs
Gondola weight: -
Overall weight: 3260 lbs

The balloon was launched on June 12th at 2:08 utc, by dynamic method using a launch vehicle called "Hercules". After a nominal ascent phase the float altitude of 133.000 ft was achieved. Then the balloon started a slow west drift over the Atlantic Ocean towards Northamerica.

Althought the flight was scheduled to fly for 5-9 day, at the fifth day of travel was decided to end the flight when flying over Northern Canada because the balloon experienced a path towards the arctic sea.

The cutdown command was sent by satellite from the NSBF's Operations Center in Palestine, Texas, at 5:48 utc on June 7th. The gondola impacted ground at 6:33 utc a few meters from the coast of Victoria Island, Canada over ice. The exact piont was located 163 nautic miles west of Cambridge Bay at coordinates 68º30' N y 112º 58' W.

This report will be completed when the ongoing recovery operations were completed.  

AESOP (Anti-Electron Sub Orbital Payload)

Responsable institution:  Bartol Research Institute - University of Delaware
Principal Investigator:  Dr. John Clem

Developed by the Delaware University in the early 90's is an instrument which measures the energy spectrum of comic ray electrons using mainly a permanent magnet and a spark chamber hodoscope to determine the charge sign of the electron.

As we can see in the scheme (click to enlarge) AESOP chambers contain 5 parallel aluminum plates connected, in alternate order, to ground and a high voltage pulser. The medium between plates is a slow moving noble gas mixture of neon and helium. As a charged particle transverses a chamber it leaves behind an ion trail in the gas. If the scintillator detectors, mounted above and below the chamber, detect coincidence light pulses from the resulting ionization track, a 10,000 volt pulser is triggered. In the presence of a high electric field, the ions in the gas are accelerated toward the plate surface producing more ions with each ion-atom collision. These multiple collisions form an ion cascade which ultimately results in a high voltage breakdown very near the original ion trail. This breakdown in each gap produces a bright red verticle spark which is digitized and recorded using a linear CCD camera.

The instrument was flown several times in a same gondola with another complementary instrument called LEE (Low Energy Electrons).