Purpose of the flight and payload description
The purpose of the instrument was to improve understanding of the mechanisms involved in many different types of solar activity, particularly flares and solar filament eruptions.
The basic design of the FGE gondola was derived from a payload (Exite instrument) developed by the Harvard/Smithsonian Center for Astrophysics (CFA). The frame was bolted together from standard aluminum angle to simplify both material procurement and construction. The structure is strong enough to support the 4400-lb weight of the instrumentation, telescope, NSBF's Support Instrument Package (SIP), ballast and solar panels, even under a design load of 10 g, as well as being rigid enough to allow stable pointing to at least 10 arcsec.
The command and control electronics and the two tape drives are housed in 4 pressure vessels. The main telescope (MT), the pointing telescope (PT) , and a pressure vessel housing the optical analysis stages are mounted together and pivoted around the elevation axis, driven by a torque motor.
This was the second antarctic flight of the instrument and on it were obtained near 50.000 images of the sun.
Details of the balloon flight
Balloon launched on: 1/10/2000 at 3:13 utc
Launch site: Williams Field, McMurdo Station, Antarctica
Balloon launched by: National Scientific Balloon Facility (NSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon Winzen - 850.000 m3 - SF3-424.37-080-NSC-X-ST
Balloon serial number: W29.47-2X-17
Flight identification number: 477N
End of flight (L for landing time, W for last contact, otherwise termination time): 1/27/2000 at 4:33 utc
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 17 d
Landing site: Near McMurdo base, Antarctica
Payload weight: 3300 lbs
Overall weight: 4825 lbs
After a long delay to allow the formation of a stable polar vortex of stratospheric winds the balloon was successfully launched by dynamic method on January 10 at 3:14 UT. After 17 days of flight -with some troubles with the onboard computer- on January 27th at 2:30 UTC was commanded the main computer to interrupt the observations, to stow the telescope and switch off the power. At 3.00 utc a Hercules C130 headed towards the balloon that at that moment was flying over the Ross Ice Shelf about 230 miles (360 Km) Sout/East from McMurdo and at an altitude of about 124500 ft (37500 m) at 3:35 UTC the termination command was transmitted to the balloon. The slow descent of the payload lasted about 30 minutes and landed on the snow at 4:15 UTC. The landing was perfect and the payload standed upright.
Nevertheless, the first trip to the payload was delayed until febraury 13 when the team was able to land with a Twin Otter near the telescope and recover the pressure vessel containing the tape driver and the data tapes, another pressure vessel with some electronics, and a few more sparse small items. The rest of the payload remained in antarctica during the winter and was recovered in October that year.