Purpose of the flight and payload description
The GRIS instrument consists of an array of seven coaxial n-Type germanium detectors surrounded by a thick active NaI shield/collimator. Located above this assembly is an active NaI coded-aperture mask for imaging and precise source location. The seven germanium detectors are each enclosed in individual cryostats. This design (rather than a single large multi-detector cryostat) was chosen for two principal reasons: to minimize the internally produced background and for easier replacement of individual detectors, as well as upgrades and modifications.
The instrument is mounted in a gondola offering a conventional azimuth-over-elevation pointing system with a momentum wheel for azimuth control. Coarse pointing control used the earth's magnetic field as a reference. A CID camera was used to image star fields and the sun to obtain an independent and more accurate measure of the absolute pointing direction.
Details of the balloon flight
Balloon launched on: 10/4/1995 at 7:30 utc
Launch site: Australian Balloon Launching Station, Alice Springs, Australia
Balloon launched by: National Scientific Balloon Facility (NSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon SF-459.37-080-NSXCHR-ST
Balloon serial number: W39.57-2-08
Flight identification number: 403N
End of flight (L for landing time, W for last contact, otherwise termination time): 10/5/1995 at 6:57 utc
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 24 h
Landing site: 13.5 miles N of Alice Springs, Australia
Payload weight: 6000 lbs
Nominal launching by dynamic technique using crane.
Balloon developed a leak shortly after launch and stopped ascending at 113.500 ft.
Minimum science altitude requirement not meet.
Leaker balloon. Observations of atmospheric growth curves.
- GRIS web site at Goddard Space Flight Center archive
- Great Moments in GRIStory at NASA's Goddard Space Flight Center website
- NASA Balloon Flights (1989-1998) in NASA Historical Data Book, Vol. VII: NASA Launch Systems, Space Transportation, Human Spaceflight, and Space Science, 1989-1998
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