Description of the payload

The instrument, is the first one aimed to obtain focused images of astronomical X-ray sources at hard X-ray energies (20-45 keV).

The key component (the hard X-ray optics) are full-shell electroformed-nickel-replicated (ENR) mirrors coated with iridium to enhance high-energy reflectivity. As the critical grazing angle for reflection varies approximately inversely with energy, these mirrors employ smaller angles than their low-energy counterparts and consequently have smaller diameters and collecting areas per shell. The mirrors have a 6 meter focal length.

To exploit the full potential of the HERO optics necessitates a balloon gondola that can provide commensurate pointing accuracy, stability, and pointing knowledge. The HERO gondola utilizes a coarse aspect system for slewing based on a differential global positioning system (GPS) and a fine inertial-mode pointing system that uses a novel day/night aspect camera system to update onboard gyroscopes.

During this flight, the science instrument functioned normally for over seven hours but then, experienced an unknown electronic failure that led to a loss of commanding of the pointing system.

This flight also included as a piggyback additional scientific payload, an experimental camera called "COSMOCAM" mounted on a side of the gondola and transmitting live from the stratosphere via internet.

Details of the balloon flight and scientific outcome

 

Launch site: Scientific Flight Balloon Facility, New Mexico, US  
Balloon launched by: Columbia Scientific Balloon Facility (CSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon Raven - 39.570.000 cu ft - 0.8 Mil.
Balloon serial number: W 39.57-2-58
Flight identification number: 560N
Payload weight: 3220 lbs
Overall weight: 5470 lbs

The balloon was launched by dynamic method with assistance from launch vehicle in excellent weather conditions on September 25th at 13:55 utc.

The release from the pin, the collar separation, and the initial ascent through the tropopause, were normal. At approximately 83,000 feet, the balloon developed an anomalous rate of ascent due to unknown causes, reaching a maxiumum altitude of approximately 92,000 feet. The following shallow rate of descent could not be arrested by dropping ballast, and
the flight was terminated using standard proceedures at the first safe opportunity.

The separation ocurred at 19:40 UTC and the impact was at 20:19 UTC in coordinates 34º 21' N / 103º 36' W (31.5 nautic miles east southeast of Fort Sumner, New Mexico). The ground recovery crew found that the payload landed upright, and was in excellent condition. Nevertheless, a more carefull examination showed some damage in the telescope, so the re-launch of the telescope the same year was cancelled.

No scientific data was obtained due to the balloon failure. Also due to the damage sustained by the telescope at landing it was returned to Huntsville, Alabama for repairings.

External references and bibliographical sources

Images of the mission

View of the balloon from the gondola. In this flight CosmoCam was used to examine in detail the failed balloon Image of the moment of the separation. The flower like pattern bellow the balloon is the opening parachute Ground view and part of the HERO telescope View of the HERO structure View of the upper part of the HERO structure