HERO was an X-Ray telescope and the first one aimed to obtain focused images of astronomical X-ray sources at hard X-ray energies (20-75 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. The total payload dimensions are 25 feet long, 6.5 ft wide and 16 ft high.
Balloon launched on: 9/19/2000 at 13:55 utc
Launch site: Scientific Flight Balloon Facility, Fort Sumner, (NM), US
Balloon launched by: National Scientific Balloon Facility (NSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon Raven - 39.570.000 cu ft - 0.8 Mil. - SF3-459.37-080-NSXHR-ST
Balloon serial number: W39.57-2-18
Flight identification number: 489N
End of flight (L for landing time, W for last contact, otherwise termination time): 9/20/2000 at 20:35 utc
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 30 h 40 m
Landing site: 10 miles E of Naturita, Colorado, US
The balloon was launched using the dynamic method with assistance of the Big Bill launch vehicle at 13:55 utc on September 19, 2000. After a nominal climb the balloon reached flaot altitude of 126.000 ft about 17:00 utc.
After more than 30 hours aloft the mission was terminated on September 19, 2000. The payload landed 10 miles E of Naturita, Colorado.
This was the first engineering flight of a basic version of the instrument consisting of a small 3-m-focal-length optical system consisting of a pair of mirror modules, each containing three nested nickel mirrors and as focal plane detectors, a pair of gas scintillation proportional counters.
On this mission were observed the Cygnus X-1 region and the Crab Nebula region.