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.
Details of the balloon flight and scientific outcome
Launch site: Scientific Flight Balloon Facility, New Mexico, 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. - SF3-39.57-.8/.8/.8-NA
Balloon serial number: W39.57-2-23
Flight identification number: 497N
The balloon was launched by dynamic method assisted by launch vehicle on May 23, 2001.
The balloon flight spent 17 hr at a float altitude of 39 km during the day and 37 km at night.
During this flight -a test one-, the hard X-ray telescopes were pointed at the Crab Nebula, Cyg X-1, and GRS 1915+105, where they captured the First high-energy focused images of cosmic sources. This test flight confirmed the stability of the optical bench and the ability of the attitude control system to hold X-ray targets with suficient stability for extended periods of time.
External references and bibliographical sources
- HERO web site Marshall Space Flight Center, NASA
- Balloon Flight 2001 of the HERO Engineering Test Payload NASA information
- First Images from HERO, a Hard X-Ray Focusing Telescope The Astrophysical Journal, 568:432-435, 2002 March 20
- HERO : High-Energy Replicated Optics for a Hard-X-Ray Balloon Payload Proc. SPIE Vol. 4138, p. 147-153, X-Ray Optics, Instruments, and Missions IV
- HERO will provide new view of X-ray universe Science NASA
- The Development of Hard-X-Ray Optics at MSFC Proc. SPIE Vol. 4851, p. 631-638, X-Ray and Gamma-Ray Telescopes and Instruments for Astronomy
- The HERO Program, high-energy replicated optics for a hard-x-ray balloon payload Proc. SPIE Vol. 3765, p. 816-821, EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy X
- Where no Telescope Has Gone Before Science NASA