HETE 1

USA

International Sat. n°:

USA satellite n°:

High-Energy Transient Experiment

Launch data:

Designation:	n/a / 96061A Failed to separate with SAC B
Launch date	04 Nov 1996
Launch site	WI, L-1011, RW04/22
Launch vehicle:	Pegasus-XL (#14)
Mission:	Scientific
Earth orbit:
Perigee / Apogee	km
Eccentricity
Inclination	deg
Period	min

The prime objective of HETE is to carry out the first multiwavelength study of gamma-ray bursts with UV, X-ray, and gamma-ray instruments mounted on a single, compact spacecraft. A unique feature of the HETE mission is its capability to localize GRBs with ~10 arc second accuracy, in near real time aboard the spacecraft, and to transmit these positions directly to a network of receivers at existing ground-based observatories, enabling rapid, sensitive follow-up studies in the radio, IR, and optical bands.

HETE was carried inside the Dual Payload Attach Fixture on which SAC B was mounted, so it was trapped and was unable to deploy its solar panels.

Mission details:

The first HETE was lost during the launch on Nov.4, 1996. The Pegasus rocket achieved a good orbit, but explosive bolts releasing HETE from another satellite (Argentina's SAC-B) and from its DPAF envelope failed to charge, dooming both satellites. A battery on the third stage of the rocket and responsible for these bolts cracked during the ascent.

Equipment:

Omnidirectional Gamma-Ray Spectrometer

Build by	CESR (France)
Instrument type	NaI(Tl); cleaved
Energy range	6 keV to > 1 MeV
Timing resolution	4 ms
Spectral resolution	~40% @ 6 keV; ~7% @ 1 MeV
Effective area	120 cm**2 (total for 4 units)
Sensitivity (10 sigma)	3 x 10-8 erg/cm2/s for 8-1000 keV
FOV	~ 2 pi sr
Angular resolution	~ 1 sr

Wide Field X-ray Monitor

Build by	RIKEN (Japan) and LANL (USA)
Instrument type	2 1-dim Coded aperture cameras, with PSPCs
Energy range	2 to 25 keV
Timing resolution	1 ms
Spectral resolution	~18% @ 6 keV
Effective area	200 cm**2 (each of 2 units)
Sensitivity (10 sigma)	8 x 10-9 erg/cm2/s for 2-10 keV
FOV	~ 2 sr (combined)
Angular resolution (1 sigma)	about 10 arcmin (location accuracy better than that)

Ultraviolet Transient Camera Array

Build by	MIT (USA)
Instrument type	4 UV CCD Detectors with 35 mm f/2 optics
Energy range	5 to 7 eV
Timing resolution	~ 4 s
Spectral resolution	n/a (Broadband imaging photometer)
Effective area	2.5 cm**2 (each of 4 units)
Sensitivity (10 sigma)	1 x 10-9 erg/cm2/s
FOV	~ 1.7 sr (total for 4 units)
Angular resolution (1 sigma)	+/- 3 arcsec

The spacecraft hardware and software is being developed by Aeroastro (USA).

Downlink frequencies: 137.963 (300 bps) & 2272 MHz

Ref: #15, #98 - update: 16.08.11