The HETE-II is a cooperative mission between NASA and a consortium of institutions: MIT CSR (PI Institution), RIKEN (Japan), Los Alamos National Laboratory, CESR (France), CNR-TESRE (Italy), UC-Berkeley, University of Chicago, UC-Santa Cruz, and Supaero.

HETE's prime objective is to carry out a multiwavelength study of Gamma Ray Bursts (GRBs) with UV, X-Ray, and gamma ray instruments. A unique feature of the mission will be its capability to localize bursts with several arcsecond accuracy, in near real-time aboard the spacecraft. These positions are transmitted to the ground, and picked up by a global network of primary and secondary ground stations, enabling sensitive follow-up studies.

Salient Features:

Project Start: 2nd quarter 1997
Spacecraft Weight: 150 kg
Planned Lifetime: 6 months, nothing to preclude 2+ years
Orbit: 600-km x 650-km, < 5 degrees inclination
Launch: 1/23/00, from Kwajalein Missile Range

Program Overview:

The original HETE was lost due to a Pegasus launch failure on November 4, 1996, but the scientific importance and continuing relevance of the mission provided the impetus for NASA, CESR, CNES, and RIKEN to fund a replacement satellite (HETE-2) scheduled for launch in early 2000. The Study of GRBs has taken on an even greater scientific significance since the demise of HETE-1 because of the recent discovery of their cosmological origin that demonstrates GRBs to be the most powerful explosions in the universe since it's creation in the Big Bang. HETE-2 will retain nearly all of the original HETE design elements. A new feature of the spacecraft is the Soft x-ray Cameras, which takes the place of the UV cameras.

The three instruments on HETE-2 are:

1) The French Gamma Telescope (FREGATE) supplied by the CESR is derived from the design of the successful Gamma Ray Burst experiment Lilas aboard the Russian Phobos mission. Its prime objectives are the detection and spectroscopy of gamma-ray bursts and the monitoring of variable X-Ray source.

2) The Wide-Field X-Ray Monitor (WXM) supplied by the Japanese and Los Alamos consists of two, crossed one dimensional position sensitive detectors with a coded aperture. Since it is unlikely that two transients will occur at the same time, two 1-D coded aperture imaging systems (in the x and y directions) can be used, simplifying the construction and software.

3) The MIT Soft X-Ray Cameras (SXC) are two 1-D coded mask systems using CCID-20's as the detecting elements. The CCD-20's used were fabricated by MIT Lincoln Lab, each consisting of 2048x4096 pixels measuring 15 um square.

Last Updated: 4/21/99