HETE 2 will detect gamma ray bursts and other cosmic phenomena during its 4 year science mission. The High Energy Transient Explorer (HETE) spacecraft was launched into 590 by 650 km (319 by 353 nmi) orbit, inclined at 1.95 degrees. The Pegasus launch cost US$15 million, with the satellite costing US$8.4 million.  

The 124 kg (273 lbm) satellite was built by Massachusetts Institute of Technology for NASA. Other partners include the Los Alamos National Laboratory, France's Centre National d'Etudes Spatiales (CNES) and Centre d'Etude Spatiale des Rayonnements (CESR) and Japan's Institute of Physical and Chemical Research (RIKEN). The science team includes members from the University of California (Berkley and Santa Cruz) and the University of Chicago. HETE 2 replaces the original HETE, which was lost in a launch failure in November, 1996.

The HETE 2 satellite is comprised of three main instruments and a computer network that transmits data to other observatories. The instruments will provide multiwavelength coverage of high-energy transient events and can work independently or with each other.

The French Gamma Telescope (FREGATE) was built by CESR to detect gamma ray bursts and very bright (higher energy) X-ray transients. The instrument's primary objective is to provide spectroscopy for these highly energetic events. FREGATE was derived from the successful Lilas gamma ray burst experiment flown on the Russian Phobos mission.

The Wide-Field X-ray Monitor (WXM) was built by RIKEN and Los Alamos National Laboratory to detect light slightly lower in energy than the FREGATE does. The WXM therefore will detect fewer gamma ray bursts than FREGATE, but because of its increased resolution, will be able to locate the FREGATE-detected bursts to within 10 arc minute.

The Soft X-ray Camera (SXC) was built by MIT to replace the ultraviolet cameras on the original HETE. As with the WXM, the SXC's strength lies in localizing bursts quickly -- to within several arc seconds. The SXC covers the lowest energy band of the three instruments and is ideal for detecting lower-energy X-ray transients, such as neutron stars.