Array of Low Energy X-ray Imaging Sensors

Array of Low Energy X -ray Imaging Sensors ( ALEXIS ) is a space telescope on a small satellite for observations in the soft X-rays and extreme ultraviolet.

ALEXIS was funded by the U.S. Department of Energy as a demonstration of the feasibility cost-effective X-ray satellites for monitoring of nuclear tests. The development in collaboration of Los Alamos National Laboratory, Sandia National Laboratories, the Space Science Laboratory of the University of California, Berkeley and Aero Astro Inc. was completed in just three years.

Construction

ALEXIS weighs 115 lbs and is without antenna only about 1 m tall. The satellite has six small telescopes with 33 ° field of view, each of an area observed in pairs in the sky in the soft X-rays and extreme ultraviolet light, as well as an experiment for monitoring radio emissions from the Earth. Unlike many telescopes for hard X-rays, which use the reflection of X-rays at grazing incidence (see Wolter telescope), the levels of ALEXIS as the mirror of an optical telescope are formed. Your reflectivity they receive a multi-layer coating. The different telescopes are built for reflection in narrow energy bands at energies 66-93 eV, these are designed in part to highly ionized iron emission lines.

Mission History

ALEXIS was taken on April 25, 1993 an airborne Pegasus rocket in the Point Arguello Western Air Drop zone off the California coast into orbit. The carrier aircraft, a B -52 took off from Edwards Air Force Base from. After starting problems with the position control after failure of a solar cell panels had to be resolved. After three months, the contact could be made. After 12 years in orbit Solar cells and power of ALEXIS were only partially functional, so that the satellite was taken on 29 April 2005 out of service.

ALEXIS by eyeing the diffuse soft X- rays and certain sources, and examined variable stars.