Array of Low Energy X-ray Imaging Sensors

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ALEXIS
ALEXIS
Type: Space telescope
Country: United StatesUnited States United States
Operator: DoE
COSPAR-ID : 1993-026A
Mission dates
Dimensions: 115 kg
Begin: April 25, 1993, 13:56 UTC
Starting place: Point Arguello WADZ
Launcher: Pegasus 004 / F4 , dropped
from B-52
Status: out of service since April 29, 2005
Orbit data
Rotation time : 99.7 min
Orbit inclination : 69.8 °
Apogee height :  746 km
Perigee height :  741 km

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

ALEXIS was funded by the US Department of Energy as a demonstration of the feasibility of inexpensive X-ray satellites for monitoring nuclear tests. The collaboration between Los Alamos National Laboratory , Sandia National Laboratories , the Space Science Laboratory of the University of California, Berkeley and AeroAstro Inc. was completed in just three years.

construction

ALEXIS weighs 115 kg and is only about 1 m tall without antenna. The satellite has six small telescopes, each with a 33 ° field of view, which in pairs observed an area in the sky in soft X-ray light or extreme ultraviolet light, as well as an experiment to monitor radio emissions from Earth. In contrast to many telescopes for harder X-rays, which use the reflection of X-rays at grazing incidence (see Wolter telescope ), the mirrors of ALEXIS are shaped like the mirrors of an optical telescope. They get their reflectivity from a multilayer coating. The various telescopes are built for reflection in narrow energy bands at energies of 66 to 93  eV , some of which are matched to emission lines of highly ionized iron.

Mission history

ALEXIS was launched into orbit on April 25, 1993 by an airborne Pegasus rocket in the Point Arguello Western Air Drop Zone off the coast of California. The carrier aircraft of type B-52 was from the Edwards Air Force Base launched from. After the start, problems with the position control had to be resolved after a solar panel failed. Contact could only be established after three months. After 12 years in orbit, the solar cells and power supply of ALEXIS were only partially functional, so that the satellite was taken out of service on April 29, 2005.

ALEXIS scanned the diffuse soft X-rays and individual sources, and examined variable stars.

Individual evidence

  1. ↑ Alexis in the NSSDCA Master Catalog , accessed on September 14, 2012 (English).
  2. ^ ALEXIS Project. NASA October 2, 2007, archived from the original on August 25, 2009 ; accessed on September 14, 2012 (English).

Web links