National Aeronautics and Space Administration

AGILE

The Astro-rivelatore Gamma a Immagini Leggero (AGILE) is a gamma-ray astronomy mission operated by ASI (Italian Space Agency). It was launched on April 23, 2007 from Satish Dhawan Space Centre in India. The original plan called for a three year mission, but the satellite operated for 17 years and ceased the scientific observations on Jan 18, 2024. It was launched into a near-equatorial orbit, giving it a good observational vantage on terrestrial gamma-ray flashes from thunderstorms and intense atmospheric electrical activity, in addition to its astrophysics observations.

Mission Characteristics

Lifetime

Energy Range

Special Features

Payload

• SuperAGILE, a coded mask imager hard X-ray detector with silicon microstrip detectors, sensitive to 15–45 keV with a wide field of view and 6 arcminute one dimensional resolution: microstrips mounted perpendicularly provide two-dimensional source placement. Because celestial gamma-ray sources frequently have small photon counts and considerable angular confusion, a co-observing hard X-ray detector such as SuperAGILE is often vital to source identification.
• The Gamma-Ray Imaging Detector (GRID) which contains a silicon-tungten tracker, anticoincidence system, and a cesium iodide calorimeter (see below). The tracker consists of a set of two-layer silicon microstrip detectors, interleaved with tungsten foil: gamma rays strike the tungsten, converting into electron/positron pairs which are followed by the microstrips to reconstruct the incident gamma ray’s direction. It is sensitive to 30 MeV–50 GeV.
• The MiniCalorimeter, which is part of the GRID instrument, but can operate independently as need. It contains perpendicular pairs of CsI scintillating bars and operates in the energy range 350 keV–100 MeV.