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The ASCA mission

The ASCA satellite
The Advanced Satellite for Cosmology and Astrophysics (ASCA; renamed from Astro D when launched) is Japan's fourth cosmic X-ray astronomy mission, and the second for which the United States is providing part of the scientific payload. The satellite was successfully launched February 20, 1993. The first eight months of the ASCA mission were devoted to performance verification. Having established the quality of performance of all the instruments, ASCA changed to a "guest observer" satellite for the remainder of the mission. In this phase, the observing program is open to astronomers based at Japanese and US institutions, as well as those who are located in member states of the European Space Agency.

Schematic diagram of ASCA


The ASCA Solid-state Imaging Spectrometer
ASCA carries four large-area X-ray telescopes ( At the focus of two of the telescopes is a Gas Imaging Spectrometer (GIS) (, while a Solid-state Imaging Spectrometer (SIS) ( is at the focus of the other two. The GIS is a gas imaging scintillation proportional counter and is based on the GSPC that flew on the second Japanese X-ray astronomy mission, Tenma. The two SIS instruments are identical Charge Coupled Device (CCD) cameras and were provided by a hardware team from MIT, Osaka University, and ISAS.

Energy Range 0.3 to 10 keV 0.7 to 1.2 keV
Spectral Resolution 2 8
ALIGN="left">Spatial Resolution 2.9 arcminutes 2.9 arcminutes
Time Resolution 1 - 10 seconds 61 microseconds
Fields of View 22 x 22 arcminutes 30 arcminute diameter
Detector Length 303 mm 580 mm
Detector Diameter 165 mm 150 mm

X-ray detectors on board ASCA

Imagine the Universe is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

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Acting Project Leader: Dr. Barbara Mattson
All material on this site has been created and updated between 1997-2012.

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