The AstroSat mission is the first dedicated Indian astronomy mission. It is equipped with instruments to observe over a wide span of the electromagnetic spectrum, including visual, near and far ultraviolet, and X-ray wavelengths. The satellite was launched on September 28, 2015 from the Satish Dhawan Space Centre, in Sriharikota, India. AstroSat was placed in a 650 km altitude orbit with a 6 degree equatorial inclination. First light occurred in early October, 2015. The initial mission plan calls for a five year duration, but the satellite continues to provide useful data.
Mission Characteristics
Lifetime
Oct 2015–present
Special Features
Simultaneous multi-wavelength monitoring of intensity variations for a broad range of cosmic sources
Payload
Ultraviolet Imaging Telescope (UVIT)
Wavelength
350–600 nm (near UV and optical), 130–300 nm (far UV)
Pair of twin telescopes
Large Area Xenon Proportional Counter (LAXPC)
Energy Range
3–100 keV
Effective Area
8000 cm2
A trio of proportional counters for detecting hard X-rays
Soft X-ray Telescope (SXT)
Energy Range
0.3–10 keV
Effective Area
120 cm2 at 1 keV
SXT has a set of conical foil mirrors and a CCD detector which is thermal-electrically cooled to -80°C
Cadmium-Zinc-Telluride Imager (CZTI)
Energy Range
20–200 keV
Effective Area
490 cm2 below 100 keV
Field of View
4.6°
Energy Resolution
11% at 60 keV
Time Resolution
20 µs
The top of the instrument is covered by a tantalum plate with a coded aperture mask, allowing image reconstruction from the shading pattern. The detector has four quadrants with 16 detectors in each quadrant, with each detector having 256 pixels with a cross-section of 2.5 mm × 2.5 mm. The detector elements are made of CdZnTe.
Scanning Sky Monitor (SSM)
Energy Range
2–10 kev
The SSM uses a set of three one-dimensional position-sensitive proportional counters equipped with coded masks. SSM is mounted on a single platform capable of being rotated to provide different orientations.
Charge Particle Monitor (CPM)
Detects high energy particles, putting instruments in a temporary safe hold in event of extreme radiation. Although AstroSat’s low inclination orbit avoids the most intense areas of the South Atlantic Anomaly, the satellite does encounter the SAA: CPM monitors to ramp down high voltage systems to prevent instrument damage.
Science Highlights
Monitor the X-ray sky for new transient sources
Perform sky surveys in hard X-ray and UV wavelengths
Collect broad-band spectroscopic data on X-ray binaries, active galactic nuclei, supernova remnants, galaxy clusters, and stellar coronae.
The AstroSat mission is the first dedicated Indian astronomy mission. It is equipped with instruments to observe over a wide span of the electromagnetic spectrum, including visual, near and far ultraviolet, and X-ray wavelengths. The satellite was launched on September 28, 2015 from the Satish Dhawan Space Centre, in Sriharikota, India. AstroSat was placed in a 650 km altitude orbit with a 6 degree equatorial inclination. First light occurred in early October, 2015. The initial mission plan calls for a five year duration, but the satellite continues to provide useful data.