Astrosat


Astrosat is India's first dedicated multi-wavelength space telescope. It was launched on a PSLV-XL on 28 September 2015. With the success of this satellite, ISRO has proposed launching AstroSat-2 as a successor for Astrosat.

Overview

After the success of the satellite-borne Indian X-ray Astronomy Experiment, which was launched in 1996, the Indian Space Research Organization approved further development for a full-fledged astronomy satellite, Astrosat, in 2004.
A number of astronomy research institutions in India, and abroad have jointly built instruments for the satellite. Important areas requiring coverage include studies of astrophysical objects ranging from nearby solar system objects to distant stars and objects at cosmological distances; timing studies of variables ranging from pulsations of hot white dwarfs to those of active galactic nuclei can be conducted with Astrosat as well, with time scales ranging from milliseconds to days.
Astrosat is a multi-wavelength astronomy mission on an IRS-class satellite into a near-Earth, equatorial orbit. The five instruments on board cover the visible, near UV, far UV, soft X-ray and hard X-ray regions of the electromagnetic spectrum.
Astrosat was successfully launched on 28 September 2015 from the Satish Dhawan Space Centre on board a PSLV-XL vehicle at 10:00AM.

Mission

Astrosat is a proposal-driven general purpose observatory, with main scientific focus on:
Astrosat performs multi-wavelength observations covering spectral bands from radio, optical, IR, UV, and X-ray wavelengths. Both individual studies of specific sources of interest and surveys are undertaken. While radio, optical, and IR observations would be coordinated through ground-based telescopes, the high energy regions, i.e., UV, X-ray and visible wavelength, would be covered by the dedicated satellite-borne instrumentation of Astrosat.
The mission would also study near simultaneous multi-wavelength data from different variable sources. In a binary system, for example, regions near the compact object emit predominantly in the X-ray, with the accretion disc emitting most of its light in the UV/optical waveband, whereas the mass of the donating star is brightest in the optical band.
The observatory will also carry out:
In particular, the mission will train its instruments at active galactic nuclei, which are believed to contain super-massive black holes.

Payloads

The scientific payload contains six instruments.
The Ground Command and Control Center for Astrosat is the ISRO Telemetry, Tracking and Command Network at Bangalore, India. Command and control of the spacecraft, and scientific data downloads is possible during every visible pass over Bangalore. 10 out of 14 orbits per day are visible to the ground station. The satellite is capable of gathering 420 gigabits of data every day that can be downloaded during the 10 visible orbits by the Tracking and Data receiving center of ISRO in Bangalore. A third 11-meter antenna at the Indian Deep Space Network became operational in July 2009 to track Astrosat.

AstroSat Support Cell

ISRO has set up a support cell for AstroSat at IUCAA, Pune. A MoU was signed between ISRO and IUCAA in May 2016. The support cell has been set up to give opportunity to the scientific community in making proposals on processing and usage of AstroSat data. The support cell will provide necessary resource materials, tools, training and help to the guest observers.

Participants

The Astrosat project is a collaborative effort of many different research institutions. The participants are:
Two of the instruments were harder to complete than expected. "The satellite’s soft x-ray telescope proved to be a huge challenge that took 11 years..."

Results

A gamma-ray burst was detected by Astrosat on 5 January 2017. There was a confusion whether this event was related to the gravitational wave signal detected by LIGO from the black hole merger event GW170104 on 4 January 2017. Astrosat helped in distinguishing between the two events. The gamma-ray burst from 4 January 2017 was identified as a distinct supernova explosion that would form a black hole.
Astrosat also captured the rare phenomenon of a 6 billion year old small star or blue straggler feeding off and sucking out the mass and energy of a bigger companion star.
On 31 May 2017, Astrosat, Chandra X-ray Observatory and Hubble Space Telescope simultaneously detected a coronal explosion on the nearest planet-hosting star Proxima Centauri
On 6 November 2017 Nature Astronomy published a paper from Indian astronomers measuring the variations of X-ray polarisation of the Crab Pulsar in the Taurus constellation. This study was a project conducted by scientists from Tata Institute of Fundamental Research, Mumbai; the Vikram Sarabhai Space Centre, Thiruvananthapuram; ISRO Satellite Centre Bengaluru; the Inter-University Centre for Astronomy and Astrophysics, Pune; and the Physical Research Laboratory, Ahmedabad.
In July 2018, Astrosat has captured an image of a special galaxy cluster that is more than 800 million light years away from earth. Named abell 2256 the galaxy cluster is made of three separate cluster of galaxy that are all merging with one another to eventually form a single massive cluster in the future. The three massive cluster contain more than 500 galaxies and the cluster is almost 100 times larger and more than 1500 times massive as our own galaxy.
On 26 September 2018, the archival data of AstroSat was publicly released. As of 28 September 2018, data from AstroSat has been cited in around 100 publications in refereed journals. This figure is expected to rise after the public release of data from AstroSat.

In popular culture

In 2019 a documentary titled Indian Space Dreams on developmental journey of Astrosat was released.