ASTROSAT

• India launched its first dedicated multi-wavelength space observatory Astrosat into space, besides six satellites for Canada, Indonesia and the United States.
• This is the first time ISRO is launching satellites for the United States.
• Though there have been scientific missions by ISRO in the past, this is the first time a space observatory is being launched into space.
• Though Astrosat may be similar to the NASA’s Hubble Space Telescope, the former is about 10 times smaller and cannot be compared to the Hubble, which is versatile.
• Besides US’ NASA, space agencies of the European Union, Japan and Russia have launched similar facilities into the space.
• Canada’s NLS-14 nano satellite, Indonesia’s LAPAN-A2 microsatellite and four identical LEMUR nano satellites for the U.S. were the other satellites put in orbit.
• With this launch, ISRO has successfully crossed the half century-mark as for foreign satellites. ISRO has launched 51 satellites for foreign satellites so far.

About Astrosat: 

• The 1,513-kg cuboid-shaped satellite would be eventually fine-tuned into 650 km above the Earth’s surface.
• The satellite can perform simultaneous multi-wavelength observations of various astronomical objects.
• The sun and star sensors, besides the gyroscopes, would provide orientation reference to the satellite, which has a mission life of five years.
• Astrosat aims at understanding the high energy processes in binary star systems containing neutron stars and black holes, to estimate magnetic fields of neutron stars, to study star birth regions and high energy processes in star systems lying beyond the Milky Way galaxy.
• The mission also intends to detect new briefly bright X-ray sources in the sky, to perform a limited deep field survey of the universe in the ultraviolet region.

Other Satellites

• Canada’s NLS-14 is a maritime monitoring nano satellite using the Automatic Identification System
• Indonesia’s LAPAN-A2 is aimed at benefiting Indonesian radio amateur communities for disaster mitigation and carrying out Earth surveillance.
• All the four identical LEMUR satellites for the United States — non-visual remote sensing satellites aims to focus on global maritime intelligence through vessel tracking.

The other institutions that participated in Astrosat launch:

Tata Institute of Fundamental Research, Indian Institute of Astrophysics, Inter-University Centre for Astronomy and Astrophysics and Raman Research Institute.

Scientific objectives

1. Understand high energy processes in binary star systems containing neutron stars and black holes,
2. Estimate magnetic fields of neutron stars,
3. Study star birth regions and high energy processes in star systems lying beyond our galaxy,
4. Detect new briefly bright X-ray sources in the sky and (5) perform a limited deep field survey of the Universe in the ultraviolet region.

Payloads

1. The Ultraviolet Imaging Telescope (UVIT, capable of observing the sky in the Visible, Near Ultraviolet and Far Ultraviolet regions of the electromagnetic spectrum.
2. Large Area X-ray Proportional Counter (LAXPC, is designed for study the variations in the emission of X-rays from sources like X-ray binaries, Active Galactic Nuclei and other cosmic sources.
3. Soft X-ray Telescope (SXT) is designed for studying how the X-ray spectrum of 0.3-8 keV range coming from distant celestial bodies varies with time.
4. Cadmium Zinc Telluride Imager (CZTI), functioning in the X-ray region, extends the capability of the satellite to sense X-rays of high energy in 10-100 keV range.
5. Scanning Sky Monitor (SSM) is intended to scan the sky for long term monitoring of bright X-ray sources in binary stars, and for the detection and location of sources that become bright in X-rays for a short duration of time.

Significance: 

The ability to simultaneously study a wide variety of wavelengths — visible light, ultraviolet and X-ray (both low- and high-energy) bands — has tremendous implications for scientists globally, particularly those in India. Though stars and galaxies emit in multiple wavebands, currently operational satellites have instruments that are capable of observing only a narrow range of wavelength band. Since the Earth’s atmosphere does not allow X-rays and ultraviolet energy from distant cosmic objects to reach ground-based telescopes, space observatories become important to unravel celestial mysteries. With Astrosat, Indian researchers will no longer have to rely on other space agencies for X-ray data, and scientists everywhere need no longer source data from more than one satellite to get a fuller picture of celestial processes.

As in the case of Chandrayaan-1 and the Mars Orbiter Mission, Mangalyaan, the Astrosat telescope will have no immediate commercial or societal implications. But the instruments have been carefully chosen to allow scientists to pursue cutting-edge research
it will enable Indian researchers to work in the frontier areas of high-energy astrophysics.

It is for the first time that a majority of the payloads for an Indian satellite has come from outside ISRO. In fact, ISRO has built just one of the five payloads for Astrosat; the rest comes from scientific institutions based in India (Tata Institute of Fundamental Research, The Inter-University Centre for Astronomy and Astrophysics in Pune, and the Indian Institute of Astrophysics in Bengaluru). This is in recognition of their contribution to the mission. Besides providing an opportunity to build world-class instruments, Astrosat will present an ideal platform for researchers in these institutions