Indian Space Research Organisation - Planetary Sciences and Astronomy

Planetary Sciences and Astronomy

India's space era dawned when the first two-stage sounding rocket was launched from Thumba in 1963. Even before this, noteworthy contributions were made by the Indian scientists in the following areas of space science research:

• Cosmic rays and high energy astronomy using both ground based as well as balloon borne experiments/studies such as neutron/meson monitors, Geiger Muller particle detectors/counters etc.
• Ionospheric research using ground based radio propagation techniques such as ionosonde, VLF/HF/VHF radio probing, a chain of magnetometer stations etc.
• Upper atmospheric research using ground based optical techniques such as Dobson spectrometers for measurement of total ozone content, air glow photometers etc.
• Indian astronomers have been carrying out major investigations using a number of ground based optical and radio telescopes with varying sophistication.

With the advent of the Indian space program, emphasis was laid on indigenous, self-reliant and state-of-the-art development of technology for immediate practical applications in the fields of space science research activities in the country.

There is a national balloon launching facility at Hyderabad jointly supported by TIFR and ISRO. This facility has been extensively used for carrying out research in high energy (i.e., X- and gamma ray) astronomy, IR astronomy, middle atmospheric trace constituents including CFCs & aerosols, ionisation, electric conductivity and electric fields.

The flux of secondary particles and X-ray and gamma-rays of atmospheric origin produced by the interaction of the cosmic rays is very low. This low background, in the presence of which one has to detect the feeble signal from cosmic sources is a major advantage in conducting hard X-ray observations from India. The second advantage is that many bright sources like Cyg X-1, Crab Nebula, Scorpius X-1 and Galactic Centre sources are observable from Hyderabad due to their favourable declination. With these considerations, an X-ray astronomy group was formed at TIFR in 1967 and development of an instrument with an orientable X-ray telescope for hard X-ray observations was undertaken. The first balloon flight with the new instrument was made on 28 April 1968 in which observations of Scorpius X-1 were successfully carried out. In a succession of balloon flights made with this instrument between 1968 and 1974 a number of binary X-ray sources including Scorpius X-1, Cyg X-1, Her X-1 etc. and the diffuse cosmic X-ray background were studied. Many new and astrophysically important results were obtained from these observations.

One of most important achievements of ISRO in this field was the discovery of three species of bacteria in the upper stratosphere at an altitude of between 20–40 km. The bacteria, highly resistant to ultra-violet radiation, are not found elsewhere on Earth, leading to speculation on whether they are extraterrestrial in origin. These three bacteria can be considered to be extremophiles. Until then, the upper stratosphere was believed to be inhospitable because of the high doses of ultra-violet radiation. The bacteria were named as Bacillus isronensis in recognition of ISRO's contribution in the balloon experiments, which led to its discovery, Bacillus aryabhata after India's celebrated ancient astronomer Aryabhata and Janibacter Hoylei after the distinguished astrophysicist Fred Hoyle.