Regional Remote Sensing Centre

ISRO is stands for Indian Space Research Organisation.

The Indian Space Research Organisation (Hindi: भारतीय अन्तरिक्ष अनुसंधान संगठन) is the primary body for space research under the control of the Government of India, and one of the leading space research organizations in the world. It was established in its modern form in 1969 as a result of coordinated efforts initiated earlier. Taking into consideration its budget, it is probably one of the most efficient space organizations on the globe.

The objective of ISRO is to develop space technology and its application to various tasks.

1.1Goals and objectives

The prime objective of ISRO is to develop space technology and its application to various national tasks. The Indian space program was driven by the vision of Dr Vikram Sarabhai, considered the father of Indian Space Programme. As stated by him:

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There are some who question the relevance of space activities in a developing nation. To us, there is no ambiguity of purpose. We do not have the fantasy of competing with the economically advanced nations in the exploration of the moon or the planets or manned space-flight. But we are convinced that if we are to play a meaningful role nationally, and in the community of nations, we must be second to none in the application of advanced technologies to the real problems of man and society.

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As also pointed out by Dr APJ Kalam:

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Many individuals with myopic vision questioned the relevance of space activities in a newly independent nation, which was finding it difficult to feed its population. Their vision was clear if Indians were to play meaningful role in the community of nations, they must be second to none in the application of advanced technologies to their real-life problems. They had no intention of using it as a mean to display our might.

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India's economic progress has made its space program more visible and active as the country aims for greater self-reliance in space technology. Hennock etc. hold that India also connects space exploration to national prestige, further stating: "This year India has launched 11 satellites, including nine from other countries—and it became the first nation to launch 10 satellites on one rocket.”

Some critics maintain that India's spending on space exploration is unjustifiable given the high levels of poverty and lack of basic services throughout parts of the country.

Indian Space programme born in the church beginning, space activities in the country, concentrated on achieving self reliance and developing capability to build and launch communication satellites for television broadcast, telecommunications and meteorological applications; remote sensing satellites for management of natural resources.

ISRO has established two major space systems, INSAT for communication, television broadcasting and meteorological services, and Indian Remote Sensing Satellites (IRS) system for resources monitoring and management. ISRO has developed two satellite launch vehicles, PSLV and GSLV, to place INSAT and IRS satellites in the required orbits.

Indian Space Research Organisation (ISRO) has successfully operationalised two major satellite systems namely Indian National Satellites (INSAT) for communication services and Indian Remote Sensing (IRS) satellites for management of natural resources; also, Polar Satellite Launch Vehicle (PSLV) for launching IRS type of satellites and Geostationary Satellite Launch Vehicle (GSLV) for launching INSAT type of satellites.

1.2 Launch vehicle fleet

Comparison of Indian carrier rockets. Left to right: SLV, ASLV, PSLV, GSLV, GSLV III.

Geopolitical and economic considerations during the 1960s and 1970s compelled India to initiate its own launch vehicle program. During the first phase (1960s-1970s) the country successfully developed a sounding rockets program, and by the 1980s, research had yielded the Satellite Launch Vehicle-3 and the more advanced Augmented Satellite Launch Vehicle (ASLV), complete with operational supporting infrastructure. ISRO further applied its energies to the advancement of launch vehicle technology resulting in the creation of Polar Satellite Launch Vehicle (PSLV) and Geosynchronous Satellite Launch Vehicle (GSLV) technologies.

1.2.1 Satellite Launch Vehicle (SLV)

The Satellite Launch Vehicle, usually known by its abbreviation SLV or SLV-3 was a 4-stage solid-fuel light launcher. It was intended to reach a height of 500 km and carry a payload of 40 kg. Its first launch took place in 1979 with 2 more in each subsequent year, and the final launch in 1983. Only two of its four test flights were successful.

1.2.2 Augmented Satellite Launch Vehicle (ASLV)

The Augmented Satellite Launch Vehicle, usually known by its abbreviation ASLV was a 5-stage solid propellant rocket with the capability of placing a 150 kg satellite into LEO. This project was started by the ISRO during the early 1980s to develop technologies needed for a payload to be placed into a geostationary orbit. Its design was based on Satellite Launch Vehicle. The first launch test was held in 1987, and after that 3 others followed in 1988, 1992 and 1994, out of which only 2 were successful, before it was decommissioned.

1.2.3 Polar Satellite Launch Vehicle (PSLV)

The Polar Satellite Launch Vehicle, usually known by its abbreviation PSLV, is an expendable launch system developed to allow India to launch its Indian Remote Sensing (IRS) satellites into sun synchronous orbits, a service that was, until the advent of the PSLV, commercially viable only from Russia. PSLV can also launch small satellites into geostationary transfer orbit (GTO). The reliability and versatility of the PSLV is proven by the fact that it has launched 30 spacecraft (14 Indian and 16 from other countries) into a variety of orbits so far.In April 2008, it successfully launched 10 satellites at once, breaking a world record held by Russia.

1.2.4 Geosynchronous Satellite Launch Vehicle (GSLV)

The Geosynchronous Satellite Launch Vehicle, usually known by its abbreviation GSLV, is an expendable launch system developed to enable India to launch its INSAT-type satellites into geostationary orbit and to make India less dependent on foreign rockets. At present, it is ISRO's heaviest satellite launch vehicle and is capable of putting a total payload of up to 5 tons to Low Earth Orbit.

1.2.5 Geosynchronous Satellite Launch Vehicle Mark-III (GSLV III)

The Geosynchronous Satellite Launch Vehicle Mark-III is a launch vehicle currently under development by the Indian Space Research Organization. It is intended to launch heavy satellites into geostationary orbit, and will allow India to become less dependent on foreign rockets for heavy lifting. The rocket is the technological successor to the GSLV, however is not derived from its predecessor. The maiden flight is scheduled to take place in 2011.

1.3 Earth observation and communication satellites

India's first satellite, the Aryabhata, was launched by the Soviets in 1975. This was followed by the Rohini series of experimental satellites which were built and launched indigenously. At present, ISRO operates a large number of earth observation satellites.

1.3.1 The INSAT series

INSAT (Indian National Satellite System) is a series of multipurpose geostationary satellites launched by ISRO to satisfy the telecommunications, broadcasting, meteorology and search-and-rescue needs of India. Commissioned in 1983, INSAT is the largest domestic communication system in the Asia-Pacific Region. It is a joint venture of the Department of Space, Department of Telecommunications, India Meteorological Department, All India Radio and Doordarshan. The overall coordination and management of INSAT system rests with the Secretary-level INSAT Coordination Committee.

1.3.2 The IRS series

Indian Remote Sensing satellites (IRS) are a series of earth observation satellites, built, launched and maintained by ISRO. The IRS series provides remote sensing services to the country. The Indian Remote Sensing Satellite system is the largest constellation of remote sensing satellites for civilian use in operation today in the world. All the satellites are placed in polar sun-synchronous orbit and provide data in a variety of spatial, spectral and temporal resolutions to enable several programs to be undertaken relevant to national development.

1.3.3 Oceansat series

Oceansat are a series of satellites to primarily study ocean, part of IRS Series. IRS P4 is also known as Oceansat-1, was launched on 27 May 1999. On 23 September 2009 Oceansat-2 was launched.

Other satellites

ISRO has also launched a set of experimental geostationary satellites known as the GSAT series. Kalpana-1, ISRO's first dedicated meteorological satellite, was launched by the Polar Satellite Launch Vehicle on 12 September 2002. The satellite was originally known as MetSat-1. In February 2003 it was renamed to Kalpana-1 by the then Indian Prime Minister Atal Bihari Vajpayee in memory of Kalpana Chawla – a NASA astronaut of Indian origin who perished in Space Shuttle Columbia.

1.4 Extraterrestrial exploration

India's first mission beyond Earth's orbit was Chandrayaan-1, a lunar spacecraft which successfully entered the lunar orbit on 8 November 2008. ISRO plans to follow up Chandrayaan-1 with Chandrayaan-2 and unmanned missions to Mars and Near-Earth objects such as asteroids and comets.

1.4.1 Lunar exploration

Chandrayaan-1 is India's first mission to the moon. The unmanned lunar exploration mission includes a lunar orbiter and an impactor called the Moon Impact Probe. India launched the spacecraft using a modified version of the PSLV is C11 on 22 October 2008 from Satish Dhawan Space Centre, Sriharikota. The vehicle was successfully inserted into lunar orbit on 8 November 2008. It carries high-resolution remote sensing equipment for visible, near infrared, and soft and hard X-ray frequencies. Over its two-year operational period, it is intended to survey the lunar surface to produce a complete map of its chemical characteristics and 3-dimensional topography. The polar regions are of special interest, as they might contain ice. The lunar mission carries five ISRO payloads and six payloads from other international space agencies including NASA, ESA, and the Bulgarian Aerospace Agency, which were carried free of cost. The Chandrayaan-1 along with NASA's LRO played a major role in discovering the existence of water on the moon.

1.4.2 Planetary exploration

The Indian Space Research Organisation had begun preparations for a mission to Mars and had received seed money of Rs10 crore from the government. The space agency was looking at launch opportunities between 2013 and 2015. The space agency would use its Geosynchronous Satellite Launch Vehicle (GSLV) to put the satellite in orbit and was considering using ion-thrusters, liquid engines or nuclear power to propel it further towards Mars. The Mars mission studies had already been completed and that space scientists were trying to collect scientific proposals and scientific objectives.

1.5 Human spaceflight program

The Indian Space Research Organization has been sanctioned a budget of Rs. 12,400 crore for its human spaceflight program. According to the Space Commission which passed the budget, an unmanned flight will be launched in 2013-2014 and manned mission likely to launch by 2014-2015.If realized in the stated time-frame, India will become only the fourth nation, after the USSR, USA and China, to successfully carry out manned missions indigenously.

1.5.1 Technology demonstration

The Space Capsule Recovery Experiment (SCRE or more commonly SRE or SRE-1) is an experimental Indian spacecraft which was launched using the PSLV C7 rocket, along with three other satellites. It remained in orbit for 12 days before re-entering the Earth's atmosphere and splashing down into the Bay of Bengal.

The SRE-1 was designed to demonstrate the capability to recover an orbiting space capsule, and the technology for performing experiments in the microgravity conditions of an orbiting platform. It was also intended to test thermal protection, navigation, guidance, control, deceleration and flotation systems, as well as study hypersonic aero-thermodynamics, management of communication blackouts, and recovery operations.

1.5.2 Astronaut training and other facilities

ISRO will set up an astronaut training centre in Bangalore by 2012 to prepare personnel for flights onboard the crewed vehicle. The centre will use water simulation to train the selected astronauts in rescue and recovery operations and survival in zero gravity, and will undertake studies of the radiation environment of space.

ISRO will build centrifuges to prepare astronauts for the acceleration phase of the mission. It also plans to build a new launchpad to meet the target of launching a manned space mission by 2015. This would be the third launchpad at the Satish Dhawan Space Centre, Sriharikota.

1.5.3 Development of crew vehicle

The Indian Space Research Organisation (ISRO) is working towards a maiden manned Indian space mission vehicle that can carry three astronauts for seven days in a near earth orbit. The Indian manned spacecraft temporarily named as Orbital Vehicle intend to be the basis of indigenous Indian human spaceflight program.

The capsule will be designed to carry three people, and a planned upgraded version will be equipped with a rendezvous and docking capability. In its maiden manned mission, ISRO's largely autonomous 3-ton capsule will orbit the Earth at 248 miles (400 km) in altitude for up to seven days with a two-person crew on board. The crew vehicle would launch atop of ISRO's GSLV Mk II, currently under development. The GSLV Mk II features an indigenously developed cryogenic upper-stage engine. The first test of cryogenic engine to be held on 15 April 2010 and after this launch India will be the Sixth country to developed such complex cryogenic technology after United States, Russia, China, Japan and Israel but unfortunately this was a failure as cryogenic engine did not work as expected.So the launch has been re-scheduled to 2011.

1.6 Planetary sciences and astronomy

Indian space era dawned when the first two-stage sounding rocket was launched from Thumba in 1963. However even before this epoch making event, 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, ionization, 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 Scorpious 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.

CONCLUSION

Unlike other networks, WSNs are designed for specific applications. Applications include, but are not limited to, environmental monitoring, industrial machine monitoring surveillance systems, and military target tracking. Each application differs in features and requirements. The sensors or nodes are placed at different locations and the environmental parameters of that locations are measured. TinyOS is a very extensive and complex system. It has many applications and tools that need to be studied before one can fully understand the entire system. For the same number of data collecting sensor nodes, the number of control and management nodes can be adjusted according to the network environment. In future work the variation in the head-set size for different network conditions will be investigated. This

work will be extended to incorporate non-uniform cluster distributions.