Space Technology

SHAR Centre is located about 100 km north of Chennai. It is the main launch centre of Indian Space Research Organisation (ISRO).
SHAR operates launch ranges at Balasore in Orissa and Thumba in Kerala besides the one at Shriharikota for launching various satellites.

The 'space race' was a long lasting competition between the United States and the then Soviet Union between 1957 and 1975. It began with the delivery of the first artificial satellite, Sputnik, into orbit in October 1957.
The competition was intimately connected to military superiority as well as general technological superiority.

Some of the foreign successful Commercial Satellites launched through ISRO's Polar Satellite Launch Vehicle (PSLV) are:
Kitsat (Korea)
Tubsat (DLR - Germany)
BIRD (DLR - Germany)
PROBA (Verhaert, Belgium)

Statement 1 is correct: ISRO Telemetry, Tracking and Command Network (ISTRAC) has the prime responsibility of providing mission support to near-earth satellites and launch vehicle mission. For this purpose, an integrated network of ground stations at Bangalore, Lucknow, Port Blair, Shriharikota, Thiruvanathapuram and Mauritius has been established by ISTRAC with a multi-mission Spacecraft Control Centre at Bengalore.
Statement 2 is also correct: INSAT Master Control Facility (MCF), located at Hassan in Karnataka, is responsible for all the post-launch operations of INSAT satellites including orbit maneuvers, station keeping and on-orbit operation of the spacecraft.

India's Satellite Launch Vehicle Programme was conceived to develop four generations of launch vehicles.

1. Satellite Launch Vehicle (SLV)
2. Augmented Satellite Launch Vehicle (ASLV)
3. Polar Satellite Launch Vehicle (PSLV)
4. Geostationary Satellite Launch Vehicle (GSLV)
   SLV was the first experimental satellite launch vehicle of India. It was launched in 1980.
   The PSLV project was initiated in the year 1982.
   PSLV has four stages using solid and liquid propulsion systems alternatively.

The majority of all satellites as well as Space Shuttles and International Space Stations, operate from Low Earth Orbit. But, when it comes specifically to remote sensing satellites, most of these satellites are deployed in Sun-synchronous Polar Orbit. It is called polar orbit because it passes over both the polar regions of the earth in the north-south direction. It is called Sun-synchronous because the orbit also keeps step with the sun in that it passes over a specific location on the sun-lit side of the earth when sun is at the same height above the eastern horizon. This helps in image interpretation because with the same sun-angle, the shadows cast by different features are then only a function of their heights.

Statement 1 is true: Launching heavy satellites weighing over 2 tons into geostationary orbit requires an upper stage powered by a cryogenic engine. Cryogenic engine is indispensable for such launch vehicles as this engine provides the required trust to the vehicle.
Statement 2 is also correct: Cryogenic technology involves the use of liquid oxygen (as oxidizer) at minus 183 degrees Celsius and liquid hydrogen (as fuel) at minus 253 degrees Celsius.

The K_u band is a portion of electromagnetic spectrum in the microwave range of frequencies. This symbol refers to the band directly below the K-band. In radar applications, K_u band ranges from 12-18 GHz. K_u band is primarily used for business communication in major cities. The first K_u band was used in INSAT-2C.
The S band is part of the microwave band of electromagnetic spectrum. S-band ranges from 2 to 4 GHz. The S band is used by weather radar, surface ship radar, and some communications satellites, especially those used by NASA to communicate with the Space Shuttle and the International Space Station. S band is used for broadcast satellite service.

GEO is the orbit at an altitude of about 36000 kms. It lies in the plane of earth's equator and its rotational period id equal to that of the earth. GEO is the most common orbit for launching communication satellites.
Despite of many advantages, one of the disadvantages of the geostationary satellites is that due to their distance from the earth these satellites have a signal delay of around 0.24 seconds for complete send and receive path. This can create problem in telephony and data transmission.

The Outer Space Treaty, formally the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, is a treaty that forms the basis of international space law. The treaty was opened for signature in the United States, the United Kingdom, and the Soviet Union on January 27, 1967, and entered into force on October 10, 1967. 
The treaty bars States Parties to the Treaty from placing nuclear weapons or any other weapons of mass destruction in orbit of Earth, installing them on the Moon or any other celestial body, or to otherwise station them in outer space. It exclusively limits the use of the Moon and other celestial bodies to peaceful purposes and expressly prohibits their use for testing weapons of any kind, conducting military maneuvers, or establishing military bases, installations, and fortifications.

1. Global Positioning System (GPS)                                                             -           USA
2. Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS)                 -           Russia
3. GALILEO                                                                                                -           Europe
4. GPS-Aided Geo Augmented Navigation (GAGAN)                                       -           India

It should be kept in mind that remote sensing is applicable to areas on the land surface of the earth and areas on and below the surface of the oceans. But it is not applicable to areas under the land surface of the earth. It is applicable for ‘ground water prospect mapping’ but not for ‘underground water mapping’.

India's first satellite, Aryabhatta, was launched in 1975.
Bhaskara, India's first experimental earth observing satellite, was launched in 1979.
Rohini was launched in 1980.
APPLE (Ariane Passenger Payload Experiment), that was launched in 1981, was the first step towards the building of communication satellites.

Multi-spectral imaging means simultaneous imaging of the earth's surface in more than one wavelength, both visible and invisible, to bring out a lot of latent information which is not available in ordinary photographs. Multi-spectral cameras used in remote sensing usually take four to six photographs at the same time of the same area using different filters. The use of filters helps in identification of different rocks, soils, vegetations, water and other features of the earth's surface, which is not possible otherwise.

Statement 1 is wrong: India's first indigenously built satellite was INSAT-2A; not INSAT-1A.
Statement 2 is correct. INSAT-2 series consisted of five satellites, one of which failed.
Statement 3 is also incorrect. India is one of seven countries that have the capability (in 2012) to launch satellites. China, Israel, Iran, Japan, India, Russia and USA are these countries.