X-band (8–12 GHz) Primarily used by the military. Used in radar applications including continuous-wave, pulsed, single-polarisation, dual- polarisation, synthetic aperture radar, and phased arrays. X-band radar frequency sub-bands are used in civil, military and government institutions for weather monitoring, air traffic control, maritime vessel traffic control, defense tracking, and vehicle speed detection for law enforcement.
Ku-band (12–18 GHz) Used for satellite communications. In Europe, the Ku-band downlink is used from 10.7 GHz to 12.75 GHz for direct broadcast satellite services, such as Astra.
Ka-band (26–40 GHz) Communications satellites for close up high resolutions applications, uplink in either the 27.5 GHz and 31 GHz bands, close-range targeting radars on military aircraft.
India has recently launched its GSAT-6 from Sriharikota in S-Band to enable multimedia applications for solely strategic military purposes and societal uses in case of emergencies.
Important Missions of ISRO – UPSC
ISRO – Indian Space Research Organisation
ISRO is the space agency under the Department of Space of Government of India, headquartered in the city of Bengaluru, Karnataka.
Its vision is to harness space technology for national development while pursuing space science research and planetary exploration.
Antrix Corporation Limited (ACL) is a Marketing arm of ISRO for the promotion and commercial exploitation of space products, technical consultancy services, and transfer of technologies developed by ISRO.
Genesis
The space research activities were initiated in India under Dr. Vikram Sarabhai, the founding father of the Indian space program, during the 1960s.
Since its inception, the Indian space program had three distinct elements such as satellites for communication and remote sensing, the space transportation system, and application programs.
The INCOSPAR (Indian National Committee for Space Research) was initiated under the leadership of Dr. Sarabhai and Dr. Ramanathan.
During 1975-76, Satellite Instructional Television Experiment (SITE) was conducted. It was hailed as ‘the largest sociological experiment in the world’. It was followed by the ‘Kheda Communications Project (KCP)’, which worked as a field laboratory for need-based and locale-specific program transmission in the state of Gujarat State.
During this period, the first Indian spacecraft ‘Aryabhata’ was developed and was launched using a Soviet Launcher. Another major landmark was the development of the first launch vehicle SLV-3 with a capability to place 40 kg in Low Earth Orbit (LEO), which had its first successful flight in 1980.
In the experimental phase during 80’s, Bhaskara-I & II missions were pioneering steps in the remote sensing area whereas ‘Ariane Passenger Payload Experiment (APPLE)’ became the forerunner for the future communication satellite system.
During the operational phase in 90’s, major space infrastructure was created under two broad classes: one for communication, broadcasting, and meteorology through a multi-purpose Indian National Satellite System (INSAT), and the other for Indian Remote Sensing Satellite (IRS) system. The development and operationalization of the Polar Satellite Launch Vehicle (PSLV) and the development of the Geosynchronous Satellite Launch Vehicle (GSLV) were significant achievements during this phase.
