Indian Spy Satellites
RISAT-2 and ANUSAT Successfully Placed On Orbit
In its fifteenth mission carried out from Satish Dhawan Space Centre SHAR (SDSC SHAR), Sriharikota on April 20, 2009 ISROs Polar Satellite Launch Vehicle (PSLV-C12) successfully placed two satellites - RISAT-2 and ANUSAT - in the desired orbit. RISAT-2 is a Radar Imaging Satellite with the capability to take images of the earth during day and night as well as cloudy conditions. At the time of launch, RISAT-2 weighed about 300 kg and was realised by ISRO in association with Israel Aerospace Industries. The satellite was placed in an orbit of 550 km height with an inclination of 41 deg to the equator and an orbital period of about 90 minutes. This satellite will enhance ISROs capability for earth observation, especially during floods, cyclones, landslides and in disaster management in a more effective way. Copyright © 2009
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The 44 metre tall PSLV-C12 weighing 230 ton was launched from the Second Launch Pad (SLP) at SDSC SHAR in the Core Alone configuration without the use of six solid strap-ons. In this mission, in addition to RISAT-2, PSLV also carried A 40 kg micro satellite named ANUSAT, built by Anna University, Chennai. ANUSAT is the first experimental communication satellite built by an Indian University under the over all guidance of ISRO and will demonstrate the technologies related to message store and forward operations. In this flight, PSLV carried the indigenously developed Advanced Mission Computers and Advanced Telemetry System, which guided the vehicle from lift-off till the injection of the two satellites in the desired orbit.
The main payload, RISAT-2, was the first satellite to be separated in orbit at 1100 seconds after lift-off at an altitude of 550 km. With this successful launch, the versatility and the reliability of PSLV has been proved again underscoring its importance as the workhorse launch vehicle of India. This launch was the fourteenth consecutive success for PSLV. In these launches, PSLV has placed a total of sixteen Indian satellites and sixteen foreign satellites into Polar, Geosynchronous Transfer and Low Earth Orbits. It may be recalled that during its previous mission on October 22, 2008, PSLV had successfully launched Chandrayaan-1 spacecraft, which is now exploring the moon from lunar orbit.
FEATURES OF PSLV, RISAT-2 AND ANUSAT:
PSLV is a four-stage launch vehicle employing both solid and liquid propulsion stages. PSLV is the trusted workhorse launch Vehicle of ISRO. During 1993-2008 period, PSLV had fourteen launches of which thirteen were consecutively successful. PSLV has repeatedly proved its reliability and versatility by launching 32 spacecrafts (16Indian and 16 for international customers) into a variety of orbits so far. It may be recalled that during its previous mission on October 22, 2008, PSLV had successfully launched Chandrayaan-1 spacecraft, which is now exploring the Moon from lunar orbit.
In its standard configuration, the 44 m tall PSLV has a lift-off mass of 295 tonne. It is a four-stage launch vehicle with the first and the third stages as well as the six strap-ons surrounding the first stage using HTPB based solid propellant. PSLVs first stage is one of the largest solid propellant boosters in the world. Its second and fourth stages use liquid propellants. PSLV-C12 was launched without the six strapons in its core alone configuration. PSLV-C12 weighs about 230 tonnes at lift off.
It may be recalled that PSLV in its core alone configuration had launched AGILE and TECSAR during 2007 and 2008 respectively. RISAT-2 is a Radar Imaging Satellite with all weather capability to take images of the earth. This Satellite will enhance ISROs capability for Disaster Management applications,ANUSAT (Anna University Satellite) is the first satellite built by an Indian University under the over all guidance of ISRO and will demonstrate the technologies related to message store and forward operationsCopyright
HISTORY OF ARTIFICIAL SATELLITE:
The first artificial satellite was Sputnik 1, launched by the Soviet Union on 4 October 1957, and initiating the Soviet Sputnik program, with Sergei Korolev as chief designer and Kerim Kerimov as his assistant. This in turn triggered the Space Race between the Soviet Union and the United States.
Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere. Because the satellite's body was filled with pressurized nitrogen, Sputnik 1 also provided the first opportunity for meteoroid detection, as a loss of internal pressure due to meteoroid penetration of the outer surface would have been evident in the temperature data sent back to Earth. The unanticipated announcement of Sputnik 1's success precipitated the Sputnik crisis in the United States and ignited the so-called Space Race within the Cold War.Sputnik 2 was launched on November 3, 1957 and carried the first living passenger into orbit, a dog named Laika.
In May, 1946, Project RAND had released the Preliminary Design of a Experimental World-Circling Spaceship, which stated, "A satellite vehicle with appropriate instrumentation can be expected to be one of the most potent scientific tools of the Twentieth Century. The United States had been considering launching orbital satellites since 1945 under the Bureau of Aeronautics of the United States Navy.
The United States Air Force's Project RAND eventually released the above report, but did not believe that the satellite was a potential military weapon; rather, they considered it to be a tool for science, politics, and propaganda. In 1954, the Secretary of Defense stated, "I know of no American satellite program." On July 29, 1955, the White House announced that the U.S. intended to launch satellites by the spring of 1958. This became known as Project Vanguard. On July 31, the Soviets announced that they intended to launch a satellite by the fall of 1957.
Following pressure by the American Rocket Society, the National Science Foundation, and the International Geophysical Year, military interest picked up and in early 1955 the Air Force and Navy were working on Project Orbiter, which involved using a Jupiter C rocket to launch a satellite.
The project succeeded, and Explorer 1 became the United States' first satellite on January 31, 1958. In June 1961, three-and-a-half years after the launch of Sputnik 1, the Air Force used resources of the United States Space Surveillance Network to catalog 115 Earth-orbiting satellites. The largest artificial satellite currently orbiting the Earth is the International Space Station.
TYPES OF ARTIFICIAL SATELLITE:
Anti-Satellite weapons/"Killer Satellites" are satellites that are armed, designed to take out enemy warheads, satellites, other space assets. They may have particle weapons, energy weapons, kinetic weapons, nuclear and/or conventional missiles and/or a combination of these weapons. Astronomical satellites are satellites used for observation of distant planets, galaxies, and other outer space objects.
Biosatellites are satellites designed to carry living organisms, generally for scientific experimentation.
Communications satellites are satellites stationed in space for the purpose of telecommunications. Modern communications satellites typically use geosynchronous orbits, Molniya orbits or Low Earth orbits.
Miniaturized satellites are satellites of unusually low weights and small sizes. New classifications are used to categorize these satellites: minisatellite (500200 kg), microsatellite (below 200 kg), nanosatellite (below 10 kg).
Navigational satellites are satellites which use radio time signals transmitted to enable mobile receivers on the ground to determine their exact location. The relatively clear line of sight between the satellites and receivers on the ground, combined with ever-improving electronics, allows satellite navigation systems to measure location to accuracies on the order of a few meters in real time.
Reconnaissance satellites are Earth observation satellite or communications satellite deployed for military or intelligence applications. Little is known about the full power of these satellites, as governments who operate them usually keep information pertaining to their reconnaissance satellites classified.
Earth observation satellites are satellites intended for non-military uses such as environmental monitoring, meteorology, map making etc.
Space stations are man-made structures that are designed for human beings to live on in outer space. A space station is distinguished from other manned spacecraft by its lack of major propulsion or landing facilities instead, other vehicles are used as transport to and from the station. Space stations are designed for medium-term living in orbit, for periods of weeks, months, or even years.
Tether satellites are satellites which are connected to another satellite by a thin cable called a tether.
Weather satellites are primarily used to monitor Earth's weather and climate.