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SCIENCE AND TECHNOLOGY NOTES DIFFERENT KINDS OF SATELLITES Features Low Earth Sun- Geosynchronous Geostationary Orbits Synchronous/ helio synchronous Height above 160 km 600-800 km 36,000 km 36,000 km the Earth Surface Period of 90 minutes Orbit Earth 15 to 24 hours 24 hours rotation 16 times per day Launch Simple PSLV GSLV(small size GSLV (small Vehicle rockets satellites can be size satellites can used launched using be launched PSLV also) using PSLV also) Purpose military Meteorological Communication Communication Served reconnaissance satellites, Remote Sensing Special very In polar orbits. Their period of They are Feature short Satellite’s rotation exactly permanently lifetimes in the orientation is matches the fixed above one order of weeks fixed relative to Earth’s rotation. point on the the Sun They are not in equator of the throughout the equatorial plane. Earth. year, allowing very accurate weather predictions to be made. SPACECRAFTS Spacecraft and its Destination Objectives/Other Details manufacturing Agency Transit Exoplanet Survey Earth’s Orbit Discovery of exoplanets in orbit around Satellite (TESS) by NASA the brightest stars in the sky. New Horizon by NASA Pluto and • To cast light on how solar system was Kuiper Belt born. JUNO by NASA Jupiter • To understand the origin and evolution of Jupiter. • To investigate the existence of a solid planetary core. • To map Jupiter’s intense magnetic field, Europa Clipper Jupiter’s icy • Europa holds a salty liquid water ocean Mission by NASA moon Europa beneath its icy crust • So, the mission would explore its habitability. 25B, 2nd Floor, Pusa Road, Old Rajendra Nagar, 119 Metro Pillar Number 117 • Tel. : 011-49274400, 9205274743 NOTES Dawn by NASA Vesta and • Asteroids belt is located between the Ceres, proto- orbits of planets Mars and Jupiter. planets in the • Dawn is the first spacecraft to orbit two asteroid belt extraterrestrial bodies. Cassini by NASA, Saturn and its • It has discovered steep sided canyons European Space moon Titan flooded with hydrocarbons on Saturn’s Agency and Italian Moon Titan. space agency • It became the first satellite to orbit the Saturn. OSIRIS-Rex (Origins, Near earth • NASA’s first asteroid sampling mission. Spectral Interpretation, asteroid • It’ll collect dust from asteroid without Resource Identification- Bennu landing on it and then return to the Regolith Explorer) by Earth. NASA • To unravel how life began on Earth, how the solar system was formed, and how to protect our planet from stray asteroids like Bennu. SOFIA (Stratospheric Stratosphere It is an aircraft modified to carry a 100- Observatory for Infrared inch diameter telescope. Astronomy) Mission by To study observations of celestial magnetic NASA and the German fields, star forming regions, comets and Aerospace Centre, DLR Saturn’s giant moon Titan. LISA Pathfinder by Space • To demonstrate the technology needed European Space Agency to build a space-based gravitational wave observatory. • LISA pathfinder was launched as a prelude to the LISA mission. Rosetta by European Comet 67P • It had an orbiter and a lander Space Agency configuration. Solar Parker Probe by Sun • NASA plans to send its first robotic NASA atmosphere spacecraft to the Sun • The spacecraft will travel directly into the sun’s atmosphere about 4 million miles from the star’s surface. • It will Trace the flow of energy that heats and accelerates the solar corona and solar wind. • It will study why the surface of the Sun, called the photosphere, is not as hot as its atmosphere, called the corona. Cartosat by ISRO sun- • Part of the Indian Remote Sensing synchronous Programme. orbit • For Earth’s resource management and monitoring. 25B, 2nd Floor, Pusa Road, Old Rajendra Nagar, 120 Metro Pillar Number 117 • Tel. : 011-49274400, 9205274743 SPACE NOTES ISRO 1. POLARIMETRY DOPPLER WEATHER RADAR • The Indian Space Research Organization (ISRO) recently launched the Polarimetry Doppler Weather Radar at Satish Dhawan Space Centre, Sriharikota. • The Polarimetry Doppler Weather Radar provides advanced information, enhances the lead-time essential for saving lives and property in the event of a natural disaster associated with severe weather. • The polarimetric capability of the radar will significantly improve the accuracy of rainfall estimation leading to accurate and timely flash flood warnings, according to ISRO's earlier release. • The radar has been indigenously developed by Bharat Electronics Ltd (BEL),Bengaluru. It is the seventh radar of such type manufactured in the country under "Make in India". 2. GAGANYAAN MISSION Recently the Prime Minister in his Independence Day speech announced that ISRO will be sending its first human spaceflight mission into the space by 2022 • GSLV Mk-III launch vehicle will be used to launch Gaganyaan. Two unmanned Gaganyaan missions will be undertaken prior to sending humans, with first unmanned flight within 30 months. • The total programme is expected to be completed before 2022 and cost is expected to be less than Rs. 10,000 Crores. • The mission will aim to send a three-member crew to space for a period of five to seven days. The spacecraft will be placed in a low earth orbit of 300-400km. • It will comprise of a crew module and service module that constitute an orbital module. The crew will do microgravity experiment during the mission. 3. HYPER SPECTRAL IMAGING SATELLITE (HYSIS) • ISRO's PSLV C43 launched India's first Hyperspectral Imaging Satellite (HysIS) along with 30 foreign satellites from Satish Dhawan Space Centre, Sriharikota. • HysIS is an earth observation satellite built around ISRO's Mini Satellite-2 (IMS-2) bus. About the Hyperspectral Imaging Technology • It combines the power of digital imaging and spectroscopy to attain both spatial and spectral information from an object. • This result can be then used to identify, measure and locate different materials and their chemical and physical properties. Every pixel in the image contains a continuous spectrum (in radiance or reflectance) and can be used to characterize the objects in the scene with great precision and detail. • Hyperspectral images provide much more detailed information about the scene by dividing the spectrum into many more bands than a normal color camera, which only acquires three different spectral channels corresponding to the visual primary colors red, green and blue. 25B, 2nd Floor, Pusa Road, Old Rajendra Nagar, 121 Metro Pillar Number 117 • Tel. : 011-49274400, 9205274743 • Application NOTES • Hyperspectral remote sensing is used for a range of applications like agriculture, forestry, soil survey, geology, coastal zones, inland water studies, environmental studies, detection of pollution from industries and the military for surveillance or anti-terror operations. • Other utilities include online industrial monitoring/sorting/classification to laboratory measurements, clinical instruments for medical diagnostic and airborne and satellite based remote sensing tools. Spectral Imaging It is imaging that uses multiple bands across the electromagnetic spectrum like using infrared, the visible spectrum, the ultraviolet, x-rays, or some combination of the above. • The main difference between multispectral and hyperspectral is the number of bands and how narrow the bands are. • Hyperspectral imaging (HSI) uses continuous and contiguous ranges of wavelengths (e.g. 400 - 1100 nm in steps of 0.1 nm) whilst multispectral imaging (MSI) uses a subset of targeted wavelengths at chosen locations (e.g. 400 - 1100 nm in steps of 20 nm). • Hyperspectral imagery consists of much narrower bands (10-20 nm). A hyperspectral image could have hundreds or thousands of bands. In general, it comes from an imaging spectrometer. 4. ADITYA-L1 MISSION AND LAGRANGE POINTS • It is the first Indian mission to study the Sun. • It is expected to be launched in 2019 by the launch vehicle PSLVXL with six payloads from Sriharikota. • The main aim of the solar mission is to do coronal and near UV studies. • It will be launched into the halo orbit around the Lagrangian point 1 (L1) of the Sun-Earth system. • This orbit has the advantage of allowing continuous monitoring of the sun. 5. GSLV -MK III D2 Recently, ISRO launched satellite-GSAT-29 through the launcher GSLV-Mk III D2. • It is the fifth generation, India's heaviest launch vehicle designed to place satellites of up-to 4,000 kg into Geosynchronous Transfer Orbit (GTO) or satellites weighing about 10,000 kg to a Low Earth Orbit (LEO). • It is the second launch of GSLV-Mk III, which earlier in 2017 carried GSAT-19 satellite as the first development flight. • It is a three-stage heavy-lift rocket with two solid fuel strap-on engines in the first stage, a liquid propellant core as second stage and a cryogenic engine for the third stage. • The cryogenic propellant system in upper stage called the C25 engine, is an advanced version of cryogenic technology. • The indigenous cryogenic C25 engine provides an unprecedented thrust power to GSLV rockets which keeps fuel loads on the rocket relatively low. A cryogenic rocket engine is a rocket engine that uses a cryogenic fuel or oxidizer, that is, its fuel or oxidizer (or both) is gases liquefied and stored at very low temperatures. 25B, 2nd Floor, Pusa Road, Old Rajendra Nagar, 122 Metro Pillar Number 117 • Tel. : 011-49274400, 9205274743 Significance of GSLV-Mk III NOTES • Its successful launch will provide a thrust to future space missions such as Chandrayaan 2, ISRO's moon and man missions etc. • India is among six nations - apart from the US, Russia, France, Japan and China - to possess cryogenic engine technology. This launch will further expand ISRO's space programmes on several fronts such as commercial international space market. LAUNCH VEHICLES OF ISRO 6. GSAT -11 GSAT-11, the heaviest satellite built by ISRO was launched from French Guiana by Areane 5 Rocket of European Space Agency. • It weighs around 5855 Kg, double the size of biggest satellite built by ISRO till now.