Sample Materials for CSAT Paper -1 (G.S.) Pre 2013: "Science & Technology: Space Research"

Subject: Science & Technology
Topic: Space Research

India’s Space Programme Origin and Development

Space activities in India started in the sixties with the establishment of Thumba Equatorial Rocket Launching Station (TERLS). The efforts were consolidating with formation of Indian Space Research Organisation (ISRO) in 1969. The space programme got further fillip in June 1972, when the Government of India constituted the Space Commission and established the Department of Space (DOS). ISRO was brought under newly formed DOS in September 1972.

Objectives

The primary objective of the Indian Space Programme is to achieve self-reliance in space technology and evolve application programmes to meet national developmental needs.

Developments

Over the last three decades, the space programme has taken important strides in meeting its objective. Two major operational space systems have been established - the Indian National Satellite (INSAT) for telecommunication, television broadcasting and metrological services and Indian Remote Sensing Satellite (IRS) system for resources monitoring and management.

Two launch vehicle, the Polar Satellite Launch vehicle (PSLV) primarily for launching remote sensing satellites into polar orbits and Geosynchronous Satellite Launch Vehicle (GSLV) for launching communication and metrological satellites into 36000 km high Geosynchronous Transfer Orbit (GTO) have been operationalised. Space application programmes with participation of user agencies have enabled the benefits of space programme to reach the grassroots level of society. Research in space science has contributed towards increased knowledge and understanding of several scientific phenomena. The capabilities built under space programme are used for commercial gains through international marketing of space hardware and services.
A bird's eye view of these developments is given in Table1 (Milestones) and Table 2 (Decade plan) below.

2008	PSLV-Cl1 successfully launches CHANDRAYAAN-1 from Sriharikota (October 22, 2008).  PSLV-C9 successfully launches CARTOSAT-2A, IMS-1 and 8 foreign nano satellites from Sriharikota (April 28, 2008).  PSLV-C10 successfully launches TECSAR satellite under a commercial contract with Antrix Corporation (January 21, 2008).
2007	Successful launch of GSLV (GSLV-F04) with INSAT-4CR on board from SDSC SHAR (September 2, 2007). ISRO’s Polar Satellite Launch Vehicle, PSLV-C8, successfully launched Italian astronomical satellite, AGILE from Sriharikota (April 23, 2007). Successful launch of INSAT-4B by Ariane-5 from Kourou French Guyana, (March, 12, 2007). Successful recovery of SRE-1 after maneuvering it to re-center the earth's atmosphere and descend over the Bay of Bengal about 140 km east of Sriharikota (January 22, 2007). ISRO’s Polar Satellite Launch Vehicle, PSLV-C7 successfully launches four satellites - India's CARTOSAT-2 and Space Capsule Recovery Experiment (SRE-1) and Indonesia's LAPAN-TUBSAT and Argentina's PEHUENSAT-1 (January 10, 2007).
2006	Second operational flight of GSLV (GSLV-F02) from SDSC SHAR with INSAT-4C on board. (July 10, 2006). Satellite could not be placed in orbit.
2005	Successfu1 launch of INSAT-4A by Ariane from Kourou French Guyana, (December 22, 2005). ISRO’s Polar Satellite Launch Vehicle PSLV-C6 successfully launched 'CARTOSAT-1 and HAMSAT satellites from Sriharikota (May 5, 2005).
2004	The first operational flight of GSLV (GSLV-F01) successfully launched EDUSAT from SDHC SHAR, Sriharikota (October 17, 2003).
2003	ISRO’s Polar Satellite Launch Vehicle, PSLV-C5, successfully launched RESOURCESAT-1 (IRS-P6 satellite from Sriharikota (October 17, 2003). Successful launch of INSAT-3E by Ariane from Kourou French Guyana, (September 28, 2003). The second developmental launch of GSLV-D2 with GSAT-2 on board from Sriharikota (May 8, 2003). Successful launch of INSAT-3A by Ariane from Kourous French Guyana, (April 2003).
2002	ISRO's Polar Satellite Launch Vehicle, PSLV-C4, successfully launched KALPANA-1 satellite from Sriharikota (September 12, 2002). Successful launch of INSAT -3C by Ariane from Kourou French Guyana, (January 24, 2002).
2001	ISRO’s Polar Satellite Launch Vehicle, PSLV-C3, successfully launched three satellites - Technology Experiment Satellite (TES) of ISRO, BIRD of Germany and PROBA of Belgium - into their intended orbits (October 22, 2001). The first developmental launch of GSLV-D1 with GSAT-1 on board from Sriharikota (April 18, 2001).

Ques. 1 : Briefly discuss the main features of the Indian National Satellite System?

Ans. The Indian National Satellite (INSAT) system is one of the largest domestic communication satellite systems in the Asia-Pacific region. In the 1980s, it initiated a major revolution in India's communications sector and sustained the same later.
The satellites of INSAT system, which are in service today, are INSAT-2E, INSAT-3A, INSAT-3B, INSAT-3C, INSAT-3E, KALPANA-1, GSAT-2, EDUSAT and INSAT-4A that was launched recently. The system provides a total of about 175 transponders in the C, Extended C and Ku-bands. Being a multipurpose satellite system, INSAT provides services t~o telecommunications, television broadcasting, weather forecasting, disaster warning and Search and Rescue fields. The INSAT system serves many important sectors of the Indian economy. Foremost amongst them is Telecommunications sector wherein INSAT is providing Mobile Satellite Service besides providing VSAT services. Today, more than 25,000 Very Small Aperture Terminals (VSATs) are in operation.
Similarly, Television broadcasting and redistribution have been immensely benefited by INSAT. Thanks to INSAT, more than 900 million people in India have access to TV through about 1400 terrestrial rebroadcast transmitters. In addition to this, social development through exclusive channels for training and developmental education has become possible through INSAT. And, a Telemedicine network to take super speciality medical services to the remote and rural population has become a reality. The network now covers 152 hospitals-120 remote rural hospitals and 32 super speciality hospitals in major cities. The launch of EDUSAT, India's first thematic satellite dedicated exclusively for educational services, has provided further fillip to the educational services offered by the INSAT system INSAT system is also providing meteorological services through Very High Resolution Radiometer (VHRR) and CCD cameras on some of its spacecraft. This apart, cyclone monitoring through meteorological imaging and issue of warnings on impending cyclones through disaster warning receivers have been operationalised. For this, 350 receivers have been installed along the east and west coasts of India.

Ques. 2 : Discuss in brief the Indian Remote Sensing Satellite System and its importance?

Ans. India has the largest constellation of Remote Sensing Satellites, which are providing services both at the national and global levels. From the Indian Remote Sensing (IRS) Satellites, data is available in a variety of spatial resolutions starting from 360 metres and highest resolution being 2.5 metres. Besides, the state-of-the-art cameras of IRS spacecraft take the pictures of the Earth in several spectral bands. In future, ISRO intends to launch IRS spacecraft with better spatial resolution and capable of imaging day and night. The satellites of IRS system which are in service today are IRS-1C, IRS-ID, IRS-P3, OCEANSAT-1, Technology Experimental Satellite (TES). RESOURCESAT-1, and the recently launched CARTOSAT-1 capable of taking stereo pictures. The upcoming Remote Sensing Satellite are Cartosat-2, RISAT (Radar Imaging Satellite) and Oceansat-2.
Imagery sent by IRS spacecraft is being put to a variety of uses in India with agricultural crop acreage and yield estimation being one of the most important uses. Besides, such imagery is being used for ground and surface water harvesting, monitoring of reservoirs and irrigation command areas to optimise water use. Forest survey and management and wasteland identification and recovery are other allied uses. This apart, IRS imagery is also used for mineral prospecting and forecasting of potential fishing zones.
With regard to applications in planning and management, IRS data is being used for urban planning, flood prone area identification and the consequent suggestions for mitigation measure. Based on this experience, the concept of Integrated Mission for Sustainable Development has been evolved wherein the spacecraft image data is integrated with the socio-economic data obtained from conventional sources to achieve sustainable development.

Ques. 3 : Give an account of the Satellite Launch Vehicles Programme of India?

Ans. After successfully testing the first indigenous launch vehicle SLV-3 in 1980, ISRO built the next generation Augmented Satellite Launch Vehicle (ASLV). ISRO’s Launch Vehicle Programme had a giant leap with the successful launch of IRS-P2 spacecraft onboard the Polar Satellite Launch Vehicle (PSLV) in October 1994. On 18 April 2001, India successfully launched its Geosynchronous Satellite Launch Vehicle (GSLV) Technology development for advanced launch vehicles made good progress with the breakthrough achieved during the year in Supersonic Combustion Ramjet (SCRAMJET) to be employed in Air-Breathing engine. This is an important element in the launch vehicle technology development. Concepts for reusable launch vehicle are also being studied.

Ques. 4 : What P.S.L.V.? Discuss its performance in the Indian Space Programme?

Ans. The four stages PSLV is capable of launching upto 1,600 kg satellites into an 620 km polar orbit. It has provision to launch payloads from 100 kg micro-satellites or mini or small satellites in different combinations. It can also launch one ton class payloads into Geosynchronous Transfer Orbit (GTO). So far, it has performed twenty missions with nineteenth consecutive successes.
Latest success of PSLV:
• PSLV-C 19 has successfully placed the RISAT-1 (Radar Imaging Satellite) of 1858 Kg in the 480 Km Polar orbit on 26 April, 2012.
• On 12 October, 2011 PSLV-V 18 placed Megha - Tropiques, SRMSAT, Jugnu, VESALSAT Sattellites.
• On 15 July, 2011 PSLV-C 17 placed GSAT-12 (Communication Satellite) in Geo-stationary orbit of 36,000 Km.

Ques. 5 : Give an account of the G.S.L.V.?

Ans. The GSLV was successful on its very first test flight. After its successful second flight in May 2003, it was commissioned. This was followed by the success of its third flight in September 2004. The GSLV is capable of launching 2,000 kg class satellites into Geosynchronous Transfer Orbit (GTO). The development of Indigenous cryogenic stage to be used as the third stage of GSLV made further progress. The cryogenic engine which forms part of this stage, has already been successfully qualified. GSLV-Mk-III, a new version of GSLV and capable of launching spacecraft weighing upto 4 tonnes to GTO is under development.

Infrastructure

As noted earlier, the Space Commission is the nodal agency for co-ordinating R&D activities in space science and technology with Department of Space being its executive wing and ISRO its chief operational arm. Thus ISRO is the apex organisation that plans, programmes, manages and controls all R&D activities in space science and technology as well as application of the same in various fields. There are many space centres through which ISRO carries out its tasks.

Ques. 6 : Comment on the following in not more than 50-word each:
i) VSSC (ii) ISAC (iii) SAC
iv) SHAR Centre v) IISU vi) LPSC
vii) NNRMS viii) NRSA
ix) ISRo Telemetey x) DECU
xi) MCF xii) RRSSCs

Ans.
i) Vikram Sarabhai Space Centre (VSSC) -located at Thumba, Thiruvanantha-puram, this is the national centre providing technology base for the country's indigenous satellite launch vehicle development efforts. It is the largest of ISRO centres with the main task of rocket research and planning and execution of satellite launch vehicles like SLV, ASLV, PSLV and GSLV.
ii) ISRO Satellite Centre (ISAC) - located at Bangalore, this centre is responsible for the design, fabrication, testing and management of application satellites. Over the years, this centre has successfully designed and fabricated satellites like Aryabhatta, Bhaskara, Apple and the IRS and INSAT series of satellites.
iii) Space Application Centre (SAC) - located at Ahmedabad, this is ISRO’s R&D Centre for conceiving, organising and building systems for practical application of space technology. It works towards finding beneficial applications of space technology in the Indian context and operationalising them. The major activities include satellite based communication, meteorology, remote sensing, environmental monitoring etc.
iv) SHAR Centre (Sriharikota High Altitude Range), Sriharikota (A.P.) - It is the main launch centre of ISRO. Starting from the launch of the first ever sounding rocket 'ROHINI' this centre has supported the launches of SLV, ASLV, PSLV and GSLV. At the centre, a second launch pad has been constructed to augment and improve the existing launching facilities. With the improvement, it was able to launch the most advanced launch vehicle such as GSLV-D1, in April 2001. The facilities at the centre now include launch pad with jet deflector, vehicle assembly building (high bay), propellant and gas storage and transfer facilities for earth storable and cryo propellants, safety systems and instrumentation and control systems of automatic filling of propellants, It has been renamed as Satish Dhawan Space Centre (SDSC).
v) ISRO Inertial Systems Unit (IISU) - Located at Thiruvananthapuram, it is responsible for carrying out R&D towards inertial sensors and systems and allied satellite elements for various missions. Its task is to ensure that the needs of ISRO launch vehicles and satellite programmes, in terms of systems like gyroscopes, reactions wheels etc., are met. It developed the navigation system for the PSLV.
vi) Liquid Propulsion Systems Centre (LPSC)- It is responsible for R&D in liquid propulsion, earth storable and cryogenic engines; stages and associated components for launch vehicles and spacecrafts. It is located on three campuses at Mahendragiri in Tamil Nadu (with large solid booster preparation and testing facility), Valiamala in Kerala (with facility for integration, checkout, structural testing, separation and jettisoning systems testing and control component development) and Bangalore in Karnataka.
vii) ISRO Telemetry, Tracking and Command Network (ISTRAC) - This centre provides telemetry, tracking and common support for the launch vehicles and satellite missions. Its headquarters and spacecraft control centre is at Bangalore and it also has a network of ground stations at Sriharikota, Thiruvananthapuram, Bangalore, Lucknow, Car Nicobar and Mauritius. It successfully provided the telemetry tracking and command support to PSLV missions.
viii) National Natural Resources Manage-ment System (NNRMS) - Under the administrative control of Department of Space, this facility has active participation of many state and central government departments and agencies. The availability of data from various satellites under the IRS programme has enabled taking up a number of nation wide remote sensing application projects relating to: natural resource manage-ment e.g. regular monitoring and estimation of crop acreage, yield etc. of various crops, monitoring of forest resources etc.
ix) National Remote Sensing Agency (NRSA)- Like NNRMS, it is another autonomous body under the administration of DOS. It is responsible for acquisition, processing and dissemination of satellite and aerial remote sensing data, training of user scientists in various applications in different disciplines for resource mapping, disaster monitoring etc. Located at Hyderabad, it also runs the Indian Institute of Remote Sensing at Dehradun.
x) Development and Educational Communication Unit (DECU)- Located at Ahmedabad, it is involved in the conception, definition, planning and socio-economic education of space application programmes. Besides carrying out R&D with themes of development and education oriented communications. It also provides training services in those areas.
xi) Master Control Facility (MCF)- located at Hassan, Karnataka, its a multi- mission control centre charged with the responsibility of control and operation of INSAT and GSAT group satellites in orbit. This is done through its network antennae, earth stations, computers and control facilities. All the post launch operation of these satellite including orbital manoeuvres, station keeping, in orbit operation, payload testing and initial orbit raising of the spacecraft are monitored and controlled by MCF. It is an integrated facility consisting of Four Satellite Control Earth Stations supporting continuous monitoring of Search Rescue Signals, VHRR and OCP downlinks. The spacecraft control centre at the MCF is the nerve centre of the entire spacecraft operations.
xii) Regional Remote Sensing Service Centres (RRSSCs) - The five operational RRSSCs at Bangalore, Dehradun, Jodhpur, Kharagpur and Nagpur are engaged in the execution of various national level projects, user projects, application validation projects and technology and software development projects.

Launch Infrastructure

An elaborate launch infrastructure exists at the Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota Island on the East Coast of India which is about 100 km from Chennai. Sriharikota is located at 13° North latitude. From here, satellites can be launched into a variety of orbital inclinations starting from 18° and extending upto 99° Full-fledged facilities for satellite integration, assembly and launch exist there. Sriharikota also houses a Telemetry, Tracking and Command network for tracking satellites and monitoring them. The newly built Second Launch Pad at SPSC SHAR as a redundancy to the existing launch pad, and to cater to the requirement of GSLV-Mk III as well as other future launch vehicles, was commissioned in May 2005 with the successful launch of PSLV-C6.

Ques. 7 : What is Cartosat-1?

Ans.
CartoSat-1

The satellite primarily intended for advanced Mapping applications. It was launched in May 2005.
Payload: Two panchromatic cameras with a spatial resolution of 2.5 meter and a swath of 30 km each.
New Technologies Used: in proved version of Star sensor, bus interface connecting control system, satellite positioning system and data handling.

Ques. 8 : What is Cartosat-2?

Ans. : It is advanced remote sensing satellite with single panchromatic camera capable of providing scene-specific spot imageries of cartographic applications. The camera with one-meter spatial resolution and swath of 10 km.
New Technologies: Two mirror on single axis camera, Carbon Fabric reinforced Plastic based electro optic structure, advanced solid state recorder, high torque reaction wheels, lightweight, large size mirrors. It was launched in 2007.

Ques. 9 : What is Radar Imaging Satellite (RISAT)?

Ans. RISAT with night and day imaging capability as well as imaging under cloudy conditions will be important system to complement band of electro-optical sensors on board IRS System.
IRSAT will have multi-mode, multi-polarisation, agile synthetic Aperature Radar (SAR) operating in C-band and providing 3.50 meters spatial resolution. It will incorporate algorithms and data products to serve the user community.

Ques. 10 : What is OCEANSAT-2?

Ans. It is envisaged for providing continuity to ocean sat-1. It will carry OCM and a Ku-band Pencil Beam scatterometer, 8-band multi-spectral camera. The scatterometer is a microwave radar for measuring ocean surface wind velocity. It will be launched in PSS orbit of 720 km altitude by PSLV.

Ques. 11 : What is TWSAT?

Ans. The 90-kg TWSAT is a remote sensing micro-satellite proposed for third world countries. The payload will be a 2-band CCD Camera with single optics and beam splitter. The 50 user terminals, which can receive payload data are to be installed in Indian Universities and selected Third World Countries.

Scientific Missions

India has a vibrant space science programme covering astronomy, astrophysics, planetary and earth sciences. There activities are mainly carried out at Physical Research Laboratory (PRL), Ahemdabad, Space Physics Laboratory (SPL), Trivandrum, ISRO Satellite Centre, Bangalore. DOS has set up ground based facilities like Udaipur Solar observatory, Mesosphere-Stratosphere- Troposphere. Radar etc. Balloons, Sounding rockets. DOS also participates in international scientific campaigns like MONEX, IGBP, STEP and INDOEX.

Ques. 12 : Discuss in brief the main objectives of the Mission CHANDRAYAN-1?

Ans. It is India's first scientific mission to Moon, to be undertaken during 2007- 2008. The Mission is aimed at expanding the scientific knowledge about the Mass, upgrading India's technological capability and providing challenging opportunities for planetary research to the younger generation.

Scientific Objectives

1. High resolution remote sensing of the, moon in the visible, near infrared, low energy x--ray and high-energy x-ray regions for preparing 3-D atlas of regions of scientific interest.
2. Chemical mapping of entire lunar surface for elements such as Magnesium, Aluminium, Iron, Titanium, and Uranium. PSLV has launched the spacecraft into GTO.

Pay Loads

1. Terrain Mapping Camera with stereo imaging facility with panchromatic band with 5 m spatial resolution and 20 km swath.
2. Hyper-spectral imager with spectral resolution of 15 nm.
3. Lunar Ranging Instrument with vertical resolution of 5 m.
4. Low energy x-ray spectrometer.
5. High energy x-ray spectrometer.
 

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Ques. 13 : What is ASTROSAT?

Ans. It is national project involving several academic institutions in the country, which will enable multi-wave length studies of variety of celestial sources and phenomena using x-ray astronomy instruments and ultra-violet imaging telescope.
During the year the development of scientific payloads has made considerable progress at "Tata Institute of Fundamental Research" (TIFR), and Indian Institute of Astrophysics and ISRO Satellite Centre.

Ques. 14 : Give an account of the Megha Tropiques?

Ans. Indian region being convectively very active in relation to Monsoon Dynamics, it is necessary to understand the life cycle of these convective systems and to understand their role in the associated energy and moisture budget.
Megha-Tropiques (Megha meaning cloud in Sanskrit and Tropiques meaning tropics in French) is envisaged for investigating the contribution of water cycle in the tropical atmosphere to climate dynamics.
ISRO and French National Space Centre (CNES) had signed a statement of intent in November 1999 for this mission. The satellite will carry three scientific instruments:
1. Multi-frequency Microwave Scanning Radiometer to be developed by "ISRO" and CNES providing information about rain above the oceans, water vapour content in atmosphere, liquid water in clouds.
2. Multi-channel microwave instru-ments to be developed by CNES for providing vertical humidity.
3. Multi-channel Instrument (SCARAB) for providing earth's radiation and budget.
ISRO will build the Megha-Tropiques Spacecraft and launch it using PSLV into 867 km high orbit at an inclination of 20° with respect to the equatorial plane. ISRO will control the satellite in orbit and also receive, process and distribute the scientific data.

Ques. 15 : Briefly discuss the ISRO’s Geosphere - Biosphere Programme?

Ans. Under ISRO-GBP scientific projects related to climate change in three mainstreams are carried out. They are
1. Climate change, modelling and paleoclimate.
2. Atomspheric chemistry, Trace Gases and Aerosols.
3. Biogeocycles.

Presently 88 scientific projects are in progress. The simulation of regional climate model, using high-resolution land cover information has revealed significant information on the regional climate scenarios.

Some Projects

1. Long Mobile Land Aerosop Campaign covering 15,000 km length across South India.
2. Land Aerosol Campaign in North India.
3. Land cover dynamics project in Godavari, Pennar, Sone Rivers.
4. Carbon-dynamics project in Arunachal Pradesh.

Ques. 16 : What is Satellite Navigation Systems (SNS)?

Ans. Satellite Navigation System use radio time signals transmitted by satellites to enable mobile receivers on the ground to determine their exact locations. The relatively clear line of light between the satellites and receivers on the ground, combined with ever-improving electronics, allows SNS to measure location to accuracies on the order of a few metres in real time.
Military Use: The original motivation for satellite navigation was for military applications are:
(1) It allows for hitherto impossible precision in delivery of weapons to targets, greatly increasing their lethality reducing inadvertent causalities (Smart Bombs).
(2) It also allow forces to be directed and to locate themselves more easily.
(3) It is a force multiplier. In particular, the ability to reduce unintended causalities has particular advantages for wars being fought by democracies, where public relations is an important aspect of welfare.

Civilian Uses

(1) Navigation: ranging from personal hand-held devices for tracking, to devices fitted to cars, trucks, ships and aircrafts.
(2) Vehicle Traffic System: The system monitors traffic loads for every needs and accordingly- necessary diversions.
(3) Remote Sensing: Surveying, entering data into geographical information systems.
(4) Search and Rescue
(5) Geophysical Sciences.
(6) Animal Tracking System

Ques. 17 : What is Global Positioning System?

Ans. GPS (Global Positioning System) : The best known satellite navigation system is the United States GPS and as of 2005, the GPS is the only fully functional Satellite System. It consists of 24 of 27 satellites that orbit in six different planes. The exact numbers of satellites are replenished when older ones are retired. They orbit at an altitude of approximately; 20,000 km with an inclination of 55°. The satellites are tracked by a world-wide network of monitor stations. The tracking data is sent to master control station that continuously updates position and clock estimates for each satellite. The updated data is then uplinked to the satellite via one of several ground patterns. The accuracy of GPS signal itself is about 5 metres (16 ft) as of 2005. The GPS System was designed by and controlled by the United States Department of Defence and can be used by anyone free of charge.

Ques. 18 : What is GLONASS?

Ans. GlONASS (Global Navigation Satellite System) : The radio satellite navigation system the Russian counterpart to the United States GPS and Europe's Galileo. It is operated for Russian Government by Russian Space Forces.
Like GPS, the complete nominal GLONASS consists of 24 satellites. 21 operating and three on-orbit 'spares' placed in three orbital planes. GLOSNASS constellation orbits the Earth at an altitude of 19,100 km. Slightly lower than GPS.
The first three test satellites were placed in orbit in October 1982. The system was announced operational on September 1993, but constellation was completed by December 1995.
Due to the economic situation in Russia there were only 8 satellites in operation in April 2002, rendering it almost useless as a navigation aid. Since the economic situation in Russia has improved, 11 satellites were in operation by March 2004. An advanced GLOSSNASS satellite GLOSSNASS-M, with an operational lifetime of 7 years, has been developed. A 3-satellite block was launched in December 2004.
A further improved GLOSSNASS-K with reduced weight and increased operational lifetime of 10-12 years.

Indian Participation

Following joint venture deal with India, which will launch two GLONASS-M satellites on its GSLV rockets.
During December 2005 Summit between India and Russia it was agreed that India would share the development costs of the GLOSNASS-K series and launch them from India.

Ques. 19 : What is GALILEO?

Ans. Galileo : It is satellite Navigation System, a joint initiative of European Commission and European-Space Agency (ESA) agreed on March 2002, to introduce their own alternative to GPS. At a cost of about $ 2.5 billion, the required satellites will be launched between 2006 and 2008, and system will be working, under civilian control from 2008. The first satellite was launched on December 28th 2005; the Galileo is expected to be compatible with next generation GPS System that will be operational by 2012. The receivers will able to combine signals from 30 Galileo and 28 GPS Satellites.
The Galileo 30 new satellites in Medium Earth Orbit will be placed at an altitude of 23,222 km.

Why Galileo for Europe?

The conclusion to build one's navigation system was taken in similar spirit to decision in 1970's to embark upon well-known. European endeavors of Arian Launcher and Airbus.
European Independence is a chief reason for taking this step. Other subsidiary reasons include.
i) By being inter-operable with GPS, and GLONASS, Galileo will be corner- stone of Global Navigation Satellite System (GNSS). This will almost cover most places on Earth.
ii) With Galileo, Europe will be able to exploit the opportunities provided by satellite navigation to extent.

Ques. 20 : What is EGNOS?

Ans. EGNOS : As a precursor to Galileo, the ESA, EU and EUROCONTROL, and developing the European Geo-stationary Navigation Overlay System (EGNOS). This is intended to supplement the GPS and GLONASS Systems by reporting on reliability and accuracy of signals, allowing position to be determined to within 5 metres. It will consist of 3 Geostationary Satellites and a network of grand stations and went operational in 2004.

Ques. 21 : What is BEIDOU?

Ans. Beidou : China has started to launch a series of satellites to form a system called Beidou Navigation System.

Ques. 22 : What is SCRAMJET technology? What are its advantages and limitations?

Ans. Air-breathing Rockets : ISRO tested the scramjet (Supersonic Combustion Ramjet) technology that uses air moving at supersonic speed of March 6 for ignition in Laboratory Condition in January 2006. Conventionally, rockets carry oxygen and fuel and do not depend on oxygen present in the atmosphere to burn the fuel. This is because rockets unlike fighter plane fitted with turbojets which this technology move at very high speed and using oxygen at such high speed is challenging task.
The achievement of producing stable combustion at a high velocity for few seconds is like lighting a matchstick in a hurricane condition. To be more precise, the achievement is not just lighting a matchstick in a hurricane condition but also sustaining the flame for more duration of operation.
ISRO’s achievement was in a Laboratory environment. The air velocity was stimulated to reach March 6 at entry conditions and combustion produced by supplying hydrogen fuel.

Advantages of Scramjet Technology

1. Greater Thrust Achieved: The rockets using liquid fuel will have specific impulse of 300 seconds (thrust generated by burning 1 kg of propellant in 1 second).
Cryogenic fuel will have 440-450 seconds compared with 2500-3000 seconds with scramjet. So compared with Cryogenic, Scramjet Propulsion has significant advantage in enhancing payload capability with cost advantage.
2. Increase in Payload Capacity
Greater the thrust achieved, the lesser the propellant that needs to be carried. Oxygen accounts for nearly 60% of the propellant's weight in a rocket. As scramjet powered rocket utilizes oxygen available in the atmosphere can thus reduce the amount of oxygen to be carried on board considerably. Thus rocket would become lighter or can carry more payloads.
3. There is substantial cost reduction, as less propellant is used for per kg. of payload carried.
But for all its advantages, air-breathing rockets have to still use conventional fuels to reach an acceleration of March 6 before scramjet technology can take over.

Limitations of Scramjet Technology

1. Oxygen Availability: The scramjet technology can be best used at height 10-12 km region, where oxygen is dense. It cannot perform well after crossing the denser region of atmosphere beyond 40-45 km where oxygen concentration decreases.
2. Trajectory Change: The use of scramjet necessitate a more horizontal trajectory. The trajectories are designed to allow the rockets to be in atmosphere for longer periods. These longer horizontal trajectories in atmosphere give rise to thermal problems, as temperature of 2200-2800 kelvin is produced when rocket is in atmosphere at higher velocities for longer periods.
Using Scramjet technology is step towards more important reusable Launch Vehicles. It will take .around 7-8 years before scramjet technology is used in launch vehicles.

Ques. 23 : What is Space Capsule Recovery Expriment (SRE)?

Ans. Space Capsule Recovery Experiment (SRE) : SRE is intended for demonstrating the capability to recover an orbiting space capsule. The experiment envisages the development of a 500 kg recoverable capsule and the associated technologies. SRE is intended to test reusable thermal protection system, navigation, guidance and control, hypersonic aero- thermodynamics, management of communication blackout, floatation system, recovery operations.
After its launch by PSLV, SRE will remain in orbit for few days during which it will be used to perform experiments in micro-gravity environment. The capsule will then be de-orbited and it re-enters the earth's atmosphere. On re-entry after initial braking, a parachute system will reduce the touch down velocity. SRE will splashdown in the Bay of Bengal about 140 km east of Sriharikota. A floatation system will keep SRE afloat and enable its recovery.

Ques. 24 : Briefly discuss the importance and future prospects of ‘ANTRIX’?

Ans. Antrix, the commercial arm of ISRO, is a single window agency for marketing Indian Space Capabilities. It is playing a key role in the world-wide availability of IRS data through Space Imaging, USA. Antrix also provides IRS specific processing equipments.
It offers launch services using India's PSLV, Two German, One Korean and Belgium Satellite have already been successfully launched by PSL V. Through Antrix, Telemetry, Tracking and Command Support from Indian ground stations are offered. In this regard, 11 transponders have already been leased to Intelsat, US based multinational consortium. The deal will fetch US $ 100 million over a period of ten years. Customers for the spacecraft components offered by Antrix include world's leading spacecraft manufacturers. Antrix has signed a commercial agreement with EOSAT of USA and entered In a MOU with Paris based Asian Space.
Antrix has access to the resource of DOS and ISOR, after having made modest entry into billion dollar global space market, it has now emerged as a major supplier of high quality satellite resource data. Currently, data from India's highly successful IRS series of earth observation spacecraft accounts for one-fourth of world-wide market for satellite resource data.
The biggest asset of Antrix is 10,000 highly skilled technical manpower in various facilities of ISRO, which has over the past three decades built up a wide spectrum of technological capabilities.
The current thrust of Antrix is on penetrating the global market for supplying custom made satellites, which is a difficult but challenging and high profit area.

Ques. 25 : What are future challenges for next generation space technologies?

Ans.
1. Tapping of solar energy from space for terrestrial use.
2. Recoverable spacecrafts
3. The prospects of space tourism could be explored
4. The exploration of newly celestial bodies like moon and mars so that they can be made habitable for humans.

NASA: Milestones and Discoveries

NASA’s Next Generation Spacecraft
It announced for its next generation spacecraft and launch system, which will be capable of delivering crew and supplies to ISS, carrying four astronauts to the mans and supporting up to six crew members on future mission to Mars.

Deep Impact Encounters Comet
The Deep Impact Spacecraft travelled approximately 268 million miles to meet comet Tempel-1. Its impact or colludeal with target nucleus, giving researchers, the best-ever comet data and images.

Mars Twins keep on Roving
The Mars exploration rovers continued studying the harsh Martian environment. The rover spirit discovered the composition of rock outcrops altered by water.
The rover opportunity found evidence that water, once flowed across the Martian surface.

Ques. 26 : Given an account of the ISRO’s international cooperation in the space technology?

Ans. International Cooperation : From the days of its inception, ISRO has had a very good record of international cooperation. It has Memoranda of Understanding/Agreements with 26 countries/space agencies. A UN sponsored Centre for Space Science and Technology Education in Asia and the Pacific (CSSTE-AP) set up in India has trained more than 400 personnel of the Asia-pacific region. During the year, CSSTE-AP completed 10 years. In addition, ISRO provides training in space applications to personnel of developing countries through its Sharing of Experience in Space (SHARES) programme.
ISRO has launched scientific payloads of other space agencies like Modular Opto-electronic Scanner of DLR, Germany that was flown on IRS-P3 spacecraft and the data is being shared by scientists of DLR, India and the US. It has a cooperative agreement with NASAOAA for the reception of meteorological data from INSAT spacecraft by those agencies.
Megha-Tropiques is a joint satellite mission of ISRO and French Space Agency CNES for atmospheric studies. The satellite will be built and launched by ISRO and CNES will develop two of the payloads and the third payload jointly with ISRO. At the same time, scientific instruments developed in the United States, Germany, Sweden, UK and Bulgaria were launched on board India's Chadrayaan-1 spacecraft. This apart, an Italian scientific instrument will be included onboard India's OCEANSAT-2 satellite. Instruments for astronomical observation jointly developed with Israel and Canada will be flown onboard India's GSAT-4 and RISAT satellites respectively. And, an Indian scientific instrument to study solar physics and solar-terrestrial sciences will be flown onboard Russia's CORONAS-PHOTON satellite.
India has also set up three local User Terminals and a Mission Control Centre for the international COSPAS / SARSAT programme for providing distress alert and position location service. A search and Rescue Transponder is included in INSAT -3A spacecraft. India is a signatory to the International Charter on Disaster Management and is providing remote sensing data for the same.

Answer of Question 1: C

Answer of Question 1: A