* Astronomy

All these years the Indian space agency ISRO had launched satellites primarily for domestic use. Opportunities to carry third-party payloads are now being actively tapped.

Chennai: The Indian Space Research Organisation (ISRO) has a busy launch calendar ahead. A slew of launches have been lined up under the country's two satellite systems-Indian National Satellite (Insat) and Indian Remote Sensing (IRS) Satellite. While Insat satellites are for communication the IRS satellites are for earth observation/remote sensing..

For the first time in its history, ISRO will launch a vehicle to carry a third-party satellite as the primary payload. Preparations have commenced for a Polar Satellite Launch Vehicle C8 (PSLV C8) launch of the commercial spacecraft Agile of Italy as the primary payload and an advanced avionic module (AAM) as the secondary payload. The launch is planned this fiscal.
Similarly preparations are underway for the launch of PSLV C7, also planned this fiscal. PSLV C7 will carry 3 satellites on board - the 660 kg Indian remote sensing (IRS) satellite, the Cartosat 2, 610 kg Space capsule Recovery Experiment (SRE) and the 56 kg Indonesian Lapan Tubsat.

The other launches are of the Insat and remote sensing satellite series.

Insat satellites in the pipeline
Established in 1983, Insat is one of the largest domestic communication satellite systems in the Asia Pacific region. The system has 9 satellites in operation - Insat 2E, Insat 3A, Insat 3B, Insat 3C, Insat 3E, Insat 4A, Kalpana, GSAT 2 and Edusat.

Insat 4C, the latest in the Insat family, will be launched from Satish Dhawan Space Centre SHAR, Sriharikota, India on July 10, 2006. It is the first Insat series satellite to be launched by an Indian launch vehicle-the Geo Synchronous Satellite Vehicle (GSLV). Weighing 2,168 kg, Insat 4C is the heaviest satellite to be carried up by the GSLV.

The satellite carries 12 high power Ku-band transponders designed to provide Direct-To-Home (DTH) television services, facilitate Video Picture Transmission (VPT) and Digital Satellite News Gathering as well as to service National Informatics Centre (NIC) for its Very Small Aperture Terminal (VSAT) connectivity.

The Insat system is a joint venture of India's Department of Space, Department of Telecommunications, India Meteorological Department, All India Radio and Doordarshan. The overall coordination and management of Insat system rests with the secretary-level Insat Coordination Committee.

Insat 4B
Insat 4B, which is identical to Insat 4A, carries 12 Ku-band transponders and 12 C-band transponders. The satellite will be co-located with Insat-3A at 93.5 degree East longitude.
Launch date: 2006-07
Launch vehicle: Probably Ariane.

GSAT 4
GSAT 4 is envisaged as a technology demonstrator. The communication payload consists of multi-beam Ka-band bent pipe and regenerative transponder and navigation payload in C-band, L1 and L5 bands. GSAT 4 will also carry TAUVEX-II, a scientific payload comprising three ultra-violet band telescopes developed by Tel Aviv University and Israel space agency, ELOP, for surveying a large part of the sky in the 1400-3200 Å wavelengths.
Launch date: 2006-07.
Launch vehicle: GSLV

Insat 3D
Insat 3D is an advanced meteorological satellite carrying imager and sounder instruments. The spacecraft has many new technology elements like the star sensor which is being flown for the first time in geo-synchronous orbit, micro stepping solar array drive (SADA) to reduce the spacecraft disturbances and the bus management unit for control of spacecraft.
Launch date: 2007-08.
Launch vehicle: Probably Ariane

GSAT 5/Insat 4D
It is a C-band and Ext C-band satellite, carrying 18 transponders. Of these, 12 transponders will operate in the normal C-band with wider coverage in uplink and downlink to cover Asia, Africa and Eastern Europe/Zonal coverage. Six transponders will operate in Ext C-band and have India coverage. The option of incorporating L-band is under consideration.
Launch date: 2007-08.
Launch vehicle: GSLV

GSAT 6/Insat 4E
GSAT6/Insat 4E will carry digital multimedia broadcasting payload. The satellite will cover the whole of India through five S-band spot beams using SXC and CXS transponders. The C-band coverage for the feeder link will have India coverage.
Launch date: 2nd quarter of 2008-09
Launch vehicle: GSLV.

GSAT 7/Insat 4F
GSAT 7/Insat 4F is proposed as a multi-band satellite carrying payloads in UHF,
S-band, C-band and Ku-band.
Launch date: 2009-10
Launch vehicle: GSLV.

GSAT 8/Insat 4G
GSAT 8/Insat 4G is proposed as a Ku-band satellite carrying 18 transponders similar to that of Insat 4A and Insat 4B. It will also carry 2 BSS transponders and a GPS aided geo augmented navigation (GAGAN) payload.
Launch date: 2008-09
Launch vehicle: GSLV

Anusat
Anusat, a 35 kg micro-satellite, is being designed by Anna University, Chennai. The main objective is to involve universities in building micro satellites as a means to promote and encourage intra-disciplinary technologies with the help of ISRO.
Anusat carries a digital store and forward payload for amateur communication. In addition, a number of technological payloads like digital receiver and turbo coder, MEMS-based gyro and magnetic field sensor are planned to be flown on board. Structure, solar panels, chemical battery, sensors and actuators will be supplied by ISRO. The payloads and the other satellite subsystems are designed and fabricated at Anna University.
Launch date: To be decided
Launch vehicle: PSLV

Forthcoming IRS satellites
The IRS has the world's largest constellation of remote sensing satellites in operation today. The seven remote sensing satellites in operation are - Cartosat 1, IRS 1C, IRS 1D, IRS P3, Oceansat 1, Resourcesat 1 and Technology Experiment Satellite (TES). They are placed in polar sun-synchronous orbits providing data in a variety of spatial, spectral and temporal resolutions, meeting the needs of many applications. The ISRO through its commercial arm Antrix Corporation earns sizeable revenue selling the data. The remote sensing satellites are launched by India's first launch vehicle viz., PSLV.

Cartosat 2

SRE being recovered after sea-drop test
Cartosat 2 is envisaged as an advanced remote sensing satellite carrying on board a single panchromatic camera capable of providing scene-specific spot imageries for cartographic and a host of other applications. The panchromatic camera is designed to provide better than 1 metre spatial resolution imageries with a swath of around 10 km. The co-passenger for Cartosat 2 will be the space recovery experiment capsule.
Launch date: 2006-07
Launch vehicle: PSLV

Risat
The 1,750 kg radar imaging satellite (Risat) is a microwave remote sensing satellite carrying a synthetic aperture radar (SAR) operating in C-band.
Launch date: 2007-08
Launch vehicle: PSLV

Oceansat 2
Oceansat 2 is envisaged to continue the services of Oceansat 1. The satellite will carry two payloads for ocean related studies, namely, ocean colour monitor (OCM) and Ku-band pencil beam scatterometer. An additional piggy-back payload called Rosa (Radio Occultation Sounder for Atmospheric studies) developed by the Italian Space Agency (ASI) is also proposed to be included.
Launch date: 2007
Launch vehicle: PSLV

Resourcesat 2
Resourcesat 2 which is aimed to provide continuation of services of Resourcesat 1 will have the imaging sensors same as its predecessor with miniaturisation of payloads electronics.
Launch date: 2008-09
Launch vehicle: PSLV

Twsat
Twsat is a remote sensing micro-satellite for the third world countries. The payload is proposed to have a 4-band CCD camera with 35 metre spatial resolution and 140 km swath supporting generation of both natural colour composite and false colour composite data products.
Launch date: As a piggy back to one of the remote sensing satellites
Launch vehicle: PSLV

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