GSAT-8, roving eye in the sky, will make your air travel safer

By Srinivas Laxman

In the early hours of May 21, Arianespace’s Ariane-5 rocket carried Indian satellite GSAT-8 weighing 3,100 kg. One of its payloads will be of much interest to lakhs of air travellers. It promises to strengthen safety standards in Indian airspace. Also, among other things, the satellite with 24 transponders will relay signals in the ku-band, thus improving direct-to-home TV telecasts.

Additionally, it will support communication using small satellite dishes known as very small aperture terminals.

Called Gagan — Geo Augmented Navigation — it is basically a satellite-based navigation system. It is a collaboration, the first of its kind, of India’s space and aviation sectors.

The introduction of Gagan is something to cheer about because it comes at a time when the image of India’s civil aviation sector has been badly tarnished on account of pilots flying with fake licences, poor air safety and erratic air schedules.

Gagan will help allay apprehensions among frequent fliers regarding the safety standards by providing navigation data in all phases of an aircraft’s flight over India, the Bay of Bengal, South-East Asia, the Middle-East and up to Africa. It is compatible with the satellite-based navigation systems launched by the US, Europe and Japan.

The main advantage of Gagan is that it can provide direct air routes  allowing airline operators to save on fuel costs, permit precision approach at runways and manage a plane’s climb, descent and engine performance profiles. It will also improve the airport and airspace access in all-weather conditions.

Gagan was carried for the first time on the GSAT-4 communication satellite by the Geo-Synchronous Satellite Launch Vehicle (GSLV), but the flight ended in failure on 15 April 2010. On Wednesday, Indian Space Research Organisation announced that testing of Gagan will be conducted from the new navigation control centre at Kundanhalli near Bangalore.

The project involves the establishment of a full complement of satellite-based augmentation system consisting of 15 Indian Reference Stations, three Indian Navigation Land Uplink Stations and three Indian Mission Control Centres. Some of these units have already been set up in different regions.

According to those involved with the project, Indian satellite-based air navigation system is required because the current global positioning system constellation of satellites cannot support requirements for all phases of an aircraft flight.

Space experts said that Gagan’s major test will be in December because it has to be seen whether it can reduce disruptions during foggy conditions at the Indira Gandhi International airport in New Delhi. Dislocation of flights at New Delhi upset the entire network.

Subsequently, Gagan will also assist in areas like marine navigation, train and road transport and search and rescue operations. Based on the Gagan experience, the government of India plans to create an autonomous regional air navigation system called the Indian Regional Navigational Satellite System.

Once it is operational towards the end of June or the beginning of July  Gagan will provide a civil aeronautical navigational signal consistent with the International Civil Aviation Organisation as established by the Global Navigation Satellite System Panel.

The total cost of the GSAT-8 project is about Rs 600 crore, of which the price of the launch alone accounts for Rs 300 crore.

A long journey In the last 30 years, Isro started designing and developing an advanced version of the three-stage GSLV, designated GSLV Mark 3, which will have the capacity to carry satellites weighing more than two tonnes.

Had this project had fructified on schedule then Isro need not have depended upon Arianespace to launch its heavy communication satellites weighing more than two tonnes like GSAT-8, and saved on launch costs. The current version of the GSLVs can lift payloads whose weight does not exceed two tonnes. Since GSAT-8 weights nearly three tonnes, it had to be flown by Ariane 5.

Like most ambitions space projects globally, the GSLV Mark 3 project’s slipped for a variety of reasons, and the current indications are that it is tentatively scheduled to take off in 2012.

Isro’s chief spokesperson, S Satish, told Firstpost that GSAT-8, with a 12-year life span, will be positioned at an altitude of about 36,000 kms above the equator and become operational in four to six weeks after all the tests are completed. This will be towards the last week of June or first week of July. “So far its performance has been satisfactory,’’ he said.

The launch of GSAT-8 assumes significance because it a replacement for the Insat-4B communication satellite which was crippled as a result of a serious power problem on July 7,2010.  Since then it has been operating at  reduced capacity which has mainly affected TV telecasts.

To make matters worse, two India-made communication satellites GSAT-4 and GSAT-SP, instead of heading towards the sky fell instead into the Bay of Bengal on April 15,2010 and December 25,2010 respectively when the GSLV rocket which was carrying them failed.

Also the life span of Insat-2E, launched in 1999, is coming to an end. So, there is an urgent need for more communication satellites for helping in areas like education, meteorology, TV and telephony just to name some of the areas.

Currently, there are seven Indian communication satellites in orbit. These are Insat (Indian National Satellite System)-2E, Insat-3A, Insat-3C, Insat-3E, Insat-4A, Insat-4B and Insat-4CR. Together they provide 151 transponders for various communication purposes, and there is a pressing requirement to increase them considering that communication needs of the country are going up.