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India launches five UK satellites

Srinivas Laxman, Indian Space Correspondent
Jul 11, 2015, 17:31 UTC

Sen—At 16.28 UTC on Friday July 10, India’s nearly 50-year-old space programme took a giant leap by successfully launching the heaviest commercial mission in its history.

This historic flight, which lifted off from the first launch pad of the Satish Dhawan Space Centre at Sriharikota, placed in orbit five UK-made satellites having an overall launch mass of 1443 kg. The rocket which carried the satellites was the advanced version of the highly proven four-stage Polar Satellite Launch Vehicle (PSLV) known as the PSLV-XL. The mission marked the 30th flight of the PSLV, and the ninth of its advanced version.

As the rocket thundered up, it lit up the night sky over the vast spaceport as though a festival was being celebrated. The last time ISRO launched a mission at night was on Oct. 16 2014 when the Indian Remote Navigation Satellite System spacecraft (IRNSS-IC) lifted off at 20.00 UTC.

At the launch control centre the mood among the scientists was one of nervous apprehension. Then as the moment of take-off neared, the weather was a ‘go’ and all flight conditions were within the launch parameters.

As the countdown hit the zero mark, the rocket lifted off with an awesome roar with its ear-deafening sound reverberating throughout the area. After a while the sound began to fade and the rocket disappeared out of sight.

The rocket performed perfectly and all the five satellites were placed into their respective orbits after about a 20-minute flight.

An ISRO official told Sen that while the commercial arrangement with the UK-based organisations could not be disclosed, the cost of the rocket was about USD $27 million. The mission, he said, was significant in one more way because it was the first time that ISRO was launching a dedicated flight for a single foreign customer with five satellites.

The flight takes the number of foreign satellites launched by ISRO to 45.

Of the five UK-made satellites, three were identical DMC3 (disaster management constellation) optical Earth observation satellites built by Surrey Satellite Technology Limited (SSTL), each weighing 447 kg, and they were placed into a 647 km Sun Synchronous Orbit.

According to ISRO, the DMC3 constellation is designed to address the need for "simultaneous high spatial and high temporal resolution optical Earth observation." Launched into a single low Earth orbit plane and phased with a separation of 120° between them, these satellites will image any target on Earth every day round-the-clock. Major application areas include surveying the resources on Earth and its environment, managing urban infrastructure and monitoring of disasters. The data will not be used in India.

Placing the three DMC3 satellites, each with a height of about three metres, within the existing payload fairing of PSLV was a challenge. To mount these satellites onto the launcher, a circular launcher adaptor called as L-adaptor and a triangular deck called multiple satellite adapter-version 2 (MSA-V2), were newly designed and realized by ISRO for this specific purpose.

Apart from the three DMC3 satellites, the rocket also flew two auxiliary satellites: CBNT-1, a technology demonstrator Earth observation micro satellite built by SSTL, and De-OrbitSail, a technology demonstrator nano satellite built by Surrey Space Centre.

CBNT-1, weighing 91 kg, is an optical Earth observation technology demonstration micro satellite built by SSTL. The seven-kg De-orbitSail from Surrey Space Centre is an experimental nano satellite for demonstration of a large thin membrane sail and drag deorbiting using this sail.

These international customer satellites are being launched as part of the arrangement entered into between DMC International Imaging (DMCii), a wholly owned subsidiary of SSTL, UK, and Antrix Corporation Limited (Antrix), the commercial arm of Indian Space Research Organisation (ISRO).

ISRO chairman Kiran Kumar said that there will be a series of launches through to March 2016.

Director of Satish Dhawan Space Centre, P Kunhi Krishnan, said that the PSLV has developed from a national workhorse to an international workhorse.

An ISRO official told Sen that with this success the queue for launching satellites by foreign customers using the PSLV will considerably increase.