Isro’s PSLV-C28 successfully places 5 British satellites in orbit

The Indian Space Research Organisation (Isro) on Friday successfully launched five British commercial satellites aboard its PSLV-C28 launch vehicle from its space port in Sriharikota, marking its heaviest commercial mission ever.

ISRO's workhorse Polar Satellite Launch Vehicle PSLV-C28, in its 13th flight, placed the five satellites, including three identical DMC3 optical earth observation satellites, in sun synchronous orbit about 20 minutes after lift-off at 9.58 PM from the Satish Dhawan Space Centre at Sriharikota.

The three DMC3 satellites, each weighing 447 kg, were launched into a 647 km sun-synchronous orbit (SSO) using the high-end version of PSLV (PSLV-XL).

''It's been a wonderful mission… an extremely successful mission,'' a beaming ISRO chairman Kiran Kumar said from the Mission Control Centre.

The three identical DMC3 optical earth observation satellites were built by Surrey Satellite Technology Limited (SSTL) of the United Kingdom.

The PSLV-C28 also carried two auxiliary satellites from the UK, viz, 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.

PSLV-C28 will be the ninth flight of the launch vehicle in 'XL' configuration.

With the overall lift-off mass of 1,440 kg of the five satellites, this launch becomes the heaviest commercial mission till date undertaken by Antrix Corporation, the commercial arm of ISRO .

Accommodating the three DMC3 satellites each with a height of about 3 metre within the existing payload fairing of PSLV was a challenge, according to Isro.

To mount these satellites onto the launcher, Isro designed a circular launcher adaptor called L-adaptor and a triangular deck called Multiple Satellite Adapter-Version 2 (MSA-V2).

These international customer satellites have been launched as part of the arrangement entered into between DMC International Imaging (DMCii), a wholly-owned subsidiary of SSTL, UK and Isro's Antrix Corporation Limited (Antrix).

The DMC3 constellation, comprising of three advanced mini-satellites DMC3-1, DMC3-2 and DMC3-3, is designed to address the need for simultaneous high spatial resolution 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 can image any target on the Earth's surface every day. Major application areas include surveying the resources on earth and its environment, managing urban infrastructure and monitoring of disasters.

CBNT-1, weighing 91 kg, is an optical earth observation technology demonstration micro satellite built by SSTL. The 7-kg De-orbitSail from Surrey Space Centre, is an experimental nano satellite for demonstration of large thin membrane sail and drag deorbiting using this sail.