Chennai: Indian space agency ISRO is all set to launch its heaviest commercial mission that would put five British satellites on board PSLV-C28 from the spaceport of Sriharikota near here on Friday.
The 62.5 hour countdown began on Wednesday at 07.28 AM and was progressing smoothly for the launch scheduled for 09.58 PM on Thursday, ISRO officials said.
Indian Space Research Organisation's workhorse would lift-off 44.4 metre tall PSLV-XL version from the Satish Dhawan Space Centre at Sriharikota and would put into orbit five satellites.
With the overall mass of five satellites is about 1,440kg, this launch becomes the "heaviest commercial mission" ever undertaken by ISRO and its commercial arm Antrix Corporation.
PSLV, in its 30th mission, would launch three identical DMC3 optical earth observation satellites, built by Surrey Satellite Technology Limited (SSTL), United Kingdom, and two auxiliary satellites.
The three DMC3 satellites, each weighing 447 kg, will be launched into a 647 km Sun-Synchronous Orbit (SSO) using the high-end version of PSLV-XL.
The earlier successful launches by ISRO Mars Orbiter Mission which was launched in November 5, 2013 and the Chandrayaan-1 launched in October 22, 2008 were with similar PSLV-XL variants.
PSLV C28, in addition to the three DMC3 satellites, will also carry two auxiliary satellites from UK 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.
The five 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.
The DMC3 constellation, comprising 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.
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 disasters.
The life of the mission is seven years.