The Indian Space Agency is taking up the project as per the agreement entered by its commercial arm Antrix with the British SSTL weighing 447-kg each and a total payload of 1,440-kg, the heaviest so far for a profitable launch by ISR. PSLV-C28 will be the ninth flight of PSLV in ‘XL’configuration. In addition, the rocket 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 instructor nano satellite built by Surrey Space Centre, it said. It covers a triangular deck christened Multiple Satellite Adapter-Version 2 and a circular sort of L-adapter. The main applications for the three DMC3 satellites comprises of keeping watch on the environment, surveying the Earth’s resources, monitoring disaster-struck areas, offering data on management of urban infrastructure, etc. They are meant to specially fulfill the need for high temporal resolution and spatial resolution optical Earth surveillance. “This is the heaviest payload for a commercial launch. A successful PSLV-C28 start would give a big boost to Isro’s commercial launch capabilities,” said Isro spokesman Deviprasad Karnik. Its last heavy mission was undertaken last year when PSLV C-23 carried 714-kg payload with French satellite SPOT-7 on June 30, 2014. The takeoff process has 20 stages in all with the First Stage Ignition followed by Strap-on 1.2 Ignition on ground 0.42 seconds after liftoff. The Strap-on 3.4 Ignition will be given at 0.62 seconds after launch. The Strap-on 5.6 Airlift Ignition will be at 25 seconds after detonation at 2.68 kilometres altitude and at a velocity of 570.51 metres per second. The first stage separation will be at 1 minute 50.38 seconds after the takeoff at 68.82 km with a velocity of 2147.52 meters per second. The second stage will follow then separating the payload in its first stage and then in the second and third stages within 4 minutes from start. The third stage separation will at 8 minutes and the fourth stage will follow within seconds. The DMC3-1 will part from the launch vehicle 17 minutes 56.58 seconds, the DMC3-2 in less than 0.20 seconds later and third one DMC3-3 will follow suit in another 0.22 seconds. All the three DMC3 satellites will separate at 653.09 km altitude with a velocity of 7532.16 metres per second. The mission life of DMC3 satellites will be 7 years and they are powered by Lithium Ion 480 Whr, Solar panel-230 W Peak BOL with an imaging resolution of 1m Panchromatic, 4m Multi-Spectral (Blue, Green, Red, NIR). Launched into a single Low-Earth Orbit plane and phased with a separation of 120 degrees between them, these satellites can image any target on the Earth’s surface every day.
