Thursday, July 9, 2015

India to Launch Five British Satellites on Friday

PSLV-C28 Strap-Ons are being assembled with Core Stage at Mobile Service Tower. Credit: ISRO

The Indian Space Research Organisation (ISRO) is gearing up for the Friday launch of its long-serving Polar Satellite Launch Vehicle (PSLV), slated to deliver five UK satellites into orbit. The lift-off will take place at 21:58 local time (12:28 p.m. EDT) from the country’s Satish Dhawan Space Centre, Sriharikota. The mission, designated PSLV-C28 will carry three identical DMC3 optical earth observation satellites built by Surrey Satellite Technology Limited (SSTL). In addition, the rocket will also haul two technology demonstrators - CBNT-1, an earth observation micro satellite, also developed by SSTL and De-OrbitSail, a nano satellite built by Surrey Space Centre.

The total lift-off mass of the five satellites is about 1.44 tons, what makes PSLV-C28 the heaviest commercial mission so far for ISRO.

“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.

India’s heaviest commercial mission so far was undertaken on June 30, 2014 when PSLV C-23 carried the French satellite SPOT-7 weighing 1,574 lbs. (714 kg).

The 144 ft. (44 m) tall PSLV is an expendable launch system developed and operated by ISRO. It was developed to allow India to launch its Indian Remote Sensing satellites into Sun synchronous orbits. PSLV can also launch small size satellites into geostationary transfer orbit. The rocket has four stages using solid and liquid propulsion systems alternately.

Friday’s launch will be the ninth flight of the PSLV in ‘XL’ configuration. ‘XL’ is the updated version of the PSLV in its standard configuration boosted by more powerful, stretched strap-on boosters. Weighing 320 tons at lift-off, the vehicle uses larger strap-on motors to achieve higher payload capability.

The third generation of Disaster Monitoring Constellation (DMC3) will consist of three identical satellites, each with a height of about 9.8 ft. (3 m) and weighing 985 lbs. (447 kg). They will be launched into a 647 km Sun-Synchronous Orbit (SSO) and thanks to the high spatial resolution and a separation of 120 degrees between them, these satellites can image any target on the Earth’s surface every day. They will be mainly used for surveying the resources on earth and its environment, managing urban infrastructure and of course disaster monitoring purposes. The constellation is expected to be operational for up to 7 years.

In addition to commercial activity the DMC works actively within the International Charter ‘Space and Major Disasters’ to provide free satellite imagery for humanitarian use in the event of major international disasters such as tsunamis, hurricanes, fires and flooding.

The first generation DMC was launched in 2002-2003 to create the first constellation designed to deliver daily repeat High resolution imaging. The second generation was put into orbit in 2009, currently remains perfectly healthy and is expected to continue operations until at least 2018.

The DMC has monitored the effects and aftermath of the Indian Ocean Tsunami (December 2004), Hurricane Katrina (August 2005), and many other floods, fires and disasters.

SSTL built the DMC satellites using its SSTL-300S1 platform equipped with advanced avionics and optical systems that make it possible to perform several different types of imaging such as mapping terrain, strip imaging and mosaic imaging for wide areas.

The CBNT-1 micro satellite, weighing 200 lbs. (91 kg) is designed to test some technical earth observation capabilities, new process and rapid-build techniques. No further information on the spacecraft was released prior to launch.

The smallest of the five PSLV-C28 passengers is the De-orbitSail nano satellite, weighing just 15 lbs. (7 kg). Built by Surrey Space Centre at the University of Surrey, the satellite is designed for demonstration of large thin membrane sail and drag deorbiting. A full mission success will be declared if orbital data shows the expected rapid decay of the satellite, leading up to destructive re-entry.

All the five satellites are planned to be separated from the PSLV rocket about 18 minutes after the lift-off, according to the launch timeline.

ISRO is on track to launch the satellites on Friday and has already started a 62 and a half hour countdown. The fourth stage of the rocket was filled with a Mono Methyl Hydrazine (MMH) propellant and a Mixed Oxides of Nitrogen (MON-3) oxidizer on Wednesday, July 8.

According to ISRO, accommodating the three DMC3 satellites within the existing payload fairing of PSLV was the biggest 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,” ISRO said in a press release.

The satellites will be launched Friday as part of the arrangement entered into between DMC International Imaging (DMCii), a wholly owned subsidiary of SSTL and Antrix Corporation Limited (Antrix), the commercial arm of ISRO, a Government of India Company under Department of Space.

The July 10 lift-off will be the 30th for the PSLV rocket. So far, 27 were successfully launched, reaching their planned orbits. All launches took place from the Satish Dhawan Space Centre. Previously, the PSLV delivered the IRNSS-1D navigational satellite into orbit on Mar. 28, 2015.

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