Friday, March 30, 2018

GSLV Rocket Carries New Indian Communications Satellite to Orbit

GSLV launch on March 29. Credit: ISRO.

A Geosynchronous Satellite Launch Vehicle (GSLV) launched by the Indian Space Research Organization (ISRO) has sent the GSAT-6A communications and technology demonstrator satellite to orbit. Liftoff occurred at 7:26 a.m. EDT (11:26 GMT) March 29, 2018.

The GSAT-6A is a follow-on to the GSAT-6 spacecraft, launched by another GSLV back in 2015. GSAT-6A carries ten S-band transponders on board as well as an unfurlable 20 foot (6 meter) diameter antenna designed to cover the entire country of India. GSAT-6A is expected to serve for at least 9 years once it reaches its assigned geostationary orbit.

If everything goes as it is currently planned, GSAT-6A will serve civil, public, and military purposes and should demonstrate new technologies for India’s space communications program, including operation with handheld ground terminals and network management technologies to help develop a satellite-based mobile communications network.

The GSAT-6A satellite is based on the I-2K spacecraft bus which was developed by the ISRO.

The GSLV is a three stage launch vehicle that includes four liquid-fueled booster rockets. The first stage is a solid-fueled rocket, supplemented by the four liquid rocket boosters. The second stage burns UDMH and N2O4, and the third stage is the Indigenous Cryogenic Upper Stage, fueled by liquid hydrogen and liquid oxygen.

The four LRBs ignite approximately 4.8 seconds before liftoff, which occurs when the first stage ignites. The boosters and core stage fire together for about 2 and a half minutes. After they shut down, the second stage ignites and then separates . Shortly after the first stage separates and the second stage is well underway, the payload fairing separates and falls away.

The second stage burned out an estimated 4 minutes and 40 seconds after the rocket left the pad, separating from the third stage immediately after. The Indigenous Cryogenic Upper Stage burns for about 13 more minutes before throttling down and burning out. The payload separates after a mission lasting about 17 minutes and 47 seconds.

The GSLV took off from Satish Dawn Space Center, from the site’s Second Launch Pad. The rocket flew on an east-southeast heading from India’s eastern coast, eventually flying over the Malay Peninsula as well as the island of Borneo.

The GSLV deposited the GSAT-6A satellite into a geosynchronous transfer orbit with a periapsis of only 106 miles (170 km) and an apoapsis of 22,354 miles (35,975 km). GSAT-6A will use its own engine to conduct three orbit-raising maneuvers to insert itself into geostationary orbit over India, in a circular orbit with a radius of about 36,000 km at the 83 degrees longitude orbital slot. The spacecraft will also reduce its inclination from an initial 20 degrees to zero degrees.

The next scheduled GSLV launch is scheduled for later in 2018, and will carry the Chandrayaan-2 mission to the Moon, which will include a soft lander and rover.

Written by: Christopher Paul
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