India sets June 5 as the day it will join the heavy-lift rocket club

GSLV Mk III to test itself on a 3,136kg sat, plans for 8,000kg payloads real soon now

The Indian Space Research Organisation has set June 5 as the next milestone in the country's ambitions to build a heavy-lift rocket.

That's when ISRO's Geosynchronous Satellite Launch Vehicle (GSLV) Mark III is due to hoist a 3,136 kg GSAT-19 satellite to a geosynchronous transfer orbit, the first time a launcher in the GSLV series has had such a large payload.

The vehicle is currently in place at the Sriharikota rocket port in Andhra Pradesh.

GSLV Mk III is still a relatively small heavy-lifter, as the table below shows:

Vehicle	LEO payload	In service
NASA SLS	70 tonnes	2019
SpaceX Falcon 9 Full Thrust	22.8 tonnes	Now
SpaceX Falcon 9 Heavy	63.8 tonnes	Q3 2017
Soyuz-2	8.2 tonnes	Now
GSLV	8 tonnes	June 5, 2017

If the destination is low-earth orbit, the GSLV can lift an eight-tonne payload.

For this flight, the GSAT-19 payload has Ka-band and Ku-band communications systems, a Geostationary Radiation Spectrometer, and it will be a test bed for the Indian-developed I-6K modular satellite bus.

It's also the first time the country will launch a rocket using cryogenic fuels – a liquid oxygen and liquid hydrogen third stage – in addition to two 205 tonne strap-on solid-fuel boosters, and liquid propellant engines as the second stage. ®