The experimental flight of India's heaviest and upgraded rocket - Geosynchronous Satellite Launch Vehicle (GSLV)-Mark III carrying crew model is scheduled to take off from Sriharikotta anytime between December 15 and 20. The Rs 155 crore mission is to test the atmospheric stability of the rocket. The incendital component of the mission is to test the crew module" said M Y S Prasad, director, Satish Dhawan Space Centre SHAR - Sriharikota.

The rocket does not have the required cryogenic engine for putting four tonnes satellites into Orbit.

"The cryogenic engine is under development and will take two years to be ready," said Prasad.

Since other stages of the other engines are ready, Isro decided to have this mission to test the rocket performance, stability while going up. On the crew capsule, which is designed to take three crew members, Prasad said it is mainly to test the safety parameters of the capsule when it reenters the atmosphere.

Though it is called crew capsule it will not carry any human.

Prasad said, the rocket will go upto 120 kms and then crew capsule will be detached and then it will fall in Bay of Bengal, after 20 minutes of blast off.

The capsule will splash down in the Bay of Bengal, 600 kms from Port Blair and 1600 kms from the space station. The capsule will be recovered by Indian Coast Guard ship.

The mission is conceived and designed to make ISRO fully self reliant in launching heavier communication satellites of INSAT-4 class, which weigh 4500 to 5000 kg, while the existing GSLV-Mark I&II are capable of placing INSAT-II class of satellites weighing 2000 - 2,500 kg into Geosynchronous Transfer Orbit (GTO).

K Radhakrishnan, chairman, Isro earlier told Business Standard that the Indian space agency is planning to launch an experimental mission, with a passive cryogenic engine, which means the cryogenic stage will not be operational.

Once this vehicle gets ready, India need not depend on European space consortium, Arianespace, to carry its four-tonne class of Insat communication satellites.

This rocket will also be used to fly astronauts from Sriharikota. It may be noted that the Narendra Modi government has increased its budgetary allocation from Rs 10 crore to Rs 171 crore to develop this vehicle, according to reports.

Radhakrishnan said the vehicle would go up to an altitude of 120 km and reach a velocity of nearly 5.3 km per second. During this ascent phase, the aerodynamic characterisation, control system will be tested. "We are also using the opportunity to test the re-enter characteristics of the crew module, by flying unmanned crew model in this," he said.

The GSLV-Mark III would also enhance the capability of the country to be a competitive player in the multimillion dollar commercial launch market.

It is envisaged to have multi-mission launch capability for GTO, low Earth orbit (LEO), Polar and intermediate circular orbits. It would also be a proof of advancement of the country's research on the indegenous cryogenic engine capabilities.

It can lift pay load weighing 4 tonne in to the GTO. It is designed to be a three stage vehicle, with 42.4 meter tall with a lift off weight of 630 tonnes. First stage comprises two identical S200 Large Solid Booster (LSB) with 200 tonne solid propellant, that are strapped on to the second stage, the L110 re-startable liquid stage.

The third stage is the C25 LOX/LH2 cryo stage. The large payload fairing measures 5 m in diameter and can accommodate a payload volume of 100 cubic meter. Realisation of GSLV Mk-III will help ISRO to put heavier satellites into orbit.

The first flight of GSLV-D1 took place from SHAR on April 18, 2001 by launching 1540 kg GSAT-1. It was followed by six more launches , GSLV-D2 on May 8, 2003 (GSAT-2 1825 kg), GSLV-F01 on September 20, 2004 (EDUSAT 1950 kg), GSLV-F02 on July 10, 2006 (Unsuccessful), GSLV-F04 on September 2, 2007 (INSAT-4CR 2130 kg), GSLV-D3 on April 15, 2010 (Unsuccessful), GSLV-F06 on December 25, 2010 (Unsuccessful) and GSLV-D5 on January 05, 2014 (GSAT-14 1982 kg).