If one is going to think scientists at Isro are going to take a break after successfully conducting the Mars Orbit Insertion, then one is wrong. The Indian space agency has lined up a series of launches, including test flight of Geosynchronous Satellite Launch Vehicle (GSLV) Mark III - an advanced version of the current GSLV - which will have double the capacity of the current launch vehicle.

GSLV MARK-III will be Isro's next major event, said K Radhakrishnan, chairman, Isro. He said the vehicle is an advanced launch vehicle and it can launch a four-tonne communication satellite into geostationary orbit.

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. The significance of the flight is that it will test the crew compartment as it re-enters earth and splashes into the Bay of Bengal.

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.

As on date, all the stages are in Sriharikota, said Radhakrishnan adding that reviews and integration process are on. "The launch of this would be after the PSLV C26. It could be late October or November, based on the weather conditions," he said. With MARK-III, Isro can launch satellites up to four tonne as compared to the current capacity of 2-2.2 tonne.

Speaking about cryogenic engine, required for Mark III, Radhakrishnan said ground test will be conducted at Mahendragiri soon. "A complete engine has been assembled, and we are going to start the ground testing of the engine in a few months from now. This engine will have a thrust level of nearly 20 tonnes, compared to 7.5 tonne of the GSLV we flew in January 2014," he said.

This engine has to be taken through a series of ground test and then the cryogenic stage will be integrated to it and it will be tested on the ground. Once it qualifies, Isro will use it for the flight. "By the time the cryogenic stage is ready for the flight we will also study from the experimental mission about the vehicle's configuration and aerodynamic behaviour, and if any marginal improvement is needed, we can will do that," said Radhakrishnan.

Before MARK-III, Isro is planning to launch PSLV C26, with IRNSS 1B satellite, which will be India's third navigation satellite.

Radhakrishnan said by December the fourth navigation satellite will be launched. Three more such satellites will be launched in 2015,.

The GSLV that was flown in January successfully will have its next flight in the second quarter of 2015, and that will be used to launch GSAT 6 satellite. A few more communication satellites are also lined up, said Radhakrishnan.