The Indian Space Research Organisation (ISRO) is developing a series of heavy lift launch vehicles (HLV) capable of lofting satellites up to 10 tonnes into the orbit.

Mindful of the need to keep development costs under control, we have adopted a modular approach to the design of the HLV, Vikram Sarabhai Space Centre Director M.C. Dathan told mediapersons here on Friday. “While the GSLV Mk3, scheduled to undergo operation flight test in December 2016, will be capable of carrying satellites up to four tonnes, the standard size of satellites is expected to go up to six tonnes in the near future, requiring rockets with more heft,” he explained.

ISRO is toying with the idea of adding a semi-cryogenic stage to the GSLV Mk3 to generate a lift up to six tonnes. A more powerful cryo upper stage is expected to add the required muscle to handle satellites up to 10 tonnes. “What we have in mind is a progressive development to come up with need-based variants of the Mk3 instead of coming up with a new rocket altogether,” Mr. Dathan said.

Explaining the rationale behind the modular approach, he said the miniaturisation of electronics could lead to the development of lighter satellites requiring lesser lift capability. “This is where the modular design makes sense.”

Mr. Dathan said ISRO was developing an orbiter, lander, and rover for Chandrayaan-2, India’s second mission to the moon planned for 2017. “The initial proposal for a Russian lander was dropped after they changed the design, making it too heavy for the PSLV rocket.”