Next stage

Indigenous cryogenic engine lift-off for India's space programme

The launch of the third-generation weather satellite Insat-3DS by the Indian Space Research Organisation (Isro) on Saturday was hailed as a big achievement. While the satellite enhances India’s weather-prediction abilities, the aerospace agency was thrilled with the trouble-free performance of the engine, the GSLV F14 rocket with a cryogenic third stage. India has struggled for four decades to develop an indigenous cryogenic engine. This “mature” and “smart” performance not only has huge positive implications for India’s aerospace ambitions but could potentially also give a new dimension to military capabilities.

Cryogenic engines use mixes of liquefied gases (usually hydrogen and oxygen), which deliver greater thrust to weight. These rockets can, therefore, carry greater payload at higher speeds. Liquid hydrogen and oxygen are stored separately at very low temperatures and combust explosively when brought together. Managing temperature differences and ensuring there is no hot “blowback” into storage tanks, etc, is tricky. Solving these technical issues requires great design and a solid grasp of material sciences. There’s a short list of six nations, including India, which are known to possess this capability. India started with engines from Russia. However, this is dual technology, since it has obvious military implications. Given Pokhran-II and India’s missile programme run by the Defence Research and Development Organisation (DRDO), the US has persistently tried to block R&D in this area. The Russians did not transfer technology, though they have provided six engines over the years. Isro had to reverse-engineer everything and developed new processes. There were four failures, and two part-failures in the first 15 launches. After this 16th launch, the technology is believed to have stabilised, and the engine, nicknamed “Naughty Boy” within Isro, is now being called “Smart Boy”. This engine can push over 6,000 kg into Low Earth Orbit and over a third of that into higher geostationary orbits (the Insat-3DS weighs about 2,275 kg). It would considerably ease the complexities of future missions to the Moon or Mars, or setting up a space station, or putting Gaganauts into orbit.

There are immediate commercial implications, since it can put larger loads into higher orbits, making India a more significant player in the global satellite business. Apart from Isro, private-sector startups are also trying to develop cryogenic engines and experimenting with different designs. The Insat-3DS offers enhanced coverage of oceans along with two earlier Insats. The next mission is launching the NISAR (Nasa-Isro Synthetic Aperture Radar) satellite, a collaboration between Isro and Nasa, and the most prestigious mission entrusted to the GSLVF14.

The military implications are more nebulous. Isro does not do military applications, but it would share technology with DRDO and the private sector after the Aerospace Act. Also, since fabrication is tendered out, India’s aerospace complex has now developed material science capabilities, which can be harnessed to many applications. The capacity to put more and larger payloads into space translates into more robust communications, including military communications. This would help boost satellite broadband.

Cryogenic engines take substantial time to fuel up, so this does not necessarily translate into missiles, which should ideally be ready for instant launch. Modern ballistic missiles with intercontinental ranges generally use semi-cryogenic engines — often fuelled by a mix of kerosene and liquid oxygen (Agni is solid-fuelled). Isro is researching this, and so are some private outfits. A grasp of cryogenic technologies will also make semi-cryogenic R&D easier. To sum up, stable cryogenic engines are good news, with some immediate payoffs and many potential long-term applications.