ISRO launched NISAR satellite using cryo engine US denied India

Yesterday, the GSLV-F15 rocket blasted off from the second launch pad at India's spaceport in Sriharikota, in clear weather conditions. The only payload on board was the NASA-ISRO Synthetic Aperture Radar (NISAR) satellite, which was deployed successfully into a Sun synchronous polar orbit at an altitude of 745 kilometres after a flawless flight. The satellite is the first collaboration of its kind between NASA's Jet Propulsion Laboratory (JPL) in California, widely considered as the foremost space research facility on the planet, and ISRO's Space Applications Centre (SAC) in Ahmedabad. This was the 12th flight to use the indigenously developed cryogenic upper stage, a technology that the US tried to prevent India from obtaining. 

In 1992, USA imposed an embargo on the transfer of rocket engine technology between Glavkosmos, then the Russian space agency and ISRO. The deputy spokesperson of the state department, Richard Boucher, explained the sanctions at that time with, "Our principal objective...is to obtain the broadest possible international cooperation in curbing the dangerous proliferation of missile technology." This was a ridiculous justification because the engines on missiles use solid propellant engines that can be stored stably for longer, and not cryogenic engines that have to be fueled within a few days of the liftoff. ISRO had plenty of previous experience with such technology transfer restrictions, and treated the US policy as little more than a nuisance. 

The cryogenic engine is a complex system because the propellants have to be stored at extremely low temperatures, -183°C for oxygen and -253°C for hydrogen. These propellants have to be pumped into the rockets at these low temperatures. The initial GSLV flights used cryogenic upper stages from Russia, but ISRO started developing its own cryogenic upper stage in the late 90s. The first flight of the indigenous cryogenic engine was conducted on April 15, 2010, with the third developmental flight of the GSLV. The payload on board was the GSAT-4 satellite. The indigenously developed cryogenic upper stage could not build up sufficient thrust to inject the satellite into the desired orbit, and instead the launch vehicle tumbled into the sea. In 2014 however, with the GSLV-D5 flight, ISRO successfully injected GSAT-14 into geosynchronous transfer orbit, using the indigenous cryogenic upper stage. 

The US embargo of the transfer of rocket technology to ISRO was lifted in 2011. At that time, the NISAR mission was planned as a satellite with both lidar and radar payloads. JPL had developed the innovative new SweepSAR technology, that allowed for fine spatial resolution without compromising on broad area coverage. NASA was looking for a suitable partner to share the cost of the mission, and approached Japan, Germany and Argentina among others. A decision was made to remove the lidar, and NASA approached ISRO. The initial proposition was a parasitic one, where NASA would just launch their radar payload using ISRO's satellite and rocket. ISRO scientists negotiated for a more equitable partnership, and built a radar payload as well. The NISAR collaboration officially started in 2014, the same year the ISRO successfully demonstrated its homegrown cryo rocket engine.