Indian Space Startup Unveils Fully 3D Printed Cryogenic Rocket Engine

Indian space tech startup Skyroot Aerospace unveiled a fully 3D printed cryogenic engine that is meant to fuel the upper stage of one of its rockets. Called Dhawan-1, the rocket engine is considered India’s first privately developed indigenous fully cryogenic rocket engine that runs on propellants, like Liquid Natural gas (LNG) and Liquid Oxygen (LoX).

The announcement coincided with the birth centenary of Indian rocket scientist Satish Dhawan. Widely considered as the father of the Indian Space Research Programme (ISRO), Dhawan steered the nascent space program through the difficult decade of the 1970s and laid the foundations for robust space research in the country. To honor the renowned engineer, Skyroot Aerospace gave their 3D printed engine design his name.

Skyroot Aerospace unveiled its fully 3D printed cryogenic rocket engine called Dhawan-1. Image courtesy of Skyroot Aerospace.

The Hyderabad-based startup founded in 2018 by former ISRO colleagues is the first private company in the country to build small satellite launch vehicles and promises to send them into space within a week of a customer’s approach. In the past, co-founder and CEO, Pawan Kumar Chandana, who worked as a systems engineer in the ISRO, expressed his desire to see India facilitate private sector participation in space activities with authorization and supervision by the government. This way, he believes the country will be able to tap into a market that is slated to grow exponentially, and expected to launch more than 7,000 satellites in the next decade. Like other space visionaries, the Skyroot Aerospace team is preparing to build technologies for responsive, reliable, and economic access to space. Part of its mission is to enable regular, reliable, and affordable spaceflight.

In the last year, the company tested sub-systems, as it prepares to commercially launch the first rockets by the end of 2021. Skyroot Aerospace successfully test-fired Raman, an upper-stage rocket engine for its Vikram-1 launch vehicle, in July 2020. The engine with a fully 3D printed Injector is capable of multiple restarts which will enable the Vikram-1 rocket to insert satellites into multiple orbits in a single mission. However, the Dhawan-1 cryogenic engine is expected to be even more significant for the company, mainly due to the extreme complexity of the technology and the use of propellants.

Skyroot Aerospace has also revealed that its Senior Vice President, Vasudevan Gnanagandhi, also a former ISRO mechanical engineer and pioneer of cryogenic rocket science in India, is responsible for leading the cryogenic propulsion design and development of the liquid engine for small scale satellite launch vehicle.

Successful test firing of Skyroot Aerospace’s Vikram-1 launch vehicle’s upper stage engine called Raman. Image courtesy of Skyroot Aerospace.

According to ISRO, the cryogenic engine is more efficient and provides more thrust for every kilogram of propellant it burns compared to solid and earth-storable liquid propellant rocket stages, giving it a substantial payload advantage. Specifically, this engine uses liquid fuel and an oxidizer that is maintained at extremely low temperatures.

Moreover, Indian news outlet YouStory reported Chandana saying “LNG is a clean-burning, low-cost, highly-reusable, and safe cryogenic fuel, which is also ideal for long-duration deep space missions carrying satellites or humans.” Making cryogenic-handling technology even more attractive.

But cryogenic engine technology is not new: the world’s first cryogenic fuel-powered rocket engine, a NASA spinoff, remains the most-used upper-stage rocket engine in the United States more than 50 years after its creation. The RL10 rocket engine, first successfully flown in 1963, has been crucial to NASA’s space exploration and has also put hundreds of commercial and military payloads into orbit. What’s more, NASA states that only a handful of countries have the technology, pioneered under the program, to power rockets with liquid hydrogen and oxygen. Now a part of Aerojet Rocketdyne, the RL10 has evolved and in 2016, the company successfully test-fired an RL10 engine with a 3D printed core main injector, which reduced the part’s cost and production time by about half.

For the time being, the startup has completed tests to check the fuel flow and structural integrity of the engine and is presently building a dedicated test facility to carry out the “hot fire” testing of Dhawan-I. While the company has successfully tested the upper-most stage engine of its first rocket Vikram-I, the initial stage engines of Vikram-I are being manufactured. If all goes well, Skyroot Aerospace is looking forward to a maiden launch of Vikram-I by December 2021, with the support and guidance of the ISRO. Nonetheless, the cryogenic engine won’t be part of Vikram-I and is meant for the company’s bigger rocket Vikram-II.