New Delhi: With the successful test firing of an advanced fully 3D-printed cryogenic engine `Dhawan-II’, Skyroot Aerospace, India’s first private rocket builder, achieved a major milestone. The endurance test of ‘Dhawan-II’ which lasted for almost 200 seconds duration (a record) was carried out using Skyroot’s indigenously developed mobile cryogenic engine test pad at Solar Industries propulsion test facility in Nagpur, Maharashtra.

The successful test takes Skyroot Aerospace a step closer to work on Vikram-II which is an upgraded version of Vikram-I which uses a cryogenic upper-stage, ready to launch by next year. In November 2022, with the launch of Vikram-S, Skyroot became the first private sector company to send rockets into space and showcased the disruptive potential of India’s emerging private space industry.

Dhawan-II is built upon the foundation laid by Skyroot’s first fully-cryogenic rocket engine, the 1.0Kn thrust Dhawan – I and was successfully test fired in November 2021. The company has named the cryogenic engine series in honour of Dr Satish Dhawan, who has played a very important role in the development of the Indian Space Programme.

The cryogenic engines use two high-performance rocket propellants which also includes Liquid Natural Gas (LNG) and Liquid Oxygen (LoX). And for storage and operation these require the cryogenic temperatures to be below -150° Celsius, said Skyroot in a statement released on April 4, 2023. Due to their higher specific impulse which helps to enhance payload-carrying capabilities these fully cryogenic engines are perfect for the upper stages of a rocket. An important aspect is that both LNG, which is more than 90 percent Methane, and LoX, are environment friendly as they are green burning propellants as compared to hypergolic, solid and semi- solid, semi-cryogenic propellants which are used in the rocket industry. Globally, only a handful of countries have mastered this advanced technology.

“Our aim is to make spaceflights reliable, regular and affordable and has several launch missions which are progressing towards launch and this includes the upcoming Vikram-I which is expected to be launched by end of 2023. This will be the first orbital private rocket launch in South Asia and will be another milestone for the Indian Space industry,” the company statement added.

The engine development was partly supported by NITI Ayog’s ANIC-ARISE programme which helps to promote technologies including the use of green rocket propellants, according to the company.

Pawan Kumar Chandana, Co-founder and CEO of Skyroot Aerospace, termed the successful test of Dhawan-II as a landmark achievement not only for Skyroot but also the private space sector. According to him, the company is at the forefront of developing cutting edge cryogenic technologies in the private sector and has also pushed the limit with advanced technologies like green propellants and 3D printing.

“This test will enhance the payload capacity of Vikram series of space launch vehicles. And to meet wider customer requirements will make them modular,” said Naga Bharath Daka, Co-founder and COO of Skyroot Aerospace.

Padma Shri awardee and veteran rocket scientist V Gnanagandhi, who leads liquid and cryogenic propulsion at Skyroot commented, “It is highly encouraging that we have achieved continuous firing of 200 seconds with stable combustion. Our 3D printed Dhawan – II engine also uses a 3D printed torch igniter and a bellow-actuated cryo-injection valve with quick response time. It is a remarkable achievement by our team and we could get valuable data for next generation cryogenic engine technology with LNG as fuel.”