India’s Agnikul launches 3D-printed rocket in sub-orbital test after delays

After two years of meticulous preparation and four delays due to technical glitches, Indian space startup Agnikul successfully launched its first sub-orbital test vehicle, powered by its unique 3D-printed rocket engines, the Indian Space Research Organisation (ISRO) announced Thursday.

The single-stage launch vehicle, named Agnibaan SOrTeD (Sub-Orbital Technology Demonstrator), took off Thursday morning local time from the startup’s mobile launchpad at the Satish Dhawan Space Center on South India’s Sriharikota island. This test flight will provide crucial data for the development of Agnikul’s Agnibaan commercial orbital launch vehicle.

Here are some key specifications of Agnibaan SOrTeD:

Agnikul initially conducted full countdown rehearsals in March, postponing the liftoff due to minor observations. The startup prepared for the launch twice in April and once earlier this week, each time aborting just before liftoff due to technical issues during last-minute inspections. The successful launch marked the culmination of these efforts, with the rocket lifting off from the spindle-shaped island on the East Coast of Andhra Pradesh and splashing down in the Bay of Bengal.

The Agnibaan SOrTeD’s engine is a key innovation. Co-founder and CEO Srinath Ravichandran explained that it takes 72 to 75 hours to 3D print one of these rocket engines in raw form. The startup can produce two fully finished engines per week, including steps from the 3D printer, de-powdering, and heat treatment. This process contrasts sharply with traditional methods, which take 10 to 12 weeks to produce a similar-sized rocket engine.

• Single-Piece Component: The engine is printed as a single piece, eliminating the need for welding or tightening.
• Efficiency: The 3D printing process is significantly faster than traditional methods.
• Material: The engines are made from inconel, a strong, high-temperature alloy that is 3D printable.
• Flexibility: The engines can be configured for specific missions and are designed for modularity.

Ravichandran emphasized that the core engine, including the fuel entry, exhaust, and igniter, is 3D printed in one piece. The engine is then integrated with the plumbing apparatus, such as fuel pipes, sensors, and valves.

While companies like Relativity Space and Rocket Lab have adopted 3D printing for their rockets, Ravichandran noted that these companies have not fully embraced 3D printing in the same way Agnikul has. He highlighted Agnikul’s approach to providing flexible, configurable launch solutions, unlike the larger capacity vehicles from other companies that often necessitate ridesharing arrangements for payloads.

Choosing inconel for the engine design presented unique challenges, particularly in heat management due to its poor heat conduction properties. Agnikul had to iterate extensively to design effective cooling channels. Additionally, ensuring the vehicle’s safety while maintaining its mobility required avoiding solid-fuel systems, which are highly explosive. Instead, Agnikul opted for a liquid propulsion-based system, eliminating the need for explosive materials.

Ravichandran detailed the safety measures implemented in Agnikul’s design. The startup avoided systems requiring jettisoning, instead using pneumatic systems for phase separation and other functions. The vehicle’s design also allows for modifications even at the last minute, providing tailored solutions for launching specific small satellites.

Founded in late 2017, Agnikul started experimenting with 3D-printed components, gradually pushing the boundaries to integrate multiple elements and avoid conventional methods like welding. Ravichandran underscored the necessity of iterative design, with the startup going through 70 to 80 iterations for fuel injectors alone. The cooling chambers also saw at least 20 design iterations.

The startup took six to nine months to produce its first set of engines from scratch and spent nearly a year making the engine flight-ready. Agnikul raised $26.7 million in funding last year to reach this milestone. Retired ISRO scientists and researchers from IIT Madras are collaborating with Agnikul to develop vehicles for commercial launches. Ravichandran mentioned that the startup is in talks with over 40 potential customers and has signed letters of intent with some. However, an orbital launch of Agnibaan is expected to take at least six months.

India’s space sector has garnered global attention, particularly with its achievements last year, including becoming the first nation to land a spacecraft on the lunar south pole. The introduction of a new space policy aimed at boosting private participation and increasing limits on foreign direct investments has further stimulated growth. With around 190 space tech startups, India is poised to take its space sector to new heights, driven by innovative companies like Agnikul.

As Agnikul continues to develop its technologies and prepare for commercial launches, the successful flight of Agnibaan SOrTeD marks a significant step forward. The startup’s focus on 3D printing and flexible launch solutions positions it as a key player in the evolving space industry, ready to contribute to India’s growing presence in the global space arena.

In conclusion, Agnikul’s successful launch of its first sub-orbital test vehicle represents a major milestone in the startup’s journey. The innovative use of 3D-printed rocket engines and the ability to overcome numerous technical challenges underscore the potential for further advancements and commercial success. With the backing of experienced scientists and a forward-looking approach, Agnikul is well on its way to becoming a significant player in the space industry.

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