India’s Agnikul is launching a 3D-printed rocket in a suborbital test after initial delays

After two years of preparation and four delays in recent months due to technical issues, India’s space launch has started Agnikul has successfully launched its first sub-orbital test vehicle powered by its unique 3D-printed rocket engines, space agency Indian Space Research Organization said on Thursday.

The single-stage launch vehicle, named Agnibaan SOrTeD (Sub-Orbital Technology Demonstrator), lifted off from the startup’s mobile launch pad at the Satish Dhawan Space Center on Sriharikota Island in southern India on Thursday morning local time. Data from the test flight will contribute to the development of the startup’s commercial orbital launch vehicle Agnibaan.

Agnikul initially conducted full countdown rehearsals for the March launch and postponed the launch due to some minor observations. The startup also prepared for the launch twice in April and once earlier this week, each time calling it off just before launch due to technical issues revealed during last-minute inspections. Today, Agnikul finally completed its long-awaited mission after the rocket took off from the spindle-shaped island off the east coast of Andhra Pradesh and crashed into the Bay of Bengal.

The 20-foot-tall vehicle is made of carbon composite, giving it a take-off mass of 1,268 lbs; At its heart is the 3D-printed semi-cryogenic motor that Agnikul has manufactured in-house, each delivering 6.2 kN of thrust.

Agnikul co-founder and CEO Srinath Ravichandran told JS in an interview before the launch that it will take 72 to 75 hours to 3D print one of the rocket engines in its raw form. The startup can produce two fully finished engines within a week, including removing them from the 3D printer, depowdering them and undergoing heat treatment. This is different from the traditional process, which takes 10 to 12 weeks to make a similar-sized rocket engine.

“We distinguish ourselves by the one-piece part where there is no human intervention in the process; what comes out of the printer is the full length, without any welding or fastening or anything like that,” he said during a phone conversation.

Elaborating on the one-piece part that makes Agnikul stand out in the competition, Ravichandran says that the core engine, “where the fuel comes in and the exhaust goes out and everything in between, and the igniter,” in one shot in 3D is printed. a single piece of hardware. The engine is then connected to the piping equipment, such as fuel lines, pressure and temperature sensors and valves.

Although Agnikul claims its 3D printed engine is a world first, companies such as Relativity Space and Rocket Lab have used 3D printing for their rockets much earlier. However, Ravichandran claimed that all these companies have not fully adopted 3D printing.

“They still don’t offer what people should offer, and that’s what we offer: extremely flexible and configurable ways to reach space,” he claimed. “If you have a 1 or 1.5 ton capacity vehicle, which Relativity or any of these other companies have, that’s like forcing people to share a ride, forcing them to figure it out, waiting for people to come in together , and again. , the same set of problems as not dropping in the last kilometer.

Agnikul chose inconel as the material for the engine design. It remains strong at high temperatures and is 3D printable. However, because the alloy is an extremely poor conductor of heat, the startup’s biggest challenge was removing the heat.

“Dissipating heat required many iterations of designing the cooling channels,” Ravichandran said.

The other challenge for Agnikul was to ensure that the vehicle remained completely safe while being a mobile system. The startup decided against using solid fuel systems, which are highly explosive, and instead made the vehicle a completely liquid propulsion system. It also preferred not to use a model that even requires an external connection to explosive material.

“Any of the systems that need to be jettisoned, like pad phase separation or two-phase separation and so on, these are all pneumatic systems,” Ravichandran said.

Agnikul designed the vehicle to be customizable “even at the last minute,” the co-founder said, offering a customized solution for organizations looking to launch specific small satellites.

Agnikul was founded in late 2017 and initially experimented with 3D printed components, such as igniters, cooling channels and fuel injection points. However, the company gradually pushed the boundaries and began to combine different elements to avoid welding and tightening – abandoning conventional methods.

“There is no shortcut to developing something like this. You just have to go through the regimen and keep repeating,” Ravichandran claimed.

He said the startup went through at least 70 to 80 iterations, mostly for fuel injectors, and finally designed an “injector plate,” combining them all into one component. Similarly, the startup went through at least 20 iterations of its cold chambers with different geometries.

The startup took about six to nine months to make its first set of engines from scratch and then spent nearly a year actually making that engine fly, the executive said. Agnikul raised $26.7 million in funding late last year to get to this point.

Retired scientists from the Indian Space Research Organization and researchers from IIT Madras are helping Agnikul develop vehicles for commercial launches. Ravichandran said the startup is already in talks with more than 40 potential customers and letters of intent have been signed with some. However, an orbital launch from Agnibaan would take at least six months.

The Indian space sector has been attracting global attention for quite some time now. Last year, the South Asian country became the first to land its spacecraft on the moon’s south pole and introduced its space policy to encourage private participation. The country, which is home to around 190 space technology startups, also recently updated its policy to increase restrictions on foreign direct investment in the space sector. Now, Indian space startups are laying the foundation to take the country’s space sector to a new level by showcasing their technologies and readying them to generate revenue from customers around the world.