On May 19, 2020, Antarctic Bear learned from foreign media that US space technology startup Rocket Crafters Inc. (RCI) has completed testing of its Comet series hybrid 3D printed rocket engine.
After completing 49 laboratory tests, the latest test launch is to conduct a large-scale proof-of-concept for Rocket Crafters ’STAR-3DTM hybrid rocket engine prior to the planned test flight this year.
Rob Fabian, President of Rocket Crafters, said: “We are very excited about the data we have seen and will soon be able to test the rocket. The engine performance of this test matches the model.”

Rocket technology and rapid prototyping manufacturing
The Florida-based aerospace company has been developing its hybrid technology with the goal of producing a more reliable and cost-effective alternative for launching payloads into orbit.
Rocket Crafters’ patented engine design method combines 3D printed solid rocket fuel particles and liquid propellant, trying to take advantage of these two methods.
The solid propellant will continue to burn until it is exhausted, and 3D printing can print the fuel into a specific pattern to determine how the propellant burns. In addition, 3D printing can also improve the consistency and reliability of solid propellant fuel, and alleviate the excessive vibration problems caused by traditional propellant. According to Rocket Crafters, compared to liquid propellants, the development cost of hybrid engines is lower, faster and safer, and it also has the ability to throttle and restart.
In July 2017, the company won a US $ 542.6 million research contract awarded by the US Defense Advanced Research Projects Agency (DARPA) for the development of 3D printed rocket fuel engines. As part of the research agreement, Rocket Crafters was allowed to use a purpose-built test bench on the Florida Space Coast to test a rocket engine capable of flying to evaluate the rocket’s throttling and emergency shutdown capabilities.

Test the 3D printed rocket
The test was conducted at the Kokokoya, Florida, site about 20 miles south of the Kennedy Space Center in the past three months. The Comet rocket has been tested in the laboratory with 250-500 pounds of thrust, but since February, the rocket has used a 5000-pound full-thrust engine, which is the largest experimental engine version to date.
Of the three tests, two were successful and closely matched the company’s performance model, but the third test had an overpressure anomaly, resulting in damage to the test bench and engine.
According to the analysis, an auxiliary component of the engine initially failed, resulting in a large overpressure inside the combustion chamber. The Rocket Team insists that there are no problems within the core design of the STAR-3DTM engine. From the research and development perspective, this test can still be considered a success.

Rocket Crafters is currently developing, testing and manufacturing the most advanced hybrid rocket engine. Compared with any previous hybrid engine, its thrust is more stable and its performance is more stable. Known as the STAR-3D ™ hybrid engine, Rocket Crafters ’proprietary engine design features safety, throttling, economical efficiency, reliability, and 3D printing.
Fabian said: “This is why we tested. We found and fixed the problem in the test, so we will not have problems on the launch pad. We have to start from here and move on.”
Rocket Crafters is planning to conduct its first test flight later this year, powered by a smaller version of the STAR-3DTM hybrid rocket engine. Subsequently, two large-scale orbital test flights will be conducted and commercial services will be provided to the low-Earth orbit using the small satellite Intrepid launch vehicle, but the launch date has not yet been determined.

Rapid prototyping manufacturing and space launch.
More and more companies are using 3D printing technology to develop different types of rocket fuel for commercial use. For example, scientists at James Cook University (JCU) in Australia use 3D printed fuel particles to power hybrid rocket engines. Using PLA and aluminum particles, 3D printed round particles were manufactured with an initial size of 100 mm long, 20 mm diameter and 6 mm straight circular burner. Despite their poor performance in the August 2019 test, the researchers insist that this fuel has potential.
Singapore startup Gilmour Space Technologies launched a homemade rocket from Australia in July 2016, which was powered by 3D printed fuel. This fuel, composed of two unnamed materials, powers a 3.6-meter-long rocket that launches into orbit from Queensland, Australia. Subsequently, the company received a $ 3.7 million Series A financing in May 2017 and continued to develop launch vehicles using 3D printed rocket fuel.
Compiled from: 3dprintingindustry