This week, Rocket Crafters, Inc. announced that it has been awarded a $542,600 contract from the Defense Advanced Research Projects Agency (DARPA) to build and test a large-scale hybrid rocket engine using D-DART, or Direct-Digital Advanced Rocket Technology. The recently patented technology will be used to design, build and test a throttle-capable hybrid rocket engine with 5,000 lbf peak thrust over the course of eight months.
So what exactly is a hybrid rocket engine? It’s a rocket that uses a combination of solid and liquid or gas fuel. Hybrid engines have several advantages over their strictly solid or strictly liquid counterparts. Solid rockets cannot be throttled and restarted, while hybrid rockets can, and hybrids are also faster and less expensive to develop than liquid rocket engines, thanks to their mechanical simplicity – Rocket Crafters’ rockets have only two moving parts. They’re also safer to handle than either liquid or solid rocket engines, because storing the fuel in two different states safeguards against accidental detonation.
These advantages would make hybrid rocket engines seem to be the obvious choice, but while both governments and industries have been trying to develop large-scale hybrid rocket engines for a while, they’ve run into some difficulties, mainly with excessive thrust and unpredictable vibration.
Those issues are nonexistent with Rocket Crafters’ D-DART hybrid rocket engines. The company uses 3D printing to create near-perfect fuel grains from its patented high-energy polymer/additive formulas. The grains serve both as the rocket engine’s fuel source and its combustion chamber. So far, Rocket Crafters has worked with lab-scale prototype engines, but with the DARPA contract, it will begin building a flight-capable rocket motor using a custom static test oxidizer system mounted on a new hybrid rocket test stand, which will be constructed at Florida’s Space Coast. The tests will aim to verify the reliability and consistency of the hybrid rocket engine as well as to demonstrate its throttling and emergency shutdown capabilities.Rocket Crafters’ original test series demonstrated a 97.5 percent thrust profile consistency, and did not show any signs of combustion instability or vibration, which is unprecedented in hybrid rocket engines. Scientists and engineers from Rocket Crafters are now working with researchers at the Florida Institute of Technology to ascertain the optimum solid fuel formulation and oxidizer/fuel mixture for the 3D printed rockets.
The end result of the work will be Intrepid-1, a safe and affordable hybrid rocket-powered launch vehicle that will send small satellites and spacecraft into Earth orbit and further, for commercial purposes. Intrepid-1 will be the first in a family of hybrid rocket-powered launch vehicles designed for this purpose. Like many other companies and organizations that have been using 3D printing to change the way we manufacture for space, Rocket Crafters’ intent is to make space travel more accessible to more people by creating rockets that are safer and more affordable than they’ve ever been before. Discuss in the Rocket Crafters forum at 3DPB.com.