Through 3D printing, or additive manufacturing, robust and high-performing rocket parts can be created and offer improvements over traditional manufacturing methods. SpaceX is pushing the boundaries of what additive manufacturing can do in the 21st century, ultimately making the Falcon 9 rocket and Dragon spacecraft more reliable, robust and efficient than ever before.
On January 6, 2014, SpaceX launched its Falcon 9 rocket with a 3D-printed Main Oxidizer Valve (MOV) body in one of the nine Merlin 1D engines. The mission marked the first time SpaceX had ever flown a 3D-printed part, with the valve operating successfully with high pressure liquid oxygen, under cryogenic temperatures and high vibration.
Compared with a traditionally cast part, a printed valve body has superior strength, ductility, and fracture resistance, with a lower variability in materials properties. The MOV body was printed in less than two days, compared with a typical castings cycle measured in months. The valve’s extensive test program – including a rigorous series of engine firings, component level qualification testing and materials testing – has since qualified the printed MOV body to fly interchangeably with cast parts on all Falcon 9 flights going forward.
SUPERDRACO ENGINE CHAMBER
For almost 3 years, SpaceX has been evaluating the benefits of 3D printing and perfecting the techniques necessary to develop flight hardware. One of our first major successes was printing a SuperDraco Engine Chamber in late 2013. Today, SpaceX is testing the SuperDraco engines as part of its crewed spaceflight program and the Dragon Version 2 vehicle. In late 2013, SpaceX successfully fired a SuperDraco engine at full thrust using a 3D-printed engine chamber developed entirely in-house.
SuperDracos will power the Dragon Version 2 spacecraft’s revolutionary launch escape system, the first of its kind. Should an emergency occur during launch, eight SuperDraco engines built into Dragon’s side walls will produce up to 120,000 pounds of axial thrust to carry astronauts to safety. The system will also enable Dragon Version 2 to land propulsively on land with the accuracy of a helicopter. This will ultimately make the spacecraft fully and rapidly reusable – able to be refueled and reflown multiple times, drastically lowering the cost of space travel.
The chamber is regeneratively cooled and printed in Inconel, a high performance superalloy. Printing the chamber resulted in an order of magnitude reduction in lead-time compared with traditional machining – the path from the initial concept to the first hotfire was just over three months.
During the hotfire test, which took place at SpaceX’s rocket development facility in McGregor, Texas, the SuperDraco engine was fired in both a launch escape profile and a landing burn profile, successfully throttling between 20% and 100% thrust levels. To date the chamber has been fired more than 80 times, with more than 300 seconds of hot fire.
The Dragon Version 2 spacecraft represents a leap forward in spacecraft technology across the board from its Version 1 predecessor. When SuperDracos are flown on a demonstration of Dragon’s launch escape system later this year, it will be the first time in history that a printed thrust chamber has ever been used in a crewed space program.
SpaceX looks forward to continuing to fine tune both the SuperDraco engines and additive manufacturing program, in order to develop the safest, most reliable vehicles ever flown.