Vandenberg Space Launch Complex in California. Cape Canaveral and the Kennedy Space Center in Florida. Van Horn and Boca Chica, Texas.
Unless you live near one of these well-known launch sites, you might not realize how many rockets depart from our planet’s surface each month—each one carrying hugely expensive telecommunications equipment, scientific research instruments, supplies for the International Space Station, and the most precious cargo of all…human beings. Simply put, the stakes are high, and the margin for error is low.
At the same time, competition in the space launch industry is also at an all-time high. SpaceX has recently taken the lead in this race, completing more than 400 missions at the time of writing. Yet, NASA still remains a driving force in space exploration and continues to lead humanity into the final frontier.
Other major players include Blue Origin, Firefly, Rocket Lab USA, and the United Launch Alliance. These are just a few of the leading private U.S. companies in this arena, not to mention the commercial and government-led enterprises in other countries such as Arianespace in France and Russia’s Roscosmos.
Regardless of which company or organizations are manning today’s space missions, it’s a high-stakes endeavor, with no margin of error anywhere in the myriad command and control technologies needed to not only launch spacecraft but also safely return them to Earth.
None of these missions would be possible without advanced materials and the manufacturing technologies that coax them into shape. This is especially true for the parts that few people think about—the complex system of tubes, domes, diaphragms, rings, chambers, and cones hidden inside the rocket fuselage. If rocket components are improperly designed or manufactured, the likelihood of a mission failure exponentially increases.
That’s why it’s quite literally mission-critical to choose a rocket component manufacturer with the most qualified and experienced teams, as well as with the latest machinery and manufacturing capabilities. Advanced Structural Technologies (AST) is proud to be one of the industry-leading manufacturers for all these reasons and more.
Let’s take a look at three products AST excels in state-of-the-art manufacturing and fast delivery: pressure vessel components, cones and nozzles, and fuel system components.
Pressure Vessel Components
Consider what many might consider to be the heart of the propulsion system: the pressure vessel. You might think of it as the gas tank. In concept, at least, it’s a relatively simple shape consisting of a tube with a dome at each end, one that’s likely wrapped in carefully engineered carbon fiber for additional structural integrity.
A rocket manufacturer has many options for designing the pressure vessel. Near the top of this list is reducing the number of welds or seams it contains, which means making it from as few sections as possible.
Ti-6Al4V titanium checks all of these boxes, with 6061-T6 aluminum used for those applications with a higher weight budget. For more extreme applications where strength is a top requirement, superalloys like Inconel® and HAYNES® are other options. These are just two of many materials AST can work with to meet our space customers’ high standards for safety and performance.
To maximize pressure vessel strength, however, controlled grain flow and metallic structure are equally important. Some manufacturers might assume that forging is the answer, or perhaps explosive forming. Each has its uses, but in terms of metallurgical integrity and design flexibility, neither can compete with rotary forging, followed by flow forming.
From a high-level point of view, a precision-sawed billet is heated and forged in a rotary forging press, which applies rotational and axial pressure to impart the metal with a fine, unidirectional grain flow. The result is a circular shape with significantly greater tensile strength and far fewer inclusions and porosity than one made using traditional drop- or closed-die forging methods.
AST specializes in top-of-the-line rotary forging as well as spin forming (for conical shapes) and flow forming (for tubular shapes), supported by the latest manufacturing machines and highly skilled and trained teams to ensure safe and precise construction of pressure vessel components.
Cones and Nozzles
Rotary forging and flow forming are mature, predictable metalworking processes, with a proven track record in this and other industries. What’s evolving quite rapidly is product design.
Because spaceflight is growing rapidly, rocket manufacturers must continue to refine their wares while also pursuing radically new concepts. To achieve both, they must develop strong partnerships with their suppliers. This is necessary not only for guidance and support as they explore all that’s possible with their chosen manufacturing process, but also to work through various design iterations in a cost-effective, expeditious manner.
For instance, designers might adapt to a new launch vehicle by changing bottle counts or opting to use cylinders with different volumes and pressure capabilities. In response to structural changes, they often need to adjust wall thicknesses or modify mounting flanges to meet application-specific requirements. The ability to create these and many other unique adaptations helps lead to an optimized, flight-certifiable design that, again, might not be possible without ongoing collaboration and a thorough understanding of the manufacturing process.
Another notable component, and the one that draws the most attention when rockets lift off, is the nozzle (and the combustion chamber to which it is attached). Considering the massive pillar of fire that emerges from its bottom end, this cone-shaped part must bear all of the attributes discussed earlier—namely great strength, structural integrity, and robust metallurgical properties—but also have extreme temperature resistance.
Due to the extreme temperatures involved (2,500°C to 3,500°C, or approximately 4,500°F to 6,300°F), the combustion chamber and nozzle are meticulously designed to generate that pillar of fire. Liquid cooled copper-chromium-zirconium (CuCrZr) liners with jackets of heat-resistant high-performance alloys like Inconel® and HAYNES® see frequent use here. Nozzle extensions of nickel alloys and niobium are also common, while titanium alloys are utilized here and in other conical components such as the nose cone.
AST has deep knowledge and experience working with a wide variety of metals according to customers’ needs. These include the previously mentioned metals such as aluminum, titanium, copper, stainless steel, Inconel®, HAYNES®, and other nickel alloys.
No matter whether materials are sourced by customers or AST assists in material sourcing, you can count on our team to deliver components manufactured to your precise requirements.
Fuel System Components
Pressure vessels and liners are additionally needed to keep fuel and oxidizers safely contained within the rocket body. Fuel lines and manifolds are needed to transfer liquids to the turbopumps and combustion chambers. Flanges, rings and seals are needed to connect different parts of the rocket engine and to manage the flow of gases and propellants. Some liquid tanks need a diaphragm, a thin, metal membrane that separates the various fluids and gases, and helps to maintain pressure differentials during launch.
As with all other components, each must meet the demanding specifications and metallurgical properties if launches are to go as planned. And as many rocket manufacturers can attest, rotary forging and spin/flow forming deliver the fewest possible seams and the greatest structural integrity possible.
As American engineer and inventor of the first liquid-fueled rocket Robert Goddard discovered nearly a century ago, there’s a great deal to launching a rocket (his first attempt only reached 41 feet). Since then, the stakes have only gotten higher as the space industry attempts to fly faster, farther, and more cost-effectively than ever before.
AST and our advanced manufacturing team look forward to supporting all partners in the exciting and evolving space industry, just as we have continued to do for over 10 years.
Our products and capabilities extend far beyond those covered here. To learn more about how AST can meet your needs for rocket components, contact us today or call us at (805) 204-9133.