In recent years, the vision of creating a worthy successor to the Space Shuttle—an affordable vehicle for space travel—has begun inching ever closer to reality.
The United States has been taking the lead in creating low-cost and reusable launch vehicles, an effort which has been accelerated by a critical fact: with the termination of the Shuttle program in 2011, the U.S. has become dependent upon Russian-built RD-180 rocket engines to move payloads (including national security satellites) into space. In 2014, the U.S. Congress mandated a 2019 deadline to eliminate this dependence and create domestic launch capabilities.
To that end, NASA has been partnering with numerous companies since 2006 to develop the capacity to transport cargoes and crews into low-earth orbit. Several U.S. companies are involved in this effort, and are now close to the promise of bringing payloads and passengers into space, deploying cost-effective (and in some cases, reusable) launch platforms, utilising nickel-containing alloys.
3D printing and nickel alloys are used in the manufacturing process
Space-X (founded by Tesla’s Elon Musk), Blue Origin (founded by Amazon billionaire Jeff Bezos) and publicly traded Aerojet Rocketdyne are three companies using additive manufacturing (3D printing) to build critical elements of their next rockets. 3D printing has some distinct advantages over the traditional manufacturing approach in rocket design and manufacture. One important advantage is it makes the manufacture of complex elements less costly. According to NASA, a critical element in cost reduction is the ability to minimise the number of components. In the case of one Aerojet engine, the printing assembly requires the manufacture of only three separate parts, compared with over 100 in the original version. And nickel-containing alloys provide the ability to withstand the intense heat and stress required by space flight.
Space-X (as previously noted in Nickel, Vol. 29, No. 2, July 2014) utilises 3D printing to manufacture its engine chamber.
Similarly, Blue Origin is building its next generation liquid natural gas-fueled rocket engine (the BE-4) with the nickel-containing alloy Monel® alloy K-500 (UNS K05500).
Blue Origin’s additive printing approach employs this alloy in the manufacture of all stages of its innovative hydraulic turbine, including some very complex engine flow passages. Monel® alloy K-500 consists principally of nickel (approximately two-thirds) and copper (slightly less than one-third), with smaller amounts of aluminum and titanium, which increases strength by a precipitation hardening mechanism.
The first of the Blue Origin BE-4 engines is now fully assembled, with more engines to follow shortly. Ultimately, eight of these engines will be combined on the company’s 270+ foot New Glenn Rocket, which will boost heavy payloads and passengers into orbit.
Competitor Aerojet Rocketdyne is also aiming at a 2019 launch date. Aerojet is using 3D printing of nickel-containing alloy MondaloyTM to manufacture its critical pre-burner engine component. Aerojet recently successfully completed hot fire tests to validate the design of the pre-burner, a critical part of the engine’s turbomachinery. Full engine testing is scheduled to occur at a future date.
MondaloyTM, which was jointly developed by Aerojet Rocketdyne in tandem with the Air Force Research Laboratory, is similar to Monel, and provides the critical strength and resistance required.
Both Blue Origin and Aerojet are vying to build the engines that will power the Vulcan. This vehicle, developed by the United Launch Alliance (ULA), a joint venture between Boeing and Lockheed Martin, will ship critical U.S. intelligence payloads into orbit in the future. ULA’s current Atlas V rocket, currently powered by Russian engines has successfully performed over 60 launches.
Given successful test experiences to date, it is abundantly clear that 3D printing and nickel-containing alloys will be critical to the future of U.S. space travel for decades to come.