The first of 10 pieces of the twin Space Launch System – SLS rocket boosters for NASA’s Artemis I mission was placed on the mobile launcher Saturday, Nov. 21, 2020, inside the Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center in Florida. Engineers used one of five overhead cranes to lift the segment from the VAB’s High Bay 4 to the newly renovated High Bay 3. The component is the bottom section of the booster, known as the aft assembly, which houses the system that controls 70% of the steering during the rocket’s initial ascent. Over several weeks, the other segments will be stacked one at a time and topped with the forward assembly.
Launching in 2021, Artemis I will be an uncrewed test of the Orion spacecraft and SLS rocket as an integrated system ahead of crewed flights to the Moon. Under the Artemis program, NASA aims to land the first woman and the next man on the Moon in 2024 and establish sustainable lunar exploration by the end of the decade.
America’s powerful new deep-space rocket, NASA’s Space Launch System, will face harsh conditions and extreme temperatures in flight when launching NASA’s Orion spacecraft and potential cargo to lunar orbit, and for that, it’ll need strong protection.
Technicians and engineers have qualified 3D printing to aid in the application of the thermal protection system to the smaller, more intricate parts of the rocket. Spray-on foam or traditional insulation is applied to both large and small components of SLS; it protects the rocket from heat during launch and keeps the propellant within the large tanks cold.
However, small hardware or cramped areas like the internal ducts of the engine section require technicians to either manually spray the foam on or apply a foam casting using, in some cases, a 3D printed mold. During the process, the foam, which is mixed and poured into the mold, expands to perfectly fit the part. This decreases overall processing time by reducing the need for complex and tedious post-process trimming. NASA and Boeing engineers performed extensive development and qualification pour foam testing early in the program.
Using this data, the team developed a refined process that reduced the amount of time required to certify individual 3D printed molds and allowed the team to spend more time focusing on the critical requirements that must be met for each flight foam application. This streamlined the process, from 3D printing to pour application, and allowed for quicker processing times.
As part of the Artemis program, NASA’s Rapid Analysis and Manufacturing Propulsion Technology project is also advancing the development and implementation of metal DED technology to 3D print large rocket engine parts. The method will bring down costs and lead times for producing large, complex engine components like nozzles and combustion chambers for use in the SLS (Space Launch System) launch vehicle, which will bring humans back to the Moon and eventually to Mars as part of the ongoing Artemis program.
This is not – by far – the first time NASA looked at 3D printing for parts of the SLS rocket. In the past PBF processes have been evaluated for the production, for example, of the pogo oscillator, for a bimetallic part, for a composite overwrap, and for a copper thrust chamber by NASA PPP partner Aerojet Rocketdyne. However, these and other prior developments in additive manufacturing did not have the large-scale capabilities that DED technology provides.
NASA is charged to get American astronauts to the Moon by 2024. SLS and Orion represent the backbone for deep space exploration. They will launch from NASA’s Kennedy Space Center in Florida to the Gateway in lunar orbit, and, from there, astronauts will ultimately use a proposed human lunar landing system for missions to the surface of the Moon.