It’s been more than 45 years since the last U.S. astronaut left the moon. And while NASA is finally making plans to send humans back to the moon and eventually to Mars, the technology we’ll use to get us there promises to be much different from the approaches we’ve used up until now.
In-space manufacturing and assembly technology, for example, could help reduce the high costs and complexity associated with traditional launch systems, two factors that have hampered the quest for space colonization.
“Manufacturing and assembling systems in space allows us to think about fundamentally new ways to design, launch, deploy and even repair space systems on orbit,” says Howard Eller, an Advanced Missions Tech Fellow with Northrop Grumman. “Instead of producing a satellite on Earth and figuring out how to fold it up and launch it on top of a large rocket, we could produce large structural elements in space, launch payloads separately on smaller rockets, then integrate the payloads with the structure in space.”
Since much of the satellite’s structure would be produced in space and thus not affected by the force of gravity, he adds, it could be designed with simpler, less costly, less rigid materials while not sacrificing its on-orbit performance.
Another way to reduce launch costs would be to launch a satellite in discrete pieces packed compactly inside a rocket fairing, then use 3D printing processes and robots to perform final assembly on orbit.
Tipping to the Future
Both of these visions will require maturation of manufacturing and assembly systems for space environments. Through its “Tipping Point Technologies” program, NASA has selected nine companies, including Made in Space (MIS), Moffett Field, Calif., to mature technologies required to stimulate the commercial space industry and enable capabilities needed for future NASA missions.
Northrop Grumman is a member of the MIS-led team, which is developing the Versatile In-Space Robotic Precision Manufacturing and Assembly System, aka Archinaut. The team is driving toward a ground demonstration of this robotic 3-D manufacturing system in a simulated space environment in summer 2018. The team hopes Archinaut will be selected by NASA for a future in-space flight demonstration.
To date, MIS has demonstrated the ability to 3D print simple, one-material parts at its Additive Manufacturing Facility inside the International Space Station. The company is printing parts using a variety of materials including PEI/PC (polyetherimide/polycarbonate), a high performance polymer; ABS (acrylonitrile butadiene styrene) plastic; and green polyethylene.
Building Stuff Outside
The long game, of course, is to produce complex, multi-material objects “outside,” in the harsh environment of space. Initially, systems such as Archinaut will focus on manufacturing structures such as reflectors, antennae, trusses and booms — objects that can be extruded into objects of any desired length using 3D printing, then assembled and integrated by robots into large space structures.
Eventually, this production process will include additional types of materials such as conductors (metals) and insulators, which would make it possible, for example, to produce structures with any required power circuitry integrated directly into the structure.
For its part, Northrop Grumman is helping MIS develop space-compatible 3D printing materials that can perform well and withstand the extreme temperatures and radiation levels of space.
“The end goal is to be able to fabricate parts with a polymer material that is light, strong, dense and stable under extreme temperature conditions,” says Eric Fodran, a materials specialist with Northrop Grumman. “Most importantly, the material has to be conductive, to ensure that it won’t build up static electricity that could discharge and damage satellite electronics.”
“In-space manufacturing could create a new ‘on-demand’ paradigm for repairing or providing new equipment for orbiting or deep space platforms,” said Lauren Smith, a Northrop Grumman program manager for applied research. “Instead of bringing to space redundant spares of components or equipment that might be needed over time,” she explains, “astronauts could simply ‘order’ new parts from Earth as needed. The appropriate print file would be ‘beamed up’ to a 3D printer in space, where astronauts could make the needed repairs.”
Raw materials will still have to be ferried to space using conventional launch systems. This approach promises to be less costly and logistically simpler, however, than producing structures on Earth and delivering them to space.
In coming years, adds Smith, the aerospace industry will be debating how and under what circumstances this type of manufacturing would benefit space missions. “On-orbit, on-demand production of components is viewed as helpful,” she says. “In-space printing of satellites and large structures, however, is a fundamentally new mission architecture; we need to understand how this approach is better, faster, or cheaper than what we’re doing today.”
Recycle, Reuse, Reinvent
Regardless of advances made in in-space manufacturing, there will likely remain categories of parts and equipment — processors, traveling wave tubes, high performance microelectronic chips — that are simply too hard to make in space. Those parts, payloads or processing modules will still have to be delivered to space by rockets, then plugged into their respective systems.
According to Eller, one way to reduce launch costs over time and facilitate in-space production of more complex items would be to scavenge all of the required raw materials from the space environment itself.
“There is a wealth of orbiting space junk – dead satellites — that we believe could be recycled and used as raw material for in-space manufacturing,” he says. A recycling system he envisions would use robotic arms to capture and place dead satellites in a large crucible. The crucible, which would be made of a material with an extremely high melting temperature, would be heated by a large solar concentrator.
“Satellites contain a variety of rare materials, each with its own unique melting temperature,” explains Eller. “We could selectively melt and capture all of the material of type A, heat it more to melt and capture material of type B and so on.”
This recycling process would create ingots of raw material with varying degrees of purity, each stored in its own compartment. In theory, this material could be processed and made available for future operations.
The Price of Progress
Even if we could get to a point where a complete satellite system could be produced in space, said Eller, there could be subtle and unintended consequences.
“When we produce satellites on Earth, we obtain parts from many suppliers, each of whom has perfected the recipe for making those part(s) with high reliability,” he says. “When we manufacture in space, we might lose that collective wealth of engineering and manufacturing know-how. So we either have to replicate the original level of expertise — a big challenge — or we have to do without it.”
Either way, he believes, the future of in-space manufacturing and assembly systems is full of promise, excitement and yet-to-be-invented technologies.
“It’s hard to know which aspects of how we use space are going to change,” says Eller. “There is a growing consensus that manufacturing in space is something that will make things completely different.”
Interested in all things in outer space and exploration? We are, too. Take a look at open positions at Northrop Grumman and consider joining our team.