using the alternative fuel during a mission in early 2015.
Aerojet Rocketdyne has made a new rocket engine from the ground up for the mission. “It’s a very different fuel. It operates at a much higher temperature, so we have to use different materials,” Myers says. “The viscosity of the propellant is different.”
The rocket completed an end-to-end checkout last month.
Meanwhile, Aerojet Rocketdyne is growing in Redmond, Myers says. The company hires people with a range of aerospace, mechanical, and electrical skills. About 40 percent of the current staff is “pure technical,” including about 20 people with PhDs, Myers among them. Another 30 percent are highly-skilled machinists and assembly technicians. The remainder are in business management and administration.
The rocket-engine-building process starts with design and analysis. Then a model is made using 3D printing, a time-saving technology employed by Aerojet Rocketdyne for the last three or four years. (The company is working with researchers at Washington State University through the new Joint Center for Aerospace Technology Innovation, established by lawmakers last year, on ways to use 3D printing for actual flight hardware, too.) The model is analyzed and design issues are corrected, and then an aluminum model is made. After yet more analysis and design, the machinists make the final parts from titanium, high-strength steels, refractory metals, and other materials. Technicians assemble the engine before sending it in a covered “dog cart” to the testing labs at the other end of the property.
Aerojet Rocketdyne’s acceptance testing program is rigorous, and for good reason.
“A typical spacecraft will run a couple hundred million dollars, and you don’t want to be the cause of a bad day,” Myers says.
First, an engine is mounted on a programmable vibration table that simulates the intense shaking from the big rockets of a launch vehicle.
After it has survived that, it is mounted on a thrust stand inside one of several mini-submarine-sized vacuum chambers that approximate certain conditions in space, such as extreme temperatures—using hot plates, lamps, and liquid nitrogen—and near-zero pressure. (Zero gravity, Myers explains, is not a significant issue for rocket-engine operation.)
The testing facility has many layers of safety and environmental controls to keep the toxic and highly combustible chemical propellants tightly controlled until they are ignited in live-fire tests within the vacuum chambers. The facility is hard-wired into area fire departments, which conduct training exercises here, just in case. “Nothing’s ever happened, but we’re very careful,” Myers says.
Engineers verify that the rockets perform in the tests as they should. Then the engines are cleaned, carefully packaged, and shipped—via standard commercial carriers—to spacecraft manufacturers, to be joined up with other complex systems, and continue on journeys that may extend for millions of miles.
Myers sees lots of opportunities for his company and others in the commercial era in space. Propulsion efficiency improvements benefit a range of existing and emerging space businesses, from communications to tourism to asteroid mining.
“If we’re going to grow this business, we need innovations that help us reduce the cost and create new demand for space applications,” he says.
