Posted: 15 September 2016, 8:50 a.m. EDT
Speaker: Vigor Yang, William R.T. Oakes professor and chair, School of Aerospace Engineering, Georgia Institute of Technology
by Hannah Thoreson, AIAA Communications
Vigor Yang, William R.T. Oakes professor and chair of the School of Aerospace Engineering at
Georgia Institute of Technology, said the biggest challenge facing the development of a launch propulsion system is cost.
Yang spoke about the development of propulsion technology from the 1950s through the present day Sept. 13 during the von Kármán Lecture in Astronautics titled “Rethinking Space Propulsion: Enabling the Future of Space Transportation and Exploration” at
AIAA SPACE 2016 in Long Beach, California.
“When we look at rocket engine development, the prime time was in the 1950s and 1960s,” he said. “There were 13 rocket engines developed.”
The cost of developing new engines has become prohibitive, Yang said.
“Nobody really knows how much money we spent on the F-1 engine,” he explained, estimating that it would have been about $17.85 billion in 2016 dollars with the J-2 costing $12.64 billion in 2016 dollars. “If we had to redo that today, that’s almost Tom Cruise: ‘Mission Impossible.’”
Vigor Yang, William R.T. Oakes professor and chair of the School of Aerospace Engineering at Georgia Institute of Technology, and an AIAA Fellow, presents the 2016 von Karman Lecture in Astronautics: "Rethinking Space Propulsion: Enabling the Future of Space Transportation and Exploration," on Tuesday evening, 14 September, at AIAA SPACE 2016, taking place 13–16 September 2016, in Long Beach, CA.
The financial aspect isn’t the only cost, Yang said. Time and the rate of production are also cost challenges.
“It’s not a technology issue,” he said. “Because the technology has been demonstrated for 50 years.”
According to Yang, there are three factors when it comes to controlling the cost: a high-fidelity design methodology and more advanced design philosophy; advanced manufacturing and materials; and more effective project management.
“A more reasonable cost structure is probably OK for initial design,” he said. “We spend 10 percent of the entire budget. Then, for testing, troubleshooting, redesign, we should probably control that number down to less than 50 percent. And that’s the future.”
Yang cited figures showing that typically the initial design has only been about 2 percent of the overall budget of a propulsion program because the redesign and troubleshooting phase lasts for so long.
Besides the cost challenges in developing a launch propulsion system, Yang also talked about ways propulsion could advance in the future. He offered pros and cons for alternative technology development concepts, such as electric propulsion, solar sails, thermal propulsion and antimatter propulsion.
“Electric propulsion is wonderful because the ISP is always one order of magnitude greater than conventional chemical propulsion systems,” Yang said, adding that the limiting factor is the power supply available to electric propulsion systems.
He explained that solar and drag sail systems, as well as solar thermal propulsion, have very low thrust compared to other options. Nuclear thermal propulsion does not, Yang said, but it requires materials such as uranium, and antimatter propulsion has not seen any serious investment and is not yet a suitable applied technology.
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