Leslie Williams, Public Affairs, NASA Armstrong Flight Research Center
Can a rocket maneuver like an airplane? And can an airplane act as a surrogate for a maneuvering rocket?
NASA engineers demonstrated just that when they used a NASA F/A-18 aircraft recently to simulate a rocket in its early flight phase to test adaptive software for NASAs new rocket the Space Launch System (SLS), the largest, most powerful launch vehicle for deep space missions.
The tests are helping engineers working on the development of the SLS at NASAs Marshall Space Flight Center in Huntsville, Ala., ensure the rocket can adjust to the environment it faces as it makes its way to space.
Engineers reviewed the root causes of historical launch vehicle failures and found that although guidance, navigation and control systems were rarely the cause of the incidents, they discovered that advancements in this technology could result in expanded capabilities to keep the rocket on track in the face of anomalies that might occur in flight.
When NASA develops new technology for launch vehicles like Adaptive Augmenting Control, we want to test it in order to mature the technology and build our confidence in it, said Tannen VanZwieten, NASA Marshalls SLS flight control lead. But in lieu of a launch vehicle flight test, we need to find creative ways to mature it through testing in a relevant environment.
With our flight software, the SLS program at Marshall partnered with NASAs Engineering and Safety Center, Armstrong Flight Research Center at Edwards, Calif., and the Space Technology Mission Directorates Game Changing Development Program to test our algorithm on a NASA F/A-18 airplane, added VanZwieten.
An early version of an adaptive control system was used on the last X-15 rocket plane that was built in the 1960s. As the X-15 reached thinning atmosphere at the edge of space, the adaptive control system automatically responded to the changing conditions by increasing the responsiveness of the control surfaces to commands.
An adaptive control system is any type of control system that changes its parameters in flight to adjust to information that it learns about the vehicle that is different from what was predicted before flight, explained Jeb Orr of the Charles Stark Draper Laboratory.
Conventional control systems are designed or tuned using models on the ground, he added. Naturally, the way the vehicle behaves in flight is never exactly the same as modeled, so the control system must be robust that is, able to tolerate flying a vehicle that is a bit different from what the designers expect.
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