In 2019 engineers and scientists at the NASA Armstrong Flight Research Center, Edwards Air Force Base, Calif., continued to advance the agency’s overall missions of aeronautics research, Earth science and space exploration.

Highlights included progress on two new experimental research craft, one designed to validate clean and quiet electric propulsion and the other to advance commercial supersonic flight technology without the typical loud sonic boom.

In keeping with national goals for returning humans to the moon in this decade, researchers at Armstrong contributed to the agency’s Artemis mission by testing a prototype navigation system being developed for use on the next lunar lander module. The center also supported space science achievements including the discovery of helium hydride, the first type of molecule that ever formed in the universe. Closer to home, NASA airborne science missions provided data on fire and smoke impact on regional and global environments.

Aeronautics
NASA Armstrong has long been known for advancing aeronautics technology through the use of a wide variety of dedicated experimental research aircraft known collectively as X-planes. Several of these met important milestones in 2019.

The X-56A Multi-Utility Technology Testbed concluded a multiyear test series that explored the benefits of long, thin, high-aspect-ratio wings for use on future long-range aircraft including fuel-efficient airliners and cargo transports. One of the major goals of the project was to investigate technologies for active flutter suppression and gust-load alleviation to improve ride quality, aerodynamic efficiency, safety, and to improve the long-term health of flexible aircraft structures.

Lockheed Martin Skunk Works and the Air Force Research Laboratory performed initial testing of the X-56A in late 2013 and early 2014 to collect flight data on highly flexible structures and flutter suppression control techniques. The MUTT was later transferred to NASA Armstrong for research involving lightweight structures and advanced control technologies for future efficient, environmentally friendly transport aircraft.

In 2019, Armstrong accepted delivery of the X-57 Mod II, an experimental all-electric aircraft that will be used to collect data in support of enabling regulators to set certification standards for the emerging electric aircraft market. The aircraft is being prepared for ground testing that will pave the way for flight tests later this year.

The primary purpose of the X-57 is to validate and demonstrate the benefits of distributed electric propulsion for future aviation applications. NASA aeronautics researchers are hoping to demonstrate how electric propulsion can make airplanes quieter, more energy efficient, and environmentally friendly.

Plans call for the X-57 to undergo several major configuration changes, or mods, the final one featuring 14 electric motors and propellers. Researchers predict the X-57 will demonstrate a 500-percent increase in high-speed cruise efficiency over conventional gas-powered propulsion, zero in-flight carbon emissions, and quieter flight characteristics that will reduce impact on communities below the airplane’s flight path.

In another X-plane milestone, the Lockheed Martin Skunk Works began building the X-59 Quiet Supersonic Technology demonstrator. NASA scientists will use the QueSST configuration to explore methods for reducing aircraft noise as well as controlling and lessening the effects of supersonic shock waves to the point where federal regulators may one day allow commercial and civil supersonic flight over land in the United States. Such flying is currently restricted to military training operations within tightly controlled supersonic corridors in the National Airspace.

In advance of supersonic testing of the X-59, researchers at Armstrong conducted a series of acoustic measurements using ground instrumentation and two T-38 jet trainers provided by the Air Force Test Pilot School at Edwards. The Carpet Determination in Entirety Measurements, or CapetDIEM, flight series featured an array of high-fidelity microphones that could be arranged in several configurations. The arrays gave researchers the ability to obtain accurate sound data and assess the loudness of sonic booms created by the T-38, just as they will measure the much quieter sonic thumps from the X-59. In addition to the acoustic measurements, scientists created a visual representation of shock effects using a background-oriented schlieren photography technique to capture the first air-to-air images of the interaction of shockwaves from the two supersonic aircraft.

In 2019, NASA Armstrong completed flight-testing associated with the Unmanned Aircraft Systems in the National Airspace System project. Beginning in 2012, NASA worked closely with the Federal Aviation Administration and industry partners to develop technologies that support safe integration of unmanned aircraft systems into the National Airspace System. Previous tests successfully demonstrated two detect-and-avoid algorithms developed by NASA, General Atomics Aeronautical Systems Inc., and Honeywell that generated precise alerts necessary for a pilot controlling a UAS from the ground to remain well clear of other aircraft.

The final series of test flights for the project, known as Flight Test Series 6 focused on low size, weight, and power sensors for DAA operations in controlled airspace to inform the FAA on minimum operational performance standards for DAA and air-to-air radar. The FT6 tests used a NAVMAR Applied Science Corporation TigerShark UAS equipped with a digital active phased array radar system. The flight series included DAA encounters with several types of intruder aircraft representing common size aircraft that a UAS might encounter in the NAS, including the King Air B200, T-34C, and TG-14 motorized sailplane. These encounters were designed to demonstrate the effectiveness of the TigerShark’s DAA alerting system and what type of guidance it recommended to avoid the intruder.

NASA was also part of the team that developed the software system that will assume control of an aircraft upon imminent ground collision, called the Automatic Ground Collision Avoidance System (Auto GCAS). This system has been integrated into military aircraft and has saved eight pilots since it was fielded about five years ago. The Auto GCAS team was awarded the 2018 Robert J. Collier Trophy, which recognizes the greatest achievements in aeronautics or astronautics in the country each year.

Airborne Science
Armstrong’s DC-8 flying laboratory and ER-2 high-altitude research aircraft participated in a joint campaign with the National Oceanic and Atmospheric Administration to improve its ground- and satellite-based forecasting models of smoke from wildland fires. The Fire Influence on Regional to Global Environments and Air Quality effort used sensors to see through smoke and flames, providing scientists with data to understand how fuel and fire conditions at the point of ignition influence the chemistry of smoke, what happens to atmospheric particulates, and how the chemical transformation of smoke affects air quality, and to a lesser extent weather downwind.

Scientists aimed a new sensor on the ER-2 at the moon in an effort to improve Earth observations. The airborne Lunar Spectral Irradiance Instrument (air-LUSI) measured and characterized the amount of sunlight reflected by the Moon at various phases to accurately calibrate Earth observation sensors.

Astronomers used NASA’s Stratospheric Observatory for Infrared Astronomy, or SOFIA, to make another breakthrough, the discovery of the universe’s first type of molecule. When the universe was still very young, only a few kinds of atoms existed. Scientists believe that around 100,000 years after the big bang, helium and hydrogen combined to make a molecule called helium hydride for the first time. They reasoned that helium hydride should be present in some parts of the modern universe, but it had never been detected in space until instruments aboard SOFIA detected it in our own galaxy for the first time after decades of searching. The molecular signature of helium hydride was found in a nebula located 3,000 light-years from Earth near the constellation Cygnus. This confirms a key part of our basic understanding of the chemistry of the early universe and how it evolved over billions of years.

Spaceflight Technology
Armstrong personnel supported the successful testing of a launch abort system for the Orion spacecraft that will enable the Artemis missions to the Moon, during which humans will land on the lunar surface for the first time since the final Apollo mission in 1972. Once proven, the next generation of planetary exploration spacecraft will be used for a new series of lunar expeditions and eventually take astronauts to Mars.

In preparation for these missions, a terrain-relative navigation system is under development by Draper of Cambridge, Mass., for the next lunar lander module. The system was tested on a Masten Space Systems Xodiac rocket at Mojave, Calif., on Sept. 11, 2019. The experiment was part of the Flight Opportunities program effort to mature space technology through flight.

Armstrong manages NASA’s Flight Opportunities program under the agency’s Space Technology Mission Directorate. The program provides opportunities for large and small businesses and universities to demonstrate technologies of interest to NASA in a space-like environment by testing them on board commercial suborbital launch vehicles, reduced-gravity parabolic aircraft flights, and high-altitude balloons. Building a flight heritage enables these technologies to be more readily included in future NASA projects and to stimulate the growth of the U.S. commercial spaceflight industry.