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By Space Force
Dr. Troy E. Meink appeard before the Senate Armed Services Committee for his nomination to be the next SecAF.
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By Space Force
The U.S. Space Force and ULA launch team successfully completed the certification process of the Vulcan rocket. The first NSSL mission on Vulcan is expected this summer.
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By NASA
2 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
NASA’s X-59 quiet supersonic research aircraft sits on a ramp at Lockheed Martin Skunk Works in Palmdale, California, during sunset. The one-of-a-kind aircraft is powered by a General Electric F414 engine, a variant of the engines used on F/A-18 fighter jets. The engine is mounted above the fuselage to reduce the number of shockwaves that reach the ground. The X-59 is the centerpiece of NASA’s Quesst mission, which aims to demonstrate quiet supersonic flight and enable future commercial travel over land – faster than the speed of sound.Lockheed Martin Corporation/Garry Tice The team behind NASA’s X-59 completed another critical ground test in March, ensuring the quiet supersonic aircraft will be able to maintain a specific speed during operation. The test, known as engine speed hold, is the latest marker of progress as the X-59 nears first flight this year.
“Engine speed hold is essentially the aircraft’s version of cruise control,” said Paul Dees, NASA’s X-59 deputy propulsion lead at the agency’s Armstrong Flight Research Center in Edwards, California. “The pilot engages speed hold at their current speed, then can adjust it incrementally up or down as needed.”
The X-59 team had previously conducted a similar test on the engine – but only as an isolated system. The March test verified the speed hold functions properly after integration into the aircraft’s avionics.
“We needed to verify that speed hold worked not just within the engine itself but as part of the entire aircraft system.” Dees explained. “This test confirmed that all components – software, mechanical linkages, and control laws – work together as intended.”
The successful test confirmed the aircraft’s ability to precisely control speed, which will be invaluable during flight. This capability will increase pilot safety, allowing them to focus on other critical aspects of flight operation.
“The pilot is going to be very busy during first flight, ensuring the aircraft is stable and controllable,” Dees said. “Having speed hold offload some of that workload makes first flight that much safer.”
The team originally planned to check the speed hold as part of an upcoming series of ground test trials where they will feed the aircraft with a robust set of data to verify functionality under both normal and failure conditions, known as aluminum bird tests. But the team recognized a chance to test sooner.
“It was a target of opportunity,” Dees said. “We realized we were ready to test engine speed hold separately while other systems continued with finalizing their software. If we can learn something earlier, that’s always better.”
With every successful test, the integrated NASA and Lockheed Martin team brings the X-59 closer to first flight, and closer to making aviation history through quiet supersonic technology.
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Last Updated Mar 26, 2025 EditorDede DiniusContactNicolas Cholulanicolas.h.cholula@nasa.gov Related Terms
Aeronautics Aeronautics Research Mission Directorate Armstrong Flight Research Center Commercial Supersonic Technology Langley Research Center Low Boom Flight Demonstrator Quesst (X-59) Supersonic Flight Keep Exploring Discover More Topics From NASA
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By NASA
2 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
A NASA F/A-18 research aircraft flies above California near NASA’s Armstrong Flight Research Center in Edwards, California, testing a commercial precision landing technology for future space missions. The Psionic Space Navigation Doppler Lidar (PSNDL) system is installed in a pod located under the right wing of the aircraft.NASA Nestled in a pod under an F/A-18 Hornet aircraft wing, flying above California, and traveling up to the speed of sound, NASA put a commercial sensor technology to the test. The flight tests demonstrated the sensor accuracy and navigation precision in challenging conditions, helping prepare the technology to land robots and astronauts on the Moon and Mars.
The Psionic Space Navigation Doppler Lidar (PSNDL) system is rooted in NASA technology that Psionic, Inc. of Hampton, Virginia, licensed and further developed. They miniaturized the NASA technology, added further functionality, and incorporated component redundancies that make it more rugged for spaceflight. The PSNDL navigation system also includes cameras and an inertial measurement unit to make it a complete navigation system capable of accurately determining a vehicle’s position and velocity for precision landing and other spaceflight applications.
NASA engineers and technicians install the Psionic Space Navigation Doppler Lidar (PSNDL) system into a testing pod on a NASA F/A-18 research aircraft ahead of February 2025 flight tests at NASA’s Armstrong Flight Research Center in Edwards, California.NASA The aircraft departed from NASA’s Armstrong Flight Research Center in Edwards, California, and conducted a variety of flight paths over several days in February 2025. It flew a large figure-8 loop and conducted several highly dynamic maneuvers over Death Valley, California, to collect navigation data at various altitudes, velocities, and orientations relevant for lunar and Mars entry and descent. Refurbished for these tests, the NASA F/A-18 pod can support critical data collection for other technologies and users at a low cost.
Doppler Lidar sensors provide a highly accurate measurement of speed by measuring the frequency shift between laser light emitted from the sensor reflected from the ground. Lidar are extremely useful in sunlight-challenged areas that may have long shadows and stark contrasts, such as the lunar South Pole. Pairing PSNDL with cameras adds the ability to visually compare pictures with surface reconnaissance maps of rocky terrain and navigate to landing at interesting locations on Mars. All the data is fed into a computer to make quick, real-time decisions to enable precise touchdowns at safe locations.
Psionic Space Navigation Doppler Lidar (PSNDL) system installed in a testing pod on a NASA F/A-18 research aircraft ahead of February 2025 flight tests at NASA’s Armstrong Flight Research Center in Edwards, California.NASA Since licensing NDL in 2016, Psionic has received funding and development support from NASA’s Space Technology Mission Directorate through its Small Business Innovative Research program and Tipping Point initiative. The company has also tested PSNDL prototypes on suborbital vehicles via the Flight Opportunities program. In 2024, onboard a commercial lunar lander, NASA successfully demonstrated the predecessor NDL system developed by the agency’s Langley Research Center in Hampton, Virginia.
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Last Updated Mar 26, 2025 EditorLoura Hall Related Terms
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By NASA
5 min read
Atomic Layer Processing Coating Techniques Enable Missions to See Further into the Ultraviolet
Astrophysics observations at ultraviolet (UV) wavelengths often probe the most dynamic aspects of the universe. However, the high energy of ultraviolet photons means that their interaction with the materials that make up an observing instrument are less efficient, resulting in low overall throughput. New approaches in the development of thin film coatings are addressing this shortcoming by engineering the coatings of instrument structures at the atomic scale.
Researchers at the NASA Jet Propulsion Laboratory (JPL) are employing atomic layer deposition (ALD) and atomic layer etching (ALE) to enable new coating technologies for instruments measuring ultraviolet light. Conventional optical coatings largely rely on physical vapor deposition (PVD) methods like evaporation, where the coating layer is formed by vaporizing the source material and then condensing it onto the intended substrate. In contrast, ALD and ALE rely on a cyclic series of self-limiting chemical reactions that result in the deposition (or removal) of material one atomic layer at a time. This self-limiting characteristic results in a coating or etchings that are conformal over arbitrary shapes with precisely controlled layer thickness determined by the number of ALD or ALE cycles performed.
The ALD and ALE techniques are common in the semiconductor industry where they are used to fabricate high-performance transistors. Their use as an optical coating method is less common, particularly at ultraviolet wavelengths where the choice of optical coating material is largely restricted to metal fluorides instead of more common metal oxides, due to the larger optical band energy of fluoride materials, which minimizes absorption losses in the coatings. Using an approach based on co-reaction with hydrogen fluoride, the team at JPL has developed a variety of fluoride-based ALD and ALE processes.
(left) The Supernova remnants and Proxies for ReIonization Testbed Experiment (SPRITE) CubeSat primary mirror inside the ALD coating facility at JPL, the mirror is 18 cm on the long and is the largest optic coated in this chamber to-date. (right) Flight optic coating inside JPL ALD chamber for Pioneers Aspera Mission. Like SPRITE, the Aspera coating combines a lithium fluoride process developed at NASA GSFC with thin ALD encapsulation of magnesium fluoride at JPL. Image Credit: NASA-JPL In addition to these metal-fluoride materials, layers of aluminum are often used to construct structures like reflective mirrors and bandpass filters for instruments operating in the UV. Although aluminum has high intrinsic UV reflectance, it also readily forms a surface oxide that strongly absorbs UV light. The role of the metal fluoride coating is then to protect the aluminum surface from oxidation while maintaining enough transparency to create a mirror with high reflectance.
The use of ALD in this context has initially been pursued in the development of telescope optics for two SmallSat astrophysics missions that will operate in the UV: the Supernova remnants and Proxies for ReIonization Testbed Experiment (SPRITE) CubeSat mission led by Brian Fleming at the University of Colorado Boulder, and the Aspera mission led by Carlos Vargas at the University of Arizona. The mirrors for SPRITE and Aspera have reflective coatings that utilize aluminum protected by lithium fluoride using a novel PVD processes developed at NASA Goddard Space Flight Center, and an additional very thin top coating of magnesium fluoride deposited via ALD.
Team member John Hennessy prepares to load a sample wafer in the ALD coating chamber at JPL. Image Credit: NASA JPL The use of lithium fluoride enables SPRITE and Aspera to “see” further into the UV than other missions like NASA’s Hubble Space Telescope, which uses only magnesium fluoride to protect its aluminum mirror surfaces. However, a drawback of lithium fluoride is its sensitivity to moisture, which in some cases can cause the performance of these mirror coatings to degrade on the ground prior to launch. To circumvent this issue, very thin layers (~1.5 nanometers) of magnesium fluoride were deposited by ALD on top of the lithium fluoride on the SPRITE and Aspera mirrors. The magnesium fluoride layers are thin enough to not strongly impact the performance of the mirror at the shortest wavelengths, but thick enough to enhance the stability against humidity during ground phases of the missions. Similar approaches are being considered for the mirror coatings of the future NASA flagship Habitable Worlds Observatory (HWO).
Multilayer structures of aluminum and metal fluorides can also function as bandpass filters (filters that allow only signals within a selected range of wavelengths to pass through to be recorded) in the UV. Here, ALD is an attractive option due to the inherent repeatability and precise thickness control of the process. There is currently no suitable ALD process to deposit aluminum, and so additional work by the JPL team has explored the development of a custom vacuum coating chamber that combines the PVD aluminum and ALD fluoride processes described above. This system has been used to develop UV bandpass filters that can be deposited directly onto imaging sensors like silicon (Si) CCDs. These coatings can enable such sensors to operate with high UV efficiency, but low sensitivity to longer wavelength visible photons that would otherwise add background noise to the UV observations.
Structures composed of multilayer aluminum and metal fluoride coatings have recently been delivered as part of a UV camera to the Star-Planet Activity Research CubeSat (SPARCS) mission led by Evgenya Shkolnik at Arizona State University. The JPL-developed camera incorporates a delta-doped Si CCD with the ALD/PVD filter coating on the far ultraviolet channel, yielding a sensor with high efficiency in a band centered near 160 nm with low response to out-of-band light.
A prototype of a back-illuminated CCD incorporating a multi-layer metal-dielectric bandpass filter coating deposited by a combination of thermal evaporation and ALD. This coating combined with JPL back surface passivation approaches enable the Si CCD to operate with high UV efficiency while rejecting longer wavelength light. Image credit: NASA JPL Next, the JPL team that developed these coating processes plans to focus on implementing a similar bandpass filter on an array of larger-format Si Complementary Metal-Oxide-Semiconductor (CMOS) sensors for the recently selected NASA Medium-Class Explorer (MIDEX) UltraViolet EXplorer (UVEX) mission led by Fiona Harrison at the California Institute of Technology, which is targeted to launch in the early 2030s.
For additional details, see the entry for this project on NASA TechPort
Project Lead: Dr. John Hennessy, Jet Propulsion Laboratory (JPL)
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Last Updated Mar 18, 2025 Related Terms
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