As part of a science mission tracking one of Earth’s most precious resources – water – NASA’s C-20A aircraft conducted a series of seven research flights in March that can help researchers track the process and timeline as snow melts and transforms into a freshwater resource. The agency’s Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) installed on the aircraft collected measurements of seasonal snow cover and estimate the freshwater contained in it.

“Seasonal snow is a critical resource for drinking water, power generation, supporting multi-billion dollar agricultural and recreation industries,” said Starr Ginn, C-20A project manager at NASA’s Armstrong Flight Research Center in Edwards, California.  “Consequently, understanding the distribution of seasonal snow storage and subsequent runoff is essential.”

The Dense UAVSAR Snow Time (DUST) mission mapped snow accumulation over the Sierra Nevada mountains in California and the Rocky Mountains in Idaho. Mission scientists can use these observations to estimate the amount of water stored in that snow.

“Until recently, defining the best method for accurately measuring snow water equivalent (SWE) – or how much and when fresh water is converted from snow – has been a challenge,” said Shadi Oveisgharan, principal investigator of DUST and scientist at NASA’s Jet Propulsion Laboratory in Southern California. “The UAVSAR has been shown to be a good instrument to retrieve SWE data.”

Recent research has shown that snow properties, weather patterns, and seasonal conditions in the American West have been shifting in recent decades. These changes have fundamentally altered previous expectations about snowpack monitoring and forecasts of snow runoff. The DUST mission aims to better track and understand those changes to develop more accurate estimates of snow-to-water conversions and their timelines.

“We are trying to find the optimum window during which to retrieve snow data,” Oveisgharan said. “This estimation will help us better estimate available fresh snow and manage our reservoirs better.”

The DUST mission achieved a new level of snow data accuracy, which is partly due to the specialized flight paths flown by the C-20A. The aircraft’s Platform Precision Autopilot (PPA) enables the team to fly very specific routes at exact altitudes, speeds, and angles so the UAVSAR can more precisely measure terrain changes.

“Imagine the rows made on grass by a lawn mower,” said Joe Piotrowski Jr., operations engineer for NASA Armstrong’s airborne science program. “The PPA system enables the C-20A to make those paths while measuring terrain changes down to the diameter of a centimeter.”

NASA engineers began using a network of ground sensors in March to collect data from an experimental air taxi to evaluate how to safely integrate such vehicles into airspace above cities – in all kinds of weather.

Researchers will use the campaign to help improve tools to assist with collision avoidance and landing operations and ensure safe and efficient air taxi operations in various weather conditions.

For years, NASA has looked at how wind shaped by terrain, including buildings in urban areas, can affect new types of aircraft. The latest test, which is gathering data from a Joby Aviation demonstrator aircraft, looks at another kind of wind – that which is generated by the aircraft themselves.

Joby flew its air taxi demonstrator over NASA’s ground sensor array near the agency’s Armstrong Flight Research Center in Edwards, California producing air flow data. The Joby aircraft has six rotors that allow for vertical takeoffs and landings, and tilt to provide lift in flight. Researchers focused on the air pushed by the propellers, which rolls into turbulent, circular patterns of wind.

This rolling wind can affect the aircraft’s performance, especially when it’s close to the ground, as well as others flying in the vicinity and people on the ground. Such wind turbulence is difficult to measure, so NASA enhanced its sensors with a new type of lidar – a system that uses lasers to measure precise distances – and that can map out the shapes of wind features.

“The design of this new type of aircraft, paired with the NASA lidar technology during this study, warrants a better understanding of possible wind and turbulence effects that can influence safe and efficient flights,” said Grady Koch, lead for this research effort, from NASA’s Langley Research Center in Hampton, Virginia.

Data to Improve Aircraft Tracking

NASA also set up a second array of ground nodes including radar, cameras, and microphones in the same location as the sensors to provide additional data on the aircraft. These nodes will collect tracking data during routine flights for several months.

The agency will use the data gathered from these ground nodes to demonstrate the tracking capabilities and functions of its “distributed sensing” technology, which involves embedding multiple sensors in an area where aircraft are operating.

This technology will be important for future air taxi flights, especially those occurring in cities by tracking aircraft moving through traffic corridors and around landing zones. Distributed sensing has the potential to enhance collision avoidance systems, air traffic management, ground-based landing sensors, and more.

“Our early work on a distributed network of sensors, and through this study, gives us the opportunity to test new technologies that can someday assist in airspace monitoring and collision avoidance above cities,” said George Gorospe, lead for this effort from NASA’s Ames Research Center in California’s Silicon Valley.

Using this data from an experimental air taxi aircraft, NASA will further develop the technology needed to help create safer air taxi flights in high-traffic areas. Both of these efforts will benefit the companies working to bring air taxis and drones safely into the airspace.

The work is led by NASA’s Transformational Tools and Technologies and Convergent Aeronautics Solutions projects under the Transformative Aeronautics Concepts program in support of NASA’s Advanced Air Mobility mission. NASA’s Advanced Air Mobility mission seeks to deliver data to guide the industry’s development of electric air taxis and drones.

Editor’s Note: This article was updated April 16, 2025, to reflect the March 26 start date of NASA’s Alta X flights and provide additional details about the data collected.

Advancements in NASA’s airborne technology have made it possible to gather localized wind data and assess its impacts on smoke and fire behavior. This information could improve wildland fire decision making and enable operational agencies to better allocate firefighters and resources. A small team from NASA’s Armstrong Flight Research Center in Edwards, California, is demonstrating how some of these technologies work.

Two instruments from NASA’s Langley Research Center in Hampton, Virginia – a sensor gathering 3D wind data and a radiosonde that measures temperature, barometric pressure, and relative humidity data – were installed on NASA Armstrong’s Alta X drone for a prescribed burn in Geneva State Forest, which is about 100 miles south of Montgomery, Alabama. The effort is part of the agency’s multi-year FireSense project, which is aimed at testing technologies that could eventually serve the U.S. Forest Service as well as local, state, and other federal wildland fire agencies.

“The objectives for the Alta X portion of the multi-agency prescribed burn include a technical demonstration for wildland fire practitioners, and data collection at various altitudes for the Alabama Forestry Commission operations,” said Jennifer Fowler, FireSense project manager. “Information gathered at the different altitudes is essential to monitor the variables for a prescribed burn.”

Those variables include the mixing height, which is the extent or depth to which smoke will be dispersed, a metric Fowler said is difficult to predict. Relative humidity must also be above 30% for a prescribed burn to meet requirements in Geneva State Forest. The technology to collect these measurements locally is not readily available in wildland fire operations, making the Alta X and its instruments key in the demonstration of prescribed burn technology.

In addition to the Alta X flights beginning March 26, NASA Armstrong’s B200 King Air will fly over actively burning fires at an altitude of about 6,500 feet. Sensors onboard other aircraft supporting the mission will fly at lower and higher altitudes before, during, and after the fire for required data collection. The multi-agency mission will provide data to improve models to better predict fire behavior and effects, including smoke lofting, trajectory, and dispersion.

Small, uncrewed aircraft system pilots from NASA Armstrong completed final preparations to travel to Alabama and set up for the research flights. The team – including Derek Abramson, chief engineer for the subscale flight research laboratory; Justin Hall, NASA Armstrong chief pilot of small, uncrewed aircraft systems; and Alexander Jaffe, a drone pilot – will set up, fly, observe airborne operations, all while keeping additional aircraft batteries charged. The launch and recovery of the Alta X is manual, the mission profile is flown autonomously to guarantee the same conditions for data collection.

“The flight profile is vertical – straight up and straight back down from the surface to about 3,000 feet altitude,” Abramson said. “We will characterize the mixing height and changes in moisture, mapping out how they both change throughout the day in connection with the burn.”

In August 2024, a team of NASA researchers used the NASA Langley Alta X and weather instruments in Missoula, Montana, for a FireSense project drone technology demonstration. These instruments were used to generate localized forecasting that provides precise and sustainable meteorological data to predict fire behavior and smoke impacts.

From agriculture and law enforcement to entertainment and disaster response, industries are increasingly turning to drones for help, but the growing volume of these aircraft will require trusted safety management systems to maintain safe operations.

NASA is testing a new software system to create an improved warning system – one that can predict hazards to drones before they occur. The In-Time Aviation Safety Management System (IASMS) will monitor, assess, and mitigate airborne risks in real time. But making sure that it can do all that requires extensive experimentation to see how its elements work together, including simulations and drone flight tests.

“If everything is going as planned with your flight, you won’t notice your in-time aviation safety management system working,” said Michael Vincent, NASA acting deputy project manager with the System-Wide Safety project at NASA’s Langley Research Center in Hampton, Virginia. “It’s before you encounter an unusual situation, like loss of navigation or communications, that the IASMS provides an alert to the drone operator.”

The team completed a simulation in the Human-Autonomy Teaming Laboratory at NASA’s Ames Research Center in California’s Silicon Valley on March 5 aimed at finding out how critical elements of the IASMS could be used in operational hurricane relief and recovery.

During this simulation, 12 drone pilots completed three 30-minute sessions where they managed up to six drones flying beyond visual line of sight to perform supply drops to residents stranded after a severe hurricane. Additional drones flew scripted search and rescue operations and levee inspections in the background. Researchers collected data on pilot performance, mission success, workload, and perceptions of the experiences, as well as the system’s usability.

This simulation is part of a longer-term strategy by NASA to advance this technology. The lessons learned from this study will help prepare for the project’s hurricane relief and recovery flight tests, planned for 2027.  

As an example of this work, in the summer of 2024 NASA tested its IASMS during a series of drone flights in collaboration with the Ohio Department of Transportation in Columbus, Ohio, and in a separate effort, with three university-led teams.

For the Ohio Department of Transportation tests, a drone flew with the NASA-developed IASMS software aboard, which communicated back to computers at NASA Langley. Those transmissions gave NASA researchers input on the system’s performance.

NASA also conducted studies with The George Washington University (GWU), the University of Notre Dame, and Virginia Commonwealth University (VCU). These occurred at the U.S. Army’s Fort Devens in Devens, Massachusetts with GWU; near South Bend, Indiana with Notre Dame; and in Richmond, Virginia with VCU. Each test included a variety of types of drones, flight scenarios, and operators.

Each drone testing series involved a different mission for the drone to perform and different hazards for the system to avoid. Scenarios included, for example, how the drone would fly during a wildfire or how it would deliver a package in a city. A different version of the NASA IASMS was used to fit the scenario depending on the mission, or depending on the flight area.

When used in conjunction with other systems such as NASA’s Unmanned Aircraft System Traffic Management, IASMS may allow for routine drone flights in the U.S. to become a reality. The IASMS adds an additional layer of safety for drones, assuring the reliability and trust if the drone is flying over a town on a routine basis that it remains on course while avoiding hazards along the way.

“There are multiple entities who contribute to safety assurance when flying a drone,” Vincent said. “There is the person who’s flying the drone, the company who designs and manufactures the drone, the company operating the drone, and the Federal Aviation Administration, who has oversight over the entire National Airspace System. Being able to monitor, assess and mitigate risks in real time would make the risks in these situations much more secure.”

All of this work is led by NASA’s System-Wide Safety project under the Airspace Operations and Safety program in support of the agency’s Advanced Air Mobility mission, which seeks to deliver data to guide the industry’s development of electric air taxis and drones.

A group of enthusiastic high school students recently visited NASA to learn about facilities and capabilities that enable the agency’s researchers to explore, innovate, and inspire for the benefit of humanity.

Engineering club students from Palmdale High School in California were able to connect classroom lessons to real-world applications, sparking curiosity and ambition while at NASA’s Armstrong Flight Research Center in Edwards, California. “I learned a lot about the different careers that you can get at a place like NASA,” student Roberto Cisnero said.

Through partnerships with the regional STEM community, NASA’s STEM Engagement provides local students with hands-on opportunities aligned with NASA’s missions. “Many students do not get the opportunity to be encouraged to pursue STEM careers. Part of our NASA mission is to be that encourager,” said Randy Thompson, deputy director for NASA Armstrong Research and Engineering.

Highlights from the visit included demonstrations at a mission control room, the Subscale Flight Research Laboratory, the Flight Loads Laboratory, and the Experimental Fabrication Shop, all of which support high-risk, atmospheric flight research and test projects. Students engaged with laboratory technicians, engineers, and program managers, asking questions about the work they do. “It was fun to see what the valued people at NASA do with all of the resources,” student Jonathan Peitz said.

NASA’s California Office of STEM Engagement hosted the visit in celebration of National Aviation History Month. By supporting students, educators, and expanding STEM participation, NASA aims to inspire future leaders and build a diverse, skilled workforce.