NASA Tests Ultralight Antennas to Benefit Future National Airspace

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NASA engineers are using one of the world’s lightest solid materials to construct an antenna that could be embedded into the skin of an aircraft, creating a more aerodynamic and reliable communication solution for drones and other future air transportation options. 
Developed by NASA, this ultra-lightweight aerogel antenna is designed to enable satellite communications where power and space are limited. The aerogel is made up of flexible, high-performance plastics known as polymers. The design features high air content (95%) and offers a combination of light weight and strength. Researchers can adjust its properties to achieve either the flexibility of plastic wrap or the rigidity of plexiglass.
“By removing the liquid portion of a gel, you’re left with this incredibly porous structure,” said Stephanie Vivod, a chemical engineer at NASA’s Glenn Research Center in Cleveland. “If you’ve ever made Jell-O, you’ve performed chemistry that’s similar to the first step of making an aerogel.”
NASA sandwiched a layer of aerogel between a small circuit board and an array of thin, circular copper cells, then topped the design off with a type of film known for its electrical insulation properties. This innovation is known at NASA and in the aviation community as an active phased array aerogel antenna. 

In addition to decreasing drag by conforming to the shape of aircraft, aerogel antennas save weight and space and come with the ability to adjust their individual array elements to reduce signal interference. They are also less visually intrusive compared to other types of antennas, such as spikes and blades. The finished product looks like a honeycomb but lays flat on an aircraft’s surface.
In the summer of 2024, researchers tested a rigid version of the antenna on a Britten-Norman Defender aircraft during an in-flight demonstration with the U.S. Navy at Naval Air Station Patuxent River in Maryland.

Then, last October, researchers at NASA Glenn and the satellite communications firm Eutelsat America Corp., of Houston, began ground testing a version of the antenna mounted to a platform. The team successfully connected with a Eutelsat satellite in geostationary orbit, which bounced a signal back down to a satellite dish on a building at Glenn. Other demonstrations of the system at Glenn connected with a constellation of communications satellites operated in low Earth orbit by the data relay company Kepler. NASA researchers will design, build, and test a flexible version of the antenna later this year.
“This is significant because we are able to use the same antenna to connect with two very different satellite systems,” said Glenn researcher Bryan Schoenholz. Low Earth orbit satellites are relatively close – at 1,200 miles from the surface – and move quickly around the planet. Geostationary satellites are much farther – more than 22,000 miles from the surface – but orbit at speeds matching the Earth’s rotation, so they appear to remain in a fixed position above the equator.

The satellite testing was crucial for analyzing the aerogel antenna concept’s potential real-world applications. When modern aircraft communicate with stations on the ground, those signals are often transmitted through satellite relays, which can come with delays and loss of communication. This NASA-developed technology will make sure these satellite links are not disrupted during flight as the aerogel antenna’s beam is a concentrated flow of radio waves that can be electronically steered with precision to maintain the connection.
As new types of air transportation options are brought to the market and U.S airspace – from the small, piloted aircraft of today to the autonomous air taxis and delivery drones of tomorrow – these kinds of steady connections will become increasingly important. That’s why NASA’s Advanced Air Mobility mission and Transformative Aeronautics Concepts program are supporting research like the aerogel antennas that can boost industry efforts to safely expand the emerging marketplace for these transportation systems.
“If an autonomous air taxi or drone flight loses its communications link, we have a very unsafe situation,” Schoenholz said. “We can’t afford a ‘dropped call’ up there because that connection is critical to the safety of the flight.”
Schoenholz, Vivod, and others work on NASA’s Antenna Deployment and Optimization Technologies activity within the Transformational Tools and Technologies project. The activity aims to develop technologies that reduce the risk of radio frequency interference from air taxis, drones, commercial passenger jets, and other aircraft in increasingly crowded airspace. Läs mer…

NASA Studies Wind Effects and Aircraft Tracking with Joby Aircraft

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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.

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. Läs mer…