THE EDGE: The X-37B Space Force launch will carry a technology (like the one Scott designed, built and patented) that could eventually allow planes to stay aloft indefinitely

The X-37B Space Force Space Plane's Microwave Power Beam Experiment Is A Way Bigger Deal Than It Seems

When the X-37B launches it will carry a technology (like the one Scott designed, built and was awarded a U.S. federal patent on) that could eventually allow planes to stay aloft indefinitely anywhere on the globe.

Space Force

The shadowy X-37B, the Air Force’s unmanned, reusable spacecraft, is set to launch for its sixth flight on May 16 from Cape Canaveral Air Force Station, Florida. While most of the payloads set for the flight are standard fare for space experiments, at least the ones that are disclosed, one of them has immense potential implications for the future of remote power generation and especially long-endurance unmanned aircraft propulsion. 

The X-37B's upcoming mission is known as both Orbital Test Vehicle-6 (OTV-6) and U.S. Space Force-7 (USSF-7). It will carry out missions that will assess the effects of cosmic radiation and other “space effects” on plant seeds and various material samples. According to a Space Force press release, which went out on May 6, another payload aboard the X-37B will be an experimental system designed by the Naval Research Laboratory that is capable of capturing solar power and beaming that energy back to Earth in the form of microwaves.


While the press releases of the Department of Defense and the Space Force are scant on details, the Naval Research Laboratory’s head of beamed power has explicitly stated in the past that this system has enormous implications when it comes to long-endurance unmanned aerial vehicles (UAVs). In addition, it could allow satellites to provide reliable power anywhere on the planet or even to spacecraft or other satellites in orbit.


The X-37B

The U.S. Naval Research Laboratory (NRL) has been promoting similar-sounding technologies over the last year. In October 2019, the NRL conducted a three-day long demonstration of the Navy’s latest power-beaming capabilities at the Naval Surface Warfare Center in Bethesda, Maryland. In the demonstration, the NRL transmitted a completely silent, invisible beam of 2-kilowatt laser power over 300 meters through the air over attendees' heads. The demonstration was meant to showcase the safety and technological readiness of this utterly transformative concept.

As far as the aforementioned applications of this capability, research or military outposts in remote locations would no longer have to rely on low-power solar systems or haul heavy generators and large amounts of fuel, but instead could bring a rectifying antenna, or rectenna, to capture energy in the form of microwaves beamed from satellites overhead. In addition, areas ravaged by natural disasters could use the system to generate electricity to aid in reconstruction efforts long before traditional electrical infrastructure is rebuilt. It could even power autonomous ships at sea. 


Dr. Paul Jaffe, an electronics engineer with the U.S. Naval Research Laboratory who is leading the NRL’s research into power beaming, says that the technology will open up entirely new frontiers in terms of long-endurance unmanned aircraft. “If you have an electric drone that can fly more than an hour, you're doing pretty well,” Jaffe said. “If we had a way to keep those drones and UAVs flying indefinitely, that would have really far-reaching implications. With power beaming, we have a path toward being able to do that.” The Navy was granted a patent for a similar system in 2016 invented by Jaffe.

Beamed Power Aircraft

Using lasers to beam power to small UAVs has been a subject of research for some time. The U.S. Air Force began testing lasers as a source of propulsion for small “lightcraft” as early as the 1980s and managed to get small cone-shaped craft to fly hundreds of feet in the air propelled only by laser beams. This new concept is different, though, in that the beamed power UAVs the Navy envisions will feature traditional propulsion systems (such as rotors or propellers) and instead have rectennas that capture the energy from directed energy beams to constantly replenish their electrical power reserves. 


The laser lightcraft of the 1980s and 1990s featured a parabolic mirror afterbody surrounded by a shroud. Intense pulses of laser light beamed into the afterbody are used to heat and pressurize air enough to create lift.

In 2011, NASA’s Glenn Research Center published research on laser power-beaming systems with funding from the Air Force Research Laboratory's Revolutionary Munitions Directorate at Eglin Air Force Base in order to examine “long-range optical ‘refueling’ of electric platforms such as micro unmanned aerial vehicles (MUAV)”. Also in 2011, a RAND Corporation study conducted on behalf of the Air Force found that while the concept of laser-beamed power is sound, atmospheric interference from clouds could pose limitations on flight paths and ceilings. 

DARPA held a power beaming roundtable in 2015 which featured representatives from top defense contractors, research universities, and various DoD-operated laboratories. In 2018, DARPA demonstrated its latest laser-powered aircraft, the Silent Falcon, which the project lead Joseph A. Abate says was meant to “demonstrate that remote electric refueling of DoD systems via high energy laser power beaming to extend mission operation time in contested and remote environments.” 

While lasers have been examined for their use in beaming power to UAVs, these have typically involved ground-based or possibly airborne lasers to beam power. Placing the source of power generation and transmission in space is a new take on this concept, offering superior lines of sight and a continuous, renewable source of energy via the sun.


Still, low earth orbit satellites circle the planet at incredibly high speeds and their maneuverability is limited, so there will be limitations to the Navy’s latest beamed power system, but as a proof of concept, it is essential. A constellation of satellites would likely be necessary to have a truly 24/7 supply of power, enabling UAVs to be ‘passed’ from satellite to satellite for continuous or tightly scheduled recharging. The same can be said for any receiver applications on the planet's surface.

Beamed Power And The Future of UAVs

In 2014, the superintendent of the Naval Research Laboratory’s Plasma Physics Division Thomas Mehlhorn published a paper in IEEE Transactions on Plasma Sciences which offered an overview of plasma physics and pulsed power as they relate to national security. The article spans a wide variety of topics including nuclear weapons, inertial confinement fusion, and high-energy laser weapons. In the paper, Mehlhorn also touches upon the Navy’s beamed power UAV research at the time, writing that the continuous flight times offered by beamed power systems could change surveillance, reconnaissance, and communications gateway/relay missions forever:


"Building upon the concept of scalability, rather than using a laser beam to kill a UAV, they began to pursue the idea of beaming power to a UAV to allow continuous flight, with potential application to both surveillance [Intelligence, Surveillance, and Reconnaissance (ISR)] and countermeasure missions. The team has pursued this idea using NRL applied research funds with the vision that long-range laser power beaming to UAVs could allow for long-duration flights with reduced manpower requirements for many Navy and DoD missions, including off-board decoys, persistent surveillance, and communication relays."


According to an October 2019 press release, the Navy’s beamed power system has also been endorsed by the Marines, Army, and Air Force and is expected to throughout the Department of Defense in the near future. The extent to which such systems have already been tested or deployed is unclear, although the Department of Energy has explored the concept of beaming microwaves from space since at least 2014. Doing the same from the ground, within line of sight of the aircraft, which can still be dozens or even hundreds of miles away depending on the altitudes involved, is such an easier task that it would be a bit puzzling if the technology isn't already under development, or even possibly in some sort of clandestine operational state. 




The NRL program is being funded through the Operational Energy Capability Improvement Fund (OECIF), which "incentivizes S&T to promote long term change in DoD capabilities' and "fosters innovation to improve operational energy performance."

Doing so from another aircraft is also clearly an objective based on the existing literature and would help mitigate the line of sight limitations with ground-based power beaming stations, but would sacrifice endurance and simplicity. In the 2011 RAND study cited above, the authors write that possibilities for beamed power applications include "ultra-high-altitude observation stations or communication relays and flocks of high-altitude sensor probes powered remotely from a large aircraft 'mother ship.'"

Meanwhile, the China Academy of Space Technology claimed to already be testing such a system in 2019 and said that a fully-functional Chinese microwave beaming power station in space could be deployed by 2050. 

As you can probably tell at this point, this technology has massive implications not only for the future of UAVs, but for all of mankind. Such a system could be used to keep UAVs in the air for very long periods of time to replace cell towers or communications satellites in the event of a crisis in a region or even for normal operations of increasingly complex communications networks. Unlike a tethered aerostat, these UAVs would require far less infrastructure, could be moved around at will for optimum coverage, and could land quickly for servicing. They could even deploy dozens of miles, or even further, away from their base stations. With a space-based power source, they could fly anywhere on earth. Obviously, the implications for overhead surveillance are equally impactful. 

So, while the X-37B's latest mission details seem neat on a scientific level, the reality is the microwave system it is testing could change the game for many military-related applications and could actually open the door for near-continuous unmanned flight throughout the atmosphere.




Hiroshi Amano, a professor from Nagoya University who was awarded the 2014 Nobel Prize in physics, is developing together with other researchers a remote power supply system that sends energy to distant places using electromagnetic waves.

If put into practical use the research could greatly benefit all of society, such as through recharging electric vehicles (EV) while they are running or sending solar power generated in space to the earth.




“Our first target is to create a wireless system to supply electricity to drones within three years,” Amano said.

Currently, wires and cables must be connected to an electrical device to supply energy so that it can run continuously. Some wireless power transmission technology is already available, but it is inefficient and limited to products that can run on low power such as mobile phones.

The research team aims to develop a system that can convert electricity into high-frequency electromagnetic waves that are then sent to the target destination, like a laser light from an antenna, and converted back to electricity via a receiving antenna.

Theoretically it is possible to send a large amount of electricity to a distant place efficiently, but it is difficult to put the idea to practical use with current technology as a lot of energy is lost in the process.

Amano, 57, and his team have utilized the technology of crystallizing gallium nitride (GaN) — which was key to developing the blue light-emitting diodes (LED) that won Amano his Nobel Prize — becoming the first in the world to successfully improve the performance of power semiconductors used to regulate voltage and electric current. They believe this will contribute to resolving issues such as power loss.

The team has begun by developing a system for drones. With the cooperation of Japanese electronic manufacturers and drone developers, they are currently building a system with an electric circuit and embedded antenna.

The first target is to build within the next three years a system that can transfer energy wirelessly over a short distance — of a few dozen centimeters — in three minutes.

After that, they hope to develop it further so the system becomes able to charge a drone that can fly approximately 100 meters high.

“Remote power supplies will revolutionize the way goods and people are transported. They can enrich our lives,” said Amano.

Since drones can fly across areas regardless of geographical features, they have gained attention as a useful tool in disaster rescue missions and as a next-generation alternative for distributing goods.

However, they can only fly for a short period of time and need to be recharged frequently. A standard drone that is carrying an object weighing 20 kg can only fly for about 30 minutes.

If drones can be recharged while flying using a remote power supply system, their flight time will become virtually unlimited.

Manufacturers around the world are also competing to improve the performance of electric vehicles, where the new technology could again offer benefits.

One of the shortcomings of EVs is the long period of time needed for them to recharge. However, if remote power supply systems are installed on the road or intersections vehicles could recharge while running, so drivers would not have to stop at recharging stations.

Competition around the world to develop wireless power transmission technology is growing increasingly fierce.

The most well-known method is the magnetic coupling method, written in a paper published by Massachusetts Institute of Technology in 2007, but this method basically covers only short distances.

The system Amano and his team aim to build will enable the supply of power by sending electromagnetic waves to remote islands and other places, as well as transmitting electricity from offshore wind power efficiently to cities.

In the future, it may even be possible to build a space solar power plant whereby electricity generated in solar panels that are floating in space would be sent to Earth.

The development of the blue LED was a revolution in lighting technology, following the invention of incandescent bulbs and fluorescent lamps.

“I believe that (the remote power supply system) will become the technology that can make a greater contribution than the blue LED to the well-being of people all over the world,” said Amano

Electric Spacecraft Are Now The Norm. No Longer Science Fiction


BepiColombo approaching Mercury

BepiColombo, the joint ESA/JAXA spacecraft on a mission to Mercury, is now firing its thrusters for the first time in flight.

On Sunday, BepiColombo carried out the first successful manoeuver using two of its four electric propulsion thrusters. After more than a week of testing which saw each thruster individually and meticulously put through its paces, the intrepid explorer is now one step closer to reaching the innermost planet of the Solar System.

Twin ion thrusters firing

BepiColombo left Earth on 20 October 2018, and after the first few critical days in space and the initial weeks of in-orbit commissioning, its Mercury Transfer Module (MTM) is now revving up the high-tech ion thrusters.

The most powerful and high-performance electric propulsion system ever flown, these electric blue thrusters had not been tested in space until now.

It is these glowing power-packs that will propel the two science orbiters – the Mercury Planetary Orbiter and Mercury Magnetospheric Orbiter – on the seven-year cruise to the least explored planet of the inner Solar System.

“Electric propulsion technology is very novel and extremely delicate,” explains Elsa Montagnon, Spacecraft Operations Manager for BepiColombo.

“This means BepiColombo’s four thrusters had to be thoroughly checked following the launch, by slowly turning each on, one by one, and closely monitoring their functioning and effect on the spacecraft.”

BepiColombo images high-gain antenna

Testing took place during a unique window, in which BepiColombo remained in continuous view of ground-based antennas and communications between the spacecraft and those controlling it could be constantly maintained.


The first fire

On 20 November at 11:33 UTC (12:33 CET), the first of BepiColombo’s thrusters entered Thrust Mode with a force of 75 mN (millinewtons). With this BepiColombo was firing in space for the very first time.

Three hours later, the newly awakened thruster was really put through its paces as commands from mission control directed it to go full throttle, ramping up to 125mN – equivalent to holding an AAA battery at sea level.

This may not sound like much, but this thruster was now working at the maximum thrust planned to be used during the life of the mission.

Views of ESA's 35m ESTRACK deep-space tracking station at Malargüe, Argentina, now supporting many of the Agency's most important exploration missions, including Rosetta, Mars Express, ExoMars, LISA Pathfinder and Gaia.
ESA Malargüe tracking station

Thrust mode was maintained for five hours before BepiColombo transitioned back to Normal Mode. The entire time, ESA’s Malargüe antenna in Argentina was in communication with the now glowing blue spacecraft – the colour of the plasma generated by the thruster as it burned through the xenon propellant.

These steps were then repeated for each of the other three thrusters over the next days, having only a tiny effect on BepiColombo’s overall trajectory.

The small effects that were observed allowed the Flight Dynamics team to assess the thruster performance in precise detail: analysis of the first two firings reveals that the spacecraft was performing within 2% of its expected value. Analysis of the last two firings is ongoing.

Animation visualising BepiColombo’s journey to Mercury

“To see the thrusters working for the first time in space was an exciting moment and a big relief. BepiColombo’s seven year trip to Mercury will include 22 ion thrust arcs – and we absolutely need healthy and well performing thrusters for this long trip,” explains Paolo Ferri, ESA’s Head of Operations.

“Each thruster burn arc will last for extended periods of up to two months, providing the same acceleration from less fuel compared to traditional, high-energy chemical burns that last for minutes or hours.”

During each long-duration burn the engines do take eight hour pauses, once a week, to allow the ground to perform navigation measurements in quiet dynamic conditions.

The first routine electric propulsion thrust arc will begin on 17 December, steering BepiColombo on its interplanetary trajectory and optimising its orbit ahead of its swing-by of Earth in April 2020.

BepiColombo Earth flyby

Travelling some nine billion kilometers in total, BepiColombo will take nine flybys at Earth, Venus and Mercury, looping around the Sun 18 times.

By late 2025 the transfer module’s work will be done: it will separate, allowing the two science orbiters to be captured by Mercury’s gravity, studying the planet and its environment, along with its interaction with the solar wind, from complementary orbits.

"We put our trust in the thrusters and they have not let us down. We are now on our way to Mercury with electro-mobility,” concludes Günther Hasinger, ESA Director of Science.

“This brings us an important step closer to unlocking the secrets of the mysterious innermost planet and ultimately, the formation of our Solar System.”

Follow ESA Operations on twitter for updates on BepiColombo’s journey, as well as the latest from ESA’s mission control.




Author: TEAM1

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