Space Solar Panel Energy

- Overview

Scientists working for the Pentagon have successfully tested a pizza-box-sized solar panel in space, designed as a prototype for a future system that could beam electricity from space back to anywhere on Earth. Known as the Photovoltaic Radio Frequency Antenna Module (PRAM), the panel first launched in May 2020 and connects to the Pentagon's X-37B unmanned drone to convert sunlight into electricity. The drone circles the Earth every 90 minutes. 

The panel is designed to take full advantage of the light in space, which doesn't pass through the atmosphere and thus retains the energy of the blue waves, making it more powerful than sunlight reaching Earth. Blue light diffuses as it enters the atmosphere, which is why the sky appears blue.

- History

Even if the energy comes from outer space, the demand for energy is growing. The U.S. Naval Research Laboratory (NRL) has discovered that solar energy captured in space over the years, with the help of photovoltaic radio frequency antenna module (PRAM) experiments, can be used as an energy source for terrestrial applications on Earth. 

The experiment launched the PRAM energy harvester on May 17, 2020, aboard the U.S. Air Force X-37B orbital test vehicle. This hardware experiment designed for solar-powered satellites is the first in-orbit test and could play an important role in our energy future.

The photovoltaic RF antenna module is a 12-inch square tile module. This is the first orbital experiment designed to convert sunlight into radio frequency (RF) microwaves. The combination of photovoltaic and EM (Electromagnetic) technologies, called PRAM, helps capture energy from space and then transmit it to power stations on Earth.   

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- Serving

The panel, called a Photovoltaic Radio Frequency Antenna Module (PRAM), is about the size of a pizza box and is mounted on the Pentagon's top-secret X-37B drone. The drone circles the Earth every 90 minutes. PRAM is like a "sandwich" module with photovoltaic panels on one side, electronics in the middle, and an antenna on the other. 

Photovoltaic panels receive solar energy, electronic equipment converts direct current into radio frequency signals, and antennas transmit the power. Since sunlight is not blocked by Earth's atmosphere, the panels receive more light than they would on Earth. 

The latest experiments show that the 12x12-inch panel can generate about 10 watts of power for transmission. That's enough to power a tablet. But the project envisions a series of dozens of panels, and if scaled up, its success could revolutionize how electricity is generated and distributed to remote corners of the globe. It can contribute to the largest grid network on the planet.

- Benefit

As the drone flies above the atmosphere, it can capture more energy from each color band of sunlight. 

The module sends data on a regular basis to help scientists better understand the mechanical and electrical performance requirements needed for the long-term success of power satellite networks. 

It also provides valuable data to advance space solar and electric launch research. 

Converting PRAM to light energy transfer may make more sense for lunar applications, since there is no atmosphere on the moon, but the disadvantage is that it can lose a lot of energy through clouds and atmosphere.

- Future

For the next experiment and demonstration of space solar power, PRAM has successfully laid the groundwork. The scientist's ultimate goal is to build a fully functional system on a dedicated spacecraft based on the experimental results. This helps to test the process by which energy is transmitted back to Earth. This development of space solar could help power many remote facilities, such as forward operating bases and disaster response areas.

[More to come ...]