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  • Writer's pictureAnchor Point

#Caltech Space #SolarPower Project: Advancing Wireless Power Transmission in Space /#greentech

The Solar Power Collector developed by the California Institute of Technology (Caltech) took off earlier this year aboard SpaceX's Falcon 9 rocket. Now, the space solar power prototype has successfully started operating, demonstrating the ability to wirelessly transmit power in space and even emit detectable power towards Earth.

Caltech's Space Solar Power Project (SSPP) aims to harness clean energy resources available in space. The orbiting solar power system can collect sunlight 24/7, disregarding weather conditions and day-night cycles. Theoretically, the potential of space solar power is eight times greater per square meter compared to Earth-based solar power.

However, the cost is a significant challenge. Launching solar panels into space translates to a Levelized Cost of Energy (LCoE) ranging between $1 to $2 per kilowatt-hour, nearly six times the retail electricity prices in the United States.

In early January, Caltech deployed the Space Solar Power Demonstrator (SSPD) prototype into orbit. Weighing 50 kilograms, the prototype comprises three key research components:

1. DOLCE (Deployable on-Orbit ultraLight Composite Experiment): This square-shaped structure, measuring 1.8×1.8 meters, demonstrates the modular architecture, packaging, and deployment mechanism of spacecraft structures in orbit.

2. ALBA: Equipped with 32 different solar cells, ALBA helps determine the solar cells suitable for survival in space environments.

3. MAPLE (Microwave Array for Power-transfer Low-orbit Experiment): MAPLE is a flexible lightweight microwave power transmitter used for power transmission experiments in low orbit. It selectively concentrates power on two different receivers, showcasing long-distance wireless power transmission in space.

According to Ali Hajimiri, Co-Director of SSPP and professor of Electrical Engineering and Medical Engineering at Caltech, initial experiments with MAPLE have successfully transmitted power to receivers in space. By editing array programs, the power can be directed towards Earth, as demonstrated in testing conducted at Caltech.

MAPLE consists of two independent receiver arrays located approximately one foot away from the transmitter. These arrays receive power and convert it into direct current (DC) to light up a pair of LEDs. The current experiment focuses on individually illuminating each LED in space and testing the switching process. It also examines the endurance of the experiment in the harsh space environment, including wide temperature fluctuations and solar radiation.

Hajimiri notes that to our knowledge, no one has demonstrated wireless power transmission in space, even with expensive rigid structures. Caltech's team is pioneering this achievement through flexible lightweight structures and their custom-designed integrated circuits.

The MAPLE device includes a small window through which the energy is emitted. The team at Caltech's Gordon and Betty Moore Laboratory of Engineering, located on the rooftop of the Pasadena campus, successfully detected the signals from the expected time and frequency shifts in accordance with the orbital trajectory.

In addition to proving the transmitter's survival and performance capabilities, the experiment involves a feedback mechanism. The power transmission antenna consists of 16 units, each driven by a flexible integrated circuit chip. The Hajimiri team is assessing the performance of individual components within the system through small-scale interference patterns and measuring the differences between various combinations. This process requires up to six months to fully analyze irregular phenomena and trace them back to each unit.

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