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- solar energy
- solar power
- solar array
space-based solar power
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What is space-based solar power?
Space-based solar power (SBSP) involves collecting solar energy in space and transmitting it to Earth as a microwave or laser beam, which is then converted into electrical energy. A key advantage of SBSP systems is that, unlike Earth-based solar arrays, space-based arrays in geostationary orbit can collect solar energy uninterrupted by nighttime or weather conditions.
The first test of SBSP occurred in 2023, when Caltech's Space Solar Power Demonstrator (SSPD-1) satellite successfully beamed solar power to Earth in the form of microwaves. Several countries, including the U.S., China, and the European Space Agency, are planning or conducting SBSP experiments.
SBSP systems could offer a plentiful source of clean energy, helping the world transition to a carbon-free future. They could also quickly beam power to areas affected by natural disasters, eliminating the need to rebuild power plants and transmission lines.
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How is space-based solar power different from regular solar power on Earth?
Space-based solar power (SBSP) systems collect solar energy in space and transmit it to Earth as a microwave or laser beam, which is then converted into electrical energy. Unlike Earth-based solar installations, SBSP systems in geostationary orbit can collect energy continuously, unaffected by nighttime or weather conditions. Space-based installations could supply several times more electricity than Earth-based ones because they can collect the solar radiation that is blocked by Earth’s atmosphere.
The first SBSP test occurred in 2023, when Caltech’s Space Solar Power Demonstrator (SSPD-1) satellite successfully beamed solar power to Earth in the form of microwaves. Several countries are planning SBSP experiments, including the U.S., China, and the European Space Agency.
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How do satellites collect solar energy in space?
Space-based solar power systems collect solar energy in space and transmit it to Earth. Solar radiation is converted directly into electricity by solar cells (photovoltaic cells). A small electric voltage is generated when light strikes the junction between a metal and a semiconductor.
To maximize efficiency, tracking systems reorient the panels to follow the Sun's movements. Once collected, the solar power is transmitted as a microwave or laser beam to the ground, where it is then converted into electrical energy.
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How is the collected solar power sent back to Earth?
Space-based solar power (SBSP) systems collect solar energy in space and transmit it to Earth as a microwave or laser beam, which is then converted into electrical energy. In 2023, the Microwave Array for Power-transfer Low-orbit Experiment (MAPLE) beamed solar power in the form of microwaves to a receiver on Earth, where it was converted into electricity to light LEDs.
Another hypothetical technology, the solar wind power satellite, would transform the remainder of the current into a laser beam for long-distance transport to Earth. However, a major limitation of this technology is the transport of energy back to Earth because existing laser technology would not be able to focus a laser beam through that distance.
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What are the main challenges in building and launching space-based solar power systems?
Space-based solar power (SBSP) systems collect solar energy in space and transmit it to Earth as a microwave or laser beam to be converted into electrical energy.
Challenges in building SBSP systems:
* High initial costs The cost of launching materials to space remains a significant hurdle, although advancements in reusable rocket technology are reducing expenses.
* Scale The large size required for solar power satellites, potentially measuring about a kilometer across, necessitates numerous launches to assemble.
* Energy Transport Getting the energy back to Earth is limited by the planet’s magnetic field, particularly the Van Allen radiation belt, requires the satellite to be placed at least 65,000 km away from Earth. Existing laser technology would not be able to focus a laser beam through that distance, especially after taking into account that the satellite may not be stationary. Hence, the beam would widen and disperse, and its energy would be lost.3 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How could space-based solar power help meet the world's energy needs in the future?
Space-based solar power (SBSP) involves collecting solar energy in space and transmitting it to Earth as a microwave or laser beam, which is then converted into electrical energy. Unlike Earth-based solar installations, SBSP systems in geostationary orbit can collect solar energy continuously, unaffected by nighttime or weather conditions. Space-based installations could potentially supply several times more electricity than Earth-based ones because they aren't limited by the Earth’s atmosphere. This plentiful, clean energy source could aid the global transition to a carbon-free future, and in natural disasters, power could be quickly beamed to affected areas.
The first SBSP test occurred in 2023, when Caltech’s Space Solar Power Demonstrator (SSPD-1) satellite successfully transmitted solar power via microwaves to a receiver on Earth. Several countries are planning SBSP experiments, including China, which hopes to build a one-megawatt solar power satellite by 2030.
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space-based solar power, the collection in space of solar energy, which is then transmitted as a microwave or laser beam to the ground and converted into electrical energy.
The idea of space-based solar power predates the space age. Konstantin Tsiolkovsky proposed in 1923 that space-based mirrors could beam sunlight to the ground. American science-fiction writer Isaac Asimov’s story “Reason” (1941) was set on a solar power satellite that beamed energy around the solar system. American engineer Peter Glaser proposed the idea of collecting solar power and transmitting it to Earth with microwaves in 1968.
Collecting solar power in space has several advantages. Unlike Earth-based installations, solar arrays in geostationary orbit would not have to stop collecting because of nighttime or bad weather. Moreover, it is estimated that space-based installations would feed several times more electricity to consumers than solely Earth-based installations, which cannot collect the portion of solar radiation blocked by Earth’s atmosphere. Power satellites in Earth orbit would be a source of plentiful clean energy that would help the world transition to a carbon-free future. In cases of natural disaster, power could be quickly beamed to the affected area without having to wait to rebuild power plants and transmission lines.
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U.S. government studies of Glaser’s concept in the late 20th century found no great technological hurdles with the efficiency of the system or the transmission of the power to Earth. However, the large size required for the solar power satellites, which together would measure about a kilometre across, would require hundreds of launches per year, each carrying hundreds of tons of material. For most of the space age, the cost of launching 1 kg to Earth orbit has been $10,000. However, with the advent of SpaceX’s reusable Falcon rockets, that cost has gone down to about $1,000, and it is estimated that SpaceX’s proposed Starship would bring the cost down to $200.
The first test of space-based solar power occurred in 2023, when the Microwave Array for Power-transfer Low-orbit Experiment (MAPLE), on board Caltech’s Space Solar Power Demonstrator (SSPD-1) satellite, beamed solar power in the form of microwaves to a receiver on Earth. There the microwaves were converted into electricity, which was used to light a pair of LEDs (light-emitting diodes). MAPLE consists of solar radiation receivers and an array of flexible lightweight microwave power transmitters. Through a small window, those transmitters can beam power to a precise location on Earth—specifically, to a receiving array at Caltech in Pasadena, California.
Several countries are conducting or planning experiments in space-based solar power. The U.S. Naval Research Laboratory launched an experiment to the International Space Station in 2023 that has used a laser beam to transmit power over a distance of 145 cm (57 inches) for months. The European Space Agency’s Project Solaris is studying the feasibility of space-based solar power with the aim of deciding in 2025 whether to proceed with further development. China hopes to build a one-megawatt solar power satellite by 2030.