NASA Scientists on Why We Might Not Spot Solar Panel Technosignatures

One of NASA’s key priorities is understanding the potential for life elsewhere in the universe. NASA has not found any credible evidence of extraterrestrial life — but NASA is exploring the solar system and beyond to help us answer fundamental questions, including whether we are alone in the universe.

For those who study the potential for life beyond Earth, one of the questions has long been trying to determine the likelihood of microbial life versus complex life versus a civilization so advanced that we can spot signs of it, called technosignatures, from here at home. Studying the answers to questions like that can help guide suggestions on new telescopes or missions to emphasize the most likely places and ways to look for life.

Now a recent paper published May 24 in the Astrophysical Journal postulates that if advanced extraterrestrial civilizations exist, one reason they might be hard to detect with telescopes from our vantage point is because their energy requirements may be relatively modest. If their culture, technology, and population size do not need vast amounts of power, they would not be required to build enormous stellar-energy harvesting structures that could be detected by current or proposed telescopes. Such structures, based on our own Earthly experience, might be solar panel arrays that cover a significant portion of their planet’s surface or orbiting megastructures to harness most of their parent star’s energy—both of which we might be able to spot from our own solar system.

“We found that even if our current population of about 8 billion stabilizes at 30 billion with a high standard of living, and we only use solar energy for power, we still use way less energy than that provided by all the sunlight illuminating our planet,” said Ravi Kopparapu of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, lead author of the paper.

The study has implications for the Fermi paradox, postulated by physicist Enrico Fermi, which asks the question that since our galaxy is ancient and vast, and interstellar travel is difficult but possible, why hasn’t an alien civilization spread across the galaxy by now?

“The implication is that civilizations may not feel compelled to expand all over the galaxy because they may achieve sustainable population and energy-usage levels even if they choose a very high standard of living,” said Kopparapu. “They may expand within their own stellar system, or even within nearby star systems, but a galaxy-spanning civilizations may not exist.”

Additionally, our own technological expertise may not yet be able to predict what more advanced civilizations could do.

“Large-scale stellar-energy harvesting structures may especially be obsolete when considering technological advances,” adds Vincent Kofman, a co-author of the paper at NASA Goddard and American University, Washington, D.C. “Surely a society that can place enormous structures in space would be able to access nuclear fusion or other space-efficient methods of generating power.”

The researchers used computer models and NASA satellite data to simulate an Earth-like planet with varying levels of silicon solar panel coverage. The team then modeled an advanced telescope like the proposed NASA Habitable Worlds Observatory to see if it could detect solar panels on the planet about 30 light-years away, which is relatively nearby in a galaxy that spans over 100,000 light-years. They found that it would require several hundreds of hours of observing time with that type of telescope to detect signatures from solar panels covering about 23% of the land area on an Earth-like exoplanet. However, the requirement for 30 billion humans at a high-living standard was only about 8.9% solar-panel coverage.

Extraterrestrial civilizations with advanced technology could be discovered by their technosignatures – observational manifestations of extraterrestrial technology that could be detected or inferred through astronomical searches. For decades, scientists have been using radio telescopes to look for potential extraterrestrial radio transmissions. More recently, astronomers have proposed using a telescope like the Habitable Worlds Observatory to look for other kinds of technosignatures, such as chemical “fingerprints” in exoplanet atmospheres or specific characteristics in the light reflected by an exoplanet that might announce the presence of vast silicon solar arrays.

The new study assumes that extraterrestrials would build solar panels out of silicon because it’s relatively abundant compared to other elements used in solar power, such as germanium, gallium, or arsenic. Also, silicon is good at converting the light emitted by Sun-like stars into electricity and it’s cost-effective to mine and manufacture into solar cells.

The researchers also assume that a hypothetical extraterrestrial civilization would rely exclusively on solar energy. However, if other sources of energy are used, such as nuclear fusion, it would reduce the silicon technosignature, making the civilization even harder to detect. The study further assumes that the civilization’s population stabilizes at some point. If this doesn’t happen for whatever reason, perhaps they will be driven to expand ever-father into deep space. Finally, it’s impossible to know if an advanced civilization may be using something we haven’t imagined yet that requires immense amounts of power.

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Searching for Signs of Intelligent Life: Technosignatures

Signs of life beyond Earth could take forms that are clearly artificial – radio or…

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Systems Engineer Douglas Wong

“When I was around 16 or 17, I came across this book by Arthur C. Clarke called Space Odyssey 2001. That was actually the first science fiction book that I’ve ever read. I was just so captured by what he had written because the things that he wrote about weren’t [happening] in the far-off future, but in the year 2001. In the book, he talks about a lot about space stations, and space shuttles that go up to the space station, and vehicles that go to the Moon or the Moon base, and all that. I mean, these are terms that you hear now all the time, right? And Arthur C. Clarke actually envisioned it at that time. So that was interesting to me. I hoped that someday I could work on something like that.

“In terms of my education, I was actually going to go into the space engineering, but then someone advised me that mechanical engineering would give me a broader background. So I followed the advice, and it was the right thing to do. I ended up learning a lot of things, not just mechanical engineering but also a lot about electrical engineering and systems engineering at the same time.

“…Then an opportunity came with NASA. It was at that time that they started talking about the space station. Ronald Reagan at that time was the President, and he proposed this initiative to develop the space station. At that time, he called the space station ‘Freedom.’

“I thought, ‘Wow, what an exciting concept; it would be great if I could work on that.’

“And of course, one thing led to another, and [I ended up working on the International Space Station.] So you never know what you’re going to end up doing.

“I believe in synchronicity sometimes. The things that you do, one way or another, lead to your final destination. Some invisible forces push you in that direction. When you look back, you realize that everything fits together.”

— Douglas Wong, Systems Engineer, ISS CRS Visiting Vehicle Safety & Mission Assurance Integration Focal, NASA’s Johnson Space Center

Image Credit: NASA/Bill Stafford
Interviewer: NASA/Thalia Patrinos

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Thalia K. Patrinos

Hubble Spies a Diminutive Galaxy

This NASA/ESA Hubble Space Telescope image reveals the subtle glow of the galaxy named IC 3430, located 45 million light-years from Earth in the constellation Virgo. This dwarf elliptical galaxy is part of the Virgo cluster, a rich collection of galaxies both large and small, many of which are very similar in type to this diminutive galaxy.

Like its larger elliptical cousins, IC 3430 has a smooth, oval shape lacking any recognizable features like arms or bars, and is missing much of the gas needed to form many new stars. Interestingly, IC 3430 does feature a core of hot, massive blue stars —an uncommon sight in elliptical galaxies — that indicates recent star-forming activity. Astronomers think that pressure from the galaxy ploughing through gas within the Virgo cluster ignited what gas IC 3430 had in its core to form the newer stars.

Dwarf galaxies are really just galaxies with fewer stars, usually less than a billion, but that is often enough for them to reproduce, in miniature, the same forms as larger galaxies. There are dwarf elliptical galaxies like IC 3430, dwarf irregular galaxies, dwarf spheroidal galaxies, and even dwarf spiral galaxies!

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Media Contact:

Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov

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NASA Shares its SpaceX Crew-10 Assignments for Space Station Mission

As part of NASA’s SpaceX Crew-10 mission, four crew members are preparing to launch for a long-duration stay aboard the International Space Station.

NASA astronauts Commander Anne McClain and Pilot Nichole Ayers, JAXA (Japan Aerospace Exploration Agency) astronaut Mission Specialist Takuya Onishi, and Roscosmos cosmonaut Mission Specialist Kirill Peskov will join astronauts at the orbiting laboratory no earlier than February 2025.

The flight is the 10th crew rotation with SpaceX to the station as part of NASA’s Commercial Crew Program. While aboard, the international crew will conduct scientific investigations and technology demonstrations to help prepare humans for future missions and benefit people on Earth.

Selected by NASA as an astronaut in 2013, this will be McClain’s second spaceflight. A colonel in the U.S. Army, she earned her bachelor’s degree in Mechanical Engineering from the U.S. Military Academy at West Point, New York, and holds master’s degrees in Aerospace Engineering, International Security, and Strategic Studies. The Spokane, Washington, native was an instructor pilot in the OH-58D Kiowa Warrior helicopter and is a graduate of the U.S. Naval Test Pilot School in Patuxent River, Maryland. McClain has more than 2,300 flight hours in 24 rotary and fixed-wing aircraft, including more than 800 in combat, and was a member of the U.S. Women’s National Rugby Team. On her first spaceflight, McClain spent 204 days as a flight engineer during Expeditions 58 and 59 and was the lead on two spacewalks, totaling 13 hours and 8 minutes. Since then, she has served in various roles, including branch chief and space station assistant to the chief of NASA’s Astronaut Office.

Ayers is a major in the U.S. Air Force and the first member of NASA’s 2021 astronaut class named to a crew. The Colorado native graduated from the Air Force Academy in Colorado Springs with a bachelor’s degree in Mathematics and a minor in Russian, where she was a member of the academy’s varsity volleyball team. She later earned a master’s in Computational and Applied Mathematics from Rice University in Houston. Ayers served as an instructor pilot and mission commander in the T-38 ADAIR and F-22 Raptor, leading multinational and multiservice missions worldwide. She has more than 1,400 total flight hours, including more than 200 in combat.

With 113 days in space, this mission also will mark Onishi’s second trip to the space station. After being selected by JAXA in 2009, he flew as a flight engineer for Expeditions 48 and 49 became the first Japanese astronaut to robotically capture the Cygnus spacecraft. He also constructed a new experimental environment aboard Kibo, the station’s Japanese experiment module. Since his spaceflight, Onishi became certified as a JAXA flight director, leading the team responsible for operating Kibo from JAXA Mission Control in Tsukuba, Japan. He holds a bachelor’s degree in Aeronautics and Astronautics from the University of Tokyo and was a pilot for All Nippon Airways, flying more than 3,700 flight hours in the Boeing 767.

NASA’s SpaceX Crew-10 mission also will be Peskov’s first spaceflight. Before his selection as a cosmonaut in 2018, he earned a degree in Engineering from the Ulyanovsk Civil Aviation School and was a co-pilot on the Boeing 757 and 767 aircraft for airlines Nordwind and Ikar. Assigned as a test-cosmonaut in 2020, he has additional experience in skydiving, zero-gravity training, scuba diving, and wilderness survival.

For more than two decades, people have lived and worked continuously aboard the International Space Station, advancing scientific knowledge and demonstrating new technologies, making research breakthroughs not possible on Earth. The station is a critical testbed for NASA to understand and overcome the challenges of long-duration spaceflight and to expand commercial opportunities in low Earth orbit. As commercial companies focus on providing human space transportation services and destinations as part of a robust low Earth orbit economy, NASA’s Artemis campaign is underway at the Moon, where the agency is preparing for future human exploration of Mars.

Find more information on NASA’s Commercial Crew Program at:

https://www.nasa.gov/commercialcrew

-end-

Joshua Finch / Claire O’Shea
Headquarters, Washington
202-358-1100
joshua.a.finch@nasa.gov / claire.a.o’shea@nasa.gov

Raegan Scharfetter
Johnson Space Center, Houston
281-910-4989
raegan.r.scharfetter@nasa.gov

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Jessica Taveau