Reaping the unexpected dividends of space exploration

Scientists examine the Kiwi B4-A reactor developed at Los Alamos National Laboratory and used to power a nuclear rocket in the 1960s. Los Alamos National Laboratory

One of the great things about scientific research is that we often make discoveries we were never planning to make — with far-reaching applications that we never planned. After all, we don’t know what we don’t know, until we do.

Since the earliest days of scientific exploration, we can chart a persistent pattern of big discoveries with important consequences. One of the most famous is antibiotics. In 1928, a biologist found mold growing on his petri dishes of bacteria colonies. While trying to save his experiment, he noticed that bacteria wasn’t growing around the mold. The result was the development of penicillin, which fundamentally changed how we treat infections and is credited with saving as many as 200 million lives since its widespread introduction in the 1940s.

Space science has likewise yielded unexpected discoveries and unintended applications — some at Los Alamos National Laboratory.

For example, in the early 1960s, Los Alamos developed technology for detecting space-based nuclear detonations when the United States signed the Limited Test Ban Treaty of 1963 that prohibited countries from testing nuclear weapons from the ground to space.

One week after the treaty went into effect, the laboratory began its nascent treaty monitoring role when its sensors rode into space on the first of the Vela satellite series. From the early 1960s to the mid-1980s, a series of 12 Vela satellites were sent into space—each with a suite of Los Alamos instruments. Their purpose? To detect radiation from potential nuclear events in the atmosphere and space. But the sensors did more than that. They also made the serendipitous discovery of cosmic gamma-ray bursts emitted from supernova, the last death throes of massive stars and the most powerful explosions in the universe.

While this discovery hasn’t given us the equivalent of penicillin, it has yielded enormous amounts of information about the early universe and how it has evolved, expanding our understanding of stellar evolution and death. Cosmic gamma-ray bursts will likely continue to spark future discoveries as we look into the distant past using new instruments to observe the deaths of the first stars after the Big Bang.

Another example can be found in Project Rover, a Los Alamos program that was never fully realized, but which continues to reap huge scientific and engineering benefits decades later.

Project Rover began in the 1950s, when the U.S. government began exploring a nuclear rocket program to defend against possible Soviet aggression. Scientists saw the potential for much broader applications—including significantly shortening long journeys to other planets and into interstellar space.

President John F. Kennedy highlighted the program in his famous “moonshot” speech in 1961, saying that Project Rover “gives promise of someday providing a means for even more exciting and ambitious exploration of space, perhaps beyond the moon, perhaps to the very end of the solar system itself.” As Clay Wellborn, one of the Los Alamos scientists to work on the early Rover program put it, the purpose was simple: “To put people on Mars, for heaven’s sake.”

Ultimately, funding was cut and the program shut down in 1972, but not without bringing forth a critical understanding of how nuclear power can be used for space exploration—something that continues to benefit us today in the form of radioisotope thermoelectric generators (RTGs).

RTGs convert heat from nuclear material into electricity and also keep the instruments and electronics at room temperature. They have powered more than 25 U.S. space vehicles, from the Pioneer missions that first explored our solar system to the Curiosity Rover currently touring and studying Mars. They have also powered the Voyager spacecraft launched in 1977 and still happily cruising through frigid interstellar space, in addition to the Juno mission that has snapped spectacular photos of the hellish storms of Jupiter. The New Horizons mission, which has transformed our understanding of Pluto and its moon Charon, also boasts an RTG power source. It is now studying the object Ultima Thule, which is 4 billion miles from Earth and a throwback to the birth of our solar system.

Nuclear is often the preferred power source for spaceflight because it doesn’t rely on bright sunlight, as solar cells do—something that is in short supply on deep space missions far from the sun. Even on Mars, dust storms can block sunlight, rendering a solar-powered spacecraft helpless. RTGs keep the lights on and warm the soul, so to speak. Nuclear power is also lightweight, which makes it easier (and less expensive) to launch to distant planetary bodies and beyond.

The legacy of Project Rover carries through to Kilopower, a safe, reliable nuclear reactor recently developed at Los Alamos to someday power a habitat on the moon or Mars. The core of the reactor, about the size of a paper towel roll, produces power ranging from 1 kilowatt—enough to power a household toaster or microwave—to 10 kilowatts—enough to run a central air conditioner or power an electric car.

This technology also has potential terrestrial applications as well: Small, portable nuclear reactors could bring temporary power to disaster areas or off-grid remote rural areas.

These are just a few examples of science leading us in directions we never imagined possible when we took the first step on the path to discovery. Nuclear treaty-monitoring satellites gave us an understanding of the life and death of stars and how our universe is evolving; a nuclear rocket program that didn’t give us nuclear rockets still gave us nuclear-powered space exploration. These consequences might have been unintended, but the benefits have been immense.

It’s the gift of exploration—and one that keeps on giving. Now the only question is: What will we discover next?

The Santa Fe Institute’s Inter Planetary Festival will feature a panel of Los Alamos National Laboratory researchers discussing the “Science of Vintage Space,” including the discovery of gamma-ray bursts and nuclear-powered space exploration, Saturday, June 15, 4:15 to 5:15 p.m., in the SITE Santa FE auditorium. For more information, visit

Herbert O. Funsten is a scientist who specializes in deep-space exploration and is the division leader of the Intelligence and Space Research Division at Los Alamos National Laboratory.