Science turned skyward

How a bomb built the space program: 
The Rover Program— Los Alamos’ solution to delivering an H-bomb around the world—was the United States’ first foray into nuclear rockets.

“America has a 40,000-pound hydrogen bomb that needs to be transported 5,700 miles to Moscow,” says Los Alamos National Laboratory historian Alan Carr. “How do we do it?” 

What sounds like a junior-high math problem is actually the question that spurred Los Alamos to delve into nuclear rockets in the 1950s. With national security as the catalyst, the Laboratory began a space program that continues to this day.

Hydrogen bombs were first built in the throes of the Cold War, when tensions were escalating between the United States and the Soviet Union, as each country developed increasingly powerful nuclear weapons. Although Los Alamos scientists constructed a new behemoth bomb—nearly four times heavier than the first wartime atomic bomb, “Little Boy”—they were unsure how to deliver it. Carr jokes that scientists “just hoped the plane would stay together,” but that’s not far from the truth. A bomb weighing nearly five tons needed a more reliable and efficient way to travel halfway around the world.

Enter Project Rover—Los Alamos’ first foray into space technology. As a part of the Nuclear Rocket Propulsion Division, Rover’s mission was to build a new kind of rocket, one that was nuclear powered, to rapidly and safely deliver a heavy-weight hydrogen bomb to Moscow.

Before Project Rover, chemical rockets were the standard for space. But the speed, power, and fuel economy that a nuclear-powered thermal rocket could offer were undeniable—nuclear rockets are three times as efficient as chemical rockets, and they significantly cut travel time in space. With a nuclear rocket, a trip to Mars could be accomplished in as little as four months, and the delivery of a hydrogen bomb to Moscow could be accomplished in 30 minutes.

When it began in 1955, Project Rover was one element of Los Alamos research that acted as a metronome for keeping pace in the Cold War. Los Alamos scientists were simultaneously working to miniaturize atomic bombs, and by 1956, the problem was solved with a design for a lighter bomb. This second-generation hydrogen bomb was tested during Operation Redwing and offered a 5-megatonyield nuclear explosion (equivalent to 5 million tons of TNT) at half the weapon weight. This newer, lighter bomb was transportable by conventional rockets, so building a nuclear rocket for bomb delivery was no longer necessary. It was time for Project Rover to abide by the rules of evolution—adapt or die.

Project Rover was on the brink of extinction when hysteria was unleashed by news of Sputnik, the first man-made satellite, which was launched by the Soviet Union. The pressure to beat the Soviets in both the arms race and the space race ballooned across America, and all eyes were back on Rover. Instantly reinvented as the solution to the Soviet’s sudden lead in space, Project Rover surged on, leaving behind its original mission of bomb delivery and focusing entirely on space travel. “Sputnik was a pivotal piece and the best thing that ever happened to space research at Los Alamos,” Carr reflects. Americans were thirsty for space research, and the Rover scientists intended to deliver.

In 1962, President John F. Kennedy brought national attention to Project Rover when he visited the Laboratory. Dressed in suit and tie, Kennedy was hands-on with the cutting-edge technology that was changing the world. Kennedy’s visit culminated in a speech to the townspeople in which he praised Los Alamos' contributions to the nation. He said, “It’s not merely what was done during the days of the second war, but what has been done since then, not only in developing weapons of destruction which, by an irony of fate, help maintain the peace and freedom, but also in medicine and in space, and all the other related fields which can mean so much to mankind if we can maintain the peace and protect our freedom.”

Kennedy’s support of space research at Los Alamos was echoed by his successor, President Lyndon Johnson, but budgets fell short with President Nixon in 1973, and the project was canceled.

Though the history of why the Laboratory’s science turned skyward is unexpected, the resulting technical contributions that came out of Los Alamos space research are invaluable.

Counterproliferation technology

One of the most important contributions to space research was the Los Alamos–developed suite of satellites called Vela, which launched in 1963 and could detect nuclear detonations in space (even at clandestine test sites, such as behind the moon) as well as on the Earth’s surface and under water. The Velas used special sensors for x-rays, gamma rays, neutrons, and the natural background of radiation in space.

Before Vela (meaning “the watchman” in Spanish), the United States lacked the technology to know whether a nuclear treaty was being followed, so we had to resort to informal agreements that relied on trust. But trust is fleeting in times of war, even in cold war, and the security Vela offered calmed the nation. “Vela changed history,” Carr notes as he explains that this new counterproliferation technology played a role in securing the 1963 Limited Nuclear Test Ban Treaty with the Soviets.

The sensor technology deployed on  Vela satellites as the eyes and ears of the nation is still in use today.

The development of Vela sensors and satellites required extreme engineering, and it was accomplished at a breakneck pace. “We built the sensors in about one year,” says Los Alamos Intelligence and Space Research Division Leader Herb Funsten. But quality was not compromised for speed: the sensor technology deployed on Vela satellites as the eyes and ears of the nation is still in use today.

In the 56 years since Vela launched, Los Alamos has flown 400 instruments carrying more than 1,400 sensors on more than 200 total launches. These five decades of space research built upon Vela’s foundation, adding monumental advances in satellites—GPS, broader nuclear weapon detection, multispectral thermal imaging, and miniaturization (see “Electronic license plates for space,” below). While Vela could detect a nuclear explosion, current satellites can detect facilities on Earth that conceal nuclear weapons (preventing an explosion in the first place).

Nuclear-powered space travel

The other important Los Alamos contribution to space research evolved on the ground through Project Rover. Three nuclear rocket designs, done in series—Kiwi (1955 to 1964), Phoebus (1964 to 1969), and Peewee (1969 to 1972)—brought about the knowledge required to achieve space travel powered by a nuclear rocket. All of these designs rely on nuclear fission (the splitting of a nucleus into smaller particles) to heat a propellant gas, in this case, hydrogen. The hydrogen expands as it reaches higher and higher temperatures, causing pressure to build inside the rocket. The pressurized gas can be funneled through a rocket nozzle to create thrust.

Kiwi (named for the flightless bird) was the first nuclear rocket series built at Los Alamos. Tested at the Nevada Test Site, it was never intended for flight; instead, Kiwi was a practice design that defined basic nuclear rocket technology.

A success in its own right, the Kiwi series led to the development of the Phoebus series. Phoebus focused on copious power, with the goal of an interplanetary voyage—such as a voyage to put a man on Mars, which was one of Kennedy’s intentions. Phoebus led to the Peewee series, which focused on a more compact nuclear rocket design, ideal for unmanned missions to space.

The science was novel and incredibly complex—literally rocket science.

This science was novel and incredibly complex—literally rocket science. It demanded numerous inventions in materials and engineering to overcome the extraterrestrial challenges these rockets would face. For example, special uranium-loaded graphite fuel and stable internal engine components were designed at the Laboratory’s Sigma Complex; heat pipes (see p. 9) were created as a cooling system solution (because nuclear cores get incredibly hot); and new techniques for advanced understanding of graphite and carbon were developed. With every barrier to rocket science success came an even greater scientific invention. More than 100 technical papers were published as a result of Project Rover.

Fifty years later, the technology from Project Rover has evolved at the Lab into the development of highly compact nuclear reactors. “These compact reactors can be safely deployed in space, providing unprecedented power—both heat and electricity,” Funsten explains.

From Rover to rover

Each of the Project Rover nuclear rocket series proved successful, but none has launched explorers on long-range space missions—yet. Space travel is expensive, but no one is questioning whether Americans will eventually land on Mars. “By the mid-2030s, I believe we can send humans to orbit Mars and return them safely to Earth,” said President Barack Obama in 2010. “And a landing on Mars will follow. And I expect to be around to see it.”

On March 11, 2019, NASA Administrator Jim Bridenstine formally announced the “Moon to Mars” initiative, financially backed by the Trump administration. Bridenstine explained, “We will go to the Moon in the next decade with innovative, new technologies and systems to explore more locations across the lunar surface than ever before. This time, when we go to the Moon, we will stay. We will use what we learn as we move forward to the Moon to take the next giant leap—sending astronauts to Mars.” The NASA timeline has the manned Mars mission slated for the 2030s, just as Obama predicted.

But before Americans can set foot on Mars, exploratory missions offering look-before-you-leap information about the planet must take place. Once again, Los Alamos is taking center stage. Laboratory space researchers are developing the power supply and two new space instruments—SuperCam and SHERLOC—for NASA’s 2020 Mars rover. “The goal is to better understand Mars, our sister planet,” explains Laboratory Fellow Roger Wiens. Wiens is not only the principal investigator for the two new instruments, he was also the mind behind the successful ChemCam instrument currently aboard NASA’s Curiosity Mars rover.

Powered by 10 pounds of non-fissionable plutonium fabricated by Los Alamos, Curiosity’s goal is to study Mars’ past habitability and characterize the planet’s hazards to humans: Can we have a sustained human presence on Mars? ChemCam is the Los Alamos–developed instrument aboard Curiosity that is currently helping to answer that question. This instrument uses a laser to identify molecules such as water and organics on Mars. Thus far, the data from ChemCam and the other rover instruments are promising; NASA will land another rover on Mars in 2020 to gather even more data.

The new rover will boast a souped-up version of ChemCam, called SuperCam, which is a suite of instrumentation: laser-induced breakdown spectroscopy, Raman and time-resolved fluorescence, color micro-imaging, and VISIR spectroscopy. Another fascinating addition is a microphone. “For the first time,” Wiens explains, “we will be able to listen to Mars!”

SuperCam’s job is to blast Martian rocks with its laser to investigate chemical and mineral compositions from a distance. In addition to SuperCam, there will be six other new instruments on the 2020 rover. SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals) is the second Los Alamos contribution, which will reside on the rover’s robotic arm. SHERLOC is equipped with an ultraviolet spectrometer and camera for studying organics. The 2020 rover will answer the question: Which resources will humans be able to use on Mars?

 A nuclear rocket is expected to cut travel time to Mars in half, making a human journey to Mars feasible and certainly in our near future.

But one remaining concern about sending Americans to Mars is radiation. As Funsten explains, “Traveling beyond the protective magnetic cocoon of Earth’s space environment and into interplanetary space, where cosmic rays continuously bathe spacecraft and solar storms can unleash high-energy particles, is our biggest challenge. Radiation from these sources can cause permanent damage to our bodies.” The current solution to this problem is the same solution we turned to for fast, efficient bomb delivery in the 1950s—nuclear rockets.

Given that total radiation exposure is a function of radiation flux and time, getting humans to Mars faster will be one way to minimize exposure. To that end, NASA is once again looking to Project Rover’s nuclear rocket technology. A nuclear rocket is expected to cut travel time to Mars in half, making a human journey to Mars feasible and certainly in our near future.

What started with a 40,000-pound bomb and a question of transport launched the field of space exploration. Coming full circle from past to present, the technology that came out of Project Rover is now leading America’s way to Mars. ★

Collision course
Could scientists deflect an asteroid headed toward Earth?

An asteroid crashing into Earth is extremely unlikely— but not unprecedented. Sixty-five million years ago, such an event occurred and caused the dinosaurs to go extinct.

Today, to prevent humans from experiencing the same fate, scientists use sophisticated telescopes to monitor the nearly 20,000 asteroids and other near-Earth objects (NEOs) that are on a possible trajectory to collide with our planet.

But what good is monitoring without a plan?

Enter planetary defender Cathy Plesko, a computational physicist at Los Alamos who studies ways to alter an NEO’s flight path. Recently, Plesko studied an asteroid named Bennu, which is as wide as the Empire State Building is tall and weighs as much as 800 aircraft carriers. Bennu approaches Earth once every six years, making it a perfect test case (even though it has only a 1 in 2,700 chance of hitting Earth, about 100 years from now).

“We used computer models to study two ways of pushing Bennu off course: smashing a spacecraft into the asteroid or detonating a nuclear device from several hundred yards away,” Plesko says.

“We fed the best estimates of Bennu’s shape, composition, mass, and strength into our computer models and predicted what would happen in each scenario.”

Smashing a spacecraft into Bennu seemed like the best bet, even though it would mean launching a spacecraft 10–25 years before the predicted impact. To further test this concept, NASA— working with Plesko—has designed the Double Asteroid Redirection Test (DART) spacecraft, which will launch in 2020. In 2022, DART is expected to crash into an asteroid called Didymos B at the speed of 6 kilometers per second—enough to shift the asteroid’s orbital path a fraction of 1 percent (but not enough to knock Didymos B onto a collision course with Earth).

“I’m glad we’re doing this research now while we can take the time to carefully study the problem and triplecheck our models without the pressure of a specific, potentially hazardous object coming at us,” Plesko says. “If we prepare well, then for the first time, our species could prevent a major natural disaster. We can’t yet push a hurricane off course, cork a volcano, or lock an earthquake-prone fault, but in a few years, we could be ready to stop an asteroid in its tracks.” ★

Electronic license plates for space
Identification for satellites solves growing space-traffic problems.

In the silent vacuum of space, an anonymous CubeSat (miniature satellite) crashes into a U.S. national security satellite, rendering the nation vulnerable and without the ability to identify the responsible party. This type of hit-and-run space traffic scenario is one the nation’s military and intelligence communities fear for the near future, as more private companies commission thousands of CubeSats—4-inch cubes, shorter than an average smartphone.

“CubeSats give the common man access to space; you don’t need a billion dollars to get to space anymore,” explains Los Alamos mechanical engineer Dan Seitz. At a reasonable price of $40,000 or less to launch, these 3-pound satellites allow anyone in the world to purchase his or her own CubeSat and send it to space aboard a large rocket.

The exponential boom in demand for commercial CubeSats comes from these satellites’ ability to gather data needed for important predictions and studies. For example, CubeSats can track port traffic and agricultural patterns for predictions of economic growth, or they can gather environmental data for studies of global warming. Commercial CubeSats can also offer services, such as internet and radio. There is great economic opportunity for companies that take to the sky, but as more and more companies do just that, the skies become overcrowded, which is why traffic congestion in space is now a hot-button issue.

“To maintain U.S. leadership in space, we must develop a new approach to space traffic management,” the National Space Council states in its Space Policy Directive-3, issued June 18, 2018. David Palmer, a Los Alamos space and remote-sensing scientist, has designed that new approach. It’s an extremely low-resource optical identifier (ELROI)— an electronic license plate technology for space.

ELROI uses a laser diode to communicate a unique serial code that identifies a CubeSat, attributing a name to who is responsible for each satellite in space. The laser on a CubeSat blinks 1,000 times each second, with each blink lasting only a millionth of a second. The blink-nonblink pattern is like a binary code of ones and zeros that translates to a serial code. Back on Earth, that code is detected by a corresponding telescope filtered to the laser’s specific wavelength, and the CubeSat is identified by name and position.

Currently, larger satellites use radio waves powered by many watts of electricity to communicate their name and position back to Earth. But this technology performs only if the satellite is working and can afford to use that much power for communication. “There are 5,000 space objects with payloads in space, but a mere 2,000 are working and able to identify themselves,” Palmer explains. Because the number of space objects is expected to more than quadruple in the next few years, this issue of unidentified space objects cluttering the skies must be addressed.

The benefit of ELROI is that it can identify a satellite whether the satellite is working or not because each ELROI is powered by its own rechargeable solar cell. The wattage used for ELROI is about that of a refrigerator light when ELROI is on, which is only 1/1000th of the time, thanks to its blinking on and off. Overall, it consumes about as much power as a laser pointer (when averaged over a second or longer) and costs the satellite nothing to operate, in terms of power.

The ultimate plan for ELROI, which initially rode to space in December 2018 and will be part of two more launches in 2020, is to enforce space safety. “The vision is to have an ELROI license plate on every object that gets registered for space launch,” Palmer says. At an expected cost of less than $1,000 per unit, the tiny ELROI (no larger than a Scrabble game tile) will be a simple solution for a growing problem. ★

Cosmic collaboration
Lisa Danielson sparks Lab-wide collaboration to advance Los Alamos planetary science.

“Does life exist beyond Earth?” That’s the question Lisa Danielson has wondered about since the age of five, when she first became interested in space. Four decades, three degrees, and one stint at NASA later, she is now equipped to find the answer as the new lead for planetary science in the Space and Remote Sensing Group at Los Alamos.

Danielson started her position on April 15. She moved to Los Alamos from Houston, where she was the manager of Basic and Applied Research for Jacobs, a contractor of NASA’s Johnson Space Center. But this isn’t her first taste of New Mexico. In her early 20s, Danielson visited the Earth and Planetary Sciences building at the University of New Mexico, where she encountered the space rocks that sparked her career. “I stepped inside and saw meteorites, and I was instantly hooked,” Danielson says.

In a sea of scientists, Danielson stands out, and not just because of her pink hair and 1,000-watt smile. Like a beacon, she radiates excitement over her new role at the Laboratory—officially, planetary science expert, but unofficially, scientist herder. “There are tons of experts at the Lab who do unique and exciting work, but they need someone who can pull those experts together to grow the field of planetary science,” Danielson says.

“Lisa is that someone,” explains Reiner Friedel, director of the Center for Earth and Space Science and manager of NASA programs at the Lab. “Lisa will help write strategy proposals, bring experts into Los Alamos and together at the Lab, and be an ambassador for the center.”

Planetary science (the study of the composition and formation of planets, moons, and planetary systems) is a broad field, and Danielson intends to make it broader, encouraging collaboration among Lab experts working in disparate fields, such as shock physics, that were traditionally far removed from space research. Space is complex, and to tackle future challenges in planetary science, the Lab needs experts from a diversity of fields working together.

Danielson’s umbrella will encompass everything planetary, from new instruments for the Mars 2020 rover (see “How a bomb built the space program,” p. 32) to the miniaturization of satellites (see “Electronic license plates for space,” p. 36). With every step forward in planetary science, there is a speed bump to overcome with new technology. “People always think of the amazing space pictures that are taken once we reach a planetary destination, but it is the journey to that destination that matters most—contributing technological improvements that benefit the public and national security.” ★

The women powering the Mars rover laser
The brains behind the Curiosity rover’s rock-penetrating laser, which last year enabled the discovery of an ancient Martian lake bed.

The laser that zaps rocks on Mars is commanded by a talented group of engineers and scientists at Los Alamos National Laboratory—a team that also happens to be made completely of women, a rarity in the engineering field.

“It’s unusual, simply because engineering still tends to be male dominated,” says Nina Lanza, a planetary scientist in the group who helped recruit other members. “Typically on teams like this, you’ll have a few women, but a majority are men. I don’t know of any other instruments on the Mars Curiosity rover that have an all-female engineering team.”

The women are responsible for sending commands to the ChemCam instrument, which shoots Martian rocks with a laser to determine their chemical make-up. The laser was developed at Los Alamos in conjunction with the French space agency and played a key role in the discovery of the existence of an ancient lake on the Red Planet.

The team meets daily with planetary scientists from around the world, who identify which rocks on the surface of Mars to zap and analyze. The engineering team then figures out what commands to send to the ChemCam instrument to make that possible.

“This job requires a lot of long hours and dedication,” says Lisa Danielson, the ChemCam operations manager. “And there’s a high intensity that requires excellent communication and teamwork. We work really well together and are very supportive of each other. We create a very positive environment and know that we can depend on each other.”

It wasn’t intentional to create the all-woman team, Lanza says. They were just looking for the best people for the job. “What matters is that they have the right set of skills and the right personality.” But as more women fill leadership roles, Lanza says, teams like this are bound to become more common.

“Women in the sciences know other women in the sciences,” Lanza says. “That’s why a diverse workforce is so important. If you have a diverse team, the members will likely have a network of talented people—so you find people you might have never found otherwise.” ★