The price tag of the first nuclear weapon was a mere four years, 130,000 people, and $26 billion (in 2014 dollars). But what did the U.S. buy with those resources, other than the Fat Man and the Little Boy? A transformed world.

Since the Manhattan Project folded in 1947, only a few other projects can arguably have said to truly match the scale and success of America’s drive to make a nuclear weapon. The Apollo program and the decoding of the human genome are two worth consideration—and both have a heritage that can be traced back to the Project itself. Was the Manhattan Project the greatest ad hoc scientific collaboration of all time? And more importantly, could we follow the Project’s model to tackle daunting modern super-problems like climate change?

“People will say all the time, ‘let’s have a Manhattan Project to conquer cancer, solve the energy crisis, do this or do that,” says Robert Norris, a senior fellow for nuclear policy at the Federation of American Scientists and biographer of Manhattan Project head Lt. Gen. Leslie Groves. “The Manhattan Project is constantly alluded to as a great success story where Americans showed that they could get the job done. But I just don’t see that the conditions are ripe for doing something on that scale again today.”

A key difference: The Manhattan Project was spurred by the reality of World War II, which invested the scientists with a sense of urgency and gave the project license to get the job done with little bureaucratic interference. “There were no committees, no evaluations; it was all done sort of on the fly,” says University of Pennsylvania physicist Gino Segre, whose uncle, Emilio Segre, worked on the Manhattan Project. “I don’t think it could happen nowadays…it’s the sort of thing that can only happen in wartime.”

The rise of Big Science

The Manhattan Project’s swords have been beaten into ploughshares that are still very much at work today, where the researchers at large federally-funded institutions are employed, more often than not, on projects aimed at curing disease and providing cleaner energy. (Some swords are still swords: Los Alamos and Lawrence Livermore National Laboratory still conduct nuclear weapons research.)

The Project’s marriage of government money and corporate technology, directed toward the public good, was a key early model of the value of “Big Science” in the newly emerging military-industrial complex. Its legacy can be seen most directly in the network of national laboratories advancing the science of energy, space travel, and computing: Los Alamos National Laboratory, Oak Ridge National Laboratory, and many more. Norris also considers the secrecy and compartmentalization measures initiated by Leslie Groves, the Project’s decisive and energetic leader, as an important step in the national security apparatus we see today in agencies like the CIA and the NSA.

“The U.S. government saw the transformative effect that it could have to bring together many great scientists under one roof and give them resources to solve problems,” says University of California Santa Barbara astronomer Andy Howell. “I have worked at Lawrence Berkeley National Laboratory, so I have benefitted personally from that legacy and seen it firsthand.”

Even though the Manhattan Project was more of an effort in applied science than actual nuclear physics research, its success helped the U.S. government see the gains that could be harvested by investing in basic science. The scientists doing the earliest work on nuclear physics, after all, could hardly have foreseen that their work would lead to the most destructive type of weapon known to mankind.

“Before World War II, physicists were considered as sort of weirdos that did things that people didn’t quite understand,” says Segre. “After the war, people said ‘these are the weirdos who built the atom bomb and radar, and we need them!’”

Beyond the bomb: Nuclear power and medicine

Less than a decade after the Manhattan Project folded, the U.S. detonated a dry fuel hydrogen bomb on Bikini Atoll in the Marshall Islands in a project codenamed Castle Bravo. Castle Bravo remains the most powerful nuclear weapon ever detonated, equivalent to 15,000 kilotons of TNT. (The “Fat Man” dropped on Nagasaki exploded with the force of just 20 kilotons of TNT.) The firepower the U.S. has today puts the Manhattan Project’s tiny arsenal to shame, and there are at least 8 known nuclear states which control and have tested nuclear weapons—a ninth, Israel, is highly suspected to have nuclear bombs but has never confirmed; also, five more countries share nuclear weapons with the U.S. through NATO. The threat of global nuclear war, and of terrorists or rogue states gaining control of nuclear weapons, are among mankind’s most high-profile existential threats.

Not all modern nuclear research is weapons-based, however. From nuclear power to particle accelerators, there are a host of other applications of nuclear physics that can be traced, directly or indirectly, to the successes of the Manhattan Project.

“Nuclear physics eventually sort of morphed into elementary particle physics,” says Segre. “These big accelerators like the one at CERN are not meant for practical applications, but have been supported by governments since World War II.”

More and more countries are harnessing nuclear fission’s energy for electricity. As of May 2014, 435 nuclear reactors in 30 countries are operating, and nuclear power provided 12.3 percent of the world’s produced electricity in 2012. As of 2011, 13 countries produce more than 25 percent of their electricity through nuclear power, with France leading the pack by a mile—nearly three-quarters of the power that lights the lights of Paris is derived from nuclear plants.

Nuclear-powered engines are also in use—sparingly. The U.S. Navy saw the value of nuclear power very early on. Unlike a diesel-electric engine, the nuclear propulsion system requires no air, meaning the sub can stay underwater much longer. Nuclear subs can also run at faster speeds much longer, and don’t have to stop for refueling nearly as often. Since the U.S. launched the first nuclear sub in 1954, five other countries have joined the club: Russia (by way of the USSR), the U.K., France, China, and India. Nuclear power is above us as well as below the waves. NASA has used small-scale nuclear power in at least 25 spacecraft, including the Apollo, Viking, Galileo, and Cassini missions. These craft make use of a radioisotope thermoelectric generator, which converts the heat generated by radioactive decay (usually fueled by plutonium-238) into electricity. The space agency has also contemplated swapping the chemically-fueled propulsion it uses to launch craft into space for nuclear-powered engines, though the idea is still unrealized at present.

Radioactive material also has applications in healthcare. Doctors use small amounts of radionuclides—unstable atoms emitting ionizing radiation—combined with pharmaceutical drugs to create images of a patient’s internal organs. The radioactivity of the material, which is either ingested, inhaled, or injected, is easily picked up by detectors after it accumulates in the organ of interest; doctors can then check the flow of blood through an organ or look for abnormalities that point to specific diseases. Sometimes radionuclides are even used to treat diseases: Radioactive iodine-131, for example, is ingested or injected to treat thyroid cancer or hyperthyroidism.

The evolution of nuclear safety

For an ad-hoc experiment working to harness an incredibly dangerous and little-understood substance, the Manhattan Project suffered mercifully few accidents. Scientists already knew the danger of ionizing radiation, and used radiation monitoring equipment to control their exposure and watch for potentially dangerous situations. The reactors built to create fuel for the Manhattan Project also had fail-safe mechanisms, including the SCRAM (the Single Control Rod Axe Man), which consisted of 29 boron-tipped rods hung by a rope over the reactor: At any sign of serious trouble, an operator could chop the rope and drop the rods in to shut down the reaction.

But tragedies did occur. Two similar incidents at the Los Alamos complex came in 1945 and 1946, while scientists Harry Daghlian and Louis Slotin were performing dangerous maneuvers known as “tickling the tail of the dragon.” This beast breathed something worse than fire.

Daghlian was trying to build a neutron reflector, a component of the atom bomb that helps reduce the amount of plutonium needed to sustain a nuclear chain reaction. He accidentally dropped a tungsten carbide brick onto the plutonium sphere, causing the assembly to emit a blast of neutron radiation. Daghlian hurriedly disassembled the pile to stop the reaction, and was exposed to gamma radiation. Less than a month later, he was dead.

Slotin suffered a similar slip-up. While he was bringing two halves of a beryllium-coated plutonium sphere together, the screwdriver separating the pieces slipped, and the assembly clanged together. Slotin managed to save the lives of seven other people in the lab by knocking the sphere halves apart, stopping the reaction. But for him, the damage was done; he died nine days later.

In 1944, chemical engineers Peter Bragg and Douglas Meigs and physicist Arnold Kramish were trying to unclog a tube used to circulate liquid uranium hexafluoride and high pressure steam at the Philadelphia Navy Yard’s experimental facility. A sudden explosion shattered the tube, and the uranium hexafluoride and steam combined to create a shower of hydrofluoric acid that killed Bragg and Meigs*.

From the very beginnings of the Atomic Age, safety questions loomed large. Should reactors be built underground to lessen the risk of radiation release into the air? How far should they be kept away from populated areas? How much containment should be built into the design? And what should be done with that functionally eternal nuclear waste?

“The history of nuclear power safety has been really trial and error,” says Edwin Lyman, a nuclear expert at the Union of Concerned Scientists. At the start of the nuclear age, regulation was “in the hands of people who wanted to promote the expansion of the technology as fast as possible.”

The Nuclear Regulatory Commission, set up in 1974, was part of the effort to separate the promotional and regulatory aims. The new agency got a safety wake-up call very soon thereafter, in the form of the Three Mile Island’s March 1979 partial meltdown.

Making nuclear power plants safer is primarily about providing backup systems, such as systems to inject water to cool a reactor if a pipe breaks, or filtered vents to sift out radioactive particles in case plant operators need to vent air from a primary containment unit (which actually happened during March 2011’s Fukushima disaster). “It’s very expensive to maintain a bunch of safety systems you may never need, so industry has pushed back,” Lyman says. “And in the post-Fukushima era, the question that’s really come to the forefront is: How safe is safe enough?”

Safety issues, though critical to the future of nuclear technology, are to a certain extent a luxury of the peaceful present. The original atomic bombs, produced in wartime as quickly as humanly possible, were designed to be contained and safe only as long as it took to get them into the air above Japan and unleash devastation. And the U.S. wasn’t alone in racing for the bomb; Germany’s “uranium project” began in 1939, soon after hometown chemists Otto Hahn and Fritz Strassman published a paper showing that when uranium is blasted with neutrally charged particles, you get barium atoms, roughly halving the original ingredient. “After they discovered fission, the cat was out of the bag,” Norris says. “Any physicist with half a brain immediately saw the potential. We just did it first.”

Were the Allies, and their scientists, justified in pursuing such a potentially apocalyptic weapon? Was it enough to know that Axis powers were frantically pursuing the same goal?

Next week we’ll take a deeper look at the ethical questions surrounding the Atomic Age in Part II of ‘The Long Shadow of the Manhattan Project.’

*Correction: This article initially said that Kramish was killed along with Bragg and Meigs in the Philadelphia incident. Kramish survived.

Image: The BADGER explosion on April 18, 1953, conducted as part of Operation Upshot-Knothole a series of U.S. nuclear tests in Nevada. (Credit: Wikimedia Commons/National Nuclear Security Administration)