In 1957, the Soviet Union changed the night sky. Sputnik, the first satellite, was in orbit for just 22 days, but its arrival brought a tremendous set of new implications for nations down on Earth, especially the United States. The USSR was ahead in orbit, and the rocket that launched Sputnik meant that the USSR would likely be able to launch atomic or thermonuclear warheads through space and back down to nations below. 

In the defense policy of the United States, Sputnik became an example of “technological surprise,” or when a rival country demonstrates a new and startling tool. To ensure that the United States is always the nation making the surprises, rather than being surprised, in 1958 president Dwight D. Eisenhower created what we now know as DARPA, the Defense Advanced Research Projects Agency.

Originally called the Advanced Research Projects Agency, or ARPA, ARPA/DARPA has had a tremendous impact on technological development, both for the US military and well beyond it. (Its name became DARPA in 1972, then ARPA again from 1993 to 1996, and it’s been DARPA ever since.) The most monumental achievement of DARPA is the precursor to the service that makes reading this article possible. That would be ARPANET, the immediate predecessor to the internet as we know it, which started as a way to guarantee continuous lines of communication over a distributed network. 

Other projects include the more explicitly military ones, like work on what became the MQ-1 Predator drone, and endeavors that exist in the space between the civilian and military world, like research into self-driving cars.

What is the main purpose of DARPA?

The specific military services have offices that can conduct their own research, designed to bring service-specific technological improvements. Some of these are the Office of Naval Research, the Air Force Research Laboratory, and the Army’s Combat Capabilities Development Command (DEVCOM). DARPA’s mission, from its founding, is to tackle research and development of technologies that do not fall cleanly into any of the services, that are considered worth pursuing on their own merits, and that may end up in the hands of the services later.

How did DARPA start?

Sputnik is foundational to the story of DARPA and ARPA. It’s the event that motivated President Eisenhower to create the agency by executive order. Missiles and rockets at the time were not new, but they were largely secret. During World War II, Nazi Germany had launched rockets carrying explosives against the United Kingdom. These V-2 rockets, complete with some of the engineers who designed and built them, were captured by the United States and the USSR, and each country set to work developing weapons programs from this knowledge.

Rockets on their own are a devastatingly effective way to attack another country, because they can travel beyond the front lines and hit military targets, like ammunition depots, or civilian targets, like neighborhoods and churches, causing disruption and terror and devastation beyond the front lines. What so frightened the United States about Sputnik was that, instead of a rocket that could travel hundred of miles within Earth’s atmosphere, this was a rocket that could go into space, demonstrating that the USSR had a rocket that could serve as the basis for an Intercontinental Ballistic Missile, or ICBM. 

ICBMs carried with them a special fear, because they could deliver thermonuclear warheads, threatening massive destruction across continents. The US’s creation and use of atomic weapons, and then the development of hydrogen bombs (H-bombs), can also be understood as a kind of technological surprise, though both projects preceded DARPA.

[Related: Why DARPA put AI at the controls of a fighter jet]

Popular Science first covered DAPRA in July 1959, with “U.S. ‘Space Fence’ on Alert for Russian Spy-Satellites.” It outlined the new threat posed to the United States from space surveillance and thermonuclear bombs, but did not take a particularly favorable light to ARPA’s work.

“A task force or convoy could no longer cloak itself in radio silence and ocean vastness. Once spotted, it could be wiped out by a single H-bomb,” the story read. “This disquieting new problem was passed to ARPA (Advanced Research Projects Agency), which appointed a committee, naturally.”

That space fence formed an early basis for US surveillance of objects in orbit, a task that now falls to the Space Force and its existing tried-and-true network of sensors.

Did DARPA invent the internet?

Before the internet, electronic communications were routed through telecommunications circuits and switchboards. If a relay between two callers stopped working, the call would end, as there was no other way to sustain the communication link. ARPANET was built as a way to allow computers to share information, but pass it through distributed networks, so that if one node was lost, the chain of communication could continue through another.

“By moving packets of data that dynamically worked their way through a network to the destination where they would reassemble themselves, it became possible to avoid losing data even if one or more nodes went down,” describes DARPA

The earliest ARPANET, established in 1969 (it started running in October of that year), was a mostly West Coast affair. It connected nodes at University of California, Santa Barbara; University of California, Los Angeles; University of Utah; and Stanford Research Institute. By September 1971 it had reached the East Coast, and was a continent-spanning network connecting military bases, labs, and universities by the late 1970s, all sending communication over telephone lines.

[Related: How a US intelligence program created a team of ‘Superforecasters’]

Two other key innovations made ARPANET a durable template for the internet. The first was commissioning the first production of traffic routers to serve as relay points for these packets. (Modern wireless routers are a distant descendant of this earlier wired technology.) Another was setting up universal protocols for transmission and function, allowing products and computers made by different companies to share a communication language and form. 

The formal ARPANET was decommissioned in 1988, thanks in part to redundancy with the then-new internet. It had demonstrated that computer communications could work across great distances, through distributed networks. This became a template for other communications technologies pursued by the United States, like mesh networks and satellite constellations, all designed to ensure that sending signals is hard to disrupt.

“At a time when computers were still stuffed with vacuum tubes, the Arpanauts understood that these machines were much more than computational devices. They were destined to become the most powerful communications tools in history,” wrote Phil Patton for Popular Science in 1995.

What are key DARPA projects?

For 65 years, DARPA has spurred the development of technologies by funding projects and managing them at the research and development stage, before handing those projects off to other entities, like the service’s labs or private industry, to see them carried to full fruition. 

DARPA has had a hand in shaping technology across computers, sensors, robotics, autonomy, uncrewed vehicles, stealth, and even the Moderna COVID-19 vaccine. The list is extensive, and DARPA has ongoing research programs that make a comprehensive picture daunting. Not every one of DARPA’s projects yields success, but the ones that do have had an outsized impact, like the following list of game-changers:

Stealth: Improvements in missile and sensor technology made it risky to fly fighters into combat. During the Vietnam War, the Navy and Air Force adapted with “wild weasel” missions, where daring pilots would draw fire from anti-air missiles and then attempt to out-maneuver them, allowing others to destroy the radar and missile launch sites. That’s not an ideal approach. Stealth, in which the shape and materials of an aircraft are used to minimize its appearance on enemy sensors, especially radar, was one such adaptation pursued by DARPA to protect aircraft. DARPA’s development of stealth demonstrator HAVE BLUE (tested at Area 51) paved the way for early stealth aircraft like the F-117 fighter and B-2 bomber, which in turn cleared a path for modern stealth planes like the F-22 and F-35 fights, and the B-21 stealth bomber.

Vaccines: In 2011, DARPA started its Autonomous Diagnostics to Enable Prevention and Therapeutics (ADEPT) program. Through this, in 2013 Moderna received $25 million from DARPA, funding that helped support its work. It was a bet that paid off tremendously in the COVID-19 pandemic, and was one of many such efforts to fund and support everything from diagnostic to treatment to production technologies.

Secret space plane: The X-37B is a maneuverable shuttle-like robotic space plane that started as a NASA program, was developed under DARPA for a time, and then became an Air Force project. Today it is operated by Space Force. This robot can remain in orbit for extraordinarily long lengths of time, with a recent mission lasting over 900 days. The vehicle serves as a testbed for a range of technologies, including autonomous orbital flight as well as sensors and materials testing. There is some speculation as to what the X-37B will lead to in orbit. For now, observations match its stated testing objectives, but the possibility that a reusable, maneuverable robot could prove useful in attacking satellites is one that many militaries are cautiously worried about. 

That may be a list of some of DARPA’s greatest hits, and in recent years it’s announced projects relating to jetpacks, cave cartography, and new orbits for satellites. It even has a project related to scrap wood and paper, cleverly called WUD.