This is a joint investigation with the German news magazine Der Spiegel. A TOP-SECRET U.S. intelligence document obtained by The Intercept confirms that the sprawling U.S. military base in Ramstein, Germany serves as the high-tech heart of America’s drone program. Ramstein is the site of a satellite relay station that enables drone operators in the American Southwest to communicate with their remote aircraft in Yemen, Somalia, Afghanistan and other targeted countries. The top-secret slide deck, dated July 2012, provides the most detailed blueprint seen to date of the technical architecture used to conduct strikes with Predator and Reaper drones. Amid fierce European criticism of America’s targeted killing program, U.S. and German government officials have long downplayed Ramstein’s role in lethal U.S. drone operations and have issued carefully phrased evasions when confronted with direct questions about the base. But the slides show that the facilities at Ramstein perform an essential function in lethal drone strikes conducted by the CIA and the U.S. military in the Middle East, Afghanistan and Africa. The slides were provided by a source with knowledge of the U.S. government’s drone program who declined to be identified because of fears of retribution. According to the source, Ramstein’s importance to the U.S. drone war is difficult to overstate. “Ramstein carries the signal to tell the drone what to do and it returns the display of what the drone sees. Without Ramstein, drones could not function, at least not as they do now,” the source said. The new evidence places German Chancellor Angela Merkel in an awkward position given Germany’s close diplomatic alliance with the United States. The German government has granted the U.S. the right to use the property, but only under the condition that the Americans do nothing there that violates German law.

The U.S. government maintains that its drone strikes against al Qaeda and its “associated forces” are legal, even outside of declared war zones. But German legal officials have suggested that such operations are only justifiable in actual war zones. Moreover, Germany has the right to prosecute “criminal offenses against international law … even when the offense was committed abroad and bears no relation to Germany,” according to Germany’s Code of Crimes against International Law, which passed in 2002. This means that American personnel stationed at Ramstein could, in theory, be vulnerable to German prosecution if they provide drone pilots with data used in attacks. While the German government has been reluctant to pursue such prosecutions, it may come under increasing pressure to do so. “It is simply murder,” says Björn Schiffbauer of the Institute for International Law at the University of Cologne. Legal experts interviewed by Der Spiegel claimed that U.S. personnel could be charged as war criminals by German prosecutors.

RAMSTEIN IS ONE of the largest U.S. military bases outside the United States, hosting more than 16,000 military and civilian personnel. The relay center at Ramstein, which was completed in late 2013, sits in the middle of a massive forest and is adjacent to a baseball diamond used by students at the Ramstein American High School. The large compound, made of reinforced concrete and masonry walls and enclosed in a horseshoe of trees, has a sloped metal roof. Inside this building, air force squadrons can coordinate the signals necessary for a variety of drone surveillance and strike missions. On two sides of the building are six massive golf ball-like fixtures known as satellite relay pads. In a 2010 budget request for the Ramstein satellite station, the U.S. Air Force asserted that without the Germany-based facility, the drone program could face “significant degradation of operational capability” that could “have a serious impact on ongoing and future missions.” Predator and Reaper drones, as well as Global Hawk aircraft, would “use this site to conduct operations” in Africa and the Middle East, according to the request. It stated bluntly that without the use of Ramstein, drone “weapon strikes cannot be supported.” “Because of multi-theater-wide operations, the respective SATCOM Relay Station must be located at Ramstein Air Base to provide most current information to the war-fighting commander at any time demanded,” according to the request. The relay station, according to that document, would also be used to support the operations of a secretive black ops Air Force program known as “Big Safari.” The classified slide deck maps out an intricate spider web of facilities across the U.S. and the globe: from drone command centers on desert military bases in the U.S. to Ramstein to outposts in Afghanistan, Djibouti, Qatar and Bahrain and back to NSA facilities in Washington and Georgia. What is clear is that most paths within America’s drone maze run through Ramstein.

Transatlantic cables connect U.S. drone pilots to their aircraft half a world away. (Josh Begley)

Creech Air Force Base in Nevada is central to multiple prongs of the U.S. drone war. Personnel stationed at the facility are responsible for drone operations in Afghanistan — which has been on the receiving end of more drone strikes than any country in the world — and Pakistan, where the CIA has conducted a covert air war for the last decade. The agency’s campaign has killed thousands of people, including hundreds of civilians. Some drone missions are operated from other locations, such as Fort Gordon in Georgia and Cannon Air Force Base in Clovis, New Mexico. The pilots at Creech and other ground control stations send their commands to the drones they operate via transatlantic fiber optic cables to Germany, where the Ramstein uplink bounces the signal to a satellite that connects to drones over Yemen, Somalia and other target countries. Ramstein is ideally situated as a satellite relay station to minimize the lag time between the commands of the pilots and their reception by the aircraft, called latency. Too much latency — which would be caused by additional satellite relays — would make swift maneuvers impossible. Video images from a drone could not be delivered to the U.S. in near real time. Without the speed and precise control an installation like Ramstein allows, pilots would practically be flying blind. A diagram in the secret document shows how the process works. Ramstein’s satellite uplink station is used to route communications between the pilots and aircraft deployed in a variety of countries. Video from the drones is routed back through Ramstein and then relayed to a variety of U.S. intelligence and military facilities around the U.S. and the globe. Another diagram shows how pilots at Creech connect to Ramstein and then to the Predator Primary Satellite Link, which facilitates direct control of the drone wherever it is operating. All of this — location, combined with the need to securely house the large quantities of equipment, buildings and personnel necessary to operate the satellite uplink — has made Ramstein one of the most viable sites available to the U.S. to serve this critical function in the drone war. When the prominent German daily newspaper Süddeutsche Zeitung and the German public television broadcaster ARD published an expose on Ramstein in May 2013 and alleged that the base was being used to facilitate drone strikes, it created a massive controversy in Germany. The report spurred parliamentary investigations and calls for the U.S. to explain exactly what it was doing at the base. In response, the German and U.S. governments mischaracterized the reporting and the German government claimed it had no hard evidence of Ramstein’s role in lethal strikes. A month later, in a June 2013 speech in Berlin, President Obama addressed the issue of Ramstein’s role in the drone war. He did not mention that the satellite relay facility at Ramstein enables U.S. drone strikes. Instead, he denied a claim that the journalists had not made: “We do not use Germany as a launching point for unmanned drones … as part of our counterterrorism activities,” Obama said.

In response to questions for this article, Pentagon spokesman Maj. James Brindle echoed the precise language of previous government statements. “We maintain robust civilian and military cooperation with Germany and manage all base activities in accordance with the agreements made between the United States and German governments,” he said. “The Air and Space Operations Center at Ramstein Air Base conducts operational level planning, monitoring and assessment of assigned airpower missions throughout Europe and Africa, but does not directly fly or control any manned or remotely piloted aircraft.” The German government has issued similar statements, saying no drone pilots are based at Ramstein and no drones are launched from the base. “The U.S. government has confirmed that such armed and remote aircrafts are not flown or controlled from U.S. bases in Germany,” government spokesperson Steffen Seibert said last year. In 2013, members of the Bundestag, the German parliament, submitted written questions to their federal government. “To the knowledge of the Federal Government, is it true that U.S. drone attacks in Africa could not be carried out without a special satellite relay station for unmanned flying objects in Ramstein?” the lawmakers asked. “The Federal Government has no reliable information in this regard,” read the official reply. Pressed further on the satellite facility and its purpose, the government replied: “The Federal Government has no information regarding the installation of the satellite system or when it started operating.” Internal German government communications provided to The Intercept by Der Spiegel show how some German officials tried and failed to get the government to confront the U.S. about what connection facilities in Germany had to drone strikes. According to a June 2013 document, a senior Foreign Office official, Emily Haber, advocated demanding a clear answer from Washington about the role U.S. facilities in Germany played in drone strikes. Haber was overruled: “The Federal Chancellery and the Defense Ministry would prefer to ‘sit out’ the pressure from parliament and the public,” the response read. The unofficial German-U.S. agreement appears to amount to a “don’t ask, don’t tell” understanding. While most, if not all, of the official statements by both governments may be technically true, it is also true that without the base, it would be very difficult for the United States to sustain the current drone war. The slide deck contains an array of arrows showing the complex system used to operate drones across the world. In the end, all arrows point to Ramstein. “Everything relies on Ramstein and Creech as central hubs for communication” in both armed and unarmed drone operations, says the source. Aside from the possibility of using an undisclosed satellite uplink station, the only drone operations that would not rely on Ramstein in these regions would be those conducted via aircraft that have a line of sight to a ground control station.

A top-secret slide deck obtained by The Intercept shows the complex architecture of the U.S. drone program.

HUMAN RIGHTS GROUPS in Germany, as well as opposition politicians, have long suspected that Ramstein has played a direct role in the U.S. drone war. They have called on the German government to stop allowing the armed U.S. drone program to operate from German soil. Lt. Gen. David Deptula, the former director of the Combined Air Operations Center, accused such critics of the drone program of being influenced by “misinformation that’s provided by terrorist organizations that these things are being effective against.” Deptula oversaw the implementation of the U.S. armed drone program starting in 2001. In an interview with The Intercept, he defended the use of drones. “Operations conducted by remotely piloted aircraft really are the most accurate and precise means of applying force,” Deptula says. “Why would the Germans want to shut down operations that effectively provide information to increase situational awareness of a community of nations that are trying to combat terrorism?” Kat Craig, the legal director at Reprieve, an international human rights organization that represents victims of drone strikes in Yemen and elsewhere, said the notion that critics of the drone program are being manipulated by propaganda from terrorist organizations “would be laughable, were it not so offensive towards civilian victims of drone strikes.” A new report from The Open Society Foundations, published this month, studied nine U.S. drone strikes in Yemen and found that 26 civilians were killed, including several children and a pregnant woman. “It has become all too clear that, too often, those carrying out the strikes simply do not know who they are hitting,” Craig said. “This misguided campaign has been allowed free rein because it has been kept hidden from public scrutiny.”

WHILE THE GERMAN government has so far managed to dodge questions on Ramstein’s role in drone strikes, the country’s judicial system may not have that option. Two related cases have been winding their way through the German legal system. In 2010, a German citizen was killed in a U.S. drone strike in Pakistan. Two years later, a federal prosecutor opened a preliminary investigation “to examine whether Bünyamin Erdogan’s violent death qualified as a war crime under Germany’s international criminal code.” The case was later dropped after investigators determined that at the time he was killed by a missile fired from a drone, Erdogan was not considered a civilian protected under international law. Rather, they asserted that he had been a “member of an organized, armed group that participated as a party in an armed conflict.” Pakistan, according to German interpretations of international law, is considered a war zone in cases involving known militants in certain areas. German courts haven’t established whether other targeted countries, such as Yemen and Somalia, qualify as war zones. Last October, a Yemeni man whose relatives were killed in a 2012 U.S. drone strike filed a lawsuit against the German government. Faisal bin Ali Jaber said his brother-in-law, a well-respected moderate imam known for his anti-al Qaeda sermons, and his nephew were killed in a strike. Jaber claimed the strike would not have been possible without the use of the satellite relay facility at Ramstein. “Were it not for the help of Germany and Ramstein, men like my brother-in-law and nephew might still be alive today. It is quite simple: without Germany, U.S. drones would not fly,” Jaber said at the time. “I am here to ask that the German people and Parliament be told the full extent of what is happening in their country, and that the German government stop Ramstein being used to help the U.S.’s illegal and devastating drone war in my country.” A member of Jaber’s legal team accused Germany of “hiding behind status-of-forces agreements,” saying the government should “admit its responsibility for civilian deaths caused by U.S. drone warfare.” In response to the suit, the German defense ministry submitted a reply on behalf of the government, which is named as the defendant in the case. “The defendant denies, by claiming ignorance, that the satellite-relay-station in use on the air base transfers field data of unmanned aerial vehicles from Yemen to the U.S. or to other unmanned aerial vehicles and that the air base is a fundamental hub for the data transfer necessary to operate unmanned aerial vehicles in Yemen,” read the January 20 filing. As for the suit’s demand that Germany prevent the relay station at Ramstein from facilitating drone strikes, the German government stated that it could not be expected to act “as a ‘global public prosecutor’ towards other sovereign states and punish alleged infringements outside of their own sovereign territory.” However, some legal scholars in Germany aren’t satisfied with that response. They argue that if U.S. personnel based at Ramstein are involved in what the government considers an extra-judicial killing in a non-declared war zone, they would not be entitled to immunity — at least not on German soil. The NATO Status of Forces Agreement explicitly grants German authorities the right to investigate members of the U.S. military suspected of having committed a crime. To date, German prosecutors have shown little interest in pursuing such action. The German government position boils down to this: We have asked the U.S. if they are violating any agreements or laws and the Americans have said no. Case closed. “What happens between the U.S., Ramstein and the drones is a division of labor in different locations,” says Wolfgang Kaleck, the head of the European Center for Constitutional and Human Rights, one of the organizations bringing the Yemen suit against the German government. “The German government doesn’t ask tough questions because they obviously don’t want to know what really happens.”

Predator drone in Southern Afghanistan, 2006. Most drone pilots operate in the U.S., but depend on Ramstein to control their aircraft. (Veronique de Viguerie/Getty Images) Getty Images

GERMANY HAS FIGURED prominently in the American drone war from the very beginning. In 2000, the U.S. Air Force launched an initiative to explore arming drones, the same year that the CIA — contemplating the assassination of Osama bin Laden — began using unarmed Predators to try to track the high-value target. It was through this surveillance project that a scientist working with the CIA and the U.S. military devised a prototype for what would become the system for operating drones from half a world away that endures to this day. Originally called “split operations,” the method involved drone pilots operating from Ramstein, while the actual aircraft would fly out of an airfield in Afghanistan’s neighbor Uzbekistan. From there, the drones could record live video over a complex near Kandahar where bin Laden was suspected of residing. “They chose Ramstein because that was the most convenient place where they could be on a very secure location and still reach a satellite that had a footprint that covered Afghanistan,” says Richard Whittle, author of the book Predator: The Secret Origins of the Drone Revolution. “And that worked.” The successful development of the split operations was welcomed by those within the U.S. intelligence community who were pushing for authorities to assassinate bin Laden — it would make their mission easier to accomplish. But plans to assassinate bin Laden with a Hellfire missile launched from a drone piloted from Ramstein hit a snag. “A Defense Department lawyer raised the issue that you couldn’t pull the trigger from German soil under the U.S. Status of Forces Agreement without telling the German government you were going to do it and getting their permission,” says Whittle. Fearing that the German government of Chancellor Gerhard Schroeder would reject the proposal or that the existence of the facility and the plot to kill bin Laden would leak, the CIA went back to the drawing board. “You have to remember at that time, the whole idea of assassinating Osama bin Laden had a different feel to it than it did later after 9/11,” Whittle told The Intercept. “He was barely known among the general public. The whole idea of the CIA running a targeted killing was entirely different and there was a lot of hesitation.” The CIA considered moving the ground control station to a ship in the ocean or to another European location. But all of those scenarios would come with risks and technical complications. In the end, the CIA decided to position pilots at a ground control station within CIA headquarters in Langley and then use fiber optic underwater cables to facilitate lightning fast communications between pilots in the U.S. and the drones they would control. The cable to Germany would be the artery connecting the pilots to the planes that would hunt bin Laden and other terror suspects. It would run from the U.S. to Ramstein, which would house a powerful satellite uplink that could hit satellites in Afghanistan. But the key was that the actual commands to deploy drones as weapons would be issued from American not German soil, thus freeing the U.S. from the obligation to get the Germans’ approval for the mission. The system was called “remote split operations.” Soon after taking office in 2009, President Obama authorized an expansion of the drone war, including opening new fronts in Somalia and Yemen. But the U.S. military discovered a gap in its satellite coverage. So, in early 2009, after “an urgent call from the Pentagon’s Joint staff,” a commercial satellite provider, Intelsat, shifted its Galaxy-26 satellite from the U.S. to orbit over the Indian Ocean. This repositioning of the Galaxy-26, which could be reached by U.S. drone operators by using the relay station at Ramstein, facilitated the rapid expansion of the U.S. drone program. Former drone sensor operator Brandon Bryant, who conducted operations in Yemen, Afghanistan and Iraq, said that without Ramstein, the U.S. would either need to find another base in the area, with the ability to hit satellites in the Middle East and Africa, or place U.S. personnel much closer to the areas they are targeting. “Instead of being able to be [inside the U.S.] with their operations, they would have to do more line-of-sight stuff, more direct deployments, more people going over there rather than [operating] in the states,” Bryant, who has become an outspoken critic of the drone program, told The Intercept. The U.S. is “doing shady stuff behind the scenes like using satellite and information technologies that, if able to continue being used, are going to just continue to perpetuate the drone war,” he charged. “Ramstein is the focal point for drone communications,” says Dan Gettinger, co-director of the Center for the Study of the Drone at Bard College. “If the communications infrastructure didn’t exist, the drone would be just a remote control plane, a toy basically.” It is “more important to the drone operations than the weapons a drone carries.” The top-secret slides show how embedded Ramstein has become in the drone war. They describe in detail the system by which a geolocating device affixed to the drone feeds back to a satellite and down to the station at Ramstein. The GILGAMESH platform, which The Intercept first reported on in February of 2014, utilizes a device placed on the bottom of the drone. It operates as a fake cell phone tower, forcing individual mobile phones of targeted individuals to connect to it so that their location can be pinpointed and used in “find, fix and finish” missions. The slides show that GILGAMESH operations ran out of several sites, including Djibouti, a base from which the U.S. has launched drone aircraft into Somalia and Yemen. The slides also describe how drones are equipped with a collection platform, “AIRHANDLER,” which relays data back to ground control stations via Ramstein.