They were not to be tried for war crimes, but, rather, were seen as potentially useful assets for developing various top-secret technological programmes for the United States, and, arguably more importantly, denying the rising threat of the Soviet Union the same benefit. 

Some of these scientists had rather shady pasts, to say the least. But, as President Truman would later explain "this had to be done and was done".

We take a look at some of the most notable technological outputs of this programme, and investigate why Operation Paperclip remains one of the most controversial government programmes of all time.  

What was 'Operation Paperclip'?

During the dying days of the Second World War, advancing Allied forces did everything they could to effectively vacuum up as much military, scientific, and technological research they possibly could. As armed forces advanced towards Berlin, teams of non-combatants followed in their wake to find and capture as much interesting stuff as they could. 

While jet engines were not exclusively invented by the Germans, the brains behind the German program were deemed potentially very useful for the US post-war. Source: Mike McBey/Flickr

Of course, it was not only American and British endeavours. The Soviet Union did its own fair share of harvesting German tech and research towards the end of the war too. From around 1946, the Soviet Union forcibly recruited more than 2,200 German specialists, and their families, of their own during Operation Osoaviakhim, much of which allegedly occurred in a single day. 

One group of Allied agents, the Combined Intelligence Objectives Subcommittee (CIOS), confiscated documents, and captured and interrogated German scientists and engineers as, and when, research facilities were occupied. 

One of the most fruitful pieces of intelligence gleaned during this operation was a document called the 'Osenberg List'. This document contained the names of the who's who of scientists, engineers, and technicians. The list was compiled on Hitler's orders when, in 1943, he officially recalled scientists, engineers, and technicians from combat duty and reassigned them to research units to assist in the war effort. 

At this point in the war, Germany's attempt to conquer the USSR ('Operation Barbarossa') had summarily failed. This had cost the Wehrmacht significantly in resources, manpower, and materiel, leaving the so-called 'Greater Reich' dangerously underprepared for a Soviet counter-attack.

Quickly realising this, it was decided to formulate a plan to shore up defences in any way they could – including through technological innovation. But, such experts would also need to be filtered for political and ideological 'acceptance'.

To this end, Werner Osenberg (a specialist in Hitler's Defence Research Association), was tasked with compiling a list of the Third Reich's greatest and most promising minds. Focusing, of course, on those whose ideals aligned with the greater Nazi ideals. 

And so, the 'Osenberg List' was born. 

Wernher Von Braun. Source: AL.com/Youtube/NASA

Sometime in March 1945, a Polish laboratory technician at Bonn University found pieces of the list stuffed into a toilet. It would eventually reach the hands of MI6 agents n the United Kingdom before being shared with intelligence agents in the US. It is this seminal document that would later lead to one of the most widely cited covert government programmes in history – Operation Paperclip. 

Originally called 'Operation Overcast', somewhere in the order of 1,600 German scientists and their families were brought to the continental United States to work on America's behalf.

In fact, a number of former enemy agents would become critical for the United States during the post-war trials and tribulations of the Cold War.

One of the main goals for the operation was to put these German scientists to work on helping to first develop, and then greatly improve, America's fledgling research in rockets, biological and chemical weapons. Managed by Joint Intelligence Objectives Agency (JIOA), another goal of this operation was to keep scientific findings and advances made by the Nazis out of the hands of the Soviet Union. 

The operation was officially sanctioned by the then president of the United States, Harry Truman, but it came with one important caveat. No Nazi members or active Nazi supporters were to be recruited under any circumstances. 

Unfortunately, or fortunately, depending on your opinion, this restriction was effectively ignored by the JIOA and Office of Strategic Services (OSS). The OSS was the forerunner to the current Central Intelligence Agency (CIA).

This allowed them to bypass the mandate by destroying or whitewashing any incriminating evidence of possible war crimes from the scientists’ records, believing their intelligence to be crucial to the country’s postwar efforts.

Probably one of the most famous German minds acquired during this operation was Wernher von Braun. A dedicated Nazi member, von Braun was the technical director at the Peenemunde Army Research Centre in Germany and was instrumental in developing the lethal V-2 rocket.

One of the most iconic results of the Wehrmacht's 'Vengeance Weapon' programme, V-2 were unleashed en masse on mainland England, devastating infrastructure and lives from afar, effectively making the V-2 the first long-range missile. 

Source: NASA

Von Braun and a number of his rocket scientist colleagues were brought to Texas, and White Sands Proving Grounds, New Mexico, as 'war department special employees' to assist the US army with rocket experimentation.

He was made director of development at the US Army Ballistic Missile Agency in Huntsville, Alabama. His work would prove so fruitful that he would later be made the director of NASA’s Marshall Space Flight Center and the chief architect of the Saturn V launch vehicle. This rocket would make history by being a fundamental component in NASA's effort to propel American astronauts to the Moon.

The results of Operation Paperclip are clear for all to see today, but it is not without some controversy. By some, the project was seen as a necessary evil that helped maintain America's technological edge over the Soviet Union during the Cold War. Critics, however, believe that ignoring potential war crimes, or at least letting them go unpunished, by captured former Nazi scientists outweighs any benefits.

How different history would have been if these scientists, engineers, and technicians were punished with jail, or allowed to fall into Soviet hands, can never really be known. But, the technological achievements made by these scientists and spin-off technologies from the US space program have, arguably, made life much better than if 'justice' had been served. 

But more on that later. 

What technologies came out of Operation Paperclip?

As we've already mentioned, "Operation Paperclip" was devised under the auspices of preventing the Soviet Union from gaining a technological advantage in the post-war world. So what technologies, if any, were yielded? Let's take a look at some notable examples. 

Please note, this list is far from exhaustive and is in no particular order.

1.) Apollo program 

The Saturn V rocket probably wouldn't exist without Operation Paperclip. Source: grizzzley/Flickr

Operation Paperclip led to some very important technological innovations for the United States, and the world at large. One of the most important was the ultimate development of the Saturn V launch vehicle. 

Saturn V, in case you are not aware, was the main launch vehicle used to power much of NASA's space program throughout the 1960s and 1970s. A super heavy-lift launch vehicle, the Saturn V was a three-stage, liquid-fuelled rocket that formed the backbone of the Apollo Program that ultimately put a human being on the Moon's surface for the first time in history. 

Amazingly, the Saturn V is still the only launch vehicle to have carried humans beyond low-Earth orbit. It is also the tallest, heaviest, and most powerful rocket ever built and used in operations. The launch vehicle still holds some very important records, including the largest payload capacity and heaviest payload launched into space.

The Saturn V would not have been possible without the groundbreaking work of one of Operation Paperclip's main acquisitions – Wernher von Braun. Von Braun spent his early career developing rocket technology for the German war effort in the 1930s and 1940s. 

Among his achievements was the co-development of the V-2 rocket. It was because of his expertise in this area that he was among one of the selected German scientists for relocation to the US at the end of the war. Once in the US, von Braun was put to work developing intermediate-range ballistic missiles for the US army and would prove instrumental in developing the launch vehicle that would ultimately put the first US satellite into orbit – Explorer 1. 

In the 1960s, von Braun, and his team, were subsumed into Nasa where he served as director of the Marshall Space Flight Center and the chief architect of the Saturn V launch vehicle program. The rest, as they say, is history. 

2.) Swept-wing aircraft

Swept wings on aircraft like the English Electric Lightning exist thanks to scientists obtained during Operation Paperclip. Source: Mike Freer/Wikimedia Commons

Another important technological achievement to come from the scientists and engineers relocated during Operation Paperclip was the development of the swept wing. This is the type of wing common in modern aircraft that angles backward, or sometimes forwards, on commercial and military aircraft. 

While normally used to refer to wings that are swept backward, forward (kike the Sukhoi Su-47), variable (like the F-14 'Tomcat' or Panavia 'Tornado'), and even oblique variants (like the NASA AD-1) of swept-wing also exist. 

While angled wings of this kind have existed since the early days of flight, the high angles seen in aircraft today are largely thanks to German innovations by Adolph Buseman and Albert Betz during the 1930s. Buseman emigrated to the US in 1947 as part of Operation Paperclip, although Betz remained in Germany.

The benefit of these kinds of wings is to delay the shockwave and accompanying aerodynamic drag caused by fluid compression of air near the speed of sound. For this reason, among others, swept wings are more commonly seen on jet-powered aircraft. 

They can, however, be employed for other reasons such as low drag, low observability, structural convenience, or pilot visibility. 

3.) 'Space Medicine' 

Source: John Keogh/Flickr

Another key area of innovation we can thank Operation Paperclip for is the field of 'space medicine'. Developed by the former Nazi scientist Hubertus Strughold, this field of study is concerned with the study of the physical and psychological effects of space flight on human beings. 

Despite allegations that Strughold's work involved experimentation on prisoners from the Dachau concentration camp, he worked on behalf of the US army air force after the war and was brought to the United States in 1947 as part of Operation Paperclip. 

For his work in this field, Strughold is often referred to as the 'Father of  space medicine'. 

His work, along with his fellow Operation Paperclip colleague Dr Heinz Haber, formed a key role in the design of pressure suits and onboard life support systems vital to the success of both the Gemini and Apollo programs. 

A specialised training programme was also developed by Strughold for flight surgeons and medical staff for the Apollo program prior to its pivotal missions to the Moon. 

Of course, this field is primarily concerned with the health and safety of actual astronauts, but like many developments from various space programs, spin-off technologies have filtered down to the general public. 

Foam cushioning, implantable pacemakers, kidney dialysis, and CAT/MRI scanners would not be possible without technology developed as part of this interesting field of scientific study. While not all these developments were directly developed by Operation Paperclip scientists, they would arguably not exist without them.

4.) Solar powered satellites 

Source: godata img/Flickr

Another highly influential acquisition under Operation Paperclip was the German scientist Hans K. Ziegler. A pioneer in communication satellites, he is widely considered the main driving force behind the existence of solar photovoltaic cells on many satellites today. 

During the war, Ziegler worked for a high tension porcelain company in Bavaria but was brought to the United States in 1947. Once in the US, Zeigler made many interesting developments in the field of military electronics, many of which were critical for the early phases of the US Space Program. 

In the 1950s, Ziegler found himself examining early solar cells developed by Bell Laboratories. He immediately saw their potential for not only satellites but also as a potential form of power generation on Earth. 

In a rare moment of accurate foresight, he is actually quoted as saying, "the future development [of the silicon solar cell] may well render it into an important source of electrical power [as] the roofs of all our buildings in cities and towns equipped with solar [cells] would be sufficient to produce this country's entire demand for electrical power".

Nostradamus would be impressed. 

Ziegler would push heavily for providing satellites with solar panels, which ultimately led to the development of Project Vanguard and the first solar-powered artificial satellite, Vanguard 1. 

The project proved to be a great success, and although the PV panels were rudimentary compared to modern examples, they managed to power the satellite for seven years. This proved the point, and solar power become the de facto energy supply for satellites thereafter. 

If that wasn't enough, Zeigler also made critical developments in the field of communication satellites leading to the creation of SCORE, the world's first communication satellite, which was launched in the late-1950s.

5.) LED bulbs and modern solar cells

Source: Juan Pablo Colasso/Flickr

Another important development that we can thank Operation Paperclip for is the P-N junction. A critical concept in various technologies, like transistors and integrated circuits, this is widely considered one of the most important electrical inventions of all time. 

This technology was first invented by one of the scientists relocated under Operation Paperclip, Kurt Lehovec. 

He developed the technology while working at the Sprague Electric Company, and tested his designs successfully. Lehovec's device was a linear structure, 2.2×0.5×0.1 mm in size, which was divided into isolated n-type cells (bases of the future transistors) by p-n junctions. 

Despite management at the company showing little interest in the product, Lehovec filed a patent on the technology in the early 1960s, from which, apparently, he received no royalties. 

This is impressive enough, but Lehovec was also one of the leading lights, pun intended, in the development of the light-emitting diode (LED).

6.) Dot matrix printer

Source: Steve Rhode/Flickr

Another interesting technology born out of Operation Paperclip is the dot matrix printer. Invented, in part, by Fritz Karl Preikschat, the dot matrix printer is still used today – albeit in a very limited capacity. 

Preikschat was first captured by the USSR just after the war and forced to work on the Soviet rocket and satellite programs. He was released by the Soviets in 1952 and returned to Soviet-occupied Berlin, where he met an American military policeman who put him into a safe house. Preikschat spent two months in there, getting debriefed by the US air force on the Soviet Union’s rocket program before eventually emigrating to the US in 1957 as part of Operation Paperclip.

While still in Germany, Preikschat submitted patents for his invention of a teleprinter with a 7×5 dot matrix, but his employer at the time was unable to interest anyone the device. 

Once in the US, he continued his career as an engineer in the aerospace sector. He invented a blind-landing system for airports, a phased array system for satellites, a new moisture meter, and a particle-size analyser. 

A prolific inventor, Preikschat also made some significant contributions to the development of hybrid cars. In 1982, he invented an early form of regenerative braking systems for cars. He patented his design but it was never prototyped or commercialised. 

7.) Synchcopters and rotors sails 

Flettner rotor sails mounted on the tanker Maersk Pelican. Source: Norsepower

Yet another key innovation to come out of Operation Paperclip is the development of modern helicopter technology. While a number of examples had existed prior to the Second World War, it was the work of Anton Flettner that really brought the technology to fruition. 

During this period, Flettner designed and help build the famous Flettner FI 282 Kolibri, aka the 'Hummingbird'. The first production helicopter, this craft was a single-seater, intermeshing rotor helicopter (or 'synch-copter').

Only a few dozen were built, and they served as spotter craft for German artillery positions. After the war, Flettner emigrated to the US as part of Operation Paperclip, where he was employed by Kaman Aircraft as chief designer. 

He also formed his own company, the Flettner Aircraft Corporation, but it never actually proved successful. 

Under Kaman's employment, Flettner was instrumental in the development of the famed HH-43 'Huskie' which would later become an icon of the Vietnam War. 

Kaman Aircraft is still in business today, and intermeshing rotor helicopters are still one of their biggest exports. 

Another interesting innovation by Flettner was the so-called 'Flettner motor'. Used a supplemental propulsion system on some transport and research vessels, this technology is currently being explored as a potential sustainable propulsion system on large freight ships today. 

8.) The popularisation of nuclear power in the 1950s might not have been possible without it

Source: Amazon

Another notable acquisition during Operation Paperclip was Heinz Haber. A former member of the SS, Haber studied physics in his youth, learned to become a fighter pilot, and was later employed at the Kaiser-Wilhelm-Institut für Physik conducting military research for the Wehrmacht. 

After the war, Haber was brought to the United States under Operation Paperclip and would prove to be a very wise choice for the US. 

Haber joined the USAF School of Aviation Medicine at Randolph Air Force Base. Together with fellow German Hubertus Strughold, he and his brother Dr Fritz Haber conducted pioneering research into space medicine in the late 1940s, including the use of parabolic flights for simulating weightlessness. 

However, Haber is best known for his work in the popularisation of science among the general public, most notable nuclear fission. 

In the 1950s, he became a scientific adviser for Walt Disney productions and played an instrumental part in helping explain the benefits of nuclear fission to the general public, at the request of the Eisenhower administration. Haber consulted on and presented the Disney production 'Our Friend the Atom', and also co-hosted Disney's popular science program 'Man in Space" with Werner von Braun. 

In the 1960s and 1970s, Haber returned to Germany and is best known there as a popular science spokesperson. He presented shows, wrote news articles, and books explaining complex scientific principles in fun and interesting ways. 

One of his most notable pieces is his explanation of nuclear chain reactions, using a series of mousetraps loaded with ping pong balls. Haber is, in part, a key inspiration for many science presenters in Germany who have followed in his wake. 

9.) The ion engine 

Source: Nasa

Another technology that might not exist without Operation Paperclip is the concept of the ion engine. While not the first to propose a potential model for making a working engine, one former-Nazi scientist, Ernst Stuhlinger, made significant advancements in the field during his time in the United States. 

He earned his doctorate in physics before the war and then worked on cosmic rays and nuclear physics at the Berlin Institute of Technology in the early days of the war. During it, he was drafted as a soldier on the Eastern Front and was one of the very few German soldiers to return from the Battle of Stalingrad. 

When he finally made it back to Germany, Stuhlinger was drafted into the German rocket program under Von Braun, whom he would accompany to the US during the initial stages of Operation Paperclip. While with von Braun, Stuhlinger worked in the field of guidance systems.

His work in the US varied widely including assisting in the development of various US satellites and telescopes such as the Hubble Space Telescope. However, some of his most interesting work was something of a hobby for Stuhlinger. 

He had something of a fascination with solar-powered spacecraft and would later develop some interesting concepts for ion propulsion using either cesium or rubidium vapor. To this end, he would later write a seminal book on the subject of electrical propulsion, and his work was later recognised by having the Electric Rocket Propulsion Society's 'Medal for Outstanding Achievement in Electric Propulsion' renamed in his honour. 

Why is it so controversial? 

We've already touched on this above, but primarily many of the scientists and other German experts had very questionable histories, to say the least. While many were former Nazi party members, some were also later shown to have partaken in very unethical crimes throughout the war. 

For example, Arthur Rudolph, a key member of the V-2 rocket program, was accused of organising forced labor from the Dora-Nordhausen concentration camp as part of the program. It has since been estimated that around a third of the 60,000 prisoners lived, worked, and died in the underground tunnels at Mittlewerk. 

Many slaves died in the tunnels of Mittlewerk. Source: Bundesarchiv/Wikimedia Commons

The causes of death did vary, but most lives were claimed by untreated diseases, malnutrition, or simply being worked to death. Some others were publically hanged. In light of these accusations, Rudolph would renounce his US citizenship and move to West Germany to avoid prosecution. 

Von Braun, who was also a key member of the V-2 rocket program, is known to have visited the same facility at least once. While his actual input into the logistics of running the facility is up for debate, this link to forced labor has certainly tainted his reputation forever.

However, it is important to note that neither Von Braun nor Rudolph was listed on any war crimes lists drawn up after the war. Other officials at the rocket factory were arrested, convicted, and either jailed or executed after the war. However, some have suggested that some records were destroyed to prevent people like von Braun from being tainted by the accusations.

Epidemiologist Walter Schreiber, who was first captured by the Soviets, then escaped and surrendered to US forces, was eventually given permission to emigrate to the US in 1951. Only weeks after his arrival in the United States, however, he was linked by the Boston Globe to grotesque human experiments during the war at Ravensbruck. He denied his involvement, but the JIOA arranged visas allowing him and his family to emigrate to Argentina, where many former Nazi members also sought refuge after the war.  

Hubertus Strughold, the aforementioned 'Father of Space Medicine' was honoured in the US with the Strughold Award for contributions to the field. This award was a highly prized one that was awarded between 1963 and 2013. However, it was later revealed that Strughold participated in human experiments on prisoners during the war. 

In light of this, from 2013, the award was retired and Stughold's reputation has since become tarnished. 

However, of all the German scientists captured during Operation Paperclip, only one has ever been formally tried – Georg Rickhey. He was returned to Germany in 1947 and stood trial for his connections to the forced labor used during the V-2 program. However, he was acquitted of any crime. 

Scientists brought over to the US under Operation Paperclip led to some of the greatest scientific advancements in modern history and helped, in part, put a human being on the Moon for the first time in history. However, some, if not all, of these men have connections, whether proven or tenuous, to some of the worst humanitarian crimes imaginable. 

For this reason, Operation Paperclip remains, and will continue to remain, one of the most controversial government programmes in history. Whether you agree that the advancements made under it outweigh the 'costs' over overlooking some very serious criminal accusations or not is ultimately "in the eye of the beholder".