© Christopher Earls Brennen


"From Stettin in the Baltic to Trieste in the Adriatic, an iron curtain has descended across the continent.”

From Winston Churchill's speech on Mar.5, 1946, in Fulton, Missouri.


The year was 1975 and the cold war was at its most intense. I had been four years old when, in 1946, Churchill had coined the name, the Iron Curtain, for the line separating the great powers in Europe in the aftermath of the Second World War. The Allies, led by the United States, occupied the western half of Europe and the Russians the eastern half. The two great armies that had defeated Hitler faced each other with barely-controlled ferocity across the barbed wire that stretched from the Baltic to the Aegean Sea and constituted the Iron Curtain. By 1975 that barrier and its small separated section that surrounded the city of Berlin had been fortified to the point that it was almost impenetrable. Occasionally, some brave and athletic soul from the eastern block would try to vault over the barbed wire to freedom (most often in Berlin) only to be gunned down by the communist troops determined to constrain the people within their domain. It was, of course, possible (though not easy) for westerners to visit the Communist Block particularly if the Soviets thought they could benefit from that visit.

The Iron Curtain   The Berlin Wall in 1961

The steel hand that had gripped Hungary (and the other Eastern European countries within the Soviet block) in the wake of the Second World War had ruthlessly suppressed all opposition for two decades. The people in eastern Europe were imprisoned by the Soviet army in their own countries and contained by the militarized Iron Curtain (and Berlin Wall). The desire for freedom and self-government finally exploded in Hungary on October 23, 1956, when workers and students in Budapest (and some units of the poorly-equipped Hungarian army) finally rose up in violent confrontation with the occupying Russian army. For a few days in October and November 1956, a brighter future for the Hungarian people seemed possible. Despite the efforts of the freedom fighters (and the invention of the "Molotov Cocktail"), the uprising was ruthlessly crushed by an invading Russian army and the revolution was over by November 10, 1956. Thousands of the rebels had been killed. Hundreds of thousands sought to flee the repercussions. Many raced for the Austrian border, hiding in ditches and swimming canals in an effort to evade the border guards. One much-used route lay along the railway line to one of the stations, like Csorna, just short of the border and then over the fields and ditches toward the small Austrian town of Andau. Just before Andau a small wooden bridge allowed passage over a modest river and 70,000 refugees passed over this bridge before the border guards destroyed it. James Michener, who was living in Austria at that time in the 1950s, wrote of these events in his novel "The Bridge at Andau" that chronicled the 1956 revolution. Indeed, Michener himself witnessed the flood of refugees at the border fleeing from Hungary.

The bridge to freedom near Andau, Austria.

Far from all this political and military tension and halfway around the world, I was working away on my research into the fundamentals of cavitation and multiphase flow at the California Institute of Technology. In 1971 my colleague Allan Acosta and I received an exploratory inquiry from the NASA George Marshall Space Flight Center in Huntsville, Alabama, asking whether we might be interested in studying the response of the cavitation in a rocket engine turbopump to structural oscillations of the rocket. Allan had many years of experience with pump fluid mechanics and was the primary contact. He recruited me to join the effort because of my experimental and analytical research into cavitation. It was a natural and very fruitful collaboration that continued throughout my career. Quite quickly we produced and published (in 1971) an analysis of one facet of NASA's enquiry. That paper generated sufficient of interest that NASA invited Allan and I to fly to Huntsville to explore an expansion of the effort. That visit was not only fascinating but, in truth, changed my life. I proceeded to embark on several decades of research (both analytical and experimental) generously funded by NASA. By 1973/4 I had become a world authority on the dynamics of cavitating turbopumps and therefore held the key to one of the most damaging instabilities that liquid-propelled rockets could experience, a phenomenon called the POGO instability. Allan was anxious that I gain recognition for these achievements and so encouraged me not only to document our results in prestigious national journals but also to submit papers to international conferences at which I could present my results. Unbeknownst to me at the time that first publication in 1971 was very quickly and unexpectedly translated into Russian and, in 1974, published in a Russian journal. I did not learn of that publication until many years later when it was retranslated back into English by one of the journals of the time that specialized in translating Russian scientific papers. The resulting retranslation was particularly garbled with many inappropriate word choices such as ``caverns'' instead of "cavities". Though unaware of this activity, at the time in 1975 I was fully aware of the international sensitivity of such rocket research.

Shortly thereafter I was invited to attend and present the opening lecture at the 1975 Conference on Fluid Machinery in Budapest, Hungary, in September 1975. This Conference was one of substantial international standing and it would be a feather in my academic hat to accept the invitation. Of course, I first needed to obtain permission from NASA. At the time NASA'S policy on fundamental research publication was much more lenient than it is today and they eventually (and somewhat surprisingly) granted me permission to accept provided I underwent a security briefing both before and after my travel. The local Pasadena branch office charged with such briefings was the purview of the Office of Naval Research (ONR) and so I made the appropriate appointment for the pre-travel briefing. That office also had oversight of another of my research projects that involved cavitation on marine propellors, so they were familiar with me and my research efforts.

Sometime in early 1975 I visited the ONR office and was forewarned of some of the pitfalls of travel behind the Iron Curtain. I had heard of some of the dangers from senior colleagues at other research institutions. Of how some had had too much to drink and been trapped into compromising situations with attractive young women. I was warned to carry only the minimum of technical literature and to avoid discussion of some specific subjects either in my formal presentation or in informal discussions. But with that briefing (and the promise to attend a post-trip briefing), I was ready for a trip that offered much reward in terms of international recognition and career enhancement.

Budapest with the Royal Palace with green roofs at bottom center.

Buda Castle  Vajdahunyad castle in the Varoslioget.

So it was that in September, 1975, at the very height of the cold war and amid all the international tensions associated with missiles and rockets, I set out for Budapest, Hungary, behind the Iron Curtain in order to attend and present the invited opening lecture at the 1975 Conference on Fluid Machinery. The conference was to be held at the Congress Hall of the Hungarian Academy of Sciences, up on the heights occupied by Buda Castle. That historical complex dating back to 1265 and known as the Royal Castle, was the site of the palace of the former Kings of Hungary. The Congress Hall was part of this complex and featured a grandiose auditorium decorated with Gothic curleques and ornate chandeliers from another age. It seemed an odd venue for such a modern forum.

The lectures were to be simultaneously translated into several languages and communicated to the audience via headphones that could be set to the language of the listener's choice. While this expensive and complex communication system might seem good in theory, it was seriously flawed in practice though it was the norm at international scientific conferences of the time. The deficiencies began with the generally inadequate training of the translator in the semantics of science; that coupled with the often-poor speaking ability of the presenter led to a very garbled and barely-understandable translation. Consequently, this old headphone/translator system was abandoned in the years that followed and replaced by recognition that all the presentations needed to be in English. Thus the acceptance of English as the worldwide language of scientific communication was hastened; it was naturally accelerated by the worldwide improvement in the teaching of English.

I have relatively limited recollection of my own opening lecture but it was well practised and the best I could do in that archaic system of communication. I knew enough to insert pauses to allow the translator to catch up. Most of the audience would, in any case, rely on the published, written version for specific details and so the slides and movies I showed served as a visual advertisement for the written paper. In the days that followed many members of the audience approached me with questions, though not many showed any real depth of understanding and some were way off the mark. A handful, like the Hungarian Arpad Fay, showed real understanding and I was glad of that. But I had achieved what I wanted and was satisfied with technical component of my visit to Hungary.

Of course, I was also fascinated by the country, its history and its social and political circumstances of the time and so I had much on my mind when, on Sunday, September 14, 1975, I flew from London to Budapest, Hungary, behind the Iron Curtain. I was met at the airport by the conference organizers and taken to the grandiose and storied Hotel Gellert by the banks of the Danube and just beside the elegant Elizabeth Bridge. There, unbeknownst to me, my hosts had made my hotel reservation, not far from Buda Castle and the site of the Conference. I checked in and installed myself in my room.

Other than the technical sessions, the week of the conference was filled with events organized for the conference attendees and by my own excursions in and around Budapest. After the lectures on Monday, we were transported back to the Hotel Gellert for a welcome reception organized for the participants and their companions. In that process I noted that several of the local faculty drove down from the castle in what appeared to be their own vehicles. Most of these were small, old Fiats (or other nondescript eastern European versions) but one professor was driving a Mercedes. At the reception, I met a number of academics in my field, a few from the west but most from eastern Europe and some from the Soviet Union. There seemed to be significant tension between those from the eastern block and the Russians. There I was introduced to the owner of the Mercedes a local professor who was attending with his adult daughter. Toward the end of the reception this professor offered to show me some of the sights of Budapest by night and I accepted his offer. However when I found myself in the back seat of his Mercedes with his daughter I felt distinctly uncomfortable and was glad when they left me back to the hotel after a brief tour. It was probably just a hospitable gesture but I was never sure and I never saw the professor, his daughter or his strangely affluent Mercedes again after that evening.

Other organized events that I enjoyed were a day-long outing on the Wednesday to the historic towns of Eger, Balatonfured, and Esztergom, along the Danube river and the closing event of the conference, the formal conference banquet in the Grand Hotel, Margit-sziget. But apart from the technical sessions and these organized events, I had quite a bit of time to roam on my own without any official restrictions. The quality of most of the presentions was not high (as I intimated, many were barely understandable) and so I also skipped some of the technical sessions to explore the city on my own. During one of my first walks I became aware that someone appeared to be following me; that was true of all my solitary excursions.

The first step in these explorations was to master sufficient Hungarian language and script to negotiate the extensive bus, tram and subway system in the city. Indeed that was neccessary to get from the Hotal Gellert to the Congress Hall, a journey that involved a tram route beside the Danube and a funicular ride up to the top of Castle Hill. Hungarian is quite different from the western European languages so this step was not trivial. One of my longer individual excursions took me across the Danube to the main railway station and from there by subway to the city park known as Varosliget. There I visited the Castle of Vajdahunyad, the biggest museum of agriculture in Europe. This was notable not so much for its content as for its conglomeration of different architectural styles with details of well-known buildings of historical Hungary.

But with my life-long fascination with railways, a much more exciting excursion was to the Buda Hills to the west of the city. I caught the 78 and 61 trams to the Varosmajor station at the foot of the Buda Hills and then took the Cogwheel Railway (or Fogaskereku) from this terminus to the top at a station called Szechenyi-hegy. This was also the starting point for the Children's Railway, a narrow gauge train that winds its way through the forests of the Buda Hills for 11 kilometers. It was designed and built to allow children to participate in its operation. I greatly enjoyed riding this narrow gauge train through the forests to its other terminus at Huvosvolgy, and wondered if my shadows were far behind. From Huvosvolgy I caught another 61 tram back into the city and my hotel.

Map of the Buda Hills outing.

The Cogwheel Railway or Fogaskereku, Buda Hills.   The Children's Railway, Buda Hills.

On several evenings when I returned to the Hotel Gellert and asked for my key at the front desk, the clerk informed me that my room had been changed and that my belongings had all been transferred to the new room. This was startling news but I was never provided with any explanation and nothing seemed to be missing. Of course, I had taken the precaution of carrying my personal papers with me at all times (the hotel held my passport throughout my visit but that was normal in most European countries at that time). At some point prior to the trip I had been told (perhaps during the pre-trip briefing) not to carry any subversive literature into Hungary with me. It was not a warning that I needed. However, before the trip I had been reading the newly published, best-selling novel by John le Carre entitled "Tinker, Tailor, Soldier, Spy", a book that follows the efforts of the taciturn, ageing spymaster George Smiley as he tries to uncover a Soviet mole in the British Secret Service. Since I had not finished it, I took the compelling story with me into Hungary. However, I was careful not to leave it in my room at any time and carried it in my briefcase throughout my visit. By Saturday morning, I had finished reading and, as I vacated my room, I left the paperback in a prominent position on the beside table before going down to check out. I hoped my shadows or the room-movers would enjoy it.

On that Saturday morning I bade goodbye to Budapest. I made my way to the central railway station and caught the Orient Express bound for Vienna, Austria, through the Iron Curtain. While still called the Orient Express this was definitely not the elegant and luxurious train of Agatha Christie and inumerable spy novels. That legendary train had once carried the famous and notorious from Paris to Istanbul (via Vienna and Budapest) in great elegance and splendour. But those days had ended with the Second World War. Instead this was a very mundane train consistent with its egalitarian surroundings. I had been assigned a reserved seat in a compartment at the end of one of the carriages. Only one other passenger was seated in the compartment, a middle-aged man who seemed somewhat uncomfortable. As the train rolled west along in the valley of the Danube, we eventually drifted into conversation. I learnt that he had escaped after the 1956 uprising and that he had done so along a route close to the railway line. Now, in 1975, having acquired US citizenship by political asylum he had returned to Hungary for the first time to visit family who had remained. Alone together in this train compartment, he told me much of his story. Most interestingly he pointed out the route of his 1956 escape, describing how he evaded the Russian tanks and border guards as he crawled across the fields and ditches. For me it was an amazing, first-hand account.

The border train stop at Hegyeshalom.   The Iron Curtain topples in 1989.

As the train approached the border train stop at a station called Hegyeshalom just inside Hungary, my traveling companion became increasingly nervous and our conversation ceased. He gripped his US passport tightly. When the train stopped at the almost deserted station there was a pregnant pause before the border guards entered the train, machine guns slung over their shoulders. They went from compartment to compartment carefully and brusquely examining the travel documents of all passengers. They made little comment on either mine or my companions though there was a brief exchange with him in Hungarian. They did take his passoport outside but quickly returned with it. Next we listened as the guards climbed along the roof of the train from one end to the other and similarly examined underneath the carriages. Finally, the train moved slowly forward through the barbed wire fences, armed guard towers and fortified ditches of the Iron Curtain itself. Even the sun seemed to shine a bit more brightly as we entered Austria. It would be another 15 years before the Iron Curtain and the Berlin Wall would finally fall.

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Last updated 8/20/02.
Christopher E. Brennen