The First War of Physics (38 page)

Kvasnikov was unavailable, so Yatskov consulted with the NKBG station chief in New York, Stepan Apresyan. They agreed that Hall and Sax were worth a risk. Yatskov instructed Kurnakov to make contact with Hall before he returned to Los Alamos. Rather embarrassingly for Hall, this brief meeting took place at Penn Station as Hall waited with his parents for a train to Chicago. Kurnakov advised him that he and Sax had been accepted into ‘the club’. It was agreed that Sax would be Hall’s go-between.

Triumvirate

Harry Gold went to see Fuchs’ sister Kristel in Cambridge, Massachusetts, in early November 1944. He explained that he was a good friend of Fuchs who had lost contact and happened to be in the Boston area on business. Fuchs had given him her address and he had decided to try to find out what had happened to him. In fact, Fuchs had contacted his sister from Chicago, either en route to Los Alamos or during a subsequent visit to the Met Lab. She told Gold that he had gone to some unknown location in the south-west, but that he intended to return to Cambridge to be with them for Christmas. Gold left a sealed message containing a contact telephone number.

Gold reported back to Yatskov, who no doubt breathed a sigh of relief. The unknown location in the south-west was obviously Los Alamos. On 16 November he sent a cable to Moscow Centre announcing that Fuchs had been found and should be in a position within months, possibly weeks, to provide information from ‘Camp No. 2’, one of the codenames for Los Alamos.

A few weeks later, on 29 November, David Greenglass celebrated his second wedding anniversary with his wife, Ruth, in Albuquerque. He had started at Los Alamos on 5 August and had been assigned to Group E-5 in Kistiakowsky’s X Division, initially working on high-speed cameras before moving on to explosive lenses. Husband and wife were missing each other terribly, and decided to get together in New Mexico rather than wait until Greenglass could take some leave towards the end of the year. Ruth’s trip to New Mexico had been paid for by David’s brother-in-law, Julius Rosenberg.

Both Julius and his wife Ethel Rosenberg, Greenglass’s elder sister, were dedicated Communists. As a graduate student in electrical engineering at City College in New York in 1935, Julius Rosenberg had joined the Steinmetz Club, the CCNY campus branch of the Young Communist League. A year later he founded the chapter of the American Student Union that Hall would subsequently join in 1938. Hall never met Rosenberg, but his suspicion that the ASU was a Communist front was justified.

Both the Rosenbergs had encouraged the teenage David Greenglass to join the Young Communist League. He became a committed convert. On joining the army shortly after his wedding in late 1942, he would write letters to Ruth which mixed declarations of love with declarations to the Communist cause: ‘Victory shall be ours and the future is Socialism’s.’ Both would sign their letters to each other ‘comrade’.

David and Ruth Greenglass were aware that the Rosenbergs were somehow involved in industrial espionage for the Soviet Union, although they were vague on the details. Julius had tried to ‘soften up’ Greenglass with the suggestion of going into business together after the war. When Greenglass discovered that he was to be assigned to work at a secret location, he alerted Rosenberg via his wife. ‘I have been very reticent in my writing about what
I am doing or going to do because it is a classified top secrecy project and as such I can’t say anything’, he wrote before arriving on the Hill.

The close surveillance of correspondence into and out of Los Alamos meant that any reference to the real subject of the dialogue between husband and wife had to be disguised, but on 4 November 1944 Greenglass passed the message back that he ‘most certainly will be glad to be part of the community project that Julius and his friends have in mind’.

During their anniversary celebrations later that month, Ruth told her husband that, according to Rosenberg’s information, he was working on the atomic bomb. He was very surprised, as this was information that had not been shared with him through official channels. Ruth then put Rosenberg’s by now familiar proposition to him. America and the Soviet Union were allies in the war against Nazi Germany and Japan. In the face of their common enemies, the Soviets were therefore entitled to information about American military projects.

Ruth had misgivings, and David’s own mind was initially clouded with doubts. But he worshipped his brother-in-law as a hero and, by next morning, his conviction had overcome his doubts. Greenglass agreed to spy for the Soviet Union. He began by providing to Ruth some general information about the layout of the laboratory and the number of scientists working there. He mentioned Kistiakowsky’s name, and those of Oppenheimer and Bohr.

Julius Rosenberg was assigned the principal liaison role, though he felt technically unqualified and asked his Soviet controller – Alexander Feklisov – for support in debriefing Greenglass during their meetings. Greenglass returned to Los Alamos, eyes and ears now fully alert for any information that might be of value.

Fuchs had arrived at Los Alamos just over a week after Greenglass. He was given a room in the bachelors’ quarters next to Feynman. They became good friends. Feynman would tease him about his personality, and suggested that he find a girlfriend. Joking about which of them would more likely be a Nazi spy, Fuchs argued that it must be Feynman, because of his frequent visits off site to see his wife in hospital in Albuquerque. Feynman agreed.

Fuchs quickly made a very strong, positive impression on his peers and superiors. Bethe regarded him as one of the most valued physicists working in the Theoretical Division. He impressed Oppenheimer. Though neither a group leader nor division head, he was invited to attend meetings of the Co-ordinating Council, allowing him to become intimately familiar with the work of every division at Los Alamos.

Pressure of work meant that Fuchs could not make the trip to Cambridge to be with his sister and her family at Christmas. The visit was postponed to February 1945.

Of the triumvirate of Soviet spies now working at the very heart of the Manhattan Project, Fuchs was clearly the most important. He had access to a wide range of secrets centred on the single most pressing problem that the physicists now faced – implosion. Hall was close to these same secrets, though as a junior scientist his access was more limited. Greenglass was a machinist, busy making moulds in which high explosive lenses would be cast. None of the spies knew about the others, but together their information provided independent corroboration of the details of the work in hand.

On 25 December, Kurchatov received another pile of espionage materials. Among the documents was a review of activity at an unnamed laboratory – most likely Los Alamos – from March 1943 to June 1944. Fuchs had not by this time had an opportunity to re-establish contact with Gold or pass any information about the work at Los Alamos. The review describes details of instrumentation that Greenglass would not likely have been familiar with. Of the trio, Hall is therefore the most likely source, the review possibly being part of the document that he had handed to Kurnakov and Yatskov in New York.

Kurchatov remained impressed with the materials. ‘On the basis of theoretical data,’ he wrote, ‘there are no grounds to believe that in this respect there will be any difficulties in implementing the bomb.’

Too many sixes

Cecil Phillips had been just nineteen years old when he joined the cryptanalysts at Arlington Hall in the summer of 1943. He was transferred to work on the ‘Russian diplomatic problem’ in May 1944.

After six months’ intensive study, he began to notice new patterns among the strings of seemingly random numbers. At the beginning of some of the coded messages there appeared a number group with a higher than average number of sixes. Richard Hallock had looked for references to the content at the beginning of each message and had stumbled on the fact that the Soviets had been using duplicate one-time pads. Now Phillips had found another vulnerability. The number group with more than its fair share of sixes was unencrypted. It was the first number group on the one-time pad that had been used to encrypt the message once it had been coded. By including it at the beginning of the message, the clerk in the receiving station could identify which one-time pad had been used and so decrypt and then decode the message.
⁴

By sorting the messages using the number group with too many sixes, Phillips could identify which messages had been encrypted using duplicate one-time pads. And from any such pair of messages, the cryptanalysts could start to unpick the one-time pad encryption.

¹
The Soviet security services underwent a number of organisational changes during the war. In July 1943 the foreign intelligence and security services of the NKVD was split out as a separate commissariat, called the People’s Commissariat for State Security (Narodny Kommisariat Gosudarstvennoye Bezopasnosti, or NKGB).

²
Kurchatov did not learn about the successful Chicago pile until the end of July 1943. His decision to focus efforts on a uranium–graphite lattice configuration was based on the assessments of his own scientists.

³
Kapitza had sought permission from Molotov before writing to Bohr, though it is likely that the purpose of his letter was simply to encourage Bohr to come to the Soviet Union, for the good of Soviet science generally.

⁴
This appears to have been a response to an April 1944 request to all stations from Moscow. By this time the Soviets had discovered the existence of an American counterespionage project and were concerned for the security of their coded and enciphered messages. The NKVD requested that cipher clerks change the system by adopting a new message starting point or key-pad indicator. The change was discovered by Phillips and actually made the messages more vulnerable.

Chapter 13

ALSOS AND AZUSA

January–December 1944

T
he Alsos mission was John Lansdale’s idea.

Largely for want of any other way to engage the enemy, the Allied forces that had secured victory in North Africa had launched an invasion of Sicily on 10 July 1943, a prelude to the invasion of the Italian mainland, Churchill’s ‘soft under-belly’ of Europe. Lansdale had suggested that a scientific intelligence mission should follow hard on the heels of the invading forces, its main purpose being to discover precisely how far the German atomic bomb programme had progressed.

Groves approved, and Lansdale spent the summer garnering support for the mission, which was codenamed Alsos.
¹
It was formally approved in September 1943 and involved army intelligence, the US Navy, representatives of the Manhattan Project and the OSRD. Pash was appointed as the mission’s military leader, which gave Groves some relief from Pash’s relentless pursuit of the Los Alamos laboratory’s scientific director.

But by this time the British believed they already knew what was happening with the German programme. Eric Welsh of the SIS and Michael Perrin of the Directorate of Tube Alloys argued in November that the Alsos
mission was unnecessary. The SIS had gathered information from scientists who had encountered various members of the Uranverein in Norway, Sweden and Switzerland. Earlier in the year, Hahn had told Lise Meitner in Stockholm that there would be ‘no practical utilisation of fission chain reactions in uranium for many years to come’. The physicist Paul Scherrer in Zurich reported a conversation he had had with the German chemist Klaus Clusius, who said that efforts to separate U-235 had been abandoned. The SIS spy Paul Rosbaud no doubt provided confirmation that the German bomb programme was all but stalled.
²

There was also circumstantial evidence. While the German rocket programme was mentioned occasionally in coded radio messages that had been deciphered by the cryptanalysts at Bletchley Park, they could find no mention of uranium, or atomic bombs. The German physicists had resumed publishing their research results in the German scientific literature. The results so reported appeared to be genuine, rather than fabrications designed to mislead Allied scientists. In January 1944 the British assessed all the evidence to hand: they concluded that the Germans were not in fact carrying out any large-scale work on an atomic bomb.