On a raw New England morning on January 10, the single-dish system finally picked up echoes from buildings in Boston. DuBridge, who was in Washington, got the news in the form of a cryptic telegram—“HAVE SUCCEEDED WITH ONE EYE”—just in time to inform a meeting of the microwave committee that was being held that day.
They were not out of the woods yet. The makeshift system was subject to frequent breakdowns, and while they had managed to obtain a signal by pointing the dish steadily at the target, a practice called searchlighting, the weak signal produced by their equipment did not seem to hold out much promise for scanning. For that, they would need still more power. As repeated attempts to pick up airborne signals failed, and frustration mounted, many of the Rad Lab physicists began to doubt that the rooftop system would ever perform this essential feat. As Bowen later recalled, “For the first, and possibly only, time a mood of pessimism crept into the group and some doubts were expressed about whether a system would ever be capable of receiving echoes from an aircraft.”
The deadline pressure was exacerbated by the tension created by the war and the political demands from Washington. Things could not move fast enough for Bush. “It was characteristic of Bush’s management,” Bowles observed later. “He wanted results. He was constantly putting the blowtorch to us.” Loomis was under enormous pressure to succeed. A great deal of jealousy had been aroused on the part of industrialists who saw the Rad Lab as future competition and were critical of the group’s fitness for the job. There was also considerable skepticism on the part of some government officials who questioned whether a bunch of academic physicists—whom the army and navy derisively called “doubledomes”—could successfully carry out such an urgent wartime project. If it turned out to be a wild goose chase, who was going to answer for the wasted taxpayers’ dollars? Even respected members of the scientific community expressed reservations. Earlier in 1940, the grand old man of American physics, Robert Millikan, had warned that it was “a mistake . . . to concentrate fifty prima donnas in physics at any one spot.”
The February 1 deadline to have a working system mounted in a B-18 bomber came and went. Even Lawrence, visiting the Roof Lab four days after the target date, wondered aloud whether the magnetron could ever be made into an operational airborne unit. Alvarez, who was taking the maestro on his rounds, defended the rooftop team’s efforts and bet Lawrence they could probably make it work well enough to detect a signal from a flying aircraft. They shook on it, and Lawrence told him he was prepared to eat his words. They had two days before he and Loomis were due back in Washington to give a progress report to the microwave committee.
Alvarez and his team worked around the clock all the next day but came up empty-handed. On Friday, February 7, the microwave committee gathered in one of Bush’s conference rooms at Carnegie. The more impatient members expressed dismay at the lab’s lack of progress and suggested junking the whole project. Loomis and Lawrence had pressed their luck as far as they could, and the army and navy were eager to see the last of the scientists and their microwave radar.
Early that same morning, there was a flurry of activity at the rooftop lab. Alvarez, a Berkeley colleague named Lauriston Marshall, and a handful of others were making a last ditch effort to track a plane and prove the project’s viability in time for the meeting. One of the physicists, operating on a hunch, decided to detach the parabola and hold the antenna by hand. Another scouted for planes, peering through a crude telescope. As he had done for days now, Alvarez gazed dully at the scope. Suddenly “a blip appeared.” Marshall stared at the monitor. As the plane gained in altitude, it was tracked on the screen. Twisting his head to look out from the rooftop lab, Alvarez saw a commercial plane disappearing into the distance. He scrambled down the penthouse’s narrow spiral stairway and raced to the phone.
When the call was announced, the meeting fell silent. DuBridge took the receiver and heard Alvarez and Marshall excitedly blurt out, “We’ve detected an airplane at two miles.” DuBridge held up two fingers. Lawrence “caught it right away,” his grin showing that he understood that they had obtained echoes at a range of two miles. For the benefit of the rest of the committee, DuBridge reported: “We’ve done it, boys.”
Lawrence telegraphed Alvarez: “I HAD MY WORDS FOR LUNCH.”
The microwave committee voted confidence. With the rooftop AI system up and working, Alvarez and McMillan—Lawrence’s two hand-picked protégés from Berkeley—immediately set to work designing and building a wooden mockup of the bombardier’s compartment in a B-18. Alvarez installed a second AI system in their wooden prototype, which was equipped with a special Plexiglas nose that was transparent to microwaves. Between February 13 and March 5, they worked over their test until the Douglas B-18 that had been assigned to the project by the U.S. Army Air Corps finally arrived. After extensive ground tests—actually roof tests, using a water tower on a building six miles away—McMillan declared that the experimental airborne ten-centimeter radar system was ready to fly. The B-18, which had been flown up from Wright Field by an army crew, was waiting at the National Guard hangar at Logan Airport. On its first outing on March 10, the radar system performed with mixed results, but after several weeks and many modifications, its performance gradually improved.
On March 27, Alvarez and McMillan headed out for the first test run using aircraft as a target, taking along Bowen as an observer. They proceeded eastward over Cape Cod in search of open skies and were surprised at how clearly the ships below showed up on their radar screen. This was a far better result than had been expected. They then made several runs at the target, a single-engine plane borrowed from the National Guard, and got satisfactory echoes at a range of two to three miles. They were feeling quite pleased and were about to turn back when several large merchant ships in Cape Cod Bay caught their attention. Switching off the elevation scan and leaving the radar set to give range and azimuth signals only, they did a run at a large ship in the bay. Flying at about two thousand feet over the water, they tracked a ten-thousand-ton vessel heading for port. While there is no record of the maximum range at which it was detected, Bowen estimated it was about ten miles. More important, the system’s admirable performance had not been hampered by the “sea return,” the interfering echoes from the ocean’s surface. While he knew this was not exceptional compared to the British long-wave ASV radar, “for the first flight of a centimeter-wave radar it was a great performance.” Over the roar of the bomber’s engines, Bowen could hear his colleagues’ wild cheering.
Unable to resist the temptation to try for the extra mile, Bowen said, “Let’s go to New London and see if we can find a submarine.” New London was home to a major navy submarine yard, and they could be there in thirty minutes’ flying time. Just a few days earlier at Tuxedo Park, Bowen had been talking to Loomis about the pressing need for a microwave sub-hunting radar, so this seemed as good a time as any to test the system’s potential. Barely able to contain their excitement, Alvarez and McMillan agreed at once and instructed the pilot to head down to Connecticut. As they flew low over Long Island Sound, the radar picked up several large submarines cruising offshore. One was fully surfaced and presented an excellent target. They made several runs broadside on and obtained a strong signal at a maximum range of four to five miles. For the scientists aboard the plane, it was a dramatic moment—no one had ever detected a submarine with airborne microwave radar. Their sightings were the first real evidence that radar performed well over water. It was “an epoch-making flight,” Bowen wrote in his memoirs. “We returned in triumph and the news spread around the Laboratory like wildfire.”
From then on, ASV radar for submarine and ship detection was added to the Rad Lab’s growing roster of projects and would soon become far more important than their original assignment, as by this time the Battle of Britain was ebbing and the British had lost interest in the night fighter. As Bowen, Alvarez, and McMillan had observed, their airborne microwave radar was perfectly suited for submarine detection, w
hich was a lucky break for the British. “After the Luftwaffe retired from the Battle of Britain, German bombers had only a nuisance value,” recalled Alvarez. “The German submarine campaign against Allied shipping, on the other hand, could starve the British to the point of surrender.” It would take only minor alterations to turn the airborne system into a highly successful ship detection system, but the tactical advantages were immense. It was a whole new kind of radar and an entirely different breed of defensive weapon. At that very moment, German submarines were beginning to appear in U.S. waters near the East Coast and were harassing the vital transatlantic freight route. The list of sinkings on the Atlantic highway was horrific—over four million tons by the end of 1940—and it was becoming very clear that England would not be able to hold out much longer unless some defense was found. If the Germans were to continue successfully to disrupt Allied shipping, they could defeat the British Isles. While America was not yet in the war, the U.S. Navy realized that airborne microwave radar provided them with a means of detecting this dangerous threat. The navy immediately ordered a trial system, and the British wanted two sets as soon as they could get their hands on them. Here were the first fruits of the Tizard Mission.
For Loomis and the Rad Lab physicists, March was a turning point. For four months, all of their efforts had been focused on building a working radar system and getting it aboard a plane within the time frame Loomis had mapped out on the blackboard in mid-December. They had accomplished that and much more, all of which was described in detail in Loomis’ first report on the lab, which the microwave committee had submitted to Bush at the beginning of the month.
In short order, the NDRC approved another $300,000 for the lab, and it was estimated that more than $1 million would be needed for salaries to prolong the work another year. When Congress was slow to approve the funds, threatening to stall the lab’s progress, Loomis and Compton pulled one of their end runs, first convincing the MIT Corporation to come up with $500,000 and then appealing to their old friend John D. Rockefeller Jr., who agreed to help underwrite the salaries of the technical staff to the tune of $500,000. Private enterprise, in Loomis’ view, could move mountains in the time it took the government to pass a single bill. With the threat of war looming, however, Congress was eventually persuaded to fork over the money, and both MIT and Rockefeller were repaid.
As Loomis continued to conspire behind the scenes to keep the lab afloat, and to agitate for preparedness among the power elite, he chafed at Roosevelt’s reluctance to publicly back Britain’s cause. Ernest Lawrence, in a letter to Robert Sproul, the president of Berkeley, recalled Loomis’ insistence that research for war required speed, and Congress’ hesitancy, coupled with the military’s intransigence, could cost them dearly:
He drew a striking parallel between the present international situation and the financial situation prior to the crash. He said that now people are asking him when we will enter the war just as in 1928 his friends were asking him when the stock market crash was coming. He said that in both cases such a question is quite beside the point. He said that once a person admitted a stock market crash was coming a prudent individual will immediately get out of the stock market and not consider when the crash is coming and thereby try to hang on and make some more profits. Likewise at the present time it is of secondary importance when we will get in; of first importance is the admission that we are going to get in, and our action accordingly should be that of preparing just as though we were actually in the war!
With that in mind, Loomis stopped at Woodley on April 21 for a long overdue visit with Stimson, whom he had not seen for some weeks. As usual, Loomis used the opportunity to lobby for the importance of the new radar detectors, which the Army Signal Corps was still fussing over and finding every excuse not to embrace. Throughout that winter and spring, Loomis’ anxiety over America’s slow pace in preparing for war had increased—it was not nearly as much as he and his colleagues had urged. After the desperate air battles fought in the British skies the previous summer, the defeat of the Luftwaffe had been followed by a strangely quiet winter in the European war. While there was little doubt that Hitler would mount another campaign that spring or summer in a final effort to conquer the British Isles, and the German U-boats were already advancing his cause, it was still difficult for most Americans to face the fact that the country might have to intervene. To prop up Britain, which was faltering, and to keep the country out of the war, the administration had enacted the lend-lease bill, allowing Britain to borrow war supplies against the promise to repay after victory. The agreement was, Churchill wrote Roosevelt, “a statement of the minimum action necessary to achieve our common purpose.” But it touched off a long, bitter debate in Congress and was eventually passed in March.
Despite the controversy, Loomis shared the secretary of war’s impatience with the isolationists and the president’s overly cautious course, which appeared to be one of waiting for circumstance to start the fight for him. Stimson argued that if the policy of sustaining Great Britain was to succeed, America had to throw the major part of her naval strength into the Atlantic battle. There was simply no other way to ensure the safe delivery of the lend-lease supplies. Both Loomis and Stimson respected Roosevelt’s political acumen, but as Stimson noted in his diary, they believed the president should take more decisive action, and if he said frankly that force was needed, and asked for the country’s approval, he would be supported:
I found both [Harvey] Bundy [Stimson’s liaison to the War Department] and Loomis at the Department and I spent a large part of the morning talking to them. . . . I found everybody rather discouraged by the war news and by the fact that the President doesn’t seem to be keeping his leadership in regard to the matter. There has been one of Walter Lippmann’s articles in last Saturday’s papers which gives the situation as a great many people are thinking it. It’s rather a defect in his tone and attitude when he does discuss the matter in his press conferences that is the cause of the trouble. We are in such a serious situation that I think people feel that it is no time to joke about it and yet the President’s press conferences are always on a light tone. I found that complaint quite universal—that he had not taken a serious enough note with the people. . . . Alfred Loomis was at lunch and dinner with me and it was very good to see him again and to talk with him. He gave me some very encouraging news about the progress of his work in Boston for the defense matters and he told me that the great victory of the British in the Mediterranean Sea a short time ago was due to their being able to locate with a new device the Italian ships in the dark.
During Loomis’ visits, Stimson often sought out his advice on various advanced weapons being developed by the services, and on this occasion he was eager to talk to him about a new device that recently had come to his attention. Drawing on Loomis’ background in the Army Ordnance Department during the previous war, Stimson wanted to know “if there was a way of using our new bantam cars with a good-sized gun in them to stop German tanks.” McCloy had suggested putting a tank-killing gun in one of the new little jeeps, and General Marshall had informed him they were working on a similar idea in connection with airplanes—the cars were light enough to be transported by a big aircraft “two at a time.” Such was Stimson’s faith in Loomis, and lack of confidence in the originality of his forces, that he asked his cousin to “apply his inventive head” to the problem and to accompany him to Fort Knox to see them in action. “These little cars will run everywhere and run very fast and are typically American because they have the flexibility which appeals to the initiative of the young.”
On May 6, Stimson delivered a radio address supporting active naval assistance to the British, stating as clearly as he dared his conviction that war was coming: “I am not one of those who think that the priceless freedom of our country can be saved without sacrifice. It can not. That has not been the way by which during millions of years humanity has slowly and painfully toiled upwards towards a better and more human civilizati
on. The men who suffered at Valley Forge and won Yorktown gave more than money to the cause of freedom. Today a small group of evil leaders have taught the young men of Germany that the freedom of other men and nations must be destroyed. Today those young men are ready to die for that perverted conviction. Unless we on our side are ready to sacrifice and, if need be, die for the conviction that the freedom of America must be saved, it will not be saved. Only by a readiness for the same sacrifice can that freedom be preserved.”
While Stimson was not the only political leader to express this view, it was one of the boldest speeches by a cabinet member at the time. Roosevelt, however, continued to listen to the contrasting advice of his State Department advisers, and Stimson’s diary entries over the next few weeks reflect his growing pessimism “that the country has it in itself to meet such an emergency.” Loomis, who had completed his assignment to study tanks, returned two weeks later, bringing with him a report and some photographs of a trial of the Bantam cars conducted by the cavalry of the 1st Division at El Paso. Stimson was delighted to learn that the idea he and McCloy had come up with had been proving successful: “The tests showed that the gun thus mounted was the realization of what everybody is trying for now—a moveable gun mount. The car is very speedy; easily maneuvered; and the gun has been put on it by these Cavalrymen without any difficulty and with it they made much better scores.”
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