Pioneer of radar and eminent astronomer Sir Bernard Lovell
If any living person epitomises the link between engineering and science as well as the very British trait of ingenuity in adversity it is Sir Bernard Lovell. Now 92, the venerable astronomer is the name behind some of the twentieth century’s great technology advances and applications. His pioneering work on radar helped swing World War II decisively in the allies’ favour, while the huge radio telescope that bears his name at Jodrell Bank remains one of the most impressive and significant scientific instruments in the world after almost 50 years of operation. As an engineering project that many said was impossible, the Lovell telescope is also a wonderful symbol of what can be achieved through sheer drive and enthusiasm.
I’d been a young man working in a lab, with equipment one made oneself and no money. Then I was launched into this massive enterprise of ships and guns and aircraft.
Today, it’s hard to picture Lovell as anything other than the grand old man of British science. But in Aug 1939, as a humble physics lecturer from Manchester University his perspective on the world was very different. About to head off to the French alps to carry out cosmic ray research, the twenty-five year old scientist found himself suddenly thrust into the heart of an enterprise which became critical to the outcome of the war. It was, he told the Engineer, quite a shock. ‘The beginning of the war was chaos - I’d been a young man working in a lab, with equipment one made oneself and no money. Then I was launched into this massive enterprise of ships and guns and aircraft. It completely changed my life and also my attitude to what could be done and the relationship between science and engineering. I don’t know of anything which can have such a vital effect on the career of a person as the war had on people of my age.’
Following the Battle of Britain in September 1940, British bomber command had increased the number of night time raids on German cities, but reconnaissance was indicating that many of these bombs were falling on open country. So, at the beginning of 1942, Lovell, who had spent the last couple of years developing short wavelength air interception radar and blind firing systems for fighter planes, was told to form a group to develop a blind bombing system.
Based at the government’s Telecommunications Research Establishment (TRE) in the Dorset clifftop village of Worth Matravers, he set to work on the development of a precision bombing device that would use a rotating antenna within a cupola attached to the belly of a bomber to build up a map of the terrain below.
with the very real threat of Britain falling to the Germans, and the war cabinet desperate for a technical advantage over the Nazis, Lovell’s team was under immense pressure
The system was the first ground mapping technology ever to be used in combat. It was also triumph of engineering complex science and bulky ground equipment into a device that could operate in one of the most demanding environments. Christened H2S (standing for “home sweet home”) and using a 10cm radar to provide unprecedented levels of accuracy, it was largely made possible by the invention of the cavity magnetron, a high-powered vacuum tube that generates coherent microwaves and is found today in microwave ovens.
But with the very real threat of Britain falling to the Germans, and the war cabinet desperate for a technical advantage over the Nazis, Lovell’s team was under immense pressure. ‘Churchill demanded that this be given the highest property. That sounds great, but as far as we were concerned it was a bit of a disaster. It was difficult enough without this constant problem from high-level,’ he said.
The group’s efforts were also frustrated by the fact that Lord Cherwell, Churchill’s chief scientific adviser, wanted them to design the system around the Klystron, a less powerful source of microwaves than the cavity magnetron. He feared that in the event of a crash over Germany, the more rugged magnetron would survive and pass its secrets on to the enemy.
‘The cavity magnetron was regarded as so secret that we were not allowed to use it, we had to use the Klystron which was destructible.’ said Lovell. Ironically, this secrecy was somewhat misplaced, with Lovell learning just a few years ago that Germany’s wartime scientists were aware of a cavity magnetron developed in Leningrad in the 1930s, but had failed to capitalise on this knowledge.
To add to the chaos, in May 1942, amid fears that a company of German paratroopers might be planning to raid the TRE, the whole organisation was moved from Dorset to Malvern college in Worcestershire. And then, on June 7th 1942, disaster struck when a Halifax performing H2S tests over England crashed, killing everyone onboard and destroying the only prototype of the cavity magnetron system.
‘I thought that was the end of it,’ Lovell reflected. ‘We were summoned by Churchill to the cabinet room and he said that he must have two squadrons with the equipment by October. I remember meekly saying “Prime minister we’ve lost our only equipment and I’m afraid this is not possible” and he became very angry and said “young man, you’ve lost one aircraft, don’t you realise we lost 30 over cologne last night?”
Working flat out, Lovell’s group came close to meeting Churchill’s demands, equipping one of the pathfinder squadrons with the H2S system by December 1942. Then, finally, following the battle of Stalingrad and with the Russians holding the Germans on the line of the Volga, the cavity magnetron made its debut in a night-time bombing raid over Hamburg.
‘What a night,’ recalled Lovell, ‘the weather was bad and a couple of aircraft turned back. Then another chap came back and said the equipment had broken down. Then the last man came in. Thumbs up! I can see him now. He said on the H2S equipment the dots on the Elbe stood out like the fingers on his hand.’ From this point on the system was used to devastating effect over Germany.
The system arguably had an even greater impact on the battle of the Atlantic, where, at the beginning of 1943, despite the cracking of the U-boat codes, shipping losses were rising rapidly to a million tonnes a month. ‘The cabinet was afraid that if Hitler staked all on U-boat warfare we would probably not survive,’ said Lovell.
People like myself were very, very closely involved with the operational commands…this did not happen in Germany and they suffered a great deal because of that
With the U-boats listening in to the 1.5m radar used on the anti-submarine aircraft and diving to avoid attack, there was an urgent need for something that would take them by surprise. Lovell’s team therefore converted some of the 10cm H2S equipment and put it in the Wellington aircraft that were being used to attack U-boats surfacing at night in the bay of Biscay. By the time the Germans realised that the radar wavelength had changed, the damage had been done. It was, said Lovell, a turning point in the war, ‘In march and April we attacked 24 unsuspecting U-boats on the surface. Shipping losses fell from nearly 1,000,000 tonnes a month to fifty thousand and Hitler complained in a radio broadcast of a “single technical invention of our enemies”.’
It seems that the German failure to recognise the wavelength change was symptomatic of a generally poor relationship between the German scientists and government. The opposite was true in Britain. ‘People like myself were very, very closely involved with the operational commands,’ Said Lovell. ‘In the last year or so of the war I spent as much of my time on the aerodromes as I did in the lab. This did not happen in Germany and they suffered a great deal because of that.’
He added that Germany’s failure to capitalise on its prior knowledge of the cavity magnetron was another illustration of the way in which this relationship between science and government shaped the outcome of the war.
After the war, in the summer of 1945, Lovell returned to Manchester. And haunted by the memory of watching echoes on military radar equipment from what he believed were cosmic ray showers, immediately began work in his Manchester laboratory. But while nine months earlier the imperatives of conflict had put almost unlimited resources at his disposal, he was now faced with the stark privations of post-war Britain, ‘I wanted money to buy a screw driver or something like that - and it was “oh gosh, who’s going to pay for it?”.
Nevertheless, using a borrowed 4.5m radar that had been used for “ack-ack” gunnery in London he attempted to continue his pre-war research into cosmic rays. In search of a quieter spot than the University quadrangle, where electrical noise from the nearby trams obliterated the cathode ray tube, Lovell eventually got permission to take his equipment to a patch of university land at Jodrell bank. There, alone in a field, he got his equipment working and in December 1945 immediately detected a flurry of echoes from the ionised trails of meteors. He quickly realised however that to detect cosmic rays he would need to use much larger aerials.
Initially, he built a large instrument made of wire and scaffolding known as the transit telescope. Consisting of a 66 metre diameter wire bowl lying on its back, the big problem with this device was its immobility. Lovell decided to develop giant steerable telescope that could be pointed to any part of the sky and turned to his wartime contacts to make it happen. ‘I’d put a 6ft cupola underneath a Lancaster and flown at nearly 30,000 feet and thought that there’d be no problem building a much bigger one to work on the ground. I was mistaken - the responses from the firms I contacted were that what I was proposing was impossible.’
I got into serious trouble because the final bill for this was £680,000 - I’d overspent by £200,000. You couldn’t build it for 40 million today.
Finally, in 1949, he found an ally in Sheffield bridge-builder Charles Husband, who informed him that ‘it’s not impossible, it’s difficult, but about the same problem as throwing a swing bridge over the Thames at Westminster.’
But the small group faced difficulties at every turn. Lovell had to face the scepticism of fellow astronomers for whom radio-telescopes were a mystery, and with none of the predictive simulation tools enjoyed by today’s engineers the design was repeatedly revised throughout the assembly process. Scrutiny over the cost of the enterprise was also a constant threat to its future, ‘I got into serious trouble because the final bill for this was £680,000 - I’d overspent by £200,000. Do you know?’ he laughed, ‘you couldn’t build it for 40 million today.’
Nevertheless, the telescope began operating in 1957, just in time to track the carrier rocket for Sputnik 1, the world’s first artificial satellite. And almost overnight Lovell noticed a change in attitude towards his beloved facility. ‘I remember at 1am in a crowded lecture room showing them a slide of the echo, I said “this is what no man has yet seen- a wonderful echo of the carrier rocket moving over the lake district”, they knew that this was the echo from what could have been a ballistic missile so then things began to turn on our favour.’
From this point on, while still spending most of its operational time on the investigation of radio waves from the universe, military interest in the facility paid helped pay the bills throughout the cold war. The telescope was also, for a time, the only instrument in the world powerful enough to track the various probes and satellites launched during US and Russia’s battle of cosmic one-upmanship. Perhaps most famously, in February 1966, it tracked the unmanned Russian moon lander Luna 9, listened in on the transmission of photographs from the moon’s surface, and sent them to the British newspapers before the Soviets had a chance to make them public.
The instrument today is very different from that originally built: It is more robust, more sensitive, and equipped with a drive system that can direct it in a few seconds to any part in the sky. But it is nevertheless underpinned by sturdy 1950s engineering, and were it not for this, commented Lovell, the instrument would probably not be with us today. ‘I constantly remind people that if we’d had computers the telescope would have been an entirely different matter, it would have been much slenderer and it would have been destroyed. We had a desk calculator and slide rule - that’s how the original telescope was built. Husband very wisely decided to build in quite a lot of redundancy in the steelwork and thank heavens he did otherwise we would have lost it.’
Thus, astonishingly, a device that was originally designed to last for just fifteen years will be celebrating its 50th birthday next year, and the man who made it all possible, although he officially retired in 1981, can still be found most afternoons at the facility which is so much a part of him.
This article appeared in a special issue published in 2006 celebrating the 150th anniversary of The Engineer Magazine