Apollo 11 mission 50 years on: The Cambridge scientist who helped put man on the moon
Buried in Little Shelford churchyard is a scientist who played a critical role in putting the first man on the moon, 50 years ago.
Such was the importance of Tom Bacon’s work on the fuel cell used in the Apollo 11 mission of July 1969 that US President Richard Nixon told him: “Without you Tom, we wouldn’t have gotten to the moon.”
Tom and his wife Barbara met the astronauts Neil Armstrong, Buzz Aldrin and Michael Collins at a reception at 10 Downing Street following their lunar landing.
Born in Billericay, Essex in 1904, Francis Thomas Bacon – known to friends as Tom – was a descendent of the Elizabethan statesman Sir Francis Bacon, often described as a pioneer of modern scientific thought.
After Eton, Tom attended Trinity College, Cambridge, studying mechanical sciences and it was there that he realised the significance of the Carnot limitation on the heat efficiency of thermal engines.
Proposed by French engineer Sadi Carnot in the 19th century, the theory describes the maximum possible efficiency of a working engine operating between two heat temperature limits.
Tom’s Royal Society obituary, by Keith Williams, notes: “This was to influence almost the whole of the rest of his life.”
After Cambridge, Tom worked at the engineering firm C A Parsons in Newcastle. Tom, who was related to the Parsons family, was particularly influenced by its founder, Sir Charles Parsons, the developer of the first steam turbine.
And it was during a lunch break, leafing through the pages of the Engineering journal, that Tom came across the articles describing a German idea of electrolysing water with off-peak electricity at night and using the hydrogen and oxygen produced to fuel an internal combustion engine for a vehicle.
“I was immediately struck by the potentialities of the thing, especially if it might be possible to make power electrochemically from the hydrogen and oxygen, rather than feed them to an engine,” Tom later said.
Further research led Tom to explore the potential of fuel cells, which generate electricity through a chemical reaction. They use two electrodes – an anode and cathode – separated by an electrolyte, which carries the electrically-charged particles from one to the other, with a catalyst speeding up the reactions.
Typically, fuel cells use hydrogen and oxygen. Hydrogen atoms enter at the anode, where a chemical reaction removes their electrons, leaving them ionised, meaning they are carrying a positive electrical charge. Negatively charged electrons then provide the current through wires. Oxygen enters at the cathode and, in various ways depending on the type of cell, combines with electrons and hydrogen ions. The byproduct is water, which is drained away.
A key benefit of producing electricity through a chemical reaction like this is that it avoids the Carnot limit, meaning it is efficient.
In 1937, Tom drafted a report to the directors of C A Parsons describing how the first practical fuel cell might be developed. He continued to experiment, both at home and on work time, ultimately being told in January 1940: Stop your fuel cell experiments or leave. He left.
For a time, he continued this work at King’s College in London, before being asked to join the Admiralty team for anti-submarine research at Fairlie on the Clyde in Scotland.
It was in 1946 that Tom moved to Little Shelford with his family – his eldest son, Francis, who died at just 23, daughter Daphne and other son Edward.
He was able to continue his fuel cell work at the University of Cambridge, carrying out experiments with potassium hydroxide solutions at 200C and gas pressures of up to 600 pounds per square inch.
He moved from the Department of Colloid Science to the Department of Metallurgy and then on to huts at the Department of Chemical Engineering in Tennis Court Road, making significant progress in the 1940s and 1950s that led to the creation of highly efficient alkaline fuel cells. The Admiralty and Ministry of Power became interested in the work, boosting Tom’s budget.
A key challenge was to prevent the oxygen electrode from corroding at high temperatures. They solved it by soaking new nickel electrodes in a lithium hydroxide solution, air drying them, then heating them for a few minutes at 700C in air.
Other members of the team – metallurgist Dr J G Bowers and chemist W J Davis – showed how very high concentrations of potassium hydroxide in the electrolyte greatly improved oxygen electrode performance, which later had a major impact on space flight.
Teflon ring shields were used to improve the jointing, which had been poisoning the hydrogen electrode.
The team had succeeded in creating a six-cell fuel battery using five-inch diameter electrodes that operated at 200C and 400psi.
It was showcased at an exhibition in London, but no interest was shown by British industry. The Electrical Research Association withdrew its support,Tom’s team disbanded and the equipment was moved for six months in 1955 to Westfield, off Little Shelford High Street.
Further funding was secured, however, from the National Research Development Corporation (NRDC), and Tom set up at Marshall in Cambridge.
Sir Arthur Marshall, writing in The Marshall Story, recalled: “A contract was established whereby Tom would provide the technical input and team up with Marshall with the object of developing a reliable, automatically controlled fuel cell to generate higher power than the lighting of a few bulbs which had previously been achieved under laboratory conditions. This was an exciting and challenging project.”
Sir Arthur appointed one of his best engineers, John Frost, as project manager, reporting to joint managing director John Huntridge.
Tom’s patents had been transferred to the NRDC, which had been interested in exploiting the technology. But then Dr Tony Moos, of the Leesona-Moos Corporation, a New York-based research and development organisation, read one of Tom’s articles on the fuel cells and visited him in Cambridge. He took out US licences on the patents.
“After two-and-a-half years’ work, on Monday 25th August 1959 we demonstrated to those interested in fuel cells, including the press, a fuel cell with an output of six kilowatts driving a forklift and a circular saw and providing power for arc welding,” wrote Sir Arthur. “This unit was not commercially viable but it was one stage closer to a practical solution than anything that had been achieved before.”
At this stage though, in the absence of commercial interest, NRDC closed down the project. Interest in the US, however, was just taking off.
Bidding for work on the proposed Apollo mission, the Pratt and Whitney Division of United Aircraft took out a licence on the patents, suggesting them as a means to provide electrical power. Hydrogen and oxygen would be present on board for propulsion and life support and the cell was capable of operating at 75 per cent thermal efficiency.
The by-product, water, could also be used for drinking and humidifying the atmosphere of the space capsule.
Without telling NASA, the company solved the problem of small bubbles forming in the electrolyte cavity of the space fuel cell – which would cause havoc in zero gravity.
And with a team of 1,000 and around $100million of NASA’s money, Pratt and Whitney overcame a series of challenges. They used a 75-85 per cent potassium hydroxide solution as electrolyte and operated at 204C at high pressure. Tom praised them as “marvellous engineeers”.
The fuel cell helped Armstrong and Buzz Aldrin land on the moon on July 20, 1969.
Dick Foley, of Pratt and Whitney, wrote to Tom to say: “Please accept my personal congratulations for the contribution your fuel cells made to Apollo XI. The three power plants performed flawlessly and provided about 400 kilo watt hours of electrical energy during the mission. This raises to 23 fuel cell power plants which have flown to date. Your satisfaction must be very great that your pioneering efforts have made this possible and practicable.”
Tom won numerous medals, and was made an OBE in 1967 and a fellow of the Royal Society in 1973, but remained modest to the last.
His work continued to have an important influence. Fuel cells were also used in subsequent manned spaceflights and the Space Shuttle missions.
Tom had foreseen that fossil fuels were a finite resource and highly polluting. He hoped to “eliminate the need for burning fossil fuels”. Today, fuel cells are used for electric transport in cars, buses and light aircraft, in uninterruptible power supplies, portable power for soldiers and in many other applications.
Tom died in 1992, but his legacy is here to stay.