We will be cheering when New Horizons makes its closest approach to Pluto on 14 July. But we also know that even if Britain gets a spaceport, it is more likely to be in Scotland than in Star Lane, E16. However, the capital can still be proud of its role over centuries as a launch pad for ideas and experiments which are still helping space exploration today.
We wonder for how many people the dismally dull sounding law of Newton ‘To every action there is always an equal and opposite reaction’ acts as a parting of the ways, either branding physics as an arid body of laws about snooker balls, or opening the way to rocket science. Literally this, Newton’s Third Law, is rocket science and the way to get around in space. Here, except for the wispy solar emanations, there is nothing to push against unless you take it with you.
The Royal Society of London published Newton’s Laws of Motion in Philosophiæ Naturalis Principia Mathematica in 1687. This landmark work arose from London comet watcher Edmond Halley’s speculations with friends in coffee houses. Halley visited Newton in Cambridge, where it emerged that Newton had already discovered the rules of planetary motion, only to have lost the proof. After Newton worked it out again, Halley nobly forked out himself to have Principia printed.
Rockets Up the Arsenal
The future Duke of Wellington faced in India a frightening weapon, a gunpowder rocket mounted not on a stick but on a scything blade that would descend from a great height to dice anyone in its path. These were fired by the army of Tipu Sultan, the formidable ruler whose fun it was to have a life size toy consisting of a tiger using a British soldier as a chew stick. Sir William Congreve of the Royal Arsenal at Woolwich, after 1801, kept the rocket alive, trying to improve on the Indian squibs. His designs reached 300 pounds in weight but were erratic in every way. Rocket development at Woolwich continued after Congreve, and included Edward Boxer’s two stage rocket in 1865.
The principle of a rocket is to throw a small mass backwards at very high speed, making the rocket pick up speed in the opposite direction (hat tip to Newton). The small mass is the rocket exhaust. The lightest fuel is hydrogen and, happily, it burns with energy sufficient to expel exhaust faster than cash leaves an oligarch’s wallet. But it is not very portable, especially being gas at room temperature. It needs to be liquefied to store it conveniently.
In 1823, Michael Faraday, working at the Royal Institution accidentally hit upon the idea of liquefying gases by compressing them. But it was his successor, James Dewar, at the same Mayfair laboratory who succeeded with hydrogen in 1898, by cooling it to -253˚C. Luckily he had already invented the vacuum flask to put it in.
In the 1830s William Grove took the unusual step of pausing a legal career in London to start a scientific one. While professor at the London Institution in Finsbury Circus he passed electric current through water in 1842, breaking down the liquid into its constituents and forming bubbles of oxygen and hydrogen. But when he disconnected the power supply, a small current began to flow the other way. He had inadvertently invented a gas battery which we now call a fuel cell. Unfortunately, it was rather feeble, and took more than a century to be anything close to useful.
That work was still done in Britain, some in a garden shed near Cambridge and some at King’s College London. It was a prerequisite for the Apollo moon missions in the 1960s to use a fuel cell for electricity. The same gases that propelled the spacecraft also powered the fuel cell. The only exhaust was drinking water.
Spacecraft bound for the inner solar system rely on careful aiming rather than continuously burning fuel, but can obtain on-board power from sunlight using solar cells. Telegraph engineer, Willoughby Smith, based at a telegraph cable factory in Islington, reported in 1873 that the electrical resistance of selenium was affected by light. It led to great interest in this peculiar material, and to the solar cell. Early selenium cells were not very effective and were superseded by silicon in the 1950s. But now selenium is once again an ingredient of many solar cells.
Looking down on the British Interplanetary Society (BIS) is partly what you do from the viaduct at Vauxhall and partly the result of a misconception that it is something crazy like the Flat Earth Society. Founded in 1933, the BIS is not mad. It just looks further ahead than most of us. Sci-fi author Arthur C. Clarke was an early member, and he first proposed there in 1945 the geostationary satellites that we now rely on to communicate and to find out where we are.
In 1981 the BIS published a study for an interstellar craft, Daedalus, which probably no one would live to see. Current spacecraft may have drifted out of the solar system on retirement but the BIS design targeted an unmanned fly-by of another star. The journey, taking 50 years, involves unprecedented speeds and long term structural resilience against cold and meteorites. The Daedalus concept craft was fusion powered, using fuel to be mined from Jupiter.
An international team of brainy volunteers (Project Icarus) has been updating the Daedalus study since 2009 with impetus from the BIS and participants in London, and now with a view to migrating people to another star system, taking a century. So now a new generation of people can look forward to never seeing it built, except, perhaps, in movies like Interstellar.