Tech Revolutions and the 50 Year Rule
Technological revolutions seem to take about half a century to reach maturity. It was roughly 50 years from Einstein's Special Relativity paper to nuclear power, from the Wright Brothers to commercial jetliners, and from the first electronic digital computers to the Internet. It was also roughly 50 years from Tsiolkovsky's work to Sputnik, and from the first liquid fueled rocket flight tests to Apollo 11. The double helix structure of DNA was discovered in 1953, the human genome mapped in 2001, and genomics is now the hot field in commercial biotech.
Going back, it was (exactly!) 50 years from Watt's steam engine of 1775 to the first steam railroad, the Stockton & Darlington of 1825. The first oceangoing steamship was 1819-1833, depending on how you qualify it. Going even farther back, to a preindustrial tech revolution, the first known progenitor of the classic full-rigged ship, with three masts combining square and fore-and-aft sails, is apparently dated to 1409, and that rig was standard for large ships before c. 1475.
I don't want to make too much of this, and maybe nothing much can be made of it. Perhaps I am cherry picking my facts and their interpretation. For airplanes the jetliners of the 50s marked a broad technical maturity; most of the world's jetliners look and perform more or less like the Boeing 707 in spite of a great many refinements (and a revolution in avionics). For railroads the Stockton & Darlington was only the beginning, while steam riverboats became practical 30 years after Watt, and soon were widespread.
More broadly, both the airplane and the steam engine were technical innovations, while Einsteinian relativity was (along with quantum mechanics) a fundamental revolution in physics. Lots of apples and oranges here, and the occasional banana peel. Newton's physics produced no obvious technical revolution on a 50-year timetable or anything like it – unless you make a case for the nautical chronometer as the first precision machine
But as a conjecture - I won't dignify it with the name of theory - the 50 year rule has a certain informal logic: a decade or two working out the implications of a discovery, a decade or two finding out which implementations are practical and which are dead ends, and a decade or two refining the successful approaches until they meet their potential. (Two techs popular in SF, controlled fusion and AI, have been 20 years away for the last 50 years; make of that what you will.)
What of space travel? The 1960s Space Age marked the maturation of a technology pioneered early last century. We are now at the another 50 year mark - but the basic technology of space rocketry is already mature. Like jetliners, our space boosters have the same basic form they had 50 years ago. Progress since then, as with most mature technologies, has been gradual and incremental. The Shuttle, like the Concorde, turned out to be an economic overreach. Enormous progress in electronics and cybernetics has allowed robotic missions to do things hardly imagined in the rocketpunk era, but it hasn't made it any cheaper to loft heavy payloads – like us and our life support – into space.
Carbon nanotubes were apparently imaged by Russian scientists as early as 1952, but their Columbus moment – the time when they stayed discovered - was 1991. For elevator fans this might suggest maturation of the technology before midcentury. Unfortunately, even if cables capable of extending down from orbit are possible by then, all the 'secondary' problems of running trains up and down them remain to be solved, with no obvious magic bullets in sight.
But speaking of trains … what happened to railroading technology after the Stockton & Darlington showed that it was viable and practical? It underwent the usual course of mature techs. A building boom ensued, along with a host of refinements that gradually improved performance. By around 1900 some trains were hitting 100 mph (~160 km/h, for you purists out there), and 50 mph overall route speed became the expected standard for express trains. Neither electricity nor dieselization really changed this – in the US, for essentially political reasons, Amtrak trains generally run slower than their predecessors of 50 years ago.
To all appearances, railroads were a fully matured technology by the middle of last century, with all practical performance improvements already squeezed out of them. Improvements in 'secondary' characteristics such as train loading and scheduling (piggyback freight and unit trains) might provide dramatic improvements in cost efficiency, much as containerization revolutionized oean shipping. But no one expected trains, in their familiar form, to run much faster – hence the rocketpunk era's fascination with monorails, a marvel of hype if not performance.
Then an odd thing happened. Trains started to get faster again – a lot faster. Japan built its bullet trains in the 1960s, but they got only limited attention, perhaps because Japan was not a major tourist destination. Then France, which is a major tourist destination, built the even faster TGVs, and now 125 mph (200 km/h) is regarded as pretty much the low end of fast train travel.
No tech revolution in the usual sense was involved. TGVs are not obviously different in appearance, or basic technical features, from streamliners of the 1930s. They run on conventional tracks – but the specialized TGV lines are built with extreme care, and with extremely gentle curves to permit continual high speed running. TVGs, and their Japanese predecessors, came about essentially because other modes of transport were hitting their own practical limits, and people were willing to make a major investment to get the most out of trains.
Space, I believe, is in broadly the position of railroads 50 years ago. It is a mature, established technology that meets existing requirements – such as the current, limited traffic demand – quite well. The commercial satellite industry can afford $100 million expendable launchers, and has no interest in spending $100 billion in development to make individual launches cheaper.
A revolution in space launch technology will probably have more in common with the TGV than the jet plane. It will come about when, and because, there is enough demand for launches to make reusable vehicles worth developing and building in order to handle the traffic load. (The Shuttle already proved that they are possible, and its deficiencies are largely what you would expect of an experimental test vehicle that was also called upon, for political reasons, to be a heavy duty truck.)
As to what might bring this revolution about, I haven't a clue. But it is worth keeping in mind that we don't need a basic technology revolution for cheaper space access. (Though one would be nice!) What we need is simply a reason to develop something that will cost a lot to get started, but requires only refinement of known techniques – and a demand for lots of space lift capacity.
Related links: The US might actually join the modern rail era. And I proposed revising the rocketpunk-era vision of space for this century.