It occurs to me that I may not have described the idea I had for this world. This is a rip-roaring, great fun idea well-suited for a SF novel about a Brave Innovative Research Team taking things a massive leap into the future. Except, its true.
*This is not based on the current Orion NASA craft, but on an idea that got worked on in the late '50's and later.
The Orion is a giant flat plate on hydraulic springs with a Coca-cola machine dispenser (scaled up) to drop nuclear bombs out underneath the plate. It sounds insane, but it should work. They built a test model with conventional explosives which worked, and actually the larger you make the thing, the more stable it is.
They were seriously considering making a manned trip to Saturn with a 4,000 tonne spaceship, and arriving by 1975 with a five year mission with a crew of about ten. For scale, the Indian Navy, in 2004, started using a guided missile frigate which weighed 4,000 tonnes. This Orion is a SpaceSHIP, not a shuttle or a capsule or a lander.
So, in this other reality, they did just that. The Russians were terrified. So were the Chinese. It made the Americans boisterous earlier than the eighties, and Communism collapsed that much earlier. It was a bit more blood than velvet in our reality, but in this reality, the Chicoms fell as well.
With the expansion into space, it became possible to put up Solar Power Satellites and O'Neill Asteroid Balloon Space Stations. Kwh's dropped to micro-pennies. The economy boomed as factories roared.
At first, the enviros were horrified, but then Off-Earth Factories became the rage in the Space Age. Instead of Microsoft and Apple, it was Nuclear Rockets, Inc. and Near-Earth Manufacturing, Inc.. The computer age, and the PC age stayed slow and calm with new and improved versions of Dos coming out every five years or so. With Off-Earth Factories, the pollution rate dropped. Also, helping in this was the turnover from Coal-fired plants to SPS power. Add in electricity being cheap enough that a nationwide network of Charger Stations was built so that the relatively poor batteries of the day could get charged every fifty miles.
Of course, with everyone using electric cars the batteries got better a lot quicker. And the pollution level dropped even further without millions of internal combustion engines.
Economically, it was a return to the 1950's for America as the middle class expanded and grew in wealth and stability. This was a world more suited to the Ordinary Guy who liked a bit of handwork and brainwork instead of the Computer Age which more favored the Nerd.
With this massive outpouring of wealth, the Second Marshall Plan was able to begin seriously reinvigorating Russia and China (after they disarmed.) There were some hard-core militarists in both nations who refused the 'devil's bargain' of massive investment aid in exchange for demilitarization, but vast majorities in both countries favored the deal. And in return, both countries became wealthy in space, and fairly pacifistic (not as pacifistic as Japan was, but close). Some of these militarists went so far as to become terrorists and this formed a continual problem for the peaceful majorities in America, Russia, and China.
Orion spacecraft became even larger with the largest one in the year 2000 being the Star of Bethleham which weighed in at a 100,000 tonnes (larger than some cruise ships). The Outer Planets were studied by the US Space Guard (descended from the Navy and Air Force). Asteroids with their huge loads of metals were towed into Earth Orbit.
These asteroids were mined, and then with giant lasers they were 'ballooned'. That is, a laser would fire down the long axis, heat the interior, and allow the asteroid to expand and form a hollow interior. After cooling, this became a space colony. By 2000, there were four space colonies like this in orbit. By 2010, there were thirty-five.
And then the Computer Age struck in earnest. It had a better basis as the Dos code had been used for decades and was very reliable. But, this also made it faster once it did strike.
=================
I'm pretty sure I did a variant on this before, but that's okay.