Humans on Mars by 1970

[radtech497]

Rynn - IMHO that is the whole point. Orion would be incredibly efficient in terms of use of resources. Most of the cost of present-day space travel is due to the need to shave as much mass as possible off the vehicles and their equipment; this is in turn due to the fact that getting to space at all using chemical fuel and propellant (which aren't quite the same thing, but let's leave that) is marginal at best and necessitates multi-stage launchers - which means huge expense.

From this, I'm guessing that you envision launches of Orion from the Earth's surface. While feasible, this sort of activity tends to depress real estate values in the vicinity of the launch site and increases in global ambient fallout levels doesn't do much good for the environment. The nascent environmental movement likely would have joined with the existing anti-nuclear weapons movement to oppose Orion launches from the surface fairly soon after the first one (if not before).

Orion-drive spacecraft would probably look fairly crude, because the necessity for shaving grams off the equipment just wouldn't be there. The difference is a little like the difference between an F1 car and a heavy goods lorry.

The public outcry against launching Orion from the ground would lead to in-orbit launch requirements; these, in turn, would require that Orion's mass still be kept to a minimum, as the components would need to be lifted into orbit by a non-nuclear launch system. Perhaps the development of the Nova launcher might have proceeded in order to meet the payload requirements. Launching from orbit may, in turn, have prompted the development of orbital infrastructure to assemble and test Orion components. This, in turn, might have provided an impetus for developing orbit-capable aerospacecraft (the X-15 was, with some proposed modifications, just barely capable of reaching low Earth orbit).
Much of the infrastructure, if built in the 1960s-1970s timeframe, would require a human presence, and getting people into orbit in sufficient numbers would also motivate rocketplane development.

In addition, cheap space travel leaves open the possibility of obtaining resources that would help the world's economy immensely. To take one example, some of the asteroids are essentially made of billions of tons of high-grade steel.

Asteroid mining might follow the development of orbital infrastructure, but it would be many years after the construction of that infrastructure before it would become economical to do so.

Radtech
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