... according to the 2001 Space Odyssey we should have already had a manned mission to Mars. So maybe by the time we have figured out space travel, we will have figured out the fusion thing.
According to Project Orion (the original Orion) we would have been on Mars since 1964 and visited Saturn back in 1970.
But calmer heads prevailed and decided it was best to follow treaty obligations, mollify the budget hawks, while pleasing the military with their pet ideas, so it was canceled in 1964.
Perhaps in was also canceled because it would have been so much cheaper to make (heavy materials, not expensive composites) and use - $250 per pound instead of $5-6,000 to LEO.
So instead of ships (10,000 tons) with crews of 150 exploring our solar system far faster than anything we have presently (125 days to Mars), we got 12 guys spending some 80 hours on the moon; instead of visiting the nearest stars in ships (40,000,000 tons) with crews in the thousands, we got movies ...
It is the creative mind that sometimes points us in the right direction. :)
Makes you appreciate the trips to the Moon. That was real and done with 60s technology. Best of all many of the gadgets that we use today can be traced back to the space race.