This touches on an interesting point, that of technological development. Not just nuclear weapons...
So much of the technology we take for granted today grew out of either necessity, one-upsmanship, or desperation in the course of the two world wars and the Cold War. Would nuclear weapons ever have been developed? Without the perceived necessity for them, nuclear weapons, or nuclear power in general, could've remained just some scribbles on a university physicist's chalkboard.
Certainly there would be no crash program to develop nuclear weapons, but it's not like pre-World War I governments were ignorant of the utility of new military technologies, and in fact often invested fairly heavily in them. And even from the beginning it was seen that nuclear power could have military applications just as much as nuclear weapons--you really think the Royal Navy is going to pass up the chance to make its ships independent of refueling?
And once someone demonstrates that nuclear weapons do work and are very powerful, then of course all of the major powers will want one. Without World War I or World War II, there probably won't be a non-proliferation treaty (although there is the counter-example of the Hague treaties...)
Space programs? Nope, not for a long time. Could've taken rocketry quite a while to get past the Robert Goddard stage, not to mention the guidance technology to make such things possible.
Neither is actually nearly as necessary as you think. The instructive example here is the Japanese space program, which launched its first satellite on top of an
unguided all-solid vehicle in 1970, and which was pretty much a project of one dude at the University of Tokyo. The modern composite solid propellants needed for this were invented quite independently of Goddard for use in JATO units and are quite simple, so there's no particular reason to suppose that they wouldn't be invented here, too and, well,
unguided. Now, if you want to do a lot of
useful things in space you need guidance, but once you demonstrate you can throw something up there's not going to a problem getting the necessary funds to work on it.
Besides, a lot of the actual work done for guidance mechanisms for space vehicles was initially for bombers and missiles. And those are still going to be around and just as important if there isn't a war as if there is. More so, even, since there are more players involved.
Jet propulsion could've happened sure, but a few Comet-type disasters in the commercial sphere could've caused public distrust to the point that something like a Lockheed Constellation could still be considered the height of technology today. And military development may not have surpassed the subsonic stage.
Extremely unlikely. The OTL Comet hardly impacted the development of jets; everyone knew it was a matter of time until they displaced propeller aircraft, because they were, in principle, just plain better: simpler and easier to maintain, capable of reaching higher speeds, even more efficient in some cases. The only real question was just
when they would come into their own to displace props from most routes. A relative lack of military spending (but there would still be Cold War-type pressures) would only delay, not prevent this.
And there is no way that the militaries of the various countries are going to be bumbling around with subsonic aircraft for
decades. Even before World War I and between the wars much of the progress in aviation came from making airplanes go faster and faster (indeed, the wars probably
slowed this trend, since the military wasn't as interested in setting world records), so once something as powerful as a jet comes around there will be a lot of interest in using it to get a plane to go faster than sound. They knew it was possible, they just had trouble getting the thrust necessary.
No space program would've impacted the development of advanced computing - a "computer" could still take up an entire floor in a large office building, and we certainly wouldn't be posting on threads in alternatehistory.com right now. And that's just a few.
The impact of the space program on the development of computers is greatly overstated. Integrated circuits were invented before the space program was much of anything, and while NASA was an important early customer there were other, smaller ones, and generally it was known that they were an attractive option for further improving the performance of electronic devices once the gains from transistors were harvested. At most, deleting the space program just pushes things back a few years, it doesn't mean that no one ever builds small computers (indeed, some of the first desktop computers, like the Datapoint 2200, actually used discrete logic, not integrated circuits).
