Actually fastmongrel hit the 'nail' on the head: Marketing
"Sheppard" would be famous for being 'first-into-space' (the US PR apparatus would ensure that) while Gagarin would be 'first-in-orbit' (the Soviet PR apparatus ensuring THAT as well) so that the two would be compared to OTL "Gagarin" and "Armstrong" for similar reasons.
No I'd never heard of Gagarin being referred to as the "Columbus of the Cosmos" either, though that makes sense as it would NOT have been a way American's would have 'related' to easily
But speaking of... Again it WOULD be the way an ATL American media would paint 'Sheppard' if he went up first. And quite logically the Soviets would refer to Gagarin as the "Magellan of the Cosmos" specifically to tie-into the American propaganda and (basically
) stick it in the eye of the US that Gagarin actually went 'around the world' where Sheppard just went 'there and back' again
Actually the quote doesn't really 'disagree' with my assessment
Going AROUND the Earth in space is quite obviously a 'greater' achievement than a sub-orbital hop, but fastmongrel has the point; What is going to 'count' here is what the various media's are going spin things and frankly they have vastly more 'media' available to do so than even in Lindbergh's time. And to be honest one reason that the USSR went straight for orbit was the fact that the US openly planned to do sub-orbital first and this was a way to 'get-ahead' of them once again. Keep in mind everyone was 'assuming' that the US suborbital flight would in fact come first! Had "Ham's" flight gone off a bit better or Von Braun been a bit less safety obsessed, (it continually surprises me how so many "space fans" see early NASA as less risk-adverse than the current one when in fact it is the opposite) Sheppard WOULD have been the first human in space. Yes the Space Race would continue but the immediate 'pressure' for the US to do 'something' in space to counter Soviet 'firsts' would actually be less. Which leads to...
Actually my turn to respectfully disagree since Kennedy was quite open about wanting to do 'anything' BUT the Moon as a goal and an American 'first' would ease the pressure enough he could probably have gotten away with a Space Station rather than a Lunar landing and return. Saturn 1 would fly in October just 6 months after Gagarin went into orbit OTL and its payload was vastly superior to anything the Soviets had available. Even if it should have developmental issues, (and given its very conservative design to specifically avoid such unlikely) the 'pacing' item would then become a manned vehicle for it to carry.
The key was 'at-that-time' (what's "The Oncoming Storm"? Never mind just found it in the listed thread
) but it was developing that capability and frankly quite a bit more. Atlas was coming along as was Titan-1 but since both were prioritized as missiles rather than launchers... And again there was Saturn-1 which would be available in a little over a year and was far beyond anything the Soviets had at the time. The key pacing item was always a capsule and experience with space launch operations. With visible 'proof' that America could do 'something' first it takes a LOT of the 'sting' out of further Soviet efforts on the level of the average American citizen and most of the government which OTL required a 'guaranteed' first at least promised in order to restore some of the lost faith. This is quite self evident actually in that America was to 'suffer' several more Soviet space 'firsts' before we began to gain traction and pull ahead.
The real 'butterfly' in such a situation is that a closer Space Race would force the Soviets to not simply settle for grasping the lower hanging fruit given their capability of launching heavy payloads, (which rapidly diminished as American launch vehicles came online) and decide to either give up the Race they started or get serious about 'competing' which would have had additional butterflies towards the whole outcome of the Space Race.
Additive trivia: Actually Von Braun was LOOKING for an excuse to delay Sheppard's flight and used Debus' objections to call for another test flight. It was the reason he called for a 'unanimous' approval rather than reaching a consensus decision as was his normal way. He would later admit that had any of the issues that delayed Sheppard's launch OTL happened without the 'pressure' to get an American into space after Gagarin happened earlier he would have aborted the flight. As it was, politically and socially Sheppard HAD to launch that day or pretty much not at all so he overrode and worked through each issue and launched anyway.
So no, actually Gagarin could very well STILL been first no matter the delays of the Soviet program because the US program was just as much 'risk-adverse' and could not 'hide' things as the Soviets could if things went wrong.
Randy