If Earth orbit only required ~4500 m/s like Kerbin, what year would we have developed an orbital rocket?

[Nightside]

If Earth orbit only required ~4500 m/s like Kerbin, what year would we have developed an orbital rocket?

[JoeSchmuckatelli]

Whenever Germany started shooting them, I'd guess.

[kerbiloid]

USSR - in 1955-1958. R-5M was a backup option for orbital R-7.

USA - in 1958, as they didn't have real interest in long range missiles till Atlas, Thor, Jupiter.

Germany - Von Braun and his colleagues once had been arrested for talking about spaceflights instead of doing rockets.

[Nuke]

the performance of german v2 rockets may have been enough to send bombs to the united states directly. it would have been a much different war. however i doubt that these rockets would be very accurate, they barely managed to hit targets in britain.

there were plans for suborbital rocket bombers, which may have been more practical. i don't think it would allow them to win the war, given how spread out industry was in the united states, but we would have had some rubble to deal with.  they probibly would have managed to cripple the manhattan project though, assuming their intelligence knew of its existence. that would have probibly added several years to us involvement in the war. 

Edited August 1, 2022 by Nuke

[kerbiloid]

9 minutes ago, Nuke said:

the performance of german v2 rockets may have been enough to send bombs to the united states directly.

Only in A9/A10 two-stage variant, with the first stage originally equipped with a sixpack of A-4 engines.

Never built, and was using highly ineffective 75% Schnaps alcohol.

If instead of the A-4 heresy they were focused on kerosene-acidic Wasserfall, they could probably build a bigger and more effective rocket.

But as Wasserfall irl was never used until the USSR/USA/French tests, so probably what happened irl is the best everyone was able to.

[wumpus]

The Paris Gun had a muzzle velocity of 1500 m/s (so sayeth  the infallible wiki), so would it be possible to build a multi-stage SRB with the rest of the velocity needed for orbit?  You'd presumably be limited to gunpowder based rockets, but you wouldn't need much TWR thanks to the initial velocity.

Granted, you'd have to shoot the thing across Germany, but assuming the French demanded this (and used it as such), this would hardly have mattered to the French at the time.

[magnemoe]

I don't think the year we get into orbit changes much, as in probably a couple of years as the underlying technology was not there 
Now if orbital velocity is just 2.4 km/s = 8640 km/h well an falcon 9 first stage is an SSTO who can deliver the second stage into orbit. x-15 is 1 km/s below orbital velocity. 

So its an world there its much easier to launch heavy payloads and spaceplanes and SSTO works. 

[Nightside]

So no orbital Chinese fireworks or Victorian steam rockets?

[kerbiloid]

In XIX they didn't have enough strong materials for high-pressure engines.

Only in XVIII they started using coal in metallurgy instead of charcoal, and thus started melting steel in much greater amounts than before.
(Because previously the furnaces were smaller and weren't providing the conditions for the coal burning.)

Immediately after that the industrial revolution started, the mass production of cheap steel allowed to equip millions of people with stronger and sharper tools which allowed to manually build first machines and power them with steam engines.
It took about a century, till the mid-XIX. The early steampunk epoch.

Since mid-XIX they got electricity, first combustion engines, periodic table and early chemical industry. The late steampunk epoch.

A half-century later they had the WWI level industry (which immediately used), the dieselpunk epoch.

To that date they had only primitive powder lightweight rockets with extremely low ISP, which weren't able to pass through the 8 km thick air regardless of the orbital delta-V.
They didn't have enough strong and lightweight steel for effective rocket engine turbopumps and the primitive engines of 1930s were passively cooled.

There was no clear idea what should be the rocket fuel.
They were trying everything they could buy for nothing or steal somewhere, usually petrol (because usually they were doing this in a car workshop) or ethanol solution (decreasing it with time from 90+% to 75% for better engine cooling) and liquid oxygen.

The Oberth, Goddard, GIRD, and German rockets of that time are a rather primitive set of duct pipes used as tanks and nozzles.
The Goddard's ones were the most advanced but closed by patents and licenses, so didn't fruit into something bigger.
(Ignoring the fact that rather primitive German rockets quickly turned into the Von Braun's Aggregat family after Von Braun had gotten acquainted with Goddard's articles.
After the war Goddard got a chance to see A-4 and ensure that copyright is not always good.)

So, the combination of the pre-WWII industrial abilities allowed to build much more complicated turbopump engines, rudders, gyroscopes, and so on.
It happened less than in a half -century after the first combustion engines and electric machines were created.

So, the IRBM-level alcohol rockets and the anti-aircraft kero-acid missiles were tested since early 1940s, and couldn't be made much earlier.
In late 1940s they were still having poor understanding of zero-G engines ignitions, so were either igniting all stages on land (R-7, Atlas), or used solid-fuel motors on top (which look weird today).

Kerolox and hypergolic engines (with almost twice as high ISP) appeared only after WWII because they were too expensive just for experiments during the war.
Germany was using the cheapest fuel it had, while others didn't make big rockets at all.

So, anything able to reach even the LKO, let alone LEO, had a chance to appear in mid-1940s or early 1950s, not earlier.

This in turn means that the spacecraft would be almost same as Vostok (the advanced Piccard stratoballoon capsule with heatproof insulation) or Mercury, depending on the first ICBM capacity.

Edited August 4, 2022 by kerbiloid