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After WWII, both the US and USSR began developing their early rockets based on the German V-2 work. USSR flew their R-1 copy of the V2 in 1948; the US flew Corporal in 1947.

It wasn't until 1957 that the first artificial satellite, Sputnik 1, was launched into orbit.

Obviously, tension between military, political, and scientific goals had a lot to do with the priorities of both nations' rocket programs, but is there any particular technical reason a Sputnik-type satellite couldn't have been launched sooner?

The Sputnik orbiter itself wasn't fancy: a tough shell around a big pack of batteries and a radio transmitter, trailing whip antennas. Contemporarily with the 84kg Sputnik, the US was building the functionally similar Vanguard satellite in a much smaller package massing 1.5kg.

Sputnik's launcher was an R-7, a fairly complex, 20-combustion-chamber, one-and-a-half-stage ICBM design (amazingly, the same basic design is still in use today!). The two US satellite programs under development when Sputnik launched, Vanguard and Explorer, were using 3- and 4-stage designs with simpler, single-chamber, liquid-fueled lower stages and solid uppers.

I assume that building a reliable, staged launcher of sufficient power was the major technical hurdle, but the US had flown the two-stage WAC Corporal to 50 miles altitude as early as 1946.

Was closed-loop guidance used/required for Sputnik, Vanguard, or Explorer? For my purposes, precise guidance isn't required; any orbit that could be sustained for at least a day or two would be acceptable for "Sputnik-style success".

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  • $\begingroup$ Although the German A4 did advance the engineering of Rockets a lot, there where many many challenges between a small-range ballistic missile and an orbital launch vehicle. The rockets in the 50s where better and more intricately designed than the A4 in almost every conceivable way. I wouldn't say that 10 years is a particularly long time to go from this to that. Also the development versions (not deployed in the war) had a closed loop guidance system. $\endgroup$
    – Rikki-Tikki-Tavi
    Sep 5, 2014 at 15:24
  • $\begingroup$ "but is there any particular technical reason a Sputnik-type satellite couldn't have been launched sooner?" From reading The Space Race I got the impression that had the political will (and money) been available, either the U.S. or the U.S.S.R. could have done it earlier. $\endgroup$
    – Andrew Thompson
    Sep 5, 2014 at 15:39
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    $\begingroup$ von Braun and his teams seem to have been technically able to send a satellite into orbit earlier. All he needed was a blank check, political will and no bombs falling on his factories. en.wikipedia.org/wiki/Aggregate_(rocket_family) $\endgroup$
    – LocalFluff
    Sep 5, 2014 at 16:08
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    $\begingroup$ The only reason our species has been to space is because we wanted to drop nuclear bombs on each other. The demand for weapon delivery systems caused rocket technology, not the other way around; in 1950ies noone needed a cheap system that can launch a small satellite but doesn't advance tech for ICBMs like R-7 does. $\endgroup$
    – Peteris
    Sep 10, 2014 at 10:47
  • $\begingroup$ @Peteris It is not quite that bad. Verein für Raumschiffahrt and other early enthusiasts wanted to go to space before the military understood that it could make use of rockets. But the US air superiority certainly sped up the German and Soviet rocket developments. $\endgroup$
    – LocalFluff
    Sep 12, 2014 at 8:37

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I'm sure it could have been done somewhat earlier, but there was still quite a big technical step between the suborbital sounding rockets / short-range ballistic missiles derived from the V-2, and a multi-stage, high performance vehicle capable of orbit.

Advances in guidance systems were definitely necessary, but I think raw performance in terms of delta V was the real differentiator. The V-2 provided less than 2 km/s of delta V to its payload; an orbital launch needs about 10 km/s (including gravity and drag loss). This requires a combination of staging, improved mass fraction, and better engine performance. That takes time to develop, no matter how you look at it. Much of the same is needed for true ICBM-like ranges (typically 7-8 km/s), which was the real driver for development of those technologies.

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The RAND Corporation issued far-seeing reports on artificial satellites as early as 1946 (http://www.rand.org/pubs/special_memoranda/SM11827.html) - a must read! There was no immediate military need to develop satellites right then, so the whole agenda lingered on. Von Braun was directed by the Army to focus on intermediate-range missiles, and the Air Force was bomber-heavy, and eager to defend its turf (even though Curtis LeMay commissioned the above-mentioned study).

Advent of the "super" (thermonuclear weapons) changed the situation drastically.

It was John von Neumann who was instrumental in advocating for ICBMs in the States, having the privileged position inside the nuclear establishment and keen insight.

The United States had a positional advantage over the Russkies, with bases around Russian borders, so there was no real pressure to develop at the very limits of technical possibilities. The USSR, prodded by Andrey Sakharov's extraordinary weight requirements (1953) for a bomb-carrying ICBM, and its own lack of reliable bomber force, made Korolyov's designers choose the now familiar "packet" design for the R-7 missile, together with radio-controlled guidance.

The rest is history: in 1955 President Eisenhower's press secretary promised to launch a small satellite during the International Geophysical Year - unfortunately, led by the NRL in Project Vanguard - and not von Braun's ABMA team. The US duplicated effort, choosing to hide the Corona/WS-117 development.

The Soviets retaliated in kind, making the decision to re-use R-7 and jury-rig the Sputnik, and were the first past the post.

To re-cap, here are the factors that delayed satellites till 1957:

  • Troubles with developing thermonuclear weapons.
  • International Geophysical Year slated for 1957.
  • Initial reliance on balloons/spy planes for aerial reconnaissance.

Some books to skim through:

  • Neil Sheehan. A Fiery Peace in a Cold War: Bernard Schriever and the Ultimate Weapon. 2010, Vintage books.
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Sputnik-1 was political statement. Its science value was close to zero. Some see the entire Space Race as a series of political statements: “If we can do this, think of what we can do to your cities.” A rocket capable of putting a satellite into orbit, even a small one such as Sputnik-1, is more than capable enough to deliver a nuclear bomb to some city a third of the way around the Earth.

There's one caveat to that last sentence: The bomb has to reasonably lightweight. There was no impetus at first to develop ballistic missiles because the first nuclear weapons were extremely massive devices with relatively low yields. Both sides of the Cold War made significant improvements to those initial Los Alamos devices. It was these improvements that provided the impetus to build long range ballistic missiles.

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    $\begingroup$ To summarize: space rockets were only built once atomic bombs small enough to fit on them were built. Makes sense. $\endgroup$
    – dotancohen
    Oct 2, 2014 at 13:45
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    $\begingroup$ Sputnik's science value was near zero? Not even McCarthyism of the fifties would have said this. You are looking at it with hindsight from the 21st century and taking for granted all the digital hi tech devices we have on probes today. At the very least, Sputnik proved that radiation is not too intense for satellites to work. Saying Sputnik has near zero science value is like saying the first digital computer had no science value because it couldn't compute much. No argument with the rest of your post, tho. $\endgroup$
    – DrZ214
    May 29, 2015 at 18:55
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    $\begingroup$ Sputnik also proved (I don't know if this had been shown before as well, but nobody had actually done it) that communication between an orbital vehicle and Earth ground stations was actually possible. That was a pretty major step in making larger, more complex and more expensive satellites a real possibility. $\endgroup$
    – user
    Jul 30, 2015 at 12:42
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    $\begingroup$ To add, Sputnik was a boon for the fields of geodesy, atmospheric science, and precision orbit determination. $\endgroup$
    – Chris
    Apr 7, 2016 at 16:32
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    $\begingroup$ Originally, the first Sputnik was planned to be a 1000—1400 kg spacecraft with 200—300 kg of scientific equipment. But its development faced delays and simple payload (as we know it) was sent instead in order to be the first. Quote from Korolev's letter to Soviet government: "There are reports that in relation to the International Geophysical Year, the United States intend to launch a satellite in 1958. We risk losing priority. I propose instead of a complex laboratory (object "D") to launch a simple satellite into space." $\endgroup$
    – Sergiy Lenzion
    Jan 2, 2020 at 11:06
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The main reason for that delay from early rockets to orbit-capable rockets is known as the rocket equation: https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation

In layman's terms, the faster you want a rocket to go, the more fuel it requires. The fuel increases the weight, requiring larger engines, and yet more fuel. To achieve orbital speeds, you need a rocket where the vast majority of the rocket's mass is fuel. For the Space Shuttle for example, approximately 80% if the vehicle's takeoff weight was fuel, 15% was the mass of the vehicle, and only 5% was the weight of the payload. Building such a craft means developing very strong and very lightweight materials. Those materials, and the means of working with them, all had to be invented. The inertial guidance systems to accurately steer the rockets had to be invented. The advanced digital and analog telemetry had to be invented.

The upside to this is that the vast majority of advanced technology that we take for granted today traces its roots directly to those inventions necessary for space exploration.

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    $\begingroup$ Inertial guidance was not an initial requirement for the R-7 (MECO was first supposed to be done on a radio signal from the ground). Telemetry was already done by the Germans in Peenemunde. Materials did not diverge significantly from those used in aviation until the 1960s. Engines are a different matter, and you have a point here. $\endgroup$
    – Deer Hunter
    Aug 1, 2015 at 8:11

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