This answer to Have any Soviet-era astronauts reported seeing Earth's aurora or related luminescent atmospheric effects? mentions sightings from both Salyut 6 and Voskhod 1.

While Salyut 6 orbited for an extended period of time, Voskhod 1 was only in space for about a day.

However, since it was at a higher inclination, it had a better chance of having line-of-sight access to atmospheric phenomena in the general area of the North Magnetic Pole, which was in a very different location in 1964 than it is today!

Question: Both missions were launched from roughly 46° degrees north latitude, but they were very different in nature, so there's no reason to expect the declinations to be the same, of course. Here I'm simply asking why Voskhod 1 was at an inclination of 64.7° degrees while Salyut 6 at 51.7°. What were the factors determined that those different inclinations were optimal for those missions?


1 Answer 1


The choice of an inclination of 51.7° for Salyut 6 (and all other space stations with Russian contribution) is straight forward: It's the lowest inclination that can be reached from Baikonur without crossing the border of China during launch. The low inclination allows for the largest possible payloads due to the additional boost from Earth rotation.

All Voskhod missions were launched to an inclination of 65°. There were several constraints for the landing of Voskhod 1: Landing had to occur after one orbit, it had to occur on land (both the Black and Caspian Sea are in the target area), and it had to be inside the Sowjet Union. I don't have a source for this, but I assume that it gave the largest margin of error to allow for a successful landing given that orbit insertion and maneuvering was far less precise than it is today.

  • $\begingroup$ This is great; just the kind of insight I was hoping for. $\endgroup$
    – uhoh
    Commented Sep 21, 2020 at 0:44
  • $\begingroup$ I read version that this inclination of 51.7° was determined by the capabilities of the Proton rocket to fly to the Moon with Soyuz 7K, and then to launch the orbital stations. $\endgroup$
    – A. Rumlin
    Commented Sep 21, 2020 at 17:51
  • 1
    $\begingroup$ @A.Rumlin If Proton is able to deliver its payload to an orbit of 51.7°, then it could take even more payload to a 46.5° orbit $\endgroup$
    – asdfex
    Commented Sep 22, 2020 at 17:19

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