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There are obviously many satellites in polar orbits or in orbits that extend to very high latitudes. There are obvious reasons to do this in terms of Earth observations, but there is probabably much less motivation for crewed flights to cover high latitudes.

Orbital inclination tends to be determined by the latitude of the launch site. There are numerous launch sites around the world but only a very limited number have been used for crewed launches. Baikonur is at 46 degrees N latitude, so presumably some of the orbits touch that latitude. Are there any launch sites further north that have been used? Are there any reasons higher inclination orbits might have been used? In long duration spaceflights, do orbits drift - possibly to higher latitudes? Have any crewed launches gone astray into higher inclination orbits?

I've just noticed this answer saying "STS-36, a classified shuttle mission, was launched to an inclination of 62 degrees". Is that the record?

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    $\begingroup$ Answered here space.stackexchange.com/a/36295/6944 $\endgroup$ Feb 7 at 0:40
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    $\begingroup$ @Organic Marble That's a good pointer. Now I see 65.09 degrees for Vostok 6 (Valentina Tereshkova). This is slightly higher than Voskhod 2 at 64.8 degrees. These numbers are much higher than the launch site latitude. Was this to accommodate a particular landing area? $\endgroup$
    – Roger Wood
    Feb 7 at 3:52
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    $\begingroup$ @RogerWood sounds like a good question post, unless it's answered in Early high-inclination crewed flights $\endgroup$
    – uhoh
    Feb 7 at 11:18
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    $\begingroup$ @uhoh thanks for the pointer. There are some speculations that are probably correct, but nothing definitive. I notice now that even ISS seems to be at a higher than necessary inclination. $\endgroup$
    – Roger Wood
    Feb 7 at 19:29
  • $\begingroup$ @RogerWood - Higher than necessary? IIRC it was put that way to avoid China. $\endgroup$ Feb 9 at 8:41

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It looks like the answer is 65.09 degrees with the winner being Valentina Tereshkova in Vostok 6.

Manned spacecraft generally move in relatively circular orbits except during launch and re-entry and the occasional dogleg maneuver. For circular orbits the maxima in latitude are exactly equal to the orbital inclination.

The Vostok capsule held a single occupant. The series included Vostok 1 (Yuri Gagarin). It is speculated that the high orbital inclination was selected to avoid Gagarin's single orbit from overflying the USA, Europe, or China. In any case it is advantageous to launch spy satellites into high inclination orbits. The Baikonur launch site allows for debris to fall on a corridor stretching East-North-East towards the Altai mountains. All of the Vostok launches were close to 65 degrees inclination, with Vostok 6 being the highest.

Today's Soyuz launches are still at a high inclination of 51.66 degrees. This matches the orbital inclination of ISS, which is presumably one reason this orbit was chosen for the ISS.

Valentina Tereshkova's flight lasted about three days during which she did 48 orbits that would have taken her close to the arctic circle and over cities like Helsinki and Reykjavik. The capsule did have two very small windows.

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    $\begingroup$ The Soviets launched at 51 to not overfly or drop things on China. All their previous space stations were at this inclination or close to as well. The ISS inclination is to accommodate the Russians, as previously SSF was supposed to be at 28 degrees IIRC. $\endgroup$ Feb 9 at 8:26
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    $\begingroup$ Russians had proposals for much higher inclinations for their next space stations but I think its some time before we see that... $\endgroup$ Feb 9 at 8:29
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    $\begingroup$ Astronautix lists Vostok 6 inclination as 64.9 astronautix.com/v/vostok6.html but still appears to be the winner $\endgroup$ Feb 9 at 15:09
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    $\begingroup$ @Organic Marble Yes, there seem to be various numbers. Even the Wikipedia article quotes 64.9 under 'mission parameters' then 65.09 under 'orbital parameters'. Maybe that's planned vs. actual? The NASA website quotes the inclination to 3 decimal places whch is 250 meters, which maybe is possible: nssdc.gsfc.nasa.gov/nmc/spacecraft/… $\endgroup$
    – Roger Wood
    Feb 9 at 20:20

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