Errors in both lists of firsts:

First satellite of Mars was Mariner 9, it may have been launched after Mars 2 but it got there first.

Plenty of satellites in polar orbit before Nimbus 1. Depending on whether Discoverer 1 was a launch failure or not, first was either Discoverer 1 or Discoverer 2, five years before Nimbus 1.

First EVA between two manned spacecraft was Soyuz 4/Soyuz 5, a few months before Apollo 9.

Pioneer 10 was first to Jupiter, Pioneer 11 was first to Saturn, Voyager 2 first to Uranus and Neptune.

First lunar soft landing and orbit were different spacecraft (Luna 9 and Luna 10).

You could give the US the first Mercury, comet and asteroid missions, too.

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