re: The Novellas
The Sentinel (discovery of a pyramid on the Moon)
Breaking Strain (a cargo ship the Star Queen is hit by a meteorite and there isn't enough oxygen for 2 astronauts before they reach Venus).
Encounter in the Dawn (a crew lands and its robot feeds awareness to a native)
From the other side of the sky: Take a deep breath.
All those short stories were published before 1964 when Sir Arthur started to concentrate on the movie.