First Spaceship on Venus

This 1960 film is an East German-Polish co-production originally titled Der Schweigende Stern. Two years later it was trimmed by about 15 minutes and dubbed into English for American release. It's sometimes known as The Astronauts which is the literal translation of the title of the novel that's based on: Astronauci, the first novel by Polish sf master Stanislaw Lem.
Sometime in the future (well, in 1985), scientists analyzing debris of the 1908 Tunguska meteor discover that it was actually a spaceship that exploded just before landing and that some of the debris is actually some sort of recording device. Its origins are traced to the planet Venus, an international expedition takes off on a spaceship for the planet, but en route they finally decipher the recordings. The Venusians had planned to attack the Earth, and this leaves the crew with a fateful decision. Do they continue on and try to make contact?
This is a great little film. What's really interesting is that the cast is multi-racial; in fact many of the lead scientists are distincly non-white, as opposed to the usual all-white casts of American sf of the time. (I could have done without the cute robot.) The special effects are sometimes a little cheap, but for the most part this is a good looking film with some stunning and arresting visuals, and excellent sets. And most importantly for an sf film, it's full of great ideas.
Lem has had other works adapted into film, most notably his novel Solaris, made into a film in 1972 and again in 2002, but if you haven't read any Lem, you really should. He's often been compared to a cross between Douglas Adams and Franz Kafka, with a little Kurt Vonnegut chaser. He wrote "straight" sf, of which Astronauci whould be an example, but I've been more partial to and highly recommend his more allegorical works like The Star Diaries, The Cyberiad, and Memoirs Found in a Bathtub.
Lem passed away in 2006.