The Mars Rocket (Die Marsrakete) (1956)

This one is not a book but does have some very nice space art in it.
Die Marsrakete (1956). Instead it is one of the many children's story records that were issued in the 1950s and 1960s.  Record players moved from the living room to the playroom in the 1950s and children had a vast number of records intended just for them.

Once again I do not read German but can get a sense of the storyline from the illustrations.  First of course are children given the opportunity to ride on a rocket. In some stories they sneak on and in others a friendly scientist "uncle" invites them on a trip.

From the expression on the rocket professor's face it looks like he was not planning to launch these boys to Mars. I will guess they snuck aboard or were accidently launched.

Luckily (this was the early space age) something went wrong and instead of going to Mars the rocket capsule came down in the Middle East.  I might not have called this "Mars Rocket" but rather "an unexpected rocket trip". But even with false advertising the images are very beautiful.