I’m looking for a vaguely remembered children’s book. It’s a picture book. I can’t reconstruct the whole plot but it had the following elements:

– EITHER a martian, extra-terrestrial or man-in-the-moon visiting earth, OR a boy that wants to fly to space. The former is more likely.

– This protagonist is reminded of his planet or the moon or the sun by seeing a balloon, and maybe also other round objects throughout the book.

– There is definitely a scene, towards the end of the book, where the protagonist walks back to his space vessel in the evening sun or moon.

– I remember the book had a melancholic feel. Maybe the protagonist is homesick or something. It was NOT a spectacular book on space travel. The martian is not scary, but cute and a little sad.

– It must predate 1983, possibly a book from much earlier (60s?) that my mother purchased at a library that got rid of old books.