The poem can be translated as:
Listen as you like, look around as you wish;
We are on the summit of the branches;
More than half way away from earth;
More than half way close to the moon.
The comical effect of ignoring what the poem is really about (being old) and putting somebody on a tree literally between earth and moon is just funny and this is what the painting is about.
The poem references the branches of a tree as the choices we make in life, as you reach the top of the tree, there is no more any possibility of leading anywhere else. The journey of life is at a dead-end; too far away from where it started yet not close enough to the final destination, and nowhere else to go and nothing else to do in between but to sit and wait.
However, this juxtaposition becomes more playful as the astronaut finds himself planted on his spaceship, which does not seem very functional and it looks as though he will probably be sitting there for a long time. However, this does not bother him: he is just sitting there, swinging his legs and watching the moon. So his message is “enjoy life”…
P.S. The spacecraft is similar to the space capsules on a return trip from the moon, not on their way to the moon. For the art critics who can overload this detail with different interpretations, I have to admit that there is no hidden meaning and the whole thing is technical. The capsule is conical, simple and blends nicely with the roots of the tree. This is the reason…