Eu li este livro infantil em 1964 ou 1965.
No romance em questão, um ou dois meninos encontram um disco de metal que martelam no nariz de uma nave espacial do quintal que construíram, dando a capacidade de sair da atmosfera da Terra. Ele ou eles são acompanhados no espaço por um ser extraterrestre que perdeu o disco de metal na Terra. Tanto quanto me lembro, o ser alienígena era do planeta (imaginário) "Eyopee".
Este poderia ser Nave espacial de Rusty (1957) por Evelyn Sibley Lampman?
There was no way for Rusty Adams to know that the shiny metal disc he had found at the city dump and used on his play space ship in the garage, was actually the flying saucer of the Mighty Gwump of Eopee in Adromeda Galaxy. When tiny Tiphia, Gwump's messenger, arrived to claim it, Rusty and his playmate Susan Northrup found themselves taking an unexpected trip to all of the planets, except Neptune and Plato. Rusty and Susan save Tiphia from attack by ants and other hazards as he vainly tries to find the moon, Eopee. It's Rusty who realizes finally that Tiphia is simply in the wrong galaxy. This is a Baedeker of Outer Space.