In many shots, Earth and its moon can be seen, but their positions and approximate distances to each other and to the space station keep changing from shot to shot, sometimes with Earth and its moon missing between wide shots and close-ups of the same scene.
The perception that Ben uses the sonic powers of Echo Echo to move himself and a projectile through space is a mistake because sound waves cannot pass through the vacuum of space is, in itself, an error, since it is neither shown nor said how Ben, as Ultimate Echo Echo, moves through space. Apparently, it was his strong jump which propelled him and the nuclear fusion grenade through a reinforced space station window and into space. The real question is how Echo Echo's sound waves, now that they ARE in the vacuum of space, continue to keep the nuclear fusion grenade's detonation contained. In addition, Ultimate Echo Echo comes to a stop before hurtling the nuclear fusion grenade far away to explode safely. Due to the physics of equal and opposite reactions, he should not have come to a stop and should have, instead, used those mighty reinforced-glass-shattering legs of his to hurtle the grenade away into space in the precise direction as to send him shooting back to the space station.