Posted 07 July 2011 - 08:51 PM
Though Frieza stated that Goku could not survive in the vacuum of space, and most of the series has him wearing a spacesuit when venturing into the vacuum of space, there have been several instances where Saiyans have been in airless environments with no ill consequences. Early in the series, Goku took Monster Carrot to the moon. Towards the beginning of the Vegeta Saga, both Vegeta and Nappa were seen outside of their Saiyan pods while Vegeta destroyed Arlia. In Bardock - The Father of Goku and a flashback in the Frieza Saga (both in the anime and the manga), Bardock was seen in orbit of Planet Vegeta when confronting Frieza. During a flashback in the Android saga, Vegeta can be seen training on an asteroid, which would be impossible to have oxygen on, right before becoming a Super Saiyan. Finally, in a flashback in the movie Dragon Ball Z: Broly - The Legendary Super Saiyan, both Broly and Paragus are seen in an asteroid field. It could be possible that Frieza was bluffing and Saiyans could breathe in space, since Goku grew up on Earth, even he would have not known about that. Though King Kai seems to also believe Saiyans can't breathe in space as he instructs the Z Warriors not to revive Goku with the Dragon Balls, because he would appear in space, where he would have died instantly from lack of oxygen. A plausible explanation is that saiyans do, indeed, need air to breath, but, due to their superior cardiovascular conditioning, are able to hold their breath for long periods of time, but still need a source of air to retreat into, after a few minutes, which Goku would not have, after Planet Namek had exploded.