Jirachi is not catchable in any game, he has to be recieved from a Nintendo Event. If you have Diamond or Pearl, look in the trade forum. Jirachi are very common there.
As for Deoxys, you don't go to space to catch him, rather you dowload a special ticket from a Nintendo event, which gets placed in your bag on the game. You can then take a boat to said island, where Deoxys will be waiting after completing a simple puzzle.