waider | seeking book (Reply)

I've a vague memory of a book I read back in primary school - that would be twenty years ago plus change - which I am having trouble recalling useful details of, such as author or title. If you can help, I'd appreciate it. The book concerns a school kid who wins a prize, in a quiz if I recall correctly. The prize is a trip into space. Events in the book include hanging out with the guy who first landed on Mars (I think; hopefully this isn't a confusion with a William Gibson short story), where he met some sort of alien life form; travelling around the far side of the moon, getting refuelled from "the Hipparchus Launcher" - a maglev railgun used to hurl cargo into lunar orbit - and finding an abandoned canister with a skull and crossbones on it floating out in space. If any of this rings a bell with you, lemme know. The only useful phrase from the book I can remember is "Hipparchus Launcher" and that's drawing a blank on Amazon and Google, which is hardly surprising for a book that's over twenty years old and probably not up there with the classics of SciFi.