Actually, Habeas Corpus has nothing to do with Graves.
It translates into English as "You have the body" or (depending on the tranlation) some variation of that phrase.
HC is the right of an inmate to challenge the legallity of his detention.
http://www.google.co.uk/search?hl=en&safe=off&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=define%3A+habeas+corpus&spell=1...
The closest it gets to being about graves is the Laurel and Hardy short film "habeas corpus" where they play a pair of grave robbers
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BUT this has nothing to do with the topic at hand. The ability to fly backwards is IMHO something very useful.
Colony Wars, uses it. and the result is deadly to my opponents.
TBP uses it, just as good results...Though my main gripe is this:
*travelling forward, your max speed is say 90m/s. When travelling in reverse, as far as i know you cant fly backwards at that speed. You should be able to do this, i've seen starfuries do this in the show.
Diaspora, no idea if it uses reverse thrust...Should do as i've seen the vipers travelling backwards on the show