Windows 7: How to use Bitlocker-to-go

As a computer engineer, how do I recover data from a bitlocked hard disk if the drive cannot boot into the OS, either because it is faulty or because the host computer hardware has failed?

If the hard drive (or removal storage) is so damaged that the file system is corrupt and data recovery techniques which bypass the FS have to be used, how do you decrypt the individual files recovered?

Can any of this be done without the password or Recovery Key?

Chippy