Successful reverse-engineering of Covenant technology has been difficult for the UNSC, primarily because of the Covenant's own poor understanding of the technologies they use. Human researchers often don't know if the applications to which the Covenant put their equipment were the original intent of its originators, the Forerunners, and a good deal of research has been simply guesswork - but very good guesses. The most well-known and successful technology that has resulted from this process is the MJOLNIR energy shield generators, which have formed the basis for all post-Reach shield technology - but they are certainly not the only success story the Navy has seen.