Knowing the missions for which her supersoldiers would be used, Doctor Catherine Halsey was aware of the risk that the spartans would, sooner or late, lose body parts in the line of duty, and thus set out to create prosthetics that would be able to mimick - and in some areas improve - the capabilities of Spartans' lost body parts. She also hoped that it would allow for crippled spartans to get back up to combat-ready status. Her studies were approved by HIGHCOM and codenamed THERMOPYLAE.