Of course during the war his work on rockets was classified information, but once the war was over the information was declassified and Rankin was released early from his war service on the condition that he wrote up the theoretical work which he had done on rockets.
Ng mga kurso sa panahon ng digmaan kanyang trabaho sa rockets ay na-uri-uri ng impormasyon, ngunit sa sandaling ang digmaan ay sa paglipas ng impormasyon ay declassified at Rankin ay inilabas mula sa maagang bahagi ng kanyang digmaan serbisyo sa kondisyon na siya wrote up ang panteorya trabaho kung saan siya had tapos na sa rockets.