The US Army started their first serious efforts in the anti-ballistic missile arena when they asked the Bell Labs missile team to prepare a report on the topic in February 1955. The Nike team had already designed the Nike Ajax system that was in widespread use around the US, as well as the Nike Hercules that was in the late stages of development as the Ajax's replacement. They returned an initial study on Nike II in January 1956, concluding that the basic concept was workable using a slightly upgraded version of the Hercules missile, but requiring dramatically upgraded radars and computers to handle interceptions that took place at thousands of miles an hour.