The Douglas GAM-87 Skybolt (AGM-48 under the 1962 Tri-service system) was an air-launched ballistic missile (ALBM), equipped with a nuclear warhead, developed by the United States during the late 1950s. The UK joined the program in 1960, intending to use it on their V bomber force. A series of test failures and the development of submarine-launched ballistic missiles (SLBMs) eventually led to its cancellation in December 1962. The UK had decided to base its entire 1960s deterrent force on Skybolt, and its cancellation led to a major confrontation between the UK and US, known today as the "Skybolt Crisis". This was solved during a series of meetings that led to the Royal Navy gaining the UGM-27 Polaris missile and construction of the Resolution class submarines to launch them.