Yes, it's preferable to have solid propellant missiles. But that does not mean it's impossible to use liquid, and even cryogenic liquid fueled rockets for deter

Yes, it's preferable to have solid propellant missiles. But that does not mean it's impossible to use liquid, and even cryogenic liquid fueled rockets for deterrence missions. The first American ICBM, Atlas, used liquid oxygen, and was used for 7 years. Its contemporaneous soviet counterpart, the R-7 Semyorka, also used liquid oxygen and was in service for 9 years.