The four standard times officially used in the USA to record space shuttle launches and landings. Those at the Kennedy Space Center in Florida occur during Eastern Standard Time (EST) from 2 am on the last Sunday in October until 2 am. on the first Sunday in April. They happen during Eastern Daylight Time (EDT) the rest of the year. Landings at Edwards Air Force Base in California occur during Pacific Standard Time (PST) from 2 am on the last Sunday in October until 2 am the first Sunday in April. The rest of the year they happen during Pacific Daylight Time (PDT).
EST is five hours behind Universal Time Coordinated (UTC); PST is three hours behind EST and eight hours behind UTC.