C’ earth parking orbit duration is a variable

See list attachedNovember 5, 196868-PA-T-242APA/Chief, Apollo Data Priority CoordinationC’ earth parking orbit duration is a variable

This note is just to make sure everyone is aware of the rather sigini- ficant variation in the time between earth orbit insertion (EOI) and translunar injection (TLI) on the C' mission, depending on day and azimuth of launch. This came as a surprise to me and may have some impact on what you are doing. According to Ron Berry, the time from EOI to TLI ignition is 2 hours and 42 minutes at the start of the December 20 launch window and decreases to 2 hours and 28 minutes at the end. On the last day of the launch window, December 27, this time period starts at 2 hours and 22 minutes and shortens at the end of the window to 2 hours and 7 minutes. All these numbers, of course, are for the first TLI opportunity. It may be desirable to perform a simulation with the shorter duration earth parking orbit just to make sure everything goes together properly. The poorer ground coverage and shortened crew timeline may give some trouble if it hasn't been thought out in advance.