Studies in the early 1960's indicated that if the hold exceeded 2 hours, the launch would probably be scrubbed for that day. If the daily launch window were missed, the mission would not necessarily have to be delayed for a month. A monthly launch window allowed the mission to be quickly rescheduled. ![]() The mission would not have to be rescheduled to another day if the daily launch window was larger than the cumulative delays or holds. A daily launch window allows for delays or holds that may occur during the countdown. It is obvious that for operational flexibility it was highly desirable to have as large a launch window as possible, both daily and monthly. Only the effects on the launch phase, of providing a launch window will be described in this section. For example, a monthly launch window could cover a 7 day period, but a daily launch window may not exist for some of the intermediate days within this period. The daily window was continuous from opening to close but a monthly window may have had gaps. Monthly window which consisted of a few days during a given month or lunar cycle.Daily window which had a duration of a few hours during a given 24 hour period. ![]() Launch windows were defined for two different time intervals: The mission planning considerations for the launch phase of the Apollo lunar mission were related primarily to launch 'windows', launch vehicle performance, and contingency planning. In order to fully understand the mission planning considerations and the effects of the various constraints, we need to look closely at the trajectory characteristics.Īn understanding of the interrelation of operational constraints and trajectory shaping is essential to understand the limitations placed on the launch opportunities.Įach mission phase will be described in flight order commencing with the launch phase. These accessible landing area limitations combined with operational constraints to limit launch opportunities to certain specific periods. Trajectory geometry constraints and spacecraft performance capabilities combined to limit the accessible area on the moon. To arrive at this landing site with the right lighting conditions for the descent and approach a journey must be planned that meets the various constraints that affected the Apollo lunar mission planning, primarily in the form of trajectory shaping and the limitation of launch opportunities, known as launch windows. The location of the launch site (for Apollo this was launch complex 39 at KSC) and the landing site you are aiming for on the moon. ![]() When launching to land on the moon there are two fixed parameters. Where shall we go? Copernicus, Gassendi, Marius Hills? Let choose along the way. Apollo lunar landing launch window: The controlling factors and constraints
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