ĭuring communications for a countdown, the launch team uses acronyms to keep channels open as much as possible. When that happens, launch personnel begin following the countdown checklist from the earlier point.
Under some circumstances, a countdown may be recycled to an earlier time. Some holds are planned: they are done so the launch-support computers can run automatic checks on the rocket.
This can be done to investigate a technical process that has gone wrong, or because of marginal weather at the launch pad. Ī hold is the suspension of the normal countdown process. The launch window is a precise time during which aerospace personnel launch a rocket so the payload can reach the proper orbital destination. A formal prelaunch weather briefing was held on Launch minus 1 day, which was a specific weather briefing for all areas of Space Shuttle launch operations. These included weather trends and their possible effects on launch day. Air Force Range Weather Operations Facility at Cape Canaveral began at Launch minus 5 days in coordination with the NOAA National Weather Service Spaceflight Meteorology Group at the Johnson Space Center in Houston. For the Space Shuttle, weather "outlooks" provided by the U. The criteria are broadly conservative and assure avoidance of possibly adverse conditions. The launch weather guidelines involving the Space Shuttle and expendable rockets are similar in many areas, but a distinction is made for the individual characteristics of each. Proceeding with the countdown depends on several factors, such as the proper launch window, weather that permits a safe launch, and the rocket and payload working properly.Ĭountdown clock at NASA's Kennedy Space Center at L-11 hours (28 April 2011) of STS-134, Space Shuttle Endeavour. Each mission requires approximately 100 procedure books. These documents are living documents, which reflect new issues and solutions as they develop. Rosie Carver, a technical writer for United Launch Alliance, has created at least 15,000 procedures for more than 300 missions since the Solar Maximum Mission, which launched Feb. For the Space Shuttle, a five-volume set, Shuttle Countdown (KSC S0007), often referred to as "S0007", was used. The procedures for each launch are written carefully. Security personnel prevent unauthorized persons from entering the "keep-out" area.Launch personnel monitor the weather and wait for the launch window.Launch-center computers communicate with sensors in the rocket, which monitor important systems on the launch vehicle and payload.Aerospace personnel bring the rocket vehicle to the launch site and load it with payload and propellants.
Depending on the type of vehicle used, countdowns can start from 72 to 96 hours before launch time. By that time everything that needs doing has been done, and therefore everybody has twenty minutes in which to think of what may not have been done, or else what could possibly go wrong.Ī countdown is a carefully devised set of procedures ending with the ignition of a rocket's engine. People involved in countdowns always say that the last twenty minutes are the worst.
10 minute countdown clock movie#
One of the first known associations with rockets was in the 1929 German science fiction movie Frau im Mond (English: Woman in the Moon) written by Thea von Harbou and directed by Fritz Lang in an attempt to increase the drama of the launch sequence of the story's lunar-bound rocket. An early use of a countdown once signaled the start of a Cambridge University rowing race. Other events for which countdowns are commonly used include the detonation of an explosive, the start of a race, the start of the New Year, or any anxiously anticipated event. NASA commonly employs the terms "L-minus" and "T-minus" during the preparation for and anticipation of a rocket launch, and even "E-minus" for events that involve spacecraft that are already in space, where the "T" could stand for "Test" or "Time", and the "E" stands for "Encounter", as with a comet or some other space object. 2015 FIFA Women's World Cup countdown at Champlain Place, Dieppe, New BrunswickĪ countdown is a sequence of backward counting to indicate the time remaining before an event is scheduled to occur. For the Canadian hip-hop producer, see T-Minus (record producer).
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