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Apollo 8 launched on December 21, 1968, and was the second crewed spaceflight mission flown in the United States Apollo space program (the first, Apollo 7, stayed in Earth orbit). Apollo 8 was the third flight and the first crewed launch of the Saturn V rocket.
Their one-way delta-v budgets from LEO range upwards from 3.8 km/s (12,000 ft/s), which is less than 2/3 of the delta-v needed to reach the Moon's surface. [10] But NEOs with low delta-v budgets have long synodic periods , and the intervals between times of closest approach to the Earth (and thus most efficient missions) can be decades long.
Sketch of a circumlunar free return trajectory (not to scale), plotted on the rotating reference frame rotating with the moon. (Moon's motion only shown for clarity) In orbital mechanics, a free-return trajectory is a trajectory of a spacecraft traveling away from a primary body (for example, the Earth) where gravity due to a secondary body (for example, the Moon) causes the spacecraft to ...
Launch of AS-506 space vehicle on July 16, 1969, at pad 39A for mission Apollo 11 to land the first men on the Moon. The Apollo program was a United States human spaceflight program carried out from 1961 to 1972 by the National Aeronautics and Space Administration (NASA), which landed the first astronauts on the Moon. [1]
The basic orbit determination task is to determine the classical orbital elements or Keplerian elements, ,,,,, from the orbital state vectors [,], of an orbiting body with respect to the reference frame of its central body. The central bodies are the sources of the gravitational forces, like the Sun, Earth, Moon and other planets.
The first crewed Apollo missions occurred in 1968. It was also the year in which Earth lifeforms first left low Earth orbit, during the successful Zond 5 mission to the Moon and the Zond 6 lunar mission which crashed upon return, and the year that humans first left low Earth orbit, during the successful Apollo 8 mission to the Moon.
For the Apollo lunar missions, TLI was performed by the restartable J-2 engine in the S-IVB third stage of the Saturn V rocket. This particular TLI burn lasted approximately 350 seconds, providing 3.05 to 3.25 km/s (10,000 to 10,600 ft/s) of change in velocity , at which point the spacecraft was traveling at approximately 10.4 km/s (34150 ft/s ...
Orbital mechanics are used to calculate flight in orbit about a central body. For sufficiently high orbits (generally at least 190 kilometers (100 nautical miles) in the case of Earth), aerodynamic force may be assumed to be negligible for relatively short term missions (though a small amount of drag may be present which results in decay of ...