In the previous article, we talked about the Apollo program and Apollo Missions from (1-7). In this article, we will take a look at Apollo 8.
While Apollo 11, landed the man on the moon and got all the glory, it was Apollo 8 that had cleared the path of most of the obstacles and shown that it was ‘possible’.
Apollo 8 was the second crewed spaceflight mission of the Apollo space program, the first having been Apollo 7 which stayed in Earth orbit. Apollo 8 was launched on December 21, 1968, and became the first crewed spacecraft to leave low Earth orbit, reach the Moon, orbit it, and return.
The three-astronaut crew—Frank Borman, James Lovell, and William Anders—were the first humans to fly to the Moon, to witness and photograph an Earthrise, and to escape the gravity of a celestial body.
Apollo 8 took 68 hours (almost three days) to travel the distance to the Moon. The crew orbited the Moon ten times over the course of twenty hours, during which they made a Christmas Eve television broadcast in which they read the first ten verses from the Book of Genesis. The Apollo 8 astronauts returned to Earth on December 27, 1968, when their spacecraft splashed down in the northern Pacific Ocean.
The Apollo spacecraft had three primary components: a command module (CM) with a cabin for the three astronauts, and the only part that would return to Earth; a service module (SM) to provide the command module with propulsion, electrical power, oxygen, and water; and a two-stage lunar module (LM), which comprised a descent stage for landing on the Moon and an ascent stage to return the astronauts to lunar orbit.
This configuration was launched by the Saturn V rocket that was then under development.
The Apollo 8 crew were the first humans to pass through the Van Allen radiation belts, which extend up to 15,000 miles (24,000 km) from Earth. Scientists predicted that passing through the belts quickly at the spacecraft’s high speed would cause a radiation dosage of no more than a chest X-ray, or 1 milligray (mGy; during a year, the average human receives a dose of 2 to 3 mGy).
To record the actual radiation dosages, each crew member wore a Personal Radiation Dosimeter that transmitted data to Earth, as well as three passive film dosimeters that showed the cumulative radiation experienced by the crew. By the end of the mission, the crew members experienced an average radiation dose of 1.6 mGy.
When the spacecraft came out from behind the Moon for its fourth pass across the front, the crew witnessed an “Earthrise” in person for the first time in human history. NASA’s Lunar Orbiter 1 had taken the first picture of an Earthrise from the vicinity of the Moon, on August 23, 1966. Anders saw the Earth emerging from behind the lunar horizon and called in excitement to the others, taking a black-and-white photograph as he did so. Anders asked Lovell for color film and then took Earthrise, a now-famous color photo, later picked by Life magazine as one of its hundred photos of the century.
Due to the synchronous rotation of the Moon about the Earth, Earthrise is not generally visible from the lunar surface. This is because, as seen from any one place on the Moon’s surface, Earth remains in approximately the same position in the lunar sky, either above or below the horizon. Earthrise is generally visible only while orbiting the Moon, and at selected surface locations near the Moon’s limb, where libration carries the Earth slightly above and below the lunar horizon.