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Against the background of the "Cold War", US President J.F. Kennedy announced in 1961, for the obvious reason of gaining prestige, that the United States would dedicate this decade to bringing a man up to the moon and returning him to Earth. The job was handed over to NASA, the United States' civilian Agency for Space Exploration.
The NASAs conquest of the moon was divided in three programs: the Mercury Program and the Gemini Program, whichs purpose it was to test the limits of NASAs space vehicles and to train astronauts for the final Apollo Program.
. The Mercury Program
The Mercury program was the earliest NASA project to put an astronaut into space. It utilized one-person, bell-shaped capsules that were boosted into orbits 161 to 283 km above the Earth. The capsules reentered the atmosphere ballistically, and parachutes were deployed on the final descent to ocean splashdown. The capsules were then recovered by U.S. naval vessels and helicopters. The project successfully flew two suborbital and four orbital manned missions.
The project cost slightly more than $400 million and involved the technical skills of more than 2 million men and women in the research, development, and testing of the spacecraft, its launch vehicles, and a worldwide tracking and communications network.
Although manned spaceflight had been studied since the late 1940s, serious development of a manned satellite was not considered by Congress until after the Soviet Union launched Sputniks 1 and 2 in October and November 1957. In March 1958, the NACE proposed a wingless, manned satellite that could follow a ballistic path to reenter the atmosphere without exposing the crew to excessively high temperatures or dangerous acceleration. The chief points of this proposal were incorporated into the Mercury program.
The size and weight of the Mercury spacecraft were dictated by the lifting capability of the intercontinental ballistic missiles of the US Army. The capsule was designed to weigh less than 1,350 kg, because the lifting capacities of these missiles was limited.
The astronaut reclined on a contour couch designed to provide protection from accelerations of as much as 20 gravities.
The attitude, or position, of the capsule was controlled by an array of 18 hydrogen-peroxide gas thrusters. These could pitch the spacecraft up or down, yaw it left or right, or roll it. The pilot could fire them by means of a hand controller or leave attitude control to an autopilot.
Following the launch, the most critical part of the flight was the firing of the braking rockets. The pilot was required to put the capsule in a precise attitude for retrofire in order to land in the sea near the recovery ships.
During 1960-61, the Mercury capsule was launched by a Redstone missile on a series of suborbital flights that tested the integrity of its structure and the effectiveness of the launch escape tower. The tower contained a powerful rocket that would pull the spacecraft away from the launch vehicle in the event the launcher failed during liftoff. It was activated only once, when the Redstone launcher failed in November 1960. The tower rocket pulled the spacecraft high above the Atlantic Ocean so that it could parachute into the water.
One of the first Mercury flights took a 17-kg chimpanzee named Ham on a suborbital flight, from which he was recovered unharmed.
During other manned suborbital flights the control systems of the spacecraft were tested.
Following a series of Mercury unmanned orbital test flights Lt. Col. John H. GLENN, Jr., flew a three-orbit (4 hr 55 min) mission (1962) in the spacecraft he named Friendship 7. As the first American to fly in orbit, Glenn received a hero's welcome on the same scale as that accorded Charles A. Lindbergh after his New York-Paris flight in 1927.
Project Mercury ended with a 22-orbit (34 hr 20 min) flight in 1963.
Four years and 10 months after NASA was created, the first American manned space program had been completed.
. The Gemini Program
The Gemini program was a series of piloted spaceflights in the mid-1960s. The series was authorized by Congress in 1961 as an intermediate step, between the Mercury Program and the Apollo Program, in the U.S. effort to land on the Moon. It was called Gemini, which means \"twins\" in Latin, because each piloted flight carried two astronauts into orbit.
The earlier Mercury program had demonstrated that a trained astronaut could fly in orbit for up to 34 hours. The NASA next had to determine whether trained crew members could endure the weightlessness of orbital freefall long enough to survive a journey to the Moon and back. This was one important objective of the Gemini program. Others were to develop rendezvous and docking techniques needed for the lunar mission and to train personnel in their use.
A highly maneuverable spacecraft was required, with an elaborate life-support system that could maintain a crew for up to 14 days. A NASA team designed a two-person spacecraft, that fulfilled all the needs it was created for. Within five years, the program had achieved all of its objectives. Its total cost was $1,283,400,000, including $797,400,000 for the spacecraft, $409,800,000 for launch vehicles, and $76,200,000 for support facilities. The flight series used the $79,900,000 global tracking and communications network established in Project Mercury.
The first piloted Gemini mission, Gemini 3, was flown in March 1965. Five days earlier, the Soviet cosmonaut Aleksei Leonov had spent ten minutes outside Vokshod 2 in the first demonstration of extravehicular activity (EVA) during orbital flight. This feat was duplicated in June on the four-day, 62-orbit flight of Gemini 4. The NASA astronaut remained outside for 20 minutes in a 14-kg space suit designed for EVA.
The program also attempted to achieve rendezvous and docking with another vehicle in orbit. The original plans called for a Gemini spacecraft to dock with an AGENA rocket. The first attempt was canceled in October 1965, when the Agena blew up after having been launched by an Atlas missile. After an unsuccessful effort during which the launch rocket sputtered but did not lift off, Gemini 6 was sent into orbit in December 1965.
Meanwhile, the Gemini 7 spacecraft had been launched and it was decided that Gemini 7 would serve as the vehicle with which Gemini 6 would rendezvous. Gemini 6 was piloted within one foot of Gemini 7 on December 15. This was the first successful rendezvous in space. The crew of Gemini 7 went on to set a new endurance record in space: they made a controlled landing in the Atlantic on December 18, 1965, after 330 hours and 35 minutes in orbit. Their mission proved that trained men could endure a round trip to the Moon. On its 220 orbits of the Earth, Gemini 7 had flown 20 times the distance to the Moon.
Rendezvous and docking with an Agena target rocket was achieved on March 16, 1966, during the mission of Gemini 8, by NASA astronaut Neil A. Armstong. The mission was abruptly terminated, however, when a malfunction in the Gemini "Orbital Attitude and Maneuvering System" thrusters forced the crew to undock and make an emergency landing in the western Pacific Ocean.
Overheating and face-plate fogging, which had interfered with early EVA (extravehicular activity) efforts, were overcome by Air Force Maj. Edwin E. "Buzz" Aldrin, Jr., on the flight of Gemini 12. After he and Lovell docked with an Agena rocket, Aldrin succeeded in performing 2 hours and 9 minutes of continuous work outside the spacecraft. The splashdown of Gemini 12 on Nov. 15, 1966, ended the program.
. The Apollo Program
The Apollo program was the successful conclusion of the NASAs effort to achieve, within the decade, the goal of landing a man on the Moon and returning him safely to Earth. It followed the Gemini manned-flight program conducted in 1966-67 to develop the necessary techniques of orbiting, docking, and extravehicular activity (EVA). The main elements of the Apollo project were the three-man Apollo spacecraft; the two-man Lunar Excursion Module or Lunar Module and the Saturn family of rockets. These units made up the first manned, interplanetary transportation system. Using this system, astronauts landed on the Moon, where they explored and collected samples at six sites on the near side between July 1969 and the end of December 1972. The total cost of developing and operating the Apollo-Saturn transportation system in the lunar program was $25 billion.
Between October 1968, when the Apollo-Saturn transportation system underwent its first full space test, and July 1975, when it was used for the last time, the NASA launched 15 manned Apollo-Saturn flights. During the testing period three fatalities occurred on the launchpad at the Kennedy Space Center, Florida, but none in actual flight.
Launched July 16, 1969, Apollo 11 made the first manned lunar landing on July 20. As Lt. Col. Michael Collins orbited the Moon in the mother ship Columbia, Neil Armstrong and Col. Edwin E. Aldrin, Jr., touched down in a region called "Sea of Tranquility", in the Lunar Module Eagle with the historic report: "Houston, Tranquility Base here. The Eagle has landed." Armstrong was the first out. Dropping the last meter from the ladder, he said: "That\'s one small step for {a} man, one giant leap for mankind" (NASA later reported that the word "a" had been lost in transmission).
On the Moon, Armstrong and Aldrin erected the American flag and set up scientific instruments, including a laser beam reflector, a seismometer that later transmitted evidence of a moonquake, and a sheet of aluminum foil to trap Solar Wind particles. The astronauts took soil and rock photographs and collected 24.4 kg of rock and dirt samples. Armstrong, the first out and the last back into the Lunar Module, spent 2 hours and 13 minutes outside. After Armstrong and Aldrin returned to Columbia in the ascent stage of the Eagle, Collins fired the Apollo main engine and lifted the vessel out of lunar orbit for the return to Earth. The ascent stage of the Eagle was left in lunar orbit. The crew landed in the Pacific Ocean on July 24, 1969, reaching the NASAs goal of visiting the moon within the 60's.
After the successful moon landing of Apollo 12, where 33.9kg of rocks were picked up and returned to Earth, the Apollo 13 mission failed.
Two days after Apollo 13 was launched in 1970, an oxygen tank exploded in the Service Module and crippled the vessel\'s power and life-support systems so badly that a planned landing in the Fra Mauro formation of the Moon was canceled. The crew used the descent engine of the Lunar Module Aquarius to accelerate the crippled spacecraft around the Moon and back to Earth. Using Aquarius as a lifeboat, they returned to the vicinity of Earth, entered the Command Module, and landed it safely on April 17. Investigation showed that a thermostatically controlled switch had failed and allowed the oxygen tank to overheat.
The Apollo Program, which started during a time of intense competition between the United States and the USSR, ended in a demonstration of detente in space: a joint orbital flight of the Apollo and Soyuz spaceships, known as the Apollo-Soyuz Test Project. Technically, the joint mission in low Earth orbit demonstrated intership crew transfer and space rescue. The total cost to NASA of the Apollo-Soyuz Test Project was $250 million.
The vessels docked over a spot in the Atlantic Ocean some 1,030 km west of Portugal on July 17, 1972. During the next two days, the crews made four transfers between the two ships and completed five planned experiments. The nine-day mission was the last one of the Apollo program.
Eleven missions of the Apollo Program were missions in the lunar landing program, including two test flights in low Earth orbit, two test flights in lunar orbit, six landings, and one circumlunar flight, during which the planned landing was aborted (Apollo 13).
The question, why the U.S. put a man on the moon before the USSR did, is easy to answer: The USSR had powerful boosters at their disposal and therefore didn't need to minimize the weight of their spacecrafts. The NASA benefited from the low weight of their spacecrafts, which made it possible to build the Lunar Module, which could land and then take off from the Moon's surface.
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