Project Mercury
Project Mercury was the first human spaceflight program of the United States, running from 1959 through 1963. An early highlight of the Space Race, its goal was to put a solo human into Earth orbit and return the person safely, ideally before the Soviet Union. Taken over from the US Air Force by the newly created civilian space agency NASA, it spanned twenty unmanned developmental missions involving test animals, and successful missions completed by six of the seven Mercury astronauts.
The Space Race had begun with the 1957 launch of the Soviet satellite Sputnik 1. This came as a shock to the American public, and led to the creation of NASA to expedite existing U.S. space exploration efforts, and place most of them under civilian control. After the successful launch of the Explorer 1 satellite in 1958, manned spaceflight became the next goal.
The Soviet Union put the first human, cosmonaut Yuri Gagarin, into a single orbit aboard Vostok 1 in April 1961. Shortly after this, on May 5, the US launched its first astronaut, Alan Shepard, on a suborbital flight. Soviet Gherman Titov followed with a day-long orbital flight in August, 1961. The U.S. reached its orbital goal on February 20, 1962, when John Glenn made three orbits around the Earth. When Mercury ended in May 1963, both nations had sent six people into space, but the US was still behind the Soviets in terms of total time spent in space.
The cone-shaped Mercury capsule was produced by McDonnell Aircraft, and carried supplies of water, food and oxygen for about one day in a pressurized cabin. Mercury flights were launched from Cape Canaveral, Florida, on modified Redstone and Atlas D missiles. The capsule was fitted with an escape rocket to carry it safely away from the launch rocket in case of a failure of the latter. The flight was designed to be controlled from the ground via the Manned Space Flight Network, a system of tracking and communications stations; back-up controls were outfitted on board. Small retrorockets were used to bring the spacecraft out of its orbit, after which an ablative heat shield protected the spacecraft from the heat of atmospheric reentry. Finally, a parachute slowed the craft for a water landing. Both astronaut and capsule were recovered by helicopters deployed from the nearest suitable U.S. Navy ship.
The program took its name from the wing-footed, fleet god of travel in Roman mythology, and is estimated to have cost $1.73 billion (current prices) and to have involved the work of 2 million people. The astronauts were collectively known as the „Mercury Seven„, and each spacecraft was given a name ending with a „7“ by its pilot.
After a slow start riddled with humiliating mistakes, the Mercury Project gained popularity, its missions followed by millions on radio and TV around the world. Its success laid the groundwork for Project Gemini, which carried two astronauts in each capsule and perfected space docking maneuvers essential for lunar travel, and the subsequent Apollo Moon-landing program announced a few weeks after the first manned Mercury flight.
Project Gemini
Project Gemini was NASA‘s second human spaceflight program. It was a United States government civilian space program started in 1961 and concluded in 1966. Project Gemini was conducted between projects Mercury and Apollo. The Gemini spacecraft carried a two-astronaut crew. Ten crews flew low Earth orbit (LEO) missions between 1965 and 1966. It put the United States in the lead during the Cold War Space Race with the Soviet Union.
Its objective was to develop space travel techniques to support Apollo’s mission to land astronauts on the Moon. Gemini achieved missions long enough for a trip to the Moon and back; perfected working outside the spacecraft with extra-vehicular activity (EVA); and pioneered the orbital maneuvers necessary to achieve rendezvous and docking. With these new techniques proven in Gemini, Apollo could pursue its prime mission without doing these fundamental exploratory operations.
All Gemini flights were launched from Cape Canaveral Air Force Station Launch Complex 19 (LC-19), in Florida. Its launch vehicle was the Gemini–Titan II, a modified Intercontinental Ballistic Missile (ICBM).[Note 1] Project Gemini was the first program to use Houston as the Mission Control for its flights.[Note 2]
The astronaut corps that supported Project Gemini included the „Mercury Seven,“ „The New Nine“ and the 1963 astronaut class. During the program, three astronauts died in air crashes during training, including the prime crew for Gemini 9. This mission was performed by the backup crew, the only time that has happened in NASA’s history.
Gemini was robust enough that the United States Air Force planned to use it for the Manned Orbital Laboratory (MOL) program, which was later canceled. Gemini’s chief designer, Jim Chamberlin, also made detailed plans for cislunar and lunar landing missions in late 1961. He believed Gemini could perform lunar operations before Project Apollo, and cost less. NASA’s administration did not approve those plans. In 1969, McDonnell-Douglas proposed a „Big Gemini“ that could have been used to shuttle up to 12 astronauts to the planned space stations in the Apollo Applications Project (AAP). The only AAP project funded was Skylab – which used existing spacecraft and hardware – thereby eliminating the need for Big Gemini.
Apollo
The Apollo spacecraft was composed of three parts designed to accomplish the American Apollo program‘s goal of landing astronauts on the Moon by the end of the 1960s and returning them safely to Earth. The expendable (single-use) spacecraft consisted of a combined Command/Service Module (CSM) and a Lunar Module (LM). Two additional components complemented the spacecraft stack for space vehicle assembly: a Spacecraft Lunar Module Adapter (SLA) designed to shield the LM from the aerodynamic stress of launch, and to connect the CSM to the Saturn launch vehicle; and a Launch Escape System (LES) to carry the crew in the Command Module safely away from the launch vehicle in the event of a launch emergency.
The design was based on the Lunar Orbit Rendezvous approach: two docked spacecraft were sent to the Moon and went into lunar orbit. While the LM separated and landed, the CSM remained in orbit. After the lunar excursion, the two craft rendezvoused and docked in lunar orbit, and the CSM returned the crew to Earth. The Command Module was the only part of the space vehicle that returned with the crew to the Earth’s surface.
The LES was jettisoned during launch upon reaching the point where it was no longer needed, and the SLA remained attached to the launch vehicle’s upper stage. Two unmanned CSM’s, one unmanned LM and one manned CSM were carried into space by Saturn IB launch vehicles for low Earth orbit Apollo missions. Larger Saturn Vs launched two unmanned CSM’s on high Earth orbit test flights, the CSM on one manned lunar mission, the complete spacecraft on one manned low Earth orbit mission and eight manned lunar missions. After conclusion of the Apollo program, four CSM’s were launched on Saturn IBs for three Skylab Earth orbital missions and the Apollo-Soyuz Test Project.
