The Apollo program, also known as Project Apollo, was the United States human spaceflight program carried out by the National Aeronautics and Space Administration (NASA), which succeeded in preparing and landing the first men on the Moon from 1968 to 1972. It was first conceived in 1960 during President Dwight D. Eisenhower's administration as a three-person spacecraft to follow the one-person Project Mercury, which put the first Americans in space. Apollo was later dedicated to President John F. Kennedy's national goal for the 1960s of "landing a man on the Moon and returning him safely to the Earth" in an address to Congress on May 25, 1961. It was the third US human spaceflight program to fly, preceded by the two-person Project Gemini conceived in 1961 to extend spaceflight capability in support of Apollo.
Apollo 9 was the third human spaceflight in NASA's Apollo program. Flown in low Earth orbit, it was the second crewed Apollo mission that the United States launched via a Saturn V rocket, and was the first flight of the full Apollo spacecraft: the command and service module (CSM) with the Lunar Module (LM). The mission was flown to qualify the LM for lunar orbit operations in preparation for the first Moon landing by demonstrating its descent and ascent propulsion systems, showing that its crew could fly it independently, then rendezvous and dock with the CSM again, as would be required for the first crewed lunar landing. Other objectives of the flight included firing the LM descent engine to propel the spacecraft stack as a backup mode, and use of the portable life support system backpack outside the LM cabin.
Apollo 10 was the fourth human spaceflight in the United States' Apollo program and the second to orbit the Moon. NASA, the mission's operator, described it as a "dress rehearsal" for the first Moon landing. It was designated an "F" mission, intended to test all spacecraft components and procedures short of actual descent and landing.
Apollo 16 was the tenth crewed mission in the United States Apollo space program, administered by NASA, and the fifth and penultimate to land on the Moon. It was the second of Apollo's "J missions", with an extended stay on the lunar surface, a focus on science, and the use of the Lunar Roving Vehicle (LRV). The landing and exploration were in the Descartes Highlands, a site chosen because some scientists expected it to be an area formed by volcanic action, though this proved not to be the case.
The Apollo Lunar Module, originally designated the Lunar Excursion Module (LEM), was the lunar lander spacecraft that was flown between lunar orbit and the Moon's surface during the United States' Apollo program. It was the first crewed spacecraft to operate exclusively in the airless vacuum of space, and remains the only crewed vehicle to land anywhere beyond Earth.
Apollo 5, also known as AS-204, was the uncrewed first flight of the Apollo Lunar Module (LM) that would later carry astronauts to the surface of the Moon. The Saturn IB rocket bearing the LM lifted off from Cape Kennedy on January 22, 1968. The mission was successful, though due to programming problems an alternate mission to that originally planned was executed.
The Constellation program was a crewed spaceflight program developed by NASA, the space agency of the United States, from 2005 to 2009. The major goals of the program were "completion of the International Space Station" and a "return to the Moon no later than 2020" with a crewed flight to the planet Mars as the ultimate goal. The program's logo reflected the three stages of the program: the Earth (ISS), the Moon, and finally Mars—while the Mars goal also found expression in the name given to the program's booster rockets: Ares. The technological aims of the program included the regaining of significant astronaut experience beyond low Earth orbit and the development of technologies necessary to enable sustained human presence on other planetary bodies.
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 and service module (CSM) and an Apollo Lunar Module (LM). Two additional components complemented the spacecraft stack for space vehicle assembly: a spacecraft–LM 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.
A space capsule is a spacecraft designed to transport cargo, scientific experiments, and/or astronauts to and from space. Capsules are distinguished from other spacecraft by the ability to survive reentry and return a payload to the Earth's surface from orbit or sub-orbit, and are distinguished from other types of recoverable spacecraft by their blunt shape, not having wings and often containing little fuel other than what is necessary for a safe return. Capsule-based crewed spacecraft such as Soyuz or Orion are often supported by a service or adapter module, and sometimes augmented with an extra module for extended space operations. Capsules make up the majority of crewed spacecraft designs, although one crewed spaceplane, the Space Shuttle, has flown in orbit.
The Apollo Applications Program (AAP) was created as early as 1966 by NASA headquarters to develop science-based human spaceflight missions using hardware developed for the Apollo program. AAP was the ultimate development of a number of official and unofficial Apollo follow-on projects studied at various NASA labs. However, the AAP's ambitious initial plans became an early casualty when the Johnson Administration declined to support it adequately, partly in order to implement its Great Society set of domestic programs while remaining within a $100 billion budget. Thus, Fiscal Year 1967 ultimately allocated $80 million to the AAP, compared to NASA's preliminary estimates of $450 million necessary to fund a full-scale AAP program for that year, with over $1 billion being required for FY 1968. The AAP eventually led to Skylab, which absorbed much of what had been developed under Apollo Applications.
Earth orbit rendezvous (EOR) is a method for conducting round trip human flights to the Moon, involving the use of space rendezvous to assemble, and possibly fuel, components of a translunar vehicle in low Earth orbit. It was considered and ultimately rejected in favor of lunar orbit rendezvous (LOR) for NASA's Apollo program of the 1960s and 1970s, mainly because LOR does not require a spacecraft big enough to both make the return trip from Earth orbit to splashdown in the ocean, and a soft landing on the lunar surface. Three decades later, it was planned to be used for Project Constellation, until that program's cancellation in October 2010.
Lunar orbit rendezvous (LOR) is a process for landing humans on the Moon and returning them to Earth. It was utilized for the Apollo program missions in the 1960s and 1970s. In a LOR mission, a main spacecraft and a smaller lunar lander travel to lunar orbit. The lunar lander then independently descends to the surface of the Moon, while the main spacecraft remains in lunar orbit. After completion of the mission there, the lander returns to lunar orbit to rendezvous and re-dock with the main spacecraft, then is discarded after transfer of crew and payload. Only the main spacecraft returns to Earth.
The Exploration Systems Architecture Study (ESAS) is the official title of a large-scale, system level study released by the National Aeronautics and Space Administration (NASA) in November 2005 of his goal of returning astronauts to the Moon and eventually Mars—known as the Vision for Space Exploration. The Constellation Program was cancelled in 2010 by the Obama Administration and replaced with the Space Launch System, later renamed as the Artemis Program in 2017 under the Trump Administration.
The Ares V was the planned cargo launch component of the cancelled NASA Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars. Ares V and the smaller Ares I were named after Ares, the Greek god of war.
The LK was a lunar module developed in the 1960s as a part of several Soviet crewed lunar programs. Its role was analogous to the American Apollo Lunar Module (LM). Three LK modules, of the T2K variant, were flown without crew in Earth orbit, but no LK ever reached the Moon. The development of the N1 launch vehicle required for the lunar flight suffered setbacks, and the first Moon landings were achieved by US astronauts on Apollo 11. As a result, having lost the Space Race, both the N1 and the LK programs were cancelled without any further development.
Advanced Gemini is a number of proposals that would have extended the Gemini program by the addition of various missions, including crewed low Earth orbit, circumlunar and lunar landing missions. Gemini was the second crewed spaceflight program operated by NASA, and consisted of a two-seat spacecraft capable of maneuvering in orbit, docking with uncrewed spacecraft such as Agena Target Vehicles, and allowing the crew to perform tethered extra-vehicular activities.
DIRECT was a late-2000s proposed alternative super heavy lift launch vehicle architecture supporting NASA's Vision for Space Exploration that would replace the space agency's planned Ares I and Ares V rockets with a family of Shuttle-Derived Launch Vehicles named "Jupiter". It was intended to be the alternative to the Ares I and Ares V rockets which were under development for the Constellation program, intended to develop the Orion spacecraft for use in Earth orbit, the Moon, and Mars.
The retirement of NASA's Space Shuttle fleet took place from March to July 2011. Discovery was the first of the three active Space Shuttles to be retired, completing its final mission on March 9, 2011; Endeavour did so on June 1. The final shuttle mission was completed with the landing of Atlantis on July 21, 2011, closing the 30-year Space Shuttle program.
The Artemis program is a Moon exploration program that is led by the United States' NASA and was formally established in 2017 via Space Policy Directive 1. The Artemis program is intended to reestablish a human presence on the Moon for the first time since Apollo 17 in 1972. The program's stated long-term goal is to establish a permanent base on the Moon to facilitate human missions to Mars.
