The Space Transportation System (STS), also known internally to

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

as the Integrated Program Plan (IPP), was a proposed system of reusable crewed

space vehicles Space is a three-dimensional continuum containing positions and directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless four ...

envisioned in 1969 to support extended operations beyond the

Apollo program The Apollo program, also known as Project Apollo, was the United States human spaceflight program led by NASA, which Moon landing, landed the first humans on the Moon in 1969. Apollo followed Project Mercury that put the first Americans in sp ...

(NASA appropriated the name for its

Space Shuttle Program The Space Shuttle program was the fourth human spaceflight program carried out by the U.S. National Aeronautics and Space Administration (NASA), which accomplished routine transportation for Earth-to-orbit crew and cargo from 1981 to 2011. Its ...

, the only component of the proposal to survive Congressional funding approval). The purpose of the system was two-fold: to reduce the cost of

spaceflight Spaceflight (or space flight) is an application of astronautics to fly objects, usually spacecraft, into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such ...

by replacing the existing method of launching capsules on expendable rockets with reusable

spacecraft A spacecraft is a vehicle that is designed spaceflight, to fly and operate in outer space. Spacecraft are used for a variety of purposes, including Telecommunications, communications, Earth observation satellite, Earth observation, Weather s ...

; and to support ambitious follow-on programs including permanent orbiting

space station A space station (or orbital station) is a spacecraft which remains orbital spaceflight, in orbit and human spaceflight, hosts humans for extended periods of time. It therefore is an artificial satellite featuring space habitat (facility), habitat ...

s around

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

and the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

, and a human landing mission to

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

. In February 1969, President

Richard Nixon Richard Milhous Nixon (January 9, 1913April 22, 1994) was the 37th president of the United States, serving from 1969 until Resignation of Richard Nixon, his resignation in 1974. A member of the Republican Party (United States), Republican ...

appointed a

Space Task Group The Space Task Group was a working group of NASA engineers created in 1958, tasked with managing America's human spaceflight programs. Headed by Robert Gilruth and based at the Langley Research Center in Hampton, Virginia, it managed Project Me ...

headed by Vice President

Spiro Agnew Spiro Theodore Agnew (; November 9, 1918 – September 17, 1996) was the 39th vice president of the United States, serving from 1969 until his resignation in 1973. He is the second of two vice presidents to resign, the first being John C. ...

to recommend human space projects beyond Apollo. The group responded in September with the outline of the STS, and three different program levels of effort culminating with a human

landing by 1983 at the earliest, and by the end of the twentieth century at the latest. The system's major components consisted of: * A permanent

module designed for 6 to 12 occupants, in a

low Earth orbit A low Earth orbit (LEO) is an geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial object ...

, and as a permanent lunar orbit station. Modules could be combined in Earth orbit to create a 50 to 100 person permanent station. * A chemically fueled Earth-to-orbit

shuttle The original meaning of the word shuttle is the device used in weaving to carry the weft. By reference to the continual to-and-fro motion associated with that, the term was then applied in transportation and then in other spheres. Thus the word ma ...

. * A chemically fueled

space tug ''Space Tug'' is a young adult fiction, young adult science fiction novel by author Murray Leinster. It was published in 1953 in literature, 1953 by Shasta Publishers in an edition of 5,000 copies. It is the second novel in the author's Joe K ...

to move crew and equipment between Earth orbits as high as

geosynchronous orbit A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital ...

, which could be adapted as a lunar orbit-to-surface shuttle. * A

nuclear-powered Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced b ...

shuttle or ferry using the

NERVA Nerva (; born Marcus Cocceius Nerva; 8 November 30 – 27 January 98) was a Roman emperor from 96 to 98. Nerva became emperor when aged almost 66, after a lifetime of imperial service under Nero and the succeeding rulers of the Flavian dynast ...

engine, to move crew, spacecraft and supplies between low Earth orbit and lunar orbit, geosynchronous orbit, or to other planets in the solar system. A crew module derived from the space station module would be used to send humans to the

or Mars. The tug and ferry vehicles would be of a modular design, allowing them to be clustered and/or

staged ''Staged'' is a British television comedy series. Set and filmed during the COVID-19 pandemic in the United Kingdom, primarily using video-conferencing technology, the series stars actors Michael Sheen and David Tennant as fictionalised versions ...

for large payloads or interplanetary missions. The system would be supported by permanent Earth and lunar orbital

propellant depot An orbital propellant depot is a cache of propellant that is placed in orbit around Earth or another body to allow spacecraft or the transfer stage of the spacecraft to be fueled in space. It is one of the types of space resource depots that ha ...

s.Space Task Group Report, "Program Objectives", 4.b. The

Saturn V The Saturn V is a retired American super heavy-lift launch vehicle developed by NASA under the Apollo program for human exploration of the Moon. The rocket was human-rated, had multistage rocket, three stages, and was powered by liquid-propel ...

might still have been used as a

heavy lift launch vehicle A heavy-lift launch vehicle (HLV) is an orbital launch vehicle capable of lifting payloads between (by NASA classification) or between (by Russian classification) into low Earth orbit (LEO).50t payloads" Heavy-lift launch vehicles often carry ...

for the nuclear ferry and space station modules. A special "

Mars Excursion Module The Mars Excursion Module (MEM) was a spacecraft proposed by NASA in the 1960s for use in a human mission to Mars, and this can refer to any number of studies by corporations and spaceflight centers for Mars landers. However, primarily a MEM referr ...

" would be the only remaining vehicle necessary for a human

landing. The STS was championed by

Administrator

Thomas O. Paine Thomas Otten Paine (November 9, 1921 – May 4, 1992) was an American engineer, scientist and advocate of space exploration, and was the third Administrator of NASA, serving from March 21, 1969, to September 15, 1970. During his administration ...

until May 1969 and gained Agnew's enthusiastic support. However, as

Apollo Apollo is one of the Twelve Olympians, Olympian deities in Ancient Greek religion, ancient Greek and Ancient Roman religion, Roman religion and Greek mythology, Greek and Roman mythology. Apollo has been recognized as a god of archery, mu ...

accomplished its objective of landing the first humans on the

, Nixon realized that

political Politics () is the set of activities that are associated with decision-making, making decisions in social group, groups, or other forms of power (social and political), power relations among individuals, such as the distribution of Social sta ...

support for further crewed space activities was beginning to wane, and the Congress would be unwilling to provide funding for most of these extended activities. Based on this, Nixon rejected all parts of the program except the

Space Shuttle The Space Shuttle is a retired, partially reusable launch system, reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. ...

, which inherited the STS name. Nixon accepted Paine's resignation in July 1970 and replaced him as administrator with

James C. Fletcher James Chipman Fletcher (June 5, 1919 – December 22, 1991) served as the 4th and 7th Administrator of NASA, first from April 27, 1971, to May 1, 1977, under Presidents Richard Nixon, Gerald Ford and Jimmy Carter, and again from May 12, 1986, to ...

. As a result of funding constraints, Shuttle was significantly scaled back from its planned degree of reusability. The overall program scheduled was also delayed. The Shuttle first flew in

1981 Events January * January 1 ** Greece enters the European Economic Community, predecessor of the European Union. ** Palau becomes a self-governing territory. * January 6 – A funeral service is held in West Germany for Nazi Grand Admiral ...

, and was

retired Retirement is the withdrawal from one's position or occupation or from one's active working life. A person may also semi-retire by reducing work hours or workload. Many people choose to retire when they are elderly or incapable of doing their j ...

2011 The year marked the start of a Arab Spring, series of protests and revolutions throughout the Arab world advocating for democracy, reform, and economic recovery, later leading to the depositions of world leaders in Tunisia, Egypt, and Yemen ...

. A second part of the system,

Space Station Freedom Space Station ''Freedom'' was a NASA-led multi-national project proposed in the 1980s to construct a permanently crewed space station in low Earth orbit. Despite initial approval by President Ronald Reagan and a public announcement in the 1984 ...

, was approved in the early 1980s and announced in 1984 by president

Ronald Reagan Ronald Wilson Reagan (February 6, 1911 – June 5, 2004) was an American politician and actor who served as the 40th president of the United States from 1981 to 1989. He was a member of the Republican Party (United States), Republican Party a ...

. However, this also became politically unviable by 1993, and was replaced with the

International Space Station The International Space Station (ISS) is a large space station that was Assembly of the International Space Station, assembled and is maintained in low Earth orbit by a collaboration of five space agencies and their contractors: NASA (United ...

(ISS), with substantial contribution by

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

. The ISS was completed in 2011.

1969 Space Task Group

System vehicles

Earth-to-orbit shuttle

The system was supposed to include a "space shuttle", sometimes also referred to as an "Earth-to-orbit shuttle", for ferrying crew and supplies to Low Earth Orbit. Larger payloads like nuclear tugs or space station modules would be transported by an upgraded version of the

rocket, specializing the "shuttle" to relatively low-mass, high-frequency payloads like crew rotations, liquid hydrogen fuel, and liquid oxygen oxidizer. This vehicle is arguably the only one that was realized with the

, albeit significantly scaled back in nearly all aspects, and for most of its operational life left lacking the infrastructure it was supposed to support.

Space tug

The MSFC space tug was designed to handle a number of missions including satellite repair, transfer to

, and as the name implies, towing payloads to the nuclear shuttle. Its modular design was centered around a cylindrical propulsion module, with an attachable crew module, cargo module, and lunar landing legs to convert it to a lunar orbit-to-surface shuttle. It was supposed to use liquid hydrogen and oxygen as its fuel and oxidizer, carried into orbit by the Earth-to-orbit shuttle.

Nuclear ferry

Planned uses for NERVA included a visit to

by 1978 and a permanent

lunar base A moonbase (or lunar base) is a human outpost on or below the surface of the Moon. More than a mere site of activity or temporary camp, moonbases are extraterrestrial bases, supporting robotic or human activity, by providing surface infrastructu ...

by 1981. NERVA rockets would be used for "nuclear tugs" or "nuclear shuttles" designed to take payloads from Low Earth Orbit to farther orbits, resupply of several

s in various orbits around the

and

, and support for a permanent lunar base. The NERVA rocket would also be used in the Saturn S-N, an upper stage for the

rocket' upgrading the Saturn's

(LEO) capability to , as well as be used to propel a pair of Mars expedition vehicles.

Space station module

The program was supposed to include multiple space stations, built out of standardized space station modules. Those would be emplaced in low Earth orbit, polar Earth orbit, geosationary orbit, and lunar orbit. The Mars-focused aspects of the plan were supposed to use the station modules as crew sections for its Mars Transfer Vehicles.

Projected program cost

References

External links

*

{{NASA space program NASA programs Spiro Agnew