Even before the Apollo moon landing in 1969, in October 1968 NASA began early studies of space shuttle designs. The early studies were denoted "Phase A", and in June 1970, "Phase B", which were more detailed and specific.

In 1969, United States Vice President Spiro T. Agnew chaired the National Aeronautics and Space Council, which discussed post-Apollo options for manned space activities ^[1]. The recommendations of this body would heavily influence these directions. 1969 (MCMLXIX) was a common year starting on Wednesday (the link is to a full 1969 calendar). ... Spiro Theodore Agnew, born Spiro Anagnostopoulos (November 9, 1918–September 17, 1996), was the thirty-ninth Vice President of the United States, serving from 1969 to 1973 under President Richard M. Nixon. ...

They considered four major options:

• manned Mars expedition
• follow-on lunar program
• low earth orbital infrastructure program
• discontinuing manned space activities

Based on the advice of the Space Council, president Richard M. Nixon made the decision to pursue the low earth orbital infrastructure program. This program mainly consisted of a space station and space shuttle. However funding restrictions precluded pursuing both simultaneously, so NASA logically chose to develop the space shuttle first, without which the space station could not be constructed or serviced. A low Earth orbit (LEO) is an orbit in which objects such as satellites are below intermediate circular orbit (ICO) and far below geostationary orbit, but typically around 350 - 1400 km above the Earths surface. ... Richard Milhous Nixon (January 9, 1913 – April 22, 1994) was the 37th President of the United States, serving from 1969 to 1974. ... A low Earth orbit (LEO) is an orbit in which objects such as satellites are below intermediate circular orbit (ICO) and far below geostationary orbit, but typically around 350 - 1400 km above the Earths surface. ... The International Space Station in 2006 Computer-generated image of the completed International Space Station A space station is an artificial structure designed for humans to live in outer space. ...

The primary intended use of the space shuttle was supporting the future space station. This function would dictate most of the shuttle's features. The U.S. Air Force was also interested in using the shuttle, and NASA welcomed their participation and influence to ensure political and financial support for the shuttle program. Seal of the Air Force. ...

Many potential shuttle designs were proposed during the 1960s, and they varied widely. Many were exceedingly complex. An attempt to re-simplify was made in the form of the "DC-3" by Maxime Faget who had designed the Mercury capsule among other vehicles. The DC-3 was a small craft with a 20,000-pound (9 metric ton) payload, a four-man capacity, and limited aerodynamic maneuverability. At a minimum, the DC-3 provided a baseline "workable" (but not significantly advanced) system by which other systems could be compared for price/performance compromises. Max Faget Maxime Max A. Faget (August 26, 1921 – October 9, 2004) was an American engineer. ...

Air Force involvement

During the mid-1960s the U.S. Air Force had both of its major piloted space projects, X-20 Dyna-Soar and Manned Orbiting Laboratory, canceled. This underscored the need to cooperate with NASA to place military astronauts in orbit. In turn, by serving Air Force needs, the Shuttle took shape as a truly national system, carrying military as well as civilian payloads. Aircraft of the 379th Air Expeditionary Wing and coalition counterparts stationed together at Al Udeid Air Base, Qatar, in southwest Asia, fly over the desert. ... Artists conception of the X-20 during re-entry The X-20 Dyna-Soar (Dynamic Soarer) was a USAF program to develop a spaceplane that could be used for a variety of military missions, including reconnaissance, bombing, space rescue, satellite maintenance, and sabotage of enemy satellites. ... Manned Orbiting Laboratory early 1960 conceptual drawing that did not use the Gemini spacecraft. ...

Air Force involvement emphasized strategic reconnaissance, which required ability to launch spy satellites southward into polar orbit from Vandenberg AFB. This required higher energies than for lower inclination orbits. The Air Force desired the ability to land at the Vandenberg liftoff point after one orbit, despite the earth rotating 1,000 miles beneath the orbital track. This required a larger delta wing size than the earlier simple "DC-3" shuttle. However NASA also desired this increased maneuvering capability since further studies had shown the DC-3 shuttle design had limitations not initially foreseen. The Air Force planned on having their own fleet of shuttles, and re-built a separate launch facility originally derived from the cancelled Manned Orbiting Laboratory program at Vandenberg called Space Launch Complex Six (SLC-6). However for various reasons, due in large part to the loss of the space shuttle Challenger on January 28, 1986, work on SLC-6 was eventually discontinued with no shuttle launches from that location ever taking place. A satellite in a polar orbit passes above or nearly above both poles of the planet (or other celestial body) on each revolution. ... Vandenberg Air Force Base is a base with a spaceport, located in Santa Barbara County, California. ... The delta-wing is a wing planform in the form of a triangle. ... Space Launch Complex-6 (SLC-6, nicknamed Slick Six) at Vandenberg Air Force Base in California was a launch pad and support area designed for the launching of the Titan III in support of the cancelled Manned Orbiting Laboratory and later for the Space Shuttle. ... Challenger may mean: Space Shuttle Challenger, the American space shuttle which broke up shortly after liftoff on January 28, 1986 Challenger was the name of the Apollo 17 lunar module Canadair Challenger series of business jets manufactured by Bombardier Challenger Equipment, AGCO Corporations division of Agricultural machinery HMS Challenger... January 28 is the 28th day of the year in the Gregorian calendar. ... 1986 (MCMLXXXVI) was a common year starting on Wednesday of the Gregorian calendar. ...

SLC-6 was eventually used for launching the Lockheed Martin-built Athena expendable launch vehicles, which included the successful IKONOS commercial Earth observation satellite in September of 1999 before being reconfigured once again to handle the upcoming generation of Boeing Delta IV's, now slated to launch in late 2006 or early 2007. Lockheed/BAE/Northrop F-35 Lockheed Trident missile C-130 Hercules; in production since the 1950s, now as the C-130J Lockheed Martin (NYSE: LMT) is an aerospace manufacturer formed in 1995 by the merger of Lockheed Corporation with Martin Marietta. ... Helmeted Athena, of the Velletri type. ... IKONOS is a commercial earth observation satellite that collects high-resolution imagery at 1- and 4-meter resolution. ... Earth observation satellites are satellites specifically designed to observe Earth from orbit, similar to reconnaissance satellites but intended for non-military uses such as environmental monitoring, meteorology, map making etc. ... The Boeing Company (NYSE: BA, TYO: 7661 ) is an aerospace and defense corporation headquartered in Chicago, Illinois. ... Delta EELV family of launch vehicles (US Govt) The Delta IV family of rockets are EELVs (evolved expendable launch vehicles) built by Boeing IDS. They come in five versions: medium, medium+ (4,2), medium+ (5,2), medium+ (5,4), and heavy. ...

Shuttle design debate

During the early shuttle studies, there was great debate over the optimal shuttle design that best balanced capability, development cost and operational cost. Initially a fully reusable design was preferred. This involved a very large winged manned booster which would carry a smaller winged manned orbiter. The booster vehicle would lift the orbiter to a certain altitude and speed, then separate. The booster would return and land horizontally, while the orbiter continued into low earth orbit. After completing its mission, the winged orbiter would reenter and land horizontally on a runway. The idea was that full reusability would promote lower operating costs. A booster in space-related applications is usually a solid rocket booster: a solid fuel rocket of which two or more are attached to the main rocket to provide the main thrust in the initial phase of the rockets flight. ... A booster in space-related applications is usually a solid rocket booster: a solid fuel rocket of which two or more are attached to the main rocket to provide the main thrust in the initial phase of the rockets flight. ... A low Earth orbit (LEO) is an orbit in which objects such as satellites are below intermediate circular orbit (ICO) and far below geostationary orbit, but typically around 350 - 1400 km above the Earths surface. ...

However further studies showed a huge booster was needed to lift an orbiter with the desired payload capability. In space and aviation systems, cost is closely related to weight, so this meant the overall vehicle cost would be very high. Both booster and orbiter would have rocket engines plus jet engines for use within the atmosphere, plus separate fuel and control systems for each propulsion mode. In addition there were concurrent discussions about how much funding would be available to develop the program.

Another competing approach was maintaining the Saturn V production line and using its large payload capacity to launch a space station in a few payloads rather than many smaller shuttle payloads. A related concept was servicing the space station using the Air Force Titan II-M to launch a larger Gemini capsule, called "Big Gemini", rather than using the shuttle. This article is about the rocket. ... Project Gemini was the second human spaceflight program of the United States of America. ... Big Gemini spacecraft concept, August, 1969. ...

The shuttle supporters answered that given enough launches, a reusable system would have lower overall costs than disposable rockets. If dividing total program costs over a given number of launches, a high shuttle launch rate would result in lower per-launch costs. This in turn would make the shuttle cost competitive with or superior to expendable launchers. Some theoretical studies mentioned 55 shuttle launches per year, however the shuttle system was never designed to support that launch rate. In particular the maximum external tank production rate was limited to 24 tanks per year at NASA's Michoud Assembly Facility. The Space Shuttle External Tank (ET) on its way to the Vehicle Assembly Building. ... Michoud Assembly Facility in 1968 The Michoud Assembly Facility is an 832 acre (3. ...

The combined space station and Air Force payload requirements weren't sufficient to reach desired shuttle launch rates. Therefore the plan was for all future U.S. space launches -- space station, Air Force, commercial satellites, and scientific research -- to use only the space shuttle. Most other expendable boosters would be phased out.

The reusable booster was eventually abandoned due to a several factors: high price (combined with limited funding), technical complexity, and development risk. Instead, a partially (not fully) reusable design was selected, where an external propellent tank was discarded for each launch, and the booster rockets and shuttle orbiter were refurbished for reuse. The Space Shuttle External Tank (ET) on its way to the Vehicle Assembly Building. ... A booster in space-related applications is usually a solid rocket booster: a solid fuel rocket of which two or more are attached to the main rocket to provide the main thrust in the initial phase of the rockets flight. ...

Initially the orbiter was to carry its own liquid propellant. However studies showed carrying the propellant in an external tank allowed a larger payload bay in an otherwise much smaller craft. It also meant throwing away the tank after each launch, but this was a relatively small portion of operating costs. A propellant is a material that is used to move an object by applying a motive force. ... The Space Shuttle External Tank (ET) on its way to the Vehicle Assembly Building. ...

Earlier designs assumed the winged orbiter would also have jet engines to assist manuvering in the atmosphere after reentering. However NASA ultimately chose an unpowered gliding orbiter, based partially on experience from previous unpowered gliding vehicles such as the X-15 and lifting bodies. Omitting the jet engines and their fuel would reduce complexity and increase payload. Description Role: Research Aircraft Crew: one, pilot Dimensions Length: 50. ... The lifting body is an aircraft configuration where the body itself produces lift. ... In cargo transport, the payload is the valuable contents of the vehicle. ...

The last remaining debate was over the nature of the boosters. NASA examined four solutions to this problem: development of the existing Saturn lower stage, simple pressure-fed liquid-fuel engines of a new design, a large single solid rocket, or two (or more) smaller ones. Engineers at NASA's Marshall Space Flight Center (where the Saturn V development was managed) were particularly concerned about solid rocket reliability for manned missions. Aerial view of the test area at Marshall Space Flight Center The George C. Marshall Space Flight Center (MSFC) is a lead NASA center for propulsion, Space Shuttle propulsion, external fuel tank, crew training and payloads, International Space Station (ISS) design and construction, for computers, networks, and information management. ... This article is about the rocket. ... The Space Shuttle is initially launched with the help of solid-fuel boosters A Solid rocket or a solid fuel rocket is a rocket with a motor that uses solid propellants (fuel/oxidizer). ...

Final design chosen

NASA eventually decided to use the smaller solid rocket boosters due to their lower development costs. While the liquid-fueled systems provided better performance and enhanced safety, delivery capability to orbit is more a function of the upper-stage performance and weight than the lower; the money was hence spent elsewhere. The final design would be a winged orbiter with three liquid fueled engines, a large expendable external tank which held liquid propellant for the main engines, and two reusable solid rocket boosters. The Space Shuttle is initially launched with the help of solid-fuel boosters A Solid rocket or a solid fuel rocket is a rocket with a motor that uses solid propellants (fuel/oxidizer). ... NASAs Space Shuttle, officially called Space Transportation System (STS), is the United States governments current manned launch vehicle. ... Space Shuttle Main Engine block The Space Shuttle orbiter has three main engines. ... The Space Shuttle External Tank (ET) on its way to the Vehicle Assembly Building. ... A liquid rocket engine has fuel and oxidizer in liquid form, as opposed to a solid rocket or hybrid rocket or gaseous propellant. ... Space Shuttle Main Engine block The Space Shuttle orbiter has three main engines. ... NASAs Space Shuttle, officially called Space Transportation System (STS), is the United States governments current manned launch vehicle. ...

The shuttle in retrospect

Opinions differ on the lessons of the Shuttle. While it was developed within the original development cost and time estimates given to President Richard M. Nixon in 1971^[2], the operational costs, flight rate, payload capacity, and reliability have been worse than anticipated.

The shuttle is sometimes criticized for adopting a simpler, compromise design than was originally envisioned. Ironically it is also criticized for being too complex or excessively pushing the state of early 1970s technology. If it had incorporated the originally planned fully reusable manned booster, it would have been far more complex than the current design. According to Bob Thompson, space shuttle program manager from 1970 to 1981, attempting the more complex fully reusable design would possibly have doomed the entire program.^[2]

Due to the two disasters, the shuttle is often viewed as an intrinsically unreliable or flawed design. However, the loss of two Shuttles out of 116 missions is really quite low for a craft of this kind, and those losses that did occur were caused when well-known technical problems were not properly addressed by management. From that standpoint, any past or future launch system, regardless of technology or design, could fail for a similar reason.

The NASA Chief Administrator Michael Griffin has recently suggested the decision to develop the Space Shuttle and International Space Station was a mistake by saying, "It is now commonly accepted that was not the right path. We are now trying to change the path while doing as little damage as we can."^[3] Dr. Michael D. Griffin Dr. Michael Douglas Griffin (born November 1, 1949 in Aberdeen, Maryland) has been the Administrator of NASA since April 13, 2005. ... ISS redirects here. ...

See also

• Space shuttle program
• Single-stage-to-orbit
• Space Shuttle abort modes

NASAs Space Shuttle, officially called Space Transportation System (STS), is the United States governments current manned launch vehicle. ... A single-stage to orbit (or SSTO) launcher describes an as-yet theoretical class of spacecraft designed to place a load into orbit as a self-contained vehicle without the use of multiple stages. ... A Space Shuttle abort is an emergency procedure due to equipment failure on NASAs Space Shuttle, most commonly during ascent. ...

References

February 1 is the 32nd day of the year in the Gregorian Calendar. ... 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... February 4 is the 35th day of the year in the Gregorian Calendar. ... 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... September 27 is the 270th day of the year (271st in leap years) in the Gregorian calendar. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... October 17 is the 290th day of the year (291st in leap years) in the Gregorian calendar. ...

External links

• CAIB transcript concerning shuttle development
• Astronautix space shuttle article
• From Dream to Reality (1968-72)
• NASA: The Space Shuttle Decision

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