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Whilst the program was designed with the capacity to recover satellites (and other payloads) from orbit and return them to Earth, this has not been used very often; it is, however, an important use of the Space Shuttle in the context of the ISS program, as only very small amounts of experimental material (or hardware needing repaired) can be returned by Soyuz.
Each shuttle was designed for a projected lifespan of 100 launches.
The program started in the late 1960s and has totally dominated NASA's manned operations since the mid 1970s.
There have been no launches since the Space Shuttle Columbia disaster in 2003. The next mission, referred to as "Return to Flight", will be STS-114, currently scheduled for no earlier than May 14, 2005.
According to the Vision for Space Exploration, use of the Space Shuttle will be focused on completing the assembly of the International Space Station in 2010, and it will then be retired. The Space Shuttle will be replaced by the Crew Exploration Vehicle (CEV), which has yet to be developed.
It has been decided that on each mission the Orbiter must be inspected externally on orbit before reentry, a task which NASA has decided is too expensive to be done without the facilities of the ISS. Therefore, for example, further service missions to the Hubble Space TelescopeHubble Space Telescope Space Shuttle Discovery during the second servicing mission of the telescope, STS-82 Organization NASA, ESA Wavelength regimeoptical Orbit height600 km Orbit period100 min Launch date 24 April 1990 Deorbit datecirca 2010 Mass11,000 (HST) are impossible, because the Orbiter is incapable of reaching both HST and ISS during the same mission.
NASA had conducted a series of paper-projects throughout the 1960s on the topic of reusable spacecrafts to replace their expedient "one-off" systems like MercuryProject Mercury was the United States's first successful manned spaceflight program. It ran from 1959 through 1963 with the goal of putting a man in orbit around the Earth. Early planning and research was carried out by NACA, while the program was officia, Gemini, and ApolloFor other meanings, see Apollo (disambiguation). Project Apollo was a series of human spaceflight missions undertaken by the United States of America using the Apollo spacecraft, conducted during the years 1961- 1972. It was devoted to the goal of landing. Meanwhile, the Air ForceThe United States Air Force USAF is the aviation branch of the United States armed forces. The mission of the USAF is "to defend the United States through the control and exploitation of air and space. Organization There are three components of the USAF: had a continuing interest in smaller systems with more rapid turn-around times, and were involved in their own spaceplaneA spaceplane is a rocket plane designed to pass the edge of space. It combines some of the features of an aircraft and some of a spacecraft. Typically, it takes the form of a spacecraft equipped with wings. The orbital spaceplanes successfully flown to da project, the X-20 Dyna-SoarDevelopment The X-20 Dyna-Soar was a USAF program to develop an orbital spaceplane that could be used for a variety of military missions including reconnaissance, bombing, space rescue, satellite maintenance, and sabotage of enemy satellites. The program. In several instances groups from both worked together to investigate the state of the art.
With the major Apollo development effort winding down in the second half of the 1960s, NASA started looking to the future of the space program. They envisioned an ambitious program consisting of a large space station being launched on huge boosters, served by a reusable logistics "space shuttle", both providing services for a permanently manned Lunar colony and eventual manned missions to Mars.
However reality was to interject and NASA found themselves with a rapidly plunging budget. Rather than stepping back and looking at their future as a whole given their new financial situation, they attempted to save as many of the individual projects as possible. The mission to Mars was quickly eliminated, but the Space Station and Shuttle continued on. Eventually only one of them could be saved, so it stood to reason that a low-cost Shuttle system would be the better bet, because without it a large station would never be affordable.
A number of designs were proposed, but many of them were complex and varied widely in their systems. An attempt to re-simplify was made in the form of the "DC-3" by one of the few people left in NASA with the political clout to pull it off, Maxime Faget, who had designed the Mercury capsule, among others. The DC-3 was a small craft with a 20,000 pound (9 t) (or less) payload, a four-man crew, and limited maneuverability. At a minimum, the DC-3 provided a baseline "workable" (but not terribly advanced) system by which other systems could be compared for price/performance tradeoffs.
The final defining moment was when NASA, in desperation to see their only remaining project saved, went to the Air Force for its blessing. NASA asked that the AF place all of their future launches on the shuttle instead of their current expendable launchers (like the Titan II), in return for which they would no longer have to continue spending money upgrading those designs -- the shuttle would provide more than enough capability.
The Air Force relucantly agreed, but only after demanding a large increase in capability to allow for launching their projected spy satellites (mirrors are heavy). These were quite large, weighing an estimated 40,000 pound (18 t), and needed to be put into polar orbit, which requires more energy to get to than the more common low Earth orbit. And since the AF also wanted to be able to abort after a single orbit (as did NASA), and land at the launch site (unlike NASA), the spacecraft would also require the ability to maneuver significantly to either side of its orbital track to adjust for the launching point rotating away from it while in polar orbit - in a 90 minute orbit Vandenberg would move over 1,000 miles (1,600 km), whereas in a "normal" equatorial orbit NASA needed the range would be less than 400. This large 'cross-range' capability meant the craft had to have a greater lift to drag ratio than originally planned. This required the addition of bigger, heavier wings.
The result was that the simple DC-3 was clearly out of the picture because it had neither the cargo capacity nor the cross-range the Air Force demanded. In fact all existing designs were far too small, as a 40,000 pound (18 t) delivery to polar orbit equates to a 65,000 pound (29 t) delivery to a "normal" 28 degree equatorial orbit. In fact any design using simple straight or fold-out wings was not going to meet the cross range requirements, so any future design would require a more complex, heavier delta wing.
Worse, any increase in the weight of the upper portion of a launch vehicle, which had just occurred, requires an even bigger increase in the capability of the lower stage used to launch it. Suddenly the two-stage system grew in size to something larger than the Saturn V, and the complexity and costs to develop it skyrocketed.
While all of this was going on, others were suggesting a completely different approach to the future. They stated that NASA was better off using the existing Saturn to launch their space station, supplied and manned using modified Gemini capsules on top of the Air Force's newer Titan II-M. The cost of development for this looked to be considerably less than the shuttle alone, and would have a large space station in orbit earlier.
The answer of those groups dedicated to the shuttle was that if you have enough launches, the development cost of the system is overwhelmed by the cost of the rockets that would otherwise be thrown away. One factor that needed to be considered though was inflation, and in the 1970s this was high enough that the payback from the development had to happen very quickly or that money would never pay for itself. In other words a very high launch rate was needed to make the system work.
But there was no way that a space station or Air Force payloads could demand such rates (roughly 1 to 2 per week), so they went further and suggested that all future US launches would take place on the shuttle, once built. In order to do this the cost of launching the shuttle would have to be lower than any other system with the exception of the very small, which they ignored for practical reasons, and very large, which were rare and terribly expensive anyway.
With a baseline project now gelling, NASA started to work though the process of obtaining stable funding for the five years the project would take to develop. Here too they found themselves increasingly backed into a corner.
With the budgets being pressed by inflation at home and the Vietnam War abroad, Congress and the Administration generally couldn't care less about anything as long-term as space exploration and were therefore looking to make further deep cuts to NASAs budget. But with a single long term project on the books, there wasn't much they could do in terms of cutting whole projects -- the shuttle was all that was left, cut that and there would be no US manned space program by 1980.
Instead they looked to reduce the year-to-year costs of development to a stable figure. That is, they wished to see the development budgets spread out over several more years. This is somewhat difficult to do--you can't build half a rocket. The result was another intense series of redesigns in which the re-usable booster was eventually abandoned as impossible to pay for. Instead a series of simpler rockets would launch the system, and then drop away for recovery. Another change was that the fuel for the shuttle itself was placed in an external tank instead of internal tanks from the previous designs. This allowed a larger payload bay in an otherwise much smaller craft, although it also meant throwing away the tankage after each launch.
The last remaining debate was over the nature of the boosters. NASA had been looking at no less than four solutions to this problem, one a development of the existing Saturn lower stage, another using "dumb" pressure-fed liquid fuel engines of a new design, and finally either a large single solid rocket, or two (or more) smaller ones. The decision was eventually made on the smaller solids due to their lower development costs (a decision that had been echoed throughout the whole Shuttle program). While the liquid fueled systems provided better performace and enhanced safety, delivery capability to orbit is much more a function of the upper-stage performance and weight than the lower. The money was simply better spent elsewhere.