Unfulfilled hopes: what was planned and what happened in the Space Shuttle program


    The other day, I accidentally noticed that five times in the comments I had answered the question about the degree of success of the Space Shuttle program. Such regularity of questions requires a full article. In it I will try to answer the questions:
    • What were the goals of the Space Shuttle?
    • What is the result?



    The topic of reusable media is very voluminous, so in this article I am specifically limited only to these issues.

    What did you plan?


    The idea of ​​reusable ships has occupied the minds of scientists and engineers in the United States since the 50s. On the one hand, it’s a pity to smash the dumped waste steps on the ground. On the other hand, an apparatus combining the properties of an airplane and a spaceship will be in line with airplane philosophy, where reusability is natural. Various projects were born: X-20 Dyna Soar , Recoverable Orbital Launch System(later Aerospaceplane). In the sixties, this rather inconspicuous activity continued in the shadow of the Gemini and Apollo programs. In 1965, two years before the Saturn-V flight, a subcommittee on reusable carrier rocket technologies was created at the Coordinating Council for Aerospace Operations (in which the US Air Force and NASA participated). The result of this work was a document published in 1966, which stated the need to overcome serious difficulties, but a bright future was promised for working in low Earth orbit. The Air Force and NASA had a different vision of the system and different requirements, therefore, instead of one project, the ideas of ships of different layouts and the degree of reusability were presented. After 1966, NASA began to think about creating an orbital station. Such a station implied the need to deliver a large amount of cargo into orbit, which, in turn, raised the question of the cost of such delivery. In December 1968, a working group was created, which began to deal with the so-called Integral Launch and Reentry Vehicle (ILRV) A report from this group was presented in July 1969 and argued that ILRV should be able to:
    • Supply the orbital station
    • Launch and return satellites from orbit
    • Put acceleration blocks and payload into orbit
    • Put fuel into orbit (for subsequent refueling of other devices)
    • Maintain and repair satellites in orbit
    • Conduct short manned missions

    The report examined three classes of ships: a reusable ship “riding” on a one-time launch vehicle, a half-speed ship (the “half” of a stage is tanks or engines that are dumped in flight) and a two-stage ship, both of which are reusable.
    In parallel, in February 1969, President Nixon created a working group whose task was to determine the direction of movement in space exploration. The result of the work of this group was the recommendation to create a reusable ship that could:
    • Become a fundamental improvement in existing space technology in terms of cost and orbit
    • Transporting people, cargo, fuel, other ships, booster blocks, etc. to orbit like an airplane is regular, cheap, often a lot.
    • Be universal for compatibility with a wide range of civilian and military payloads.

    Initially, engineers moved in the direction of a two-stage fully reusable system: a large winged manned ship carried a small winged manned ship that was already in orbit:

    This combination was theoretically the cheapest to operate. However, the requirement of a large payload made the system too large (and therefore expensive). In addition, the military wanted the possibility of a horizontal maneuver of 3,000 km for landing at the launch site at the first turn from the polar orbit , which limited engineering decisions (for example, straight wings became impossible).

    Judging by the signature “high cross-range” (large horizontal maneuver), the military liked this picture. The

    final layout depended very much on the following requirements:
    • Cargo compartment size and capacity
    • Horizontal maneuver
    • Engines (type, traction and other parameters)
    • Landing method (on engines or planning)
    • Materials used

    As a result, at the hearings in the White House and Congress the final requirements were adopted:
    • Cargo Compartment 4.5 x 18.2 m (15 x 60 ft)
    • 30 tons to low Earth orbit, 18 tons to polar orbit
    • Possibility of horizontal maneuver for 2000 km


    In the 1970 area, it turned out that there would not be enough money for the orbital station and the shuttle at the same time. And the station for which the shuttle was supposed to carry goods was canceled.
    At the same time, an unrestrained optimism reigned in the engineering environment. Based on the experience of operating experimental rocket aircraft ( X-15 ), engineers predicted a reduction in the cost of a kilogram per orbit by two orders of magnitude (a hundred times). At the Space Shuttle Symposium in October 1969, the shuttle “father” George Muller said:
    “Our goal is to reduce the cost of a kilogram into orbit from $ 2000 for Saturn-V to the level of $ 40-100 per kilogram. This will usher in a new era of space exploration. The challenge for the coming weeks and months for this symposium, for the Air Force and NASA, is to ensure that we can do this. ”

    B.E. The line in the fourth part of "Missiles and People" gives somewhat different numbers, but of the same order:
    For various options based on the Space Shuttle, it was predicted that the launch cost would be between $ 90 and $ 330 per kilogram. Moreover, it was assumed that the Space Shuttle of the second generation will reduce these figures to 33-66 dollars per kilogram.

    According to Mueller’s calculations, the launch of the shuttle should cost $ 1-2.5 million (compare with $ 185 million for Saturn-V).
    Quite serious economic calculations were also carried out, which showed that in order to at least equal the cost of the “Titan-III” launch vehicle with direct price comparison without discount, the shuttle needs to start 28 times a year. For fiscal 1971, President Nixon allocated $ 125 million for the production of disposable launch vehicles, which amounted to 3.7% of NASA's budget. That is, if the shuttle was already in 1971, then it would save only 3.7 percent of the NASA budget. Nuclear physicist Ralph Lapp calculated that for the period 1964-1971 the shuttle, if it had already, would save 2.9% of the budget. Naturally, such numbers could not protect the shuttle, and NASA stood on the slippery track of the numbers game: “if an orbital station were built, and if it needed a supply mission every two weeks, then the shuttles would save a billion dollars a year.” The idea was also advanced "with such launch capabilities, payloads will become cheaper, and there will be more than now, which will further increase savings."

    Economic calculations. Please note that if you remove the "new satellites" (the lower third of the table), then the shuttles become economically disadvantageous.

    Economic calculations. We pay more now (left side) and win in the future (right shaded part).

    In parallel, complex political games took place with the participation of potential manufacturers, the Air Force, the government and NASA. For example, NASA lost the battle for the first-stage accelerators to the Office of Management and Budget of the Executive Office of the President of the United States. NASA wanted rocket accelerators, but because the solid rocket accelerators were cheaper to develop, the latter were chosen. The Air Force, which sought military manned programs with the X-20 and MOL, actually received the shuttle military missions for free in exchange for political support from NASA. Shuttle production was deliberately spread across the country between different companies for economic and political effect.
    As a result of these complex maneuvers, a contract for the development of the Space Shuttle system was signed in the summer of 1972. The history of production and operation is beyond the scope of this article.

    What did you get?


    Now that the program is completed, it is possible to say with sufficient accuracy which goals were achieved and which were not.

    Goals Achieved :
    1. Cargo delivery of various types (satellites, upper stages, ISS segments).
    2. Ability to repair satellites in low Earth orbit.
    3. The ability to return satellites to Earth.
    4. The ability to send in flight up to eight people.
    5. Reusability implemented.
    6. A fundamentally new spacecraft layout has been implemented.
    7. Possibility of horizontal maneuver.
    8. Large cargo hold.
    9. The cost and development time were within the deadlines promised to President Nixon in 1971.


    Not achieved goals and failures :
    1. Qualitative facilitation of access to space. Instead of lowering the price per kilogram by two orders of magnitude, the Space Shuttle has become one of the most expensive means of delivering satellites into orbit.
    2. Fast shuttle preparation between flights. Instead of the expected period of two weeks between flights, the shuttles were preparing for launch for months. Before the Challenger crash, the record between flights was 54 days, after the Challenger - 88 days. For all years of operation of the shuttles, they were launched on average 4.5 times a year instead of the minimum permissible by calculations 28 times a year.
    3. Ease of maintenance. The selected technical solutions were very labor intensive to maintain. The main engines required dismantling and a lot of time for service. The turbopump units of the engines of the first model required a complete overhaul and repair after each flight. Thermal protection tiles were unique - each tile had its own tile. There are 35,000 tiles in total, and besides, they can be lost or damaged in flight.
    4. Replace all disposable media. Shuttles never launched into polar orbits, which is needed mainly for reconnaissance satellites. Preparatory work was underway, but they were stopped after the Challenger disaster.
    5. Reliable access to space. Four orbiters meant that the crash of the shuttle was the loss of a quarter of the fleet. After the crash, flights ceased for years. Also, the shuttles were notorious for the constant carry-over of launches.
    6. The shuttle's carrying capacity was five tons below the specifications required (24.4 instead of 30)
    7. Great opportunities for horizontal maneuver were never used in reality due to the fact that the shuttle did not fly into polar orbits.
    8. The return of satellites from orbit ceased in 1996. Only five satellites were returned from orbit.
    9. Satellite repair was also poorly in demand. In total, five satellites were repaired (although Hubble was serviced five times).
    10. The engineering decisions taken adversely affected the reliability of the system. On take-off and landing there were sections with no chance of saving the crew in an accident. Because of this, the Challenger died. The STS-9 mission almost ended in disaster due to a fire in the tail that had already occurred on the landing strip. If this fire happened a minute earlier, the shuttle would have fallen without a chance of saving the crew.
    11. The fact that the shuttle always flew manned put people at risk unnecessarily - automation was enough for the routine launch of satellites.
    12. Due to the low intensity of operation, shuttles are outdated morally than physically. In 2011, the Space Shuttle was a very rare example of operating the 80386 processor. Disposable media could be upgraded gradually with new series.
    13. The closure of the Space Shuttle program was superimposed on the cancellation of the Constellation program, which led to the loss of independent access to space for many years, image losses and the need to buy space on spaceships of another country.
    14. New control systems and nadkaliberny fairings allowed to launch large satellites on disposable missiles.
    15. The shuttle holds a sad anti-record among space systems in the number of dead people.


    The Space Shuttle program has given the United States unique opportunities to work in space, but from the point of view of the difference “what they wanted, what they got”, we have to conclude that it did not achieve its goals.

    Why did this happen?

    I specially emphasize that in this paragraph I express my thoughts, perhaps some of them are incorrect.
    1. The shuttles were the result of many compromises between the interests of several large organizations. Perhaps if there was one person or a team of like-minded people who had a clear vision of the system, it could turn out to be more successful.
    2. The requirement to “be everything for everyone” and replace all disposable rockets increased the cost and complexity of the system. Universality when combining dissimilar requirements leads to complication, appreciation, excessive functionality and worse efficiency than specialization. It’s easy to add an alarm clock to your mobile phone - you already have a speaker, a clock, buttons and electronic components. But a flying submarine will be more expensive and worse than specialized aircraft and submarines.
    3. The complexity and cost of a system grows exponentially with size. Perhaps a 5-10 ton shuttle payload (3-4 times less than realized) would be more successful. They could have been built more, part of the fleet made unmanned, made a one-time module to increase the carrying capacity of rare heavier missions.
    4. "Dizziness from success." The successful implementation of three programs of successively increasing complexity could turn the heads of engineers and managers. In fact, that a manned first launch without unmanned testing, that the lack of crew rescue systems in the launch / launch sections indicate some self-confidence.


    Hey, what about Buran?

    Anticipating the inevitable comparisons, you have to say a little about him. There are no operation statistics for many years for Buran. It turned out to be somewhat simpler with him - he was covered with the wreckage of the collapsed USSR, and it cannot be said if this program would be successful. The first part of this program - “make it like the Americans” was completed, and what would happen next is unknown.
    And for those wishing to arrange a holivar “What is better?” In the comments, I ask you to first give a definition of what is “better” in your opinion. Because both phrases “Buran has a larger margin of characteristic speed (delta-V) than the Space Shuttle” and “The Shuttle does not reset expensive marching engines with a booster stage” are correct.

    List of sources (excluding Wikipedia):
    1. Ray A. Williamson "Developing the Space Shuttle"
    2. TA Heppenheimer "The Space Shuttle Decision"
    3. The cost of a kilogram into orbit (for some reason, the wiki was thrown out of a good table)
    4. Information about the satellites who repaired and returned the shuttles.
    5. Thank you for the pictures . VK Encyclopedia of Military Aviation .


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