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What you need spaceships tomorrow?
When in the 1970s thought the space shuttles in the dreams of engineers was to create a new type of spacecraft – which can transport people and cargo into orbit, return to Earth, and then used again. It is possible, but only partially.
In 1997, the National Aeronautics and Space Administration (NASA) worked on the creation of the spacecraft, which operated mostly as an airplane. They wanted to create a spaceship that not only can be used repeatedly, but also to be a reliable and efficient enough to fly more often and less expensive than the shuttle.
Why shuttle launch was so expensive?
Of the four major components of the shuttle only one – winged orbiter – was completely reusable. Huge external fuel tank was discarded when opustevayut after eight minutes of flight and burned when re-entering the atmosphere. Two booster (on the sides of the fuel tank) and were shot when opustevayut already after two minutes of flight. They then parachuted into the ocean, and then restored. Later missiles dismantled and filled with solid fuel. However, restoring and refueling require much special equipment and work that would be cheaper to buy a set of expendable launchers for each shuttle launch.
These and other difficulties made the shuttle vehicle is extremely expensive – $ 400 million per launch the most conservative estimates. And this is only one flight, not counting satellites and laboratories on board. As a result, after 40 years of the space age, disposable rockets are cheaper to use than the shuttle.
Nevertheless, the idea of disposable vehicle always seemed wasteful. In the end, not to throw out the car after every trip? In theory, you can create a long, single-stage fully reusable orbital transport. But a variety of factors, including the performance of engines and materials used in the fuel tanks and other structures that have acquired such a high cost that became impractical, anyway, if subjected to the payload.
Technologies aimed at creating a reusable rocket
Some of these factors have changed in recent years, making the idea of a single-stage reusable rocket more viable. Several key technologies have advanced significantly since it was built shuttle. Development of some composite materials (graphite-epoxy), powerful alloys (aluminum-lithium) and allowed to create new ceramics lightweight fuel tanks and heat shields. engines are lighter and more reliable. In addition, the flight control systems, electromechanical replace heavy and problematic hydraulic system. Smaller, much more capable computers and advanced navigation systems have simplified the navigation and maintenance.
Some of these technologies are already being used in the development of certain aircraft such as the F-22 bomber, as well as Boeing-777 airliner. Some of these studies began in the 80s in the development of aerospace plane capable of flying in orbit.
In the early 90’s supporters convinced DARPA reusable rockets to carry out experiments and make sure that a single-stage rocket can be practical and inexpensive. McDonnell Douglas Corporation built the first such vehicle under the name Delta Clipper Experimental, or DC-X.
After the flight, the team showed that the DC-X is ready to fly the next day.
Association with private industry
Need not so many operations to reduce the cost of space transportation. Many experts believe that the cost savings will new customers, including space tourists. Other experts believe that the costs can not be reduced until the government let private entrepreneurs in the pilot’s seat.
NASA agrees with this view. In 1995, the agency announced that it wants to help private industry to develop new experimental spacecraft called X-33. The hope was that the trucks will show that space travel can be cost effective. Has also set a target to reduce the cost of launching a payload by 90%, to $ 3,000 per kilogram. If this goal is achieved, NASA suggested that the private segment will be to create and maintain a fleet of commercial reusable launch vehicle (RLV).
Although often portrayed as MPH replacement shuttles themselves, they were not the target. There was no need to replace the shuttles, as they easily could fly for 15 years, and with the improvements – and 2030. The aim was to reduce costs MPH on the run.
Lockheed Martin wins the tender NASA
In the development of X-33 were interested in three major aerospace companies. McDonnel Douglas suggested larger version DC-X, DC-XA, or Clipper Graham. Rockwell International (together with Northrop Grumann) suggested on the basis of vehicle shuttle shuttle with many improvements. But in July 1996, NASA chose a policy of rapprochement with the Lockheed Martin Corporation, as their plan involves many technological innovations, and the company promised a lot of interesting things in terms of development MPH after X-33.
Lockheed Martin plan was to equip the new engine MPH – klinovozdushnym rocket engine. Instead of using a conventional cluster conical rocket nozzle, this arrangement has used a number of nozzles arranged linearly along the edges of the rectangular wedges. Automatic flight control system alone would regulate chokes on each of the seven motor vehicle. The plan also included the construction of the “lifting body” in which all the traffic was a body with small wings. Large area X-33 would effectively distribute heat when re-entering the atmosphere and involving a new type of heat shields.
X-33 was to be 20.4 meters long and 20.7 m wide. Speed - 17 000 kilometers per hour, which is insufficient for reaching orbit. First flight is expected in March 1999.
Ship named VentureStar
Lockheed Martin has named his concept MPH, which was supposed to go after the X-33 VentureStar. It would be identical to X-33, but twice as long and wide. She was able to raise 18,160 pounds of payload. The first flight was scheduled for 2004.
According to the plan VentureStar had to be fully automated – the ship would not have included the crew. Direction for each mission is programmed to on-board computer system. Automatic control system would control everything from the engine and directions to the flight path. People on the vehicle would be just passengers. Separate capsule with life support system would be in the cargo hold of MPH.
Unfortunately, the project was canceled in 2001 on the stage of development of X-33 after a collision with serious technical difficulties and lack of funding. Now all hope remains only on SpaceX and its development . It Elon Musk, like anyone else, understands the importance of creating a reusable launch vehicle than actually now engaged SpaceX.
NASA to plan the development of rockets by private companies had to facilitate the delivery of astronauts to the ISS. Actually, it happened: Now NASA has contracted with Lockheed Martin, Boeing and, more recently, SpaceX.
Since its first flight in 1981, the space shuttle, despite its limitations, has been a very useful tool. Crews shuttle launched commercial and military satellites into space, repair broken satellites (including not working the Hubble Space Telescope) and conduct important scientific experiments. But in the future reusable booster can significantly facilitate the entry of people into space. Such vehicles would be the best way to expand our last frontier.
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Tags: Space Mission , Space flight , Rockets .
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