What is a Space Shuttle?
The Space Shuttle is a manned, reusable vehicle that carries people between low-Earth orbit and the ground. It can take off vertically like a launch vehicle, or land at an airport after returning to the atmosphere like an airplane. The space shuttle consists of an orbiter, an outer tank, and a solid booster. [1]
- In April 1969, at the end of the costly "Apollo Moon Landing Project",
- The United States Space Shuttle is composed of an orbiter, an external fuel tank and a solid rocket booster. [7]
- Compared with ballistic launch vehicles, the space shuttle has the following advantages: [1]
- All American space shuttles are manufactured by Rockwell, and each space shuttle is named after a ship with scientific and exploratory influence. [6]
- US-Russia space shuttle comparison
- Low safety factor: 2 space shuttles exploded, killing 14 astronauts
- Due to the repeated use of the space shuttle, its technical difficulties, complicated system design, and parts are easier to wear. From takeoff, ascent, orbital operation, reentry into the atmosphere, and return to landing, it needs to withstand various extremely harsh environments. The weakness of the space shuttle is gradually exposed in use, and its system goes far beyond simply adding both a manned spacecraft and a launch vehicle. When the cost of a single operation is too high, the risk cannot be ignored, and the transmission frequency is reduced from 24 to 5 times a year as planned. The accident rate of the space shuttle is very high. Two of the five space shuttles in the United States exploded and disintegrated during the mission, and 14 astronauts were killed. Unlike one-off vehicles such as rockets and spaceships, the space shuttle s rocket engine needs to be reused multiple times, and the total working time during its life spans up to several hours, which also brings safety hazards to its mission: as it flies The increase in tasks is bound to have more potential dangers. [3]
- High launch cost: one flight costs $ 500 million, nearly 100 times more than the design expectation
- A total of five space shuttles were developed and put into use by the United States, each with a research and development cost of 2 billion U.S. dollars, a total of more than 100 launches, and each flight costing up to 500 million U.S. dollars. After returning, a lot of time-consuming and labor-intensive repairs were required. The bureau's finances are overwhelmed. Although the original intention of the space shuttle was to reduce the cost of the entire human spaceflight development and launch process, Americans found that this was not the case during the implementation of this program. Earlier data showed that from 1985 to October 1988, the launch price of the space shuttle increased by 85%, that is, the cost of each launch soared to $ 90 million. This cost completely violated NASA's original design of the shuttle. When NASA determined the structural layout of the space shuttle, it had estimated that the space shuttle launch cost was US $ 100 per catty, and the cost of each launch did not exceed US $ 6 million. [3]
- Although NASA has taken various measures to save costs, the development costs have been overrun for several years. In September 1978, NASA announced that the development cost of the space shuttle may increase by 8% -9% over the original plan. In April 1980, NASA revealed that the cost of the entire shuttle program would increase to $ 8.9 billion. In this case, NASA had to repeatedly apply to Congress for additional funding. The then Carter administration considered that the space shuttle was beneficial to national security and had high value for scientific research and commercial development. Therefore, it did not dispute the additional funding. The cost of the plan was resolved. In addition, the space shuttle's landing site is very far from the launch site. After each landing, a large passenger plane is taken back to the launch site for maintenance, which adds additional costs. These conditions exceeded NASA's original good expectations, which indicates that the shuttle's economic benefits have been greatly reduced. [3]
- Space shuttle ages much faster than expected, missions forced to shrink significantly
- In the use of the space shuttle, NASA found that, like the development and launch costs, the maintenance and operation costs of the space shuttle have skyrocketed. For example, in 1984, the cost of a space shuttle flight was US $ 150-200 million, and the highest compensation that can be obtained in a commercial launch is only US $ 71 million. Most importantly, NASA found that launching a satellite with a space shuttle was more expensive than launching a satellite with a rocket. Therefore, after 1988, NASA decided not to undertake commercial payload launch missions, reducing the number of space shuttle flights to about 9 per year. According to the plan, the space shuttle of the United States has a maximum life of 20 years, and each of them should fly 100 times. As of today, the five space shuttles have flown only 132 times, of which two exploded in flight and two have severely exceeded their service life. [3]
- The space shuttle is aging faster than expected. Although the number of missions performed is reduced by nearly a quarter than expected, the space shuttle is damaged and aging, and the maintenance cost is very expensive. Especially after the crash of the "Columbia" space shuttle (2003), the cost of inspecting thermal protection tiles increased. The "Discovery" has been in small conditions frequently since its first flight in 1984. The fuel tank's thermal insulation foam has fallen off and the external hydrogen tank's liquid hydrogen transmission tube has leaked. This has led to increased inspection and maintenance before each mission. Drag and drop. [3]
- For the end of the space shuttle era, Long Lehao, a Chinese expert in strategic missile and launch vehicle technology and an academician of the Chinese Academy of Engineering, believes that it means the end of a phase, but also the beginning of a higher starting point. [twenty three]