The reporter learned on the 3rd from the first aerospace institute of China Aerospace Science and Technology Corporation that the academy has recently made a breakthrough in "control technology for low-temperature propellant evaporation." This technology can extend the duration of China's low-temperature rockets in orbit to 30 days, and provides feasible conditions for China's deep space exploration and long-distance space transportation.
Low-temperature rockets are also called "ice arrows". The liquid hydrogen, liquid oxygen and other low-temperature chemical propellants used are non-toxic, non-polluting, economical, and efficient. Therefore, they have been widely used at home and abroad in launch vehicles and upper stages. China's Long March 5 and Long March 7 launch vehicles are all low-temperature rockets. However, at present, most of the low-temperature rockets in orbit at home and abroad can only be maintained at tens of minutes to a few hours. How to extend their orbit time has always been a problem that puzzles aerospace designers.
Zhang Shaohua, a member of the technical team of the First Institute, introduced that the main factor restricting the time of low-temperature rockets in orbit is the evaporation loss of propellant. Under normal pressure, liquid hydrogen is -253 ° C and liquid oxygen is -183 ° C. Low-temperature rockets flying in orbit for a long time will face a severe thermal environment. When heated, low-temperature propellants will evaporate a lot, affecting fuel supply and restricting the time of on-orbit missions. For example, if the fuel tank of a car continuously leaks, it will inevitably affect its cruising range.
In addition, when the rocket is in flight, it must be exhausted at intervals to maintain the pressure of the tank not to exceed the limit. However, in the microgravity environment of space, gas and liquid cryogenic propellant are intertwined, which is difficult to separate. During exhaust, a large amount of liquid propellant is entrained in the gas and is discharged from the tank, causing the loss of propellant.
The first hospital strives to solve the above problems by using two advanced materials and one exhaust scheme.
Zhang Shaohua said that the "new polyurethane foam insulation material" developed by the First Hospital can improve the insulation capacity by more than 50% under low temperature conditions compared with traditional foam materials; "variable density multilayer insulation materials", compared with ordinary multilayer insulation The thermal insulation capacity of thermal materials has been increased by more than 18%. The evaporation of low-temperature propellant for active rockets in China is more than 2.5% per day. If these two new insulation materials are used, the evaporation of propellant per day can be reduced to 0.5%. (Reporter Fu Yifei from Gao Chongrui)
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