The specific impulse of chemical energy rocket engine can reach ____.
A. 3000 m/s
B. 5000 m/s
C. 8000 m/s
D. 10000 m/s
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Which of the following engine has the highest specific impulse? ____.
A. Liquid rocket engines
B. Solid rocket engines
C. Nuclear rocket engines
D. Electrostatic rocket engine
V-2 missile is a kind of ____ missile.
Air-supported
B. Air-to-ground
C. Ground-to-air
D. Ballistic
Which following is true about the re-entry angle of the spacecraft’s return stage? ____.
A. The re-entry angle is the angle between the direction of the spacecraft’s flight speed and the local horizon.
B. If the re-entry angle is too small, the spacecraft might been destroy due to high temperature.
C. If the re-entry angle is too large, the spacecraft might skim the atmosphere.
D. If the re-entry angle is too large, the spacecraft might been destroy due to high temperature.
Spacecrafts using semi-ballistic re-entry mode include: ____.
A. “"Shenzhou" series spacecraft
B. "Soyuz" spacecraft
C. "Apollo" spacecraft
D. "Vostok 1" manned spacecraft
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