Pre-launch and launch environments

Question 1

Why is the launch environment thermally challenging?

Answer 1

Because of the presence of cryogenic propellants combined with frictional heating from airflow

Question 2

What happens to the ambient pressure during launch?

Answer 2

Rapid change as a result of the rocket’s rapid acceleration

Question 3

What are the two main sources of vibration during launch?

Answer 3

Structural components and acoustic noise from the launch of the rocket

Question 4

What types of component are more susceptible to acoustic noise than vibrations?

Answer 4

Light flexible ones like solar panels

Question 5

At what two points during a launch is the acoustic/vibration environment at its most intense

Answer 5

1. At the moment of lift off since there are reflection from the ground
2. as the rocket goes supersonic (unstable airflow)

Question 6

At what two moments do mechanical shocks occur during launch?

Answer 6

1. During booster ignition such as during stage separation
2. When pyrotechnic devices are operated to detach stages from the rocket

Question 7

Why must the spacecraft be adequately vented?

Answer 7

because as it ascends the pressure environment decreases

Question 8

What does the shroud do for the spacecraft?

Answer 8

As it ascends through the atmosphere, the aerothermal energy is incident on the shroud rather than the spacecraft. The shroud is shaped such that the air it is colliding with does not meet with the spacecraft underneath