LS2022 23 Call2

Pagina 1

First name Last name Personal ID number Score Launch systems (8 credits) Feb. 8th, 2023 First part - Closed book Each question is worth 1 point. The student must obtain at least 6 points (without rounding) otherwise the second part of the exam will not be corrected. WRITE THE ANSWERS IN THIS SHEET Scenario – Reusable space launcher The launcher is characterized by the following properties • Payload 1000: kg • Number of stages: 2 • Recovery methodology: burn-back maneuver • Reuse: variable times, from 2 times to 8. 1. Coffee-time discussion with one of your colleagues Do you agree? Mark them as true (T) or false (F) (correct answer +2, wrong answer -1, no answer 0) If we move to parachute recovery we may increment the payload This reuse plan is always cost-effective Guidance: we can do it with gyroscopes Guidance: we can do it with GPS As we do the first stage, we can easily recover the second one 2. What are the most important requirements for the first stage of this launcher? (Three valid questions. The selection of a wrong answer invalidates the question.) Readiness High energy density solid propulsion Throttling capability T/W > 1 High-drag shape easing recovery Reignition capability Airbreathing propulsion Infrared homing Launch Systems Page 1 3. Consider the condition shown in the picture for the reentering first stage. The stage is falling and the main propulsion is firing the burn-back maneuver and slows down the descending velocity (figure not precise … do not rely on it). Select the correct statements. (Two valid questions. The selection of a wrong answer invalidates the question.) The flight condition is intrinsically stable The rocket plume causes strong base heating The propellant settles at bottom side of the tank (towards the nozzle) A wing placed close…