Revised rocket man

B1: Effect of air and altitude

Depending on higher or lower altitude, effect of air density and force at which the air pushes against the rocket directly affects the descent rate of rocket.

B2: Effect of air pushing against rocket

As descent rate increases. Rocket is getting close to the earth. Hence there is higher force of air resistance on the rocket, which in turn slows down the rocket’s descent rate.

B3: Left over fuel

As throttle setting increase the rate at which fuel burns also increases which results in less remaining fuel then before, which in turn makes the rocket lighter, Once the rocket is lighter the force of gravity on rocket increases which increases rockets downward acceleration and in turn decent rate. If decent rate increases, altitude decreases which increases the goal decent rate. Finally when goal decent rate increases the throttle setting of the rocket decreases.

B4: Fuel control

As throttle setting increases the fuel burn rate also increases, because of that there is decreases in remaining fuel in rocket. If there is a decrease in remaining fuel in rocket, goal decent rate of the rocket increase which in turn decreases the throttle setting.

B5: Safe Decent

Once the descent rate of the rocket increases, altitude of the rocket above the earth decreases. Which brings us close to our goal decent rate. If the goal descent rate decreases then we increase the rockets throttle setting, which also increases the rocket’s fuel burn rate. If the fuel-burn rate increases then the thrust from the rocket burn also increases. Once the thrust from the rocket burn increases rockets upward acceleration from the rocket engine also increases, which in turn decreases the descent rate of the rocket.

B6: Effect of mass and gravity pull

As rockets descent rate increases the altitude decreases, if the altitude decreases then the goal descent rate of the rocket also decreases, which in turn increases the throttle setting of the rocket. Increase in throttle setting also increases the fuel burn rate of the rocket. If the fuel-burn rate increases then the remaining rocket fuel decreases. Which in turn decreases the rocket mass. If the rocket’s mass decreases, upward acceleration from the rocket engine increases. Which in turn decrease the rockets decent rate.   

R1: Effect of gravity

If descent rate of rocket increase then rocket gets closer and closer to the earth decreasing the altitude. Due to which earth’s gravity pull on rocket gets stronger and rocket’s downward acceleration increases. Which in turn also increase the descent rate of rocket. 

• Delay: There might be some delay between fuel burn rate setting of the rocket and thrust from the rocket burn. It might take some time (not much but some) for rocket engine to burn the fuel and effect the rocket thrust setting.
  
  

Behavior of the system at different times through the flight.  

1. I think B3 and B6 loops will help in determining the flight of the rocket early in the flight, because in early stages of rocket descending towards earth rockets engine and earths gravity will do most the work.
2. Loop R1, B2, B4 and B1 will dominate in final seconds of the flight of the rocket, because by now rocket will be close to the earth. Which means rocket will be effected by lots of variables like gravity, air density, air resistance on the rocket and downward acceleration from gravity stronger than before.