Rockets Flashcards
How does a rocket work
High temperature and pressure
Nozzle throat creates a choke that maintains high pressure
Pressure drops through diverging section so velocity is supersonic
How can you increase the thrust of a rocket
Increase the exit velocity as the mass of propellant is fixed in carrying weight
What are the characteristics of a good rocket
High upstream temperature
High upstream pressure
Low molecular mass gas
Summarise the German V2 rocket characteristics
Steam turbine driven pumps
Sharp tip caused aerodynamic heating
Clustered combustion chambers for stability
Difficult to cool walls
Regenerative cooling
Summarise the Soviet R7 rocket characteristics
Blunt aerodynamic head
Breakaway engines and central core for multi staging
Corrugated steel between copper and steel walls for more efficient regen cooling
What innovation did the RD107 bring
Variable mixture ratio of fuel and oxidiser to prevent uneven finishing of boosters
What was notable about the Soyuz rocket
Descendant of the R7
Low cost
High reliability
Most used space launcher
What conditions must fuel be delivered at if it is being used as a coolant
High pressure as some will be lost during cooling
What innovations tie in with reusable rockets
Thrust vector control
Multiple cold thrusters
Re-ignitable engines
Inertial navigation and GPS
Deployable landing gear and grid fins
What are the pros and cons of reuse
Pros: fuel costs are small percentage of total cost with savings on manufacturing
Cons: reduced payload capability, added costs in initial development, manufacture, recovery and refurb, need lots of reuses for economic viability
What are some reusable launch system landing mechanisms
Chopsticks catching method
Jettison engine and protect during high speed fall with parachute
What is the concept of a ram rocket
Rocket launch and then the ramjet takes over once at the required velocity
What are the pros of air launch to orbit
Avoid flying through low dense atmosphere
Nozzle optimisation for conditions
More choice in propellants
Launch from select location
Weather less limiting
What are the cons of air launch to orbit
Limited by aircraft size
Rocket has to change from horizontal to vertical flight
Savings may not be worth it
What propulsion is used in the Bloodhound SSC
Jet engine for initial acceleration
Hybrid solid rocket engine that kicks in at high speed to go supersonic
Auxiliary power unit used to pump fuel
