Maneuvering/Traveling in Space II

1. Maneuvering/Traveling in Space II • Understand the factors and requirements associated with a spacecraft launch • Understand the dynamics of Gravity Assist and the basic principles of placing a spacecraft into orbit • Understand the dynamics of spacecraft reentry in terms of the environment and spacecraft design considerations

2. Space Shuttle Rendezvous Maneuvers • Space shuttle and Russian Soyuz capsules rendezvous with the ISS and then dock • Rendezvous maneuvers are tricky and dangerous • You speed up when you drop into a lower orbit where your velocity is higher and your orbital path shorter

3. Understanding Re-Entry Motion: • Understanding Re-entry Motion • Re-entering a Planet’s Atmosphere • Trade-offs for Re-Entry Design • Re-Entry Motion Re-Entry 1:13

4. Understanding Re-Entry Motion:Atmosphere • Mission requirements of a vehicle entering an atmosphere • Engineering trade-offs for mission design • Deceleration • Heat • Accuracy of Landing or Impact

5. Understanding Re-Entry Motion:Atmosphere -- Deceleration • Too many g-forces can collapse a structure or threaten a crew. • Humans can withstand about 12 g’s which is equal to you having about 11 people standing on your shoulders. • Too little deceleration could mean “skipping” off the atmosphere back into space.

6. Understanding Re-Entry Motion:Atmosphere -- Heat • Spacecraft in orbit have a lot of energy: • Kinetic energy: orbital velocity • Potential energy: orbital altitudes • Energy is converted to heat caused by friction between the atmosphere and the spacecraft. • Space Shuttle traveling at about 17,225 m.p.h. in orbit, slows to several hundred m.p.h. to land in about ½ hour. • Shuttle surface temperatures can reach over 1400 degrees Centigrade.

7. Understanding Re-Entry Motion:Atmosphere – Accuracy in Landing • Depending on the vehicle’s mission, accuracy may or may not be a driving design consideration. • Mission requirement • Safety • Recovery and Reuse (Funding) • Support Requirements

8. Trade-offs for Re-entry Corridor • The spacecraft must be able to steer to make the re-entry successful. • Deceleration, heat and accuracy limit the re-entry velocity and angle. • If limits are too tight to achieve other parameters, the re-entry vehicle’s control system may not be precise enough to handle them.

9. Re-entry Motion: Terms of Reference • Re-entry angle: angle between local horizon and velocity vector • Re-entry velocity: velocity at which re-entry begins

10. Re-entry Motion: Analysis • Forces (F) acting on spacecraft during re-entry • Drag • Lift • Gravity • Other forces

11. Re-entry Motion: Analysis Drag • Drag force can be more than 160 times the force of gravity • Drag on a vehicle affected by: • Its velocity • How BIG it is (Cross-sectional area) • How dense the air is • It’s drag coefficient (How streamlined it is)

12. Re-entry Motion: Analysis Lift • Offsets gravity (weight of the vehicle) • Lift on a vehicle affected by: • Airfoils (lifting body) • How BIG it is (Cross-sectional area) • How dense the air is • Bernoulli Principle

13. Maneuvering/Traveling in Space II • Understand the factors and requirements associated with a spacecraft launch • Understand the dynamics of Gravity Assist and the basic principles of placing a spacecraft into orbit • Understand the dynamics of spacecraft reentry in terms of the environment and spacecraft design considerations