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

Maneuvering/Traveling in Space II

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

Understanding Re-entry MotionRe-entering a Planet’s

AtmosphereTrade-offs for Re-Entry

DesignRe-Entry Motion

Understanding Re-Entry Motion:

Re-Entry 1:13

Mission requirements of a vehicle entering an atmosphere

Engineering trade-offs for mission designDecelerationHeatAccuracy of Landing or Impact

Understanding Re-Entry Motion:Atmosphere

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.

Understanding Re-Entry Motion:Atmosphere -- Deceleration

Spacecraft in orbit have a lot of energy:Kinetic energy: orbital velocityPotential 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.

Understanding Re-Entry Motion:Atmosphere -- Heat

7

Depending on the vehicle’s mission, accuracy may or may not be a driving design consideration.Mission requirementSafetyRecovery and Reuse

(Funding)Support Requirements

Understanding Re-Entry Motion:Atmosphere – Accuracy in Landing

Trade-offs for Re-entry CorridorThe 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.

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

Forces (F) acting on spacecraft during re-entryDragLiftGravityOther forces

Re-entry Motion: Analysis

DragDrag force can be more than 160 times the force of gravityDrag on a vehicle affected by:

Its velocityHow BIG it is (Cross-sectional area)How dense the air isIt’s drag coefficient (How streamlined it is)

Re-entry Motion: Analysis

LiftOffsets 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

Re-entry Motion: Analysis

Bernoulli Principle

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

Maneuvering/Traveling in Space II