CIVIL AIR PATROL CAP-STK Aerospace Program 2013!! Learning Lab for CAP National Conference, Denver, Colorado 17 Aug 13 Colorado Springs Cadet Squadron Lt Col M. T. McNeely
STK Aerospace Program Elements • STK Curriculum Text • Orbital Mechanics PP Presentation • STK Scenario Files
STK Curriculum Text • Chapter One – Orbital Mechanics • After completing the chapter, you should be able to: - Define the size of an orbit. - Define the shape of an orbit. - Define the Inclination of an orbit. - Define Right Ascension. - Define Argument of Perigee. - Define True Anomaly. • Demonstrate each orbital element for a satellite using STK
STK Curriculum Text • Chapter Two – Orbit Orientations • After completing this chapter, you should be able to: - Describe the characteristics of a Low Earth Orbit (LEO) - Describe the characteristics of a Medium Earth Orbit (MEO) - Describe the characteristics of a Highly Elliptical Orbit (HEO) - Describe the characteristics of a Geo-Synchronous Orbit (GEO) - Describe the characteristics of a Sun-Synchronous Orbit • Demonstrate each orbital altitude in STK
STK Curriculum Text • Chapter Three – Space Operations • After completing this chapter, you should be able to: - Describe how to find satellites in the satellite database and display in STK. - Describe how to launch a satellite from a specific location to meet up with an orbiting object. - Describe how to display the planets and planet moons in the solar system. - Describe how to link ground and space objects together in a chain, using Constellations. • Demonstrate each topic above using STK.
STK Curriculum Text • Chapter Four – Space and a System of Systems - Describe how to connect STK Space, Air, Sea, and Ground assets for a specific mission. - Describe how to connect STK Space, Air, and Sea assets to monitor Earth’s Polar Regions. - Describe how to connect STK assets to accomplish a specific mission: Humanitarian Relief. - Describe how to connect STK assets to accomplish a global Reconnaissance Operation. - Demonstrate thorough knowledge and understanding of STK by performing an integrated scenario using all aspects of STK presented in this program.
ORBITAL MECHANICS • Two men in history that were essential to formulating orbital mechanics: Kepler and Newton!! • Kepler’s 3 Laws: • Law of Ellipses • Law of Equal areas • Law of Harmonics • Newton’s 3 Laws: • Law of Inertia • Law of Momentum • Law of Action -Reaction
PHYSICAL LAWSKepler’s 1st Law: Law of Ellipses The orbits of the planets are ellipses with the sun at one focus. Or, the orbits of satellites around the earth are ellipses with the earth at one focus…..
PHYSICAL LAWS Is this orbit possible?
T4 T3 T5 T2 A4 A3 T1 A5 A2 A1 T6 A6 PHYSICAL LAWSKepler’s 2nd Law: Law of Equal Areas The line joining the planet to the center of the sun sweeps out equal areas in equal times
PHYSICAL LAWSKepler’s 2nd Law: Law of Equal Areas Satellites travel at the same speed!!
PHYSICAL LAWSKepler’s 2nd Law: Law of Equal Areas t1-t0 = t3-t2 Area 1 = Area 2 t2 t1 Area 1 Area 2 t0 t3 Satellites travel at varying speeds!!
PHYSICAL LAWSNewton’s 1st Law: Law of Inertia • Every body continues in a state of uniform motion unless it is compelled to change that state by a force imposed upon it
F F PHYSICAL LAWSNewton’s 2nd Law: Law of Momentum • Change in momentum is proportional to and in the direction of the force applied • Momentum equals mass x velocity • Change in momentum gives: F = ma
PHYSICAL LAWSNewton’s 3rd Law: Action - Reaction • For every action, there is an equal and opposite reaction • Hints at conservation of momentum
INJECTION REQUIREMENTSSpeed A satellite must be going 17,500 mph to stay in a low earth orbit 17,500 mi/hr 100 miles
INJECTION REQUIREMENTSAltitude Are you moving FASTER or SLOWER the higher your altitude?
ORBITAL ELEMENTSorThe Six Keplerian Elements • Size/Period • Shape (Circular or Ellipse) • Inclination • Right Ascension • Argument of Perigee • True Anomaly
e = 0.75 e = .45 e = 0 ORBIT CLASSIFICATIONSEccentricity The closer your Eccentricity is to 1, the more elliptical your orbit is Why could you never have an Eccentricity of 1??
GROUND TRACKSDefinition • One way to define a satellite’s orbit is to determine its track across the ground • It is as if you had a big pencil from the satellite to the ground. The track it traces is called the ground track
Ground TracksWestward Regression - Earth rotates east under a satellite => satellite appears to walk west - Earth rotates 360 degrees in 24 hours (15 degrees per hour)
Ground TracksEccentricity Ground Track for Molnyia orbit eccentricity = .7252
Ground tracks Inclination 60 30 45N 0 30 60 45S Inclination = 45 degrees Eccentricity ~ 0
PERTURBATIONS • Space is a vacuum • Once a satellite is in orbit, in the vacuum of space, is there anything that will affect it?? • Yes – these things are called Perturbations…….
PERTURBATIONS • Definition • A disturbance in the regular motion of a celestial body • Types • Gravitational • Atmospheric Drag • Third Body Effects • Solar Wind/Radiation Effects • Electro-magnetic
PERTURBATIONSGravitational • Ellipticity of the Earth causes gravity wells and hills • Stable points: 75E and 105W -- Himalayas and Rocky Mountains • Unstable points: 165E and 5W -- Marshall Islands and Portugal • Drives the requirement for station keeping
LAUNCH CONSIDERATIONS • Launch Windows • Azimuth Vs. Inclination
DE-ORBIT/DECAY • De-Orbit is the controlled re-entry of a satellite to a specific location • Used for the recovery of payload • Manned missions • Decay is uncontrolled re-entry • Potential impact anywhere along ground track • Re-entry Assessment (by CMAS)
TYPES OF ORBITS -Uses of Satellites • Daily Uses of Satellites • Big Picture • Affects of Altitude
TYPES OF ORBITS -Uses of Satellites Global Positioning System!!
TYPES OF ORBITS -Uses of Satellites A Remote Sensing Satellite’s view of Earthquake Damage in Haiti
PLACING SATELLITES IN ORBITOVERVIEW • How Satellites are Launched • Location Advantages of the Two Primary US Launch Site
PLACING SATELLITES IN ORBIT • Boosters DELTA IV
PLACING SATELLITES IN ORBIT • Boosters ATLAS V
PLACING SATELLITES IN ORBIT • Boosters TAURUS
PLACING SATELLITES IN ORBIT • Launch Locations • Cape Canaveral (Patrick AFB) Eastern Range) • Vandenberg AFB (Western Range)
PLACING SATELLITES IN ORBIT • Launch Constraints
SATELLITE OPERATIONSELEMENTS • Ground Segment • Space Segment • Data Link Segment
SATELLITE OPERATIONSFUNCTIONS • GPS Example
SATELLITE OPERATIONSACCESS • Field of View (FOV) • Location of Ground station/Observer • Satellite Orbital Position
ORBITAL MECHANICS • Classroom Presentations using Powerpoint • Demonstrate with STK • Let’s Demo !! The world of Space Operations awaits you!!