ETP_satellite_basics_02 1 Satellite Basics

ETP_satellite_basics_022 Source:

ETP_satellite_basics_02 3 Objectives The student will be able to: Describe orbital inclination Define satellite orbit orientation Describe and sketch satellite ground tracks Summarize orbital altitudes Describe Lagrange points and their usefulness in space telescopes.

ETP_satellite_basics_02 4 Orbital Information - 1 Ө Source:

Definitions ETP_satellite_basics_02 5 Type of OrbitCharacteristics Polarθ = 90° Equatorialθ = 0° Inclined0° < θ < 90° Geocentric – a satellite that orbits earth (e.g. moon, artificial satellites) with the following characteristics

ETP_satellite_basics_02 6 Definitions - 2 OrbitCharacteristic Low earth orbit (LEO) Up to 1240 miles Medium earth orbit (MEO) Between 1240 miles and just below 22,240 miles GeosynchronousAt 22,240 miles High earth orbit> 22, 240 miles

Orbital altitudes ETP_satellite_basics_02 7 “Various earth orbits to scale; cyan represents low earth orbit, yellow represents medium earth orbit, the black dashed line represents geosynchronous orbit, the green dash-dot line the orbit of Global Positioning System (GPS) satellites, and the red dotted line the orbit of the International Space Station (ISS).”Global Positioning SystemInternational Space Station Source:

Lagrange points ETP_satellite_basics_02 8 “Lagrange points are locations in space where gravitational forces and the orbital motion of a body balance each other. They were discovered by French mathematician Louis Lagrange in 1772 in his gravitational studies of the ‘Three body problem’: how a third, small body would orbit around two orbiting large ones. There are five Lagrangian points in the Sun-Earth system and such points also exist in the Earth-Moon system.” Source: European Space Agency,

Lagrange Point Orbit ETP_satellite_basics_02 9 Source:

Planck spacecraft at L2 ETP_satellite_basics_02 10 Source: Artist conception

Orbital information ETP_satellite_basics_02 11

Activity 1 ETP_satellite_basics_02 12 Activity 1: Complete activity given in “Orbital worksheet_altitude-speed.doc”

Technology connection – TI-83/84 (Optional) ETP_satellite_basics_02 13

Satellite Ground Track ETP_satellite_basics_02 14

Basics of ground track ETP_satellite_basics_02 15 Source: The Physics of Satellite Security, A Reference Manual, American Academy of Arts and Sciences, Section 5, p. 31

Ground track ETP_satellite_basics_02 16 Source: The Physics of Satellite Security, A Reference Manual, American Academy of Arts and Sciences, Section 5, p. 31

Ground track – 2 nd pass ETP_satellite_basics_02 17 Source: The Physics of Satellite Security, A Reference Manual, American Academy of Arts and Sciences, Section 5, p. 31

Real time tracking data ISS ETP_satellite_basics_02 18 Source: Snapshot taken: July, 9, 2009 At ~9:05 PDT

Activity 2 ETP_satellite_basics_02 19 Activity 2 Use regression equation derived earlier to compare theoretical speed to actual ISS speed.

Real time tracking ETP_satellite_basics_02 20 Source: spacecraft.html Snapshot taken: July, 9, 2009 At ~9:55 PDT

Activity 3 ETP_satellite_basics_02 21 Activity 3: For the snapshots in slides 18 and 20, what is the major noticeable difference? Explain.

Calculating satellite elevation angle ETP_satellite_basics_02 22

Satellite elevation angle ETP_satellite_basics_02 23 Source: The Physics of Satellite Security, A Reference Manual, American Academy of Arts and Sciences, Section 5, p. 32

Elevation equation ETP_satellite_basics_02 24 Source: Gerard Maral and Michel Bousquet, Satellite Communication Systems, 4 th ed. (West Sussex, England: Wiley, 2002), As reported in The Physics of Satellite Security, A Reference Manual, American Academy of Arts and Sciences, Section 5, p. 47

Activity 4 ETP_satellite_basics_02 25 Activity 4: 1) What is the order of operations in the equation for the maximum elevation angle? Explain. 2) Find the maximum elevation angle for an observer under the specified conditions at latitude 45° and satellite altitude of 500km.

Special Web sites ETP_satellite_basics_02 26 TopicURL Planck and Hershel launch. Java appletshttp:// EMK2AZVNUF_0.html NASA satellite ground trackshttp://science.nasa.gov/Realtime/Jtrack/sp acecraft.html NASA manned spacecraft ground trackshttp://spaceflight.nasa.gov/realdata/trackin g/index.html