lecture12 - ECE ‐ 2984 Lecture 12: ORBITAL MANEUVERS...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ECE ‐ 2984 Lecture 12: ORBITAL MANEUVERS Joseph Baker (ECE Dept) Lecture 12: Orbital Maneuvers ECE ‐ 2984:Exploration of Space Exam ‐ 1 Results • The exam was scored out of 65 points: MAXIMUM SCORE: 62 AVERAGE SCORE: 47.8 STANDARD DEVIATION: 8.1 • “APPROXIMATE” GRADE SCALE: A: >58 A ‐ : 54 ‐ 58 B+: 52 ‐ 54 B: 50 ‐ 52 8 B ‐ : 48 ‐ 50 C+: 46 ‐ 48 C: 44 ‐ 46 C ‐ : 42 ‐ 44 Joseph Baker (ECE Dept) Lecture 12: Orbital Maneuvers ECE ‐ 2984:Exploration of Space D: 36 ‐ 42 F: <36 Last Lecture LAST LECTURE: • Newton’s Laws and Orbital Mechanics • Orbital Elements THIS LECTURE: • Ground Tracks • Orbital Maneuvers: (1) Hohmann Transfer (2) Rendezvous (3) Orbit Plane Changes Joseph Baker (ECE Dept) Lecture 12: Orbital Maneuvers ECE ‐ 2984:Exploration of Space Equatorial Coordinates • A s pacecraft in Earth orbit is best described in the “Geocentric ‐ Equatorial Coordinate” (GEC) stem system: – The Earth’s center is the “origin”. – The equatorial plane is the q p “principal plane” – The line from the Earth to the vernal equinox i s t he “principal direction”. Joseph Baker (ECE Dept) Lecture 12: Orbital Maneuvers ECE ‐ 2984:Exploration of Space Orbital Elements • Kepler orbits can be concisely described by six numbers called the “orbital elements”: – Eccentricity (e) – Semimajor Axis (a) – Inclination ( i) – Right Ascension of Ascending Node ( Ω ) – Argument of Perigee ( ω ) – True Anomaly ( ν ) y ( ) • The first and second quantities define the shape and size of the orbit • The third and fourth quantities define the orientation of the orbital plane • The fifth quantity describes the orientation of the orbit in the orbital plane Joseph Baker (ECE Dept) Lecture 12: Orbital Maneuvers ECE ‐ 2984:Exploration of Space • The sixth quantity describe the location of the object in the orbit Orbital Ground Tracks Joseph Baker (ECE Dept) Lecture 12: Orbital Maneuvers ECE ‐ 2984:Exploration of Space Orbital Ground Tracks • The “Ground Track” of a spacecraft is the projection of the spacecraft orbit onto the surface of the Earth. • In other words, the ground track is the collection of points on the Earth where the spacecraft passes directly overhead. • The ground track is useful for determining where and when the spacecraft can communicate with ground stations to download data and upload new commands. • For an Earth ‐ imaging spacecraft the ground track provides information about the data coverage of the imaging system. • An analysis of the ground track can also provide quick information about the orbital elements. Joseph Baker (ECE Dept) Lecture 12: Orbital Maneuvers ECE ‐ 2984:Exploration of Space Zero Inclination Orbit (i=0) • For a satellite orbiting with clination ngle = e an inclination angle i 0 the ground track is simply a straight line along the equator....
View Full Document

This note was uploaded on 09/19/2011 for the course ENGE 1114 taught by Professor Twknott during the Fall '06 term at Virginia Tech.

Page1 / 54

lecture12 - ECE ‐ 2984 Lecture 12: ORBITAL MANEUVERS...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online