590 likes | 690 Views
Present:. Sea Launch/ Zenit Thrust: 8,180,000 N Fueled Weight: 450,000 kg Payload to LEO: 13,740 kg Cost per launch: $100,000,000 Cost per kg: $7,300 Launches: 31/28. Gateway To Space ASEN 1400 / ASTR 2500 Class #20. T -30. Colorado Space Grant Consortium. Today:. Announcements
E N D
Present: Sea Launch/Zenit Thrust: 8,180,000 N Fueled Weight: 450,000 kg Payload to LEO: 13,740 kg Cost per launch: $100,000,000 Cost per kg: $7,300 Launches: 31/28
Gateway To Space ASEN 1400 / ASTR 2500 Class #20 T-30 Colorado Space Grant Consortium
Today: • Announcements • One minute Report Questions • Mid Semester Team Evaluations • - Orbits and Mission Design – Part II • Launch is in 30 days
Announcements… pCDR peer reviews… - 3rd place is Team #5 - 2nd place is Team #7 - 1st place is Team #4 DD Rev A/B Grades HW #8 Due 4:00 PM November 9th Office Hours and Questions in Class
Mid Semester Team Evaluations… Please pass them forward now New grades posted next Tuesday Community Service project will be included
Next Tuesday… Guest Lecture on ADCS Colorado Space Grant Consortium
One Minute Reports: Geostationary VS. Geosynchronous
One Minute Reports: - What types of orbits do they do around other planets? - Is there a polar orbit that is also geosynchronous? - Could spacecraft ever be launched from Colorado? - How do you get on elliptical orbit? - What is the advantage of elliptical orbit vs. a circular orbit around the Earth? - Does the angle at which you launch a satellite affect its eccentricity? - How many different orbits are there? - Do you have launch a satellite at an angle to get it into orbit or can you shoot it straight up?
One Minute Reports: - Who owns the geosync orbit space? UN through the International Telecommunications Union - When is our Movie Night? - What is the amount of time between turning on the Sat at launch? - Do you have to write a journal about every chapter? - How will the in-class simulation work? - Do we need to have all the satellite building and testing done before the in-class simulation? - What chances do students have to go to those big conferences? -
One Minute Reports: - Where does Tom Kelly work now?
One Minute Reports: -- What is an acoustic test? - Are vibration tests done with mass models or the actual products? - Did they use Velcro on floor to keep them in place? - Has an emergency ever occurred on an EVA? - Is Grumman still making space vehicles? - Arduino is beginning to look like a next of wires? - Why is water blue? - Why is this class so awesome? - What is the craziest thing I ever did…
Orbits and Mission Design – Part 2 ASEN 1400 / ASTR 2500 Class #19 Colorado Space Grant Consortium
Orbits: A Brief Historical Look
Earth, the Moon, Mars, and the Stars Beyond A Brief Discussion on Mission Design
Universal Gravitation, Applied: • What is an orbit?
Newton’s Laws: • Newton Continued... • 1687, Principia Published • Law of Universal Gravitation (Attraction)
Orbit History: • Kepler’s 3 Laws of Planetary Motion: • All planets move in elliptical orbits, sun at one focus
Orbit History: • Kepler’s 3 Laws of Planetary Motion: • A line joining any planet to the sun, sweeps out equal areas in equal times
Orbit History: • Kepler’s 3 Laws of Planetary Motion: • The square of the period of any planet about the sun is proportional to the cube of the of the planet’s mean distance from the sun. • If you can observe the period of rotation, you can determine the distance
Types of Orbits: • Orbits are conic sections: • Circle • Ellipse • Parabola • Hyperbola • From Kepler’s Law, the central body is at a focus of the conic section
Kepler: Kepler’s Laws...Orbits described by conic sections Velocity of an orbit described by following equation For a circle (a=r): For a ellipse (a>0): For a parabola (a=):
Earth, the Moon, Mars, and the Stars Beyond A Brief Discussion on Mission Design
Orbit Introduction: • What is an orbit? • - The path of a satellite around the Earth • (or any central body) • What shape is it? • - Orbits are conic sections • - Circles, Ellipses, Parabolas, Hyperbolas • How are orbits described? • - Position and Velocity at any one time • - Keplerian Elements (from Kepler’s Laws)
Orbit Definition: Velocity & Position - Given position and velocity of a satellite at time t, you can calculate the position and velocity at any other time
Orbit Definition: Keplerian Elements - Semi major axis (a) - Size - Eccentricity (e) - Shape
Orbit Definition: Keplerian Elements - Inclination (i) - Angle to the Equator
Orbit Definition: Keplerian Elements - Right Ascension of Ascending Node (RAAN, Ω) - Rotation about the Earth’s Spin Axis
Orbit Definition: Keplerian Elements - Argument of Perigee (ω) - Rotation of the conic section in the plane
Orbit Definition: Keplerian Elements - True Anomaly (θ) - Defines the position of a body in orbit - Angle between the Position Vector and the vector to Perigee - Elliptical only
Types of Orbits (cont.) • Geosynchronous/Geostationary (equator)
Types of Orbits (cont.) • Critical Inclination
Types of Orbits (cont.) • Repeating Ground Trace
Types of Orbits (cont.) • Polar/ Sun Synchronous
Types of Orbits (cont.) • Molniya
Circular Orbit: For a 250 km circular Earth Orbit Orbital Velocity
Circular Orbit: Orbital Period
Circular Orbit: For a 500 km circular Earth Orbit Orbital Velocity
Circular Orbit: For a 500 km circular Earth Orbit Orbital Period Conclusions???
Changing Orbits: How about 250 km to 500 km How would you do it?
Changing Orbits: Changing orbits usually involves an elliptical orbit or Transfer Orbit Perigee = close Apogee = far
Changing Orbits: 1) Velocity of initial orbit 2) Velocity of final orbit 3) Velocity at perigee 4) Velocity at apogee
Changing Orbits: Since orbit is elliptical at Vper and Vapoa > 0, so where
Changing Orbits: So back to our DV’s 3) Velocity at perigee
Changing Orbits: So back to our DV’s 4) Velocity at apogee
Changing Orbits: 1) Velocity of initial orbit 2) Velocity of final orbit 3) Velocity at perigee 4) Velocity at apogee
Changing Orbits: Therefore: DV1 is to start transfer
Changing Orbits: DV2is to circularize orbit