Gateway To Space T-18 ASEN / ASTR 2500 Class #15 Colorado Space Grant Consortium

Gateway To Space T-18 ASEN / ASTR 2500 Class #15 Colorado Space Grant Consortium

Gateway To Space T-18 ASEN / ASTR 2500 Class #17 Colorado Space Grant Consortium

Student Hands On Training Workshop (SHOT 2007) Today… - Announcements - One Minute Reports - Project Q/A and Orbits and Mission Design – Part I Thursday - Orbits and Mission Design – Part II (15 minutes) - Spider June 14 - 16, 2007

Student Hands On Training Workshop (SHOT 2007) Announcements… June 14 - 16, 2007

Student Hands On Training Workshop (SHOT 2007) Announcements… June 14 - 16, 2007

Student Hands On Training Workshop (SHOT 2007) Announcements… June 14 - 16, 2007

Student Hands On Training Workshop (SHOT 2007) Announcements… June 14 - 16, 2007

Student Hands On Training Workshop (SHOT 2007) Announcements… June 14 - 16, 2007

Student Hands On Training Workshop (SHOT 2007) Announcements… - DD Rev C is due 11-02-10 - Don’t forget about HW #7 due 11-18-10 - Don’t forget about community service - Updated grades will be posted this week - Spacecraft Communications lecture? - Spacecraft Propulsion lecture? June 14 - 16, 2007

Student Hands On Training Workshop (SHOT 2007) One Minute Report… - Can satellites that remain in the same spot in the sky be seen with a telescope? - How long after landing do we get our payloads? - What role does congress have in deciding what NASA is and is not allowed to do? - How do this year’s experiments compare to previous years? - Does the mass of the satellite include the flight tube? - What do we have to talk about when we do our community service? June 14 - 16, 2007

Student Hands On Training Workshop (SHOT 2007) One Minute Report… - If we are overweight can we use margin of other teams? - How is the camera programming coming along? June 14 - 16, 2007

A Brief Historical Look Orbits: A Brief Historical Look

Earth, the Moon, Mars, and the Stars Beyond A Brief Discussion on Mission Design Chris: Everything from here on looked ok to me. I don’t know how to better explain it, your numbers and equations look fine to me, and I don’t know how to use STK well enough to do an animation for you of the interplanetary stuff, sorry.

Universal Gravitation, Applied: When in space why do you float? i.e. Weightlessness Chris- I still wasn’t quite sure what you wanted to illustrate with this slide, so I left it as was. Sorry.

Universal Gravitation, Applied: How does this apply to orbits? Chris- I still wasn’t quite sure what you wanted to illustrate with this slide, so I left it as was. Sorry.

Questions: • How fast can you throw a snowball? - A baseball? - A shot put? - A Subway sandwich out a moving car? • Could you throw any of these in to an orbit? - How fast would it have to be going?

Questions: • Let’s figure it out… v is velocity G is Universal Gravitational Constant M is mass of planet or satellite R is radius of planet of satellite

Atmosphere: • How about throwing something into orbit on the moon? golf ball

Atmosphere: • Let’s figure it out… v is velocity G is Universal Gravitational Constant M is mass of planet or satellite R is radius of planet of satellite

A Brief Historical Look Orbits: A Brief Historical Look Arthur C. Clarke Discovered This Orbit

Ancient Orbit History: “ORBIT” from Latin word “orbita” orbitus = circular; orbis = orb • 1800 B.C. Stonehenge - Study of the vernal equinox

1500 B.C.: Egyptians and Babylonians Written evidence of stellar observations Solar Calendar of 365 days Time divided into 60 even units

Said earth is center of the universe 350 B.C.: Greek Thoughts Aristotle Said earth is center of the universe Dominated scientific thought for 1800 years

Start of the Heliocentric Model: 1543 A.D. Nicholas Copernicus Said Sun-centered rotations Measurements crude but thinking shifts Didn’t release findings until the end of his life

Orbit History : • 1580 A.D. Tycho Brahe Accurate measurements of planets (Mars) as a function of time Even though telescope had not been invented

Good friends with Copernicus Observations with TELESCOPE reinforced Orbit History : • 1610 A.D. Galileo Galilei Good friends with Copernicus Observations with TELESCOPE reinforced Discovered Venus has phases

Orbit History: • 1600 A.D. Johannes Kepler Used Tycho’s careful Mars observations to smash Aristotle theories Presented 3 laws of planetary motion Basis of understanding of spacecraft motion However, “Why was not understood” Calculus?

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: 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: A line joining any planet to the sun, sweeps out equal areas in equal times

T2 = R3 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 Planet P (yr) a (AU) T2 R3 Mercury 0.24 0.39 0.06 Venus 0.62 0.72 0.37 Earth 1.00 Mars 1.88 1.52 3.53 3.51 Jupiter 11.9 5.20 142 141 Saturn 29.5 9.54 870 868 T2 = R3

Orbit History: • 1665 A.D. Isaac Newton At 23, plague while at Cambridge Went to be one with nature He studied gravity Discovered “Newton’s Laws of Motion” 1666, he understood planetary motion Did zip for 20 years until Edmund Halley

Body at rest stays at rest, a body in motion stay in motion Newton’s Laws: 1st Law..... Body at rest stays at rest, a body in motion stay in motion 2nd Law.... F = m * a 3rd Law... For every action, there is an equal and opposite reaction Chris: I couldn’t find any really useful pictures for this slide.

Newton’s Laws: Newton Continued... 1687, Principia Published Law of Universal Gravitation (Attraction)

Newton’s Laws: Newton Continued... 1687, Principia Published Law of Universal Gravitation (Attraction)

Universal Gravitation, Applied: When in space why do you float? i.e. Weightlessness Chris- I still wasn’t quite sure what you wanted to illustrate with this slide, so I left it as was. Sorry.

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=):

Questions: • Let’s figure it out… v is velocity G is Universal Gravitational Constant M is mass of planet or satellite R is radius of planet of satellite

Earth, the Moon, Mars, and the Stars Beyond A Brief Discussion on Mission Design Chris: Everything from here on looked ok to me. I don’t know how to better explain it, your numbers and equations look fine to me, and I don’t know how to use STK well enough to do an animation for you of the interplanetary stuff, sorry.

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

Keplerian Elements Orbit Definition: - Semi major axis (a) - Size - Eccentricity (e) - Shape

Keplerian Elements Orbit Definition: - Inclination (i) - Angle to the Equator

Keplerian Elements Orbit Definition: - Right Ascension of Ascending Node (RAAN, Ω) - Rotation about the Earth’s Spin Axis

Keplerian Elements Orbit Definition: - Argument of Perigee (ω) - Rotation of the conic section in the plane - True Anomaly (θ) - Angle between the Position Vector and the vector to Perigee

Orbital Elements: Used to determine a satellite’s location in orbit:

Types of Orbits:

Types of Orbits:

Types of Orbits (cont.) Geosynchronous/ Geostationary Satellite remains over same spot on earth

Types of Orbits (cont.) Critical Inclination Pass repeats the longitude

Types of Orbits (cont.) Repeating Ground Trace Satellite covers same territory over and over

Types of Orbits (cont.) Polar/ Sun Synchronous Sun sync precesses at the same rate as the sun, so it stays in the sun more per orbit than a normal polar orbit

Types of Orbits (cont.) Molniya A very elliptical polar orbit, designed by the Russians to be used for their spy and communication satellites because it stays over the northern hemisphere for 75% of its orbit.

Circular Orbit: For a 250 km circular Earth Orbit Orbital Velocity Orbital Period

Circular Orbit: For a 500 km circular Earth Orbit Orbital Velocity Orbital Period Conclusions???

Changing Orbits: How about 250 km to 500 km How would you do it? Chris: I would recommend referring back and forth to the picture and the video clip, so people can get an idea of what the pictures translate to in 3-D and so that they can get a fixed reference view on the video (since it’s kinda hard to see). So you know, the satellite doesn’t do the first burn when the lower half of the orbit changes to blue, it does the first burn when the “satellite” gets to the perigee of the elliptical orbit (so when green turns to blue). The second burn is easier to see, and happens when the satellite passes the apogee of the elliptical (blue) orbit for the second time- the second circular orbit (in red) shows up. –Kendra

Changing Orbits: Changing orbits usually involves an elliptical orbit Perigee = close Apogee = far Since orbit is elliptical a > 0, so where

Changing Orbits: Here’s what you need: 1) Velocity of initial orbit 2) Velocity of final orbit 3) Velocity at perigee 4) Velocity at apogee Then figure out your DV’s

Changing Orbits: Therefore: DV1 is to start transfer DV2 is to circularize orbit Time to do transfer is

How well do you understand Hohmann Transfers? • 1 to 2? • 2 to 3? • 3 to 1? • 1 to 3? 3 2 1

Circular Orbit: