ASEN 5050 SPACEFLIGHT DYNAMICS Interplanetary

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ASEN 5050SPACEFLIGHT DYNAMICSInterplanetary

• Prof. Jeffrey S. Parker
• University of Colorado Boulder

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Announcements

• HW 8 is out now!
• Due in one week Wednesday, Nov 12.
• J2 effect
• Using VOPs
• Mid-Term handed back today!
• Concept quiz after todays lecture, due 8 am
  Friday
• Not quite ready, but Ill send out an email.
• Reading Chapter 12

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Schedule from here out

• 11/5 Interplanetary 1
• 11/7 Interplanetary 2
• 11/10 Entry, Descent, and Landing
• 11/12 Low-Energy Mission Design
• 11/14 STK Lab 3
• 11/17 Low-Thrust Mission Design (Jon Herman)
• 11/19 Finite Burn Design
• 11/21 STK Lab 4
• Fall Break
• 12/1 Constellation Design, GPS
• 12/3 Spacecraft Navigation
• 12/5 TBD
• 12/8 TBD

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Final Project

• Due 12/18. If you turn it in by 12/12, Ill
  forgive 5 pts of deductions.
• Worth 20 of your grade, equivalent to 6-7
  homework assignments.
• Final Exam is worth 25.
• Find an interesting problem and investigate it
  anything related to spaceflight mechanics (maybe
  even loosely, but check with me).
• Requirements Introduction, Background,
  Description of investigation, Methods, Results,
  Conclusions, References.
• You will be graded on quality of work, scope of
  the investigation, and quality of the
  presentation. The project will be built as a
  webpage, so take advantage of web design as much
  as you can and/or are interested and/or will help
  the presentation.

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Final Project

• Instructions for delivery of the final project
• Build your webpage with every required file
  inside of a directory.
• Name the directory LastName_FirstName i.e.,
  Parker_Jeff/
• there are a lot of duplicate last names in this
  class!
• You can link to external sites as needed.
• Name your main web page index.html
• i.e., the one that you want everyone to look at
  first
• Make every link in the website a relative link,
  relative to the directory structure within your
  named directory.
• We will move this directory around, and the links
  have to work!
• Test your webpage! Change the location of the
  page on your computer and make sure it still
  works!
• Zip everything up into a single file and upload
  that to the D2L dropbox.

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HTML

• If youve never coded in HTML, dont fret (but
  dont wait to try it out).
• Lots of tutorials online
• One student suggested this page for HTML
  tutorials http//www.codecademy.com/dashboard
• Think of a webpage as a blank canvas, fill it
  with invisible tables, lists, links, animations,
  pictures, and text.
• Word, LaTex, and other programs can save
  documents as HTML, but then its awful to edit /
  personalize.

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Space News

• Chinas lunar swingby vehicle successfully
  landed.
• Philae lands next week.
• Neat video of the Aurora Australis, viewed from
  the ISS http//www.usatoday.com/story/weather/2
  014/11/04/aurora-new-zealand-space-station/1847001
  5/

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ASEN 5050SPACEFLIGHT DYNAMICSMid-Term

• Prof. Jeffrey S. Parker
• University of Colorado Boulder

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Statistics

• High score 98
• Mean 88
• I tried my best to knock down your grades, but
  couldnt find many holes.

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ASEN 5050SPACEFLIGHT DYNAMICSInterplanetary

• Prof. Jeffrey S. Parker
• University of Colorado Boulder

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Interplanetary Missions
Destination Missions
Mercury Mariner 10, MESSENGER
Venus LOTS
Mars LOTS
Asteroids, Comets ISEE-3/ICE, NEAR, Deep Impact, Galileo, Dawn, Rosetta, etc.
Jupiter Pioneer 10, 11, Voyager 1, 2, Ulysses, Galileo, Cassini, New Horizons, Juno
Saturn Pioneer 11, Voyager 1, 2, Cassini
Uranus Voyager 2
Neptune Voyager 2
Pluto / KBO New Horizons
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History of Interplanetary Exploration
This timeline may be found here http//nssdc.gsfc
.nasa.gov/planetary/chronology.html
Earth
Moon
1st Mission to get close to the Moon
Moon
1st Mission to impact the Moon
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History of Interplanetary Exploration
Moon
Mars
Moon
1st Mission to fly by Venus
Venus
Moon
Moon
Americans fly by Venus
Venus
Moon
Mars
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History of Interplanetary Exploration
Americans successfully impact the Moon
First Mars Flyby
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History of Interplanetary Exploration
1st Soft Lunar Landing
1st American soft lunar landing
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History of Interplanetary Exploration
1st Venus Atmospheric probe
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History of Interplanetary Exploration
Humans are at the Moon!
Humans are at the Moon!
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History of Interplanetary Exploration
Apollo
Nuff Said
Apollo
Apollo
Robotic lunar sample return
Robotic lunar rover
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History of Interplanetary Exploration
Apollo
Mars orbiters
Apollo
1st Mission to Jupiter!
Apollo
Final Apollo mission
Apollo
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History of Interplanetary Exploration
1st Mission to Saturn!
1st Mission to Mercury
1st Mars lander
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History of Interplanetary Exploration
Grand Tour
1st libration orbiter and Comet flyby
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History of Interplanetary Exploration
1st Japanese mission
1st ESA mission
1st Jupiter Orbiter
1st Low-Energy Lunar Transfer
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History of Interplanetary Exploration
1st Asteroid Orbiter
1st Mars Rover
1st Saturn Orbiter
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History of Interplanetary Exploration
1st Comet Sample Return
1st Asteroid Sample Return
1st Low-Thrust Lunar Transfer
1st Mercury Orbiter
1st Comet Impact
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History of Interplanetary Exploration
1st Mission to Pluto/KBOs
1st Low-Thrust to Main Belt Asteroids
1st Chinese mission
1st Indian mission
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Future Exploration

• Ongoing exploration at Mars
• Human exploration aiming for Mars
• Waypoints may include the Moon, L2, Asteroids,
  and/or Phobos/Deimos.
• Europa
• Enceladus
• Titan Lakes
• Uranus/Neptune systems
• Other stars!?
• Plenty of proposals being submitted for every
  major (and many minor) destinations in the solar
  system.

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Interplanetary Trajectories

• Pioneer 10s Interplanetary Trajectory
• Earth Jupiter

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Interplanetary Trajectories

• Pioneer 11s Interplanetary Trajectory
• Earth Jupiter Saturn

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Interplanetary Trajectories

• Mariner 10s Interplanetary Trajectory
• Earth Venus Mercury

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Interplanetary Trajectories

• Voyager 1s and Voyager 2s Interplanetary
  Trajectories Earth Jupiter Saturn Beyond

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Interplanetary Trajectories

• Galileos Trajectory to Jupiter
• VEEGA (Venus Earth Earth Gravity Assist)

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Interplanetary Trajectories

• Cassinis Trajectory to Saturn
• VVEJGA (Venus Venus Earth - Jupiter Gravity
  Assist)

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Interplanetary Trajectories

• Ulysses Trajectory past Jupiter

Image courtesy of Planetary and Space Science,
Volume 54, Issues 910, August 2006, Pages 932956
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Interplanetary Trajectories

• Junos Trajectory to Jupiter

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Interplanetary Trajectories

• MESSENGERs Trajectory to Mercury

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Interplanetary Trajectories

• DAWNs Trajectory to Main Belt Asteroids

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Moon Tours

• Jupiter Galileo

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Moon Tours

• Saturn Cassini

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Cassinis Extended Mission
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Cassinis Extended Mission
Why are there no small body flybys here?
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Building an Interplanetary Transfer

• Simple
• Step 1. Build the transfer from Earth to the
  planet.
• Step 2. Build the departure from the Earth onto
  the interplanetary transfer.
• Step 3. Build the arrival at the destination.
• Added complexity
• Gravity assists
• Solar sailing and/or electric propulsion
• Low-energy transfers

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Patched Conics

• Use two-body orbits

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Patched Conics

• Gravitational forces during an Earth-Mars transfer

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Sphere of Influence

• Measured differently by different
  astrodynamicists.
• Hill Sphere
• Laplace derived an expression that matches real
  trajectories in the solar system very well.
• Laplaces SOI
• Consider the acceleration of a spacecraft in the
  presence of the Earth and the Sun

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Sphere of Influence

• Motion of the spacecraft relative to the Earth
  with the Sun as a 3rd body
• Motion of the spacecraft relative to the Sun with
  the Earth as a 3rd body

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Sphere of Influence

• Laplace suggested that the Sphere of Influence
  (SOI) be the surface where the ratio of the 3rd
  bodys perturbation to the primary bodys
  acceleration is equal.

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Sphere of Influence

• Laplace suggested that the Sphere of Influence
  (SOI) be the surface where the ratio of the 3rd
  bodys perturbation to the primary bodys
  acceleration is equal.

Primary Earth Accel
3rd Body Sun Accel
Primary Sun Accel
3rd Body Earth Accel
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Sphere of Influence

• Laplace suggested that the Sphere of Influence
  (SOI) be the surface where the ratio of the 3rd
  bodys perturbation to the primary bodys
  acceleration is equal.

Primary Earth Accel
3rd Body Sun Accel

Primary Sun Accel
3rd Body Earth Accel
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Sphere of Influence

• Find the surface that sets these ratios equal.

After simplifications
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Sphere of Influence

• Find the surface that sets these ratios equal.

Earths SOI 925,000 km Moons SOI 66,000 km
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Patched Conics

• Use two-body orbits

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Interplanetary Transfer

• Use Lamberts Problem
• Earth Mars in 2018

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Interplanetary Transfer

• Lamberts Problem gives you
• the heliocentric velocity you require at the
  Earth departure
• the heliocentric velocity you will have at Mars
  arrival
• Build hyperbolic orbits at Earth and Mars to
  connect to those.
• V-infinity is the hyperbolic excess velocity at
  a planet.

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Earth Departure

• We have v-infinity at departure
• Compute specific energy of departure wrt Earth
• Compute the velocity you need at some parking
  orbit

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Earth Departure
Departing from a circular orbit, say, 185 km
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Launch Target
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Launch Target
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Launch Targets

• C3, RLA, DLA

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Launch Targets
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Mars Arrival

• Same as Earth departure, except you can arrive in
  several ways
• Enter orbit, usually a very elliptical orbit
• Enter the atmosphere directly
• Aerobraking. Aerocapture?

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Aerobraking
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Comparing Patched Conics to High-Fidelity
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Gravity Assists

• A mission designer can harness the gravity of
  other planets to reduce the energy needed to get
  somewhere.
• Galileo launched with just enough energy to get
  to Venus, but flew to Jupiter.
• Cassini launched with just enough energy to get
  to Venus (also), but flew to Saturn.
• New Horizons launched with a ridiculous amount of
  energy and used a Jupiter gravity assist to get
  to Pluto even faster.

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Gravity Assists

• Gravity assist, like pretty much everything else,
  must obey the laws of physics.
• Conservation of energy, conservation of angular
  momentum, etc.

So how did Pioneer 10 get such a huge kick of
energy, passing by Jupiter?
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Designing Gravity Assists

• Rule Unless a spacecraft performs a maneuver or
  flies through the atmosphere, it departs the
  planet with the same amount of energy that it
  arrived with.
• Guideline Make sure the spacecraft doesnt
  impact the planet (or rings/moons) during the
  flyby, unless by design.

Turning Angle
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How do they work?

• Use Pioneer 10 as an example

OUT OF FLYBY
INTO FLYBY
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Gravity Assists

• We assume that the planet doesnt move during the
  flyby (pretty fair assumption for initial
  designs).
• The planets velocity doesnt change.
• The gravity assist rotates the V-infinity vector
  to any orientation.
• Check that you dont hit the planet

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Gravity Assists

• We assume that the planet doesnt move during the
  flyby (pretty fair assumption for initial
  designs).
• The planets velocity doesnt change.
• The gravity assist rotates the V-infinity vector
  to any orientation.
• Check that you dont hit the planet

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Designing a Gravity Assist

• Build a transfer from Earth to Mars (for example)
• Defines at Mars
• Build a transfer from Mars to Jupiter (for
  example)
• Defines at Mars
• Check to make sure you dont break any laws of
  physics

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Gravity Assists
Please note! This illustration is a compact,
beautiful representation of gravity assists.
But know that the incoming and outgoing
velocities do NOT need to be symmetric about the
planets velocity! This is just for illustration.
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Gravity Assists

• We can use them to increase or decrease a
  spacecrafts energy.
• We can use them to add/remove out-of-plane
  components
• Ulysses!
• We can use them for science