ASEN 5050 SPACEFLIGHT DYNAMICS Mars Odyssey

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ASEN 5050SPACEFLIGHT DYNAMICSMars Odyssey

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

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Announcements

• Homework 4 is due right now
• Homework 3 is re-active. Submit a new HW3
  submission to the Dropbox or in person by Friday
  10/3!
• CAETE by Friday 10/10
• You can recover ½ of the points you lost, or get
  a 90, whichever is higher.
• Mid-term Exam will be handed out Friday, 10/17
  and will be due Wed 10/22. (CAETE 10/29)
• Take-home. Open book, open notes.
• Once you start the exam you have to be finished
  within 24 hours.
• It should take 2-3 hours.
• Reading Chapter 6

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Grading

• Homework grading
• Tough. Were dropping points pretty easily.
• Units
• Work
• Not answering questions
• This is a graduate course, so it takes pretty
  good work to get an A. At a minimum, you need to
  read the questions and provide answers to what
  were asking.
• This class will ultimately be graded on a curve
  of some sort. Its soooo much easier to give
  everyone a better grade than to knock everyone
  down at the end!

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HW3

• Im posting the solutions online now.
• If you missed anything, go redo it until your
  answers match the online solutions.
• If you do, well give you half of your points
  back, or a 90, whichever is higher.

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D2L

• Request
• Please submit your answers in a Word Doc or a PDF
• Its fine to include code in a .zip file, but
  its harder to grade the HW if the HW is also
  included in the .zip file.

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Quiz 9
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Quiz 9
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Quiz 9
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ASEN 5050SPACEFLIGHT DYNAMICSMars Odyssey

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

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ASEN 5050SPACEFLIGHT DYNAMICSLaunch

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

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Launch

• Launching a satellite
• For a direct launch, the launch site latitude
  must be less than or equal to the desired
  inclination, otherwise we must change the
  inclination of the orbit.

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Right Spherical Triangle
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Launch

• We can show this using spherical trigonometry for
  a right spherical triangle (eq. C-23)
• Thus,
• Because sin b 1, the launch latitude fgc i
• Another useful relation sin fgc sin(i)
  sin(wn)

Cannot direct launch into orbit with inclination
lt fgc
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Launch

• The launch site velocity is
• Note all the velocity is Eastward in the SEZ
  system, so launching from the equator on a 90?
  azimuth may be best.
• The velocity at the equator is vL 0.465 km/s.
  Westward launches must make this up, so
  difference is 0.93 km/s.

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Launch Azimuths

• Launch sites and allowable azimuths

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Launch Sites
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Noncoplanar Transfers
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Noncoplanar Transfers

• Launch window select UT to achieve orbits
  desired initial nodal location (determine qgst)
• First determine launch azimuth b (inverse sine
  gives two possible answers b and 180?-b, for
  ascending (-90? lt u lt 90?) and descending (90? lt
  u lt 270?) passes.)
• Now, determine the auxiliary angle from
• The values lu and 360?-lu represent prograde and
  retrograde orbits respectively.

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Noncoplanar Transfers

• Tolerance on ascending node (DW) creates launch
  window, or range of values of qGST. Once qGST
  is chosen
• Substitution of qGST0 for each day (GST at 0 hrs
  on that day) gives the launch time on each day.
• Dv is more complicated.