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Unformatted text preview: Transfers Goal: Shift to an orbit that does NOT intersect the original orbit To accomplish: use multipleimpulse transfers Usually propellant is the limiting factor so use the transfer that requires the minimum total v Δ (Note: min Δ v ≠ min number of impulses ) Approach transfer problems: (1) Define transfer geometry Given a transfer orbit type , what are the departure/arrival points on initial/final orbits and the departure/arrival conditions? (2) Define departure/arrival points Solve for the transfer that meets the specifications Since (2) more difficult, begin by considering some types from (1) Assume the simplest example: circletocircle transfer J1 much more difficult Simplest twoimpulse transfer (also the minimum v Δ twoimpulse solution) Hohmann Transfer Walter Hohmann – first to draw attention to problem and compute mission times 1925 (Munich) “The Accessibility of the Heavenly Bodies” Simplest version of Hohmann transfer: circletocircle transfer J2 Example 1 2 2 4 r R r R ⊕ ⊕ = = Solution: (a) Establish current orbit 1 2 a r R e ⊕ = = = (b) Conditions at thrust point before maneuver 1 1 1 2 5.59km/s r R v γ ⊕ = = = D To calculate v Δ requires conditions on the transfer ellipse so...
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This note was uploaded on 12/22/2010 for the course A&AE 532 taught by Professor Kathleenhowell during the Spring '10 term at Purdue.
 Spring '10
 KathleenHowell

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