Porkchop plot

<h2 id="math">Math</h2>
<p>The general form of <i>characteristic energy</i> can be computed as:
</p><p>
  
    
      
        
          C
          
            3
          
        
        =
        
          v
          
            ∞
          
          
            2
          
        
        
        
      
    
    {\displaystyle C_{3}=v_{\infty }^{2}\,\!}

</p><p>where 
  
    
      
        
          v
          
            ∞
          
        
        
      
    
    {\textstyle v_{\infty }\,}
  
 is the <a href="/facts/Orbital_speed/6yAYqeqC">orbital velocity</a> when the orbital distance tends to infinity. Note that, since the kinetic energy is 
  
    
      
        
          
            1
            2
          
        
        m
        
          v
          
            2
          
        
      
    
    {\textstyle {\frac {1}{2}}mv^{2}}
  
, C3 is in fact equal to twice the magnitude of the <a href="/facts/Specific_orbital_energy/TvB2yk8a">specific orbital energy</a>, 
  
    
      
        ϵ
      
    
    {\textstyle \epsilon }
  
, of the escaping object.
</p>
<h2 id="use">Use</h2>
<p>For the <a href="/facts/Voyager_program/cPm6qnNx">Voyager program</a>, engineers at <a href="/facts/JPL/zPXnxRBf">JPL</a> plotted around 10,000 potential trajectories using porkchop plots, from which they selected around 100 that were optimal for the mission objectives. The plots allowed them to reduce or eliminate planetary encounters taking place over the <a href="/facts/Thanksgiving/B1f0NtI2">Thanksgiving</a> or <a href="/facts/Christmas/EsuI0Gds">Christmas</a> holidays, and to plan the completion of the mission's primary goals before the end of the <a href="/facts/Fiscal_year/qcR3PIXe">fiscal year</a> 1981.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>
</p>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Orbit/nD2TPySG">Orbit</a></li>
<li><a href="/facts/Parabolic_trajectory/vDNtF83E">Parabolic trajectory</a></li>
<li><a href="/facts/Hyperbolic_trajectory/4wEAXaez">Hyperbolic trajectory</a></li></ul>

<h2 id="external-links">External links</h2>
<ul><li><a href="https://marsprogram.jpl.nasa.gov/spotlight/porkchopAll.html">JPL Introduction to Porkchop plots</a></li>
<li><a href="http://sdg.aero.upm.es/index.php/online-apps/porkchop-plot">Pork-chop plot online computation tool</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Goldman, Elliot. "Launch Window Optimization: The 2005 Mars Reconnaissance Orbiter (MRO) Mission". Colorado Center for Astrodynamics Research. Archived from the original on 2017-04-13. Retrieved 2007-12-30. <a href="http://ccar.colorado.edu/asen5050/projects/projects_2003/goldman/" target="_blank">http://ccar.colorado.edu/asen5050/projects/projects_2003/goldman/</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>"'Porkchop' is the First Menu Item on a Trip to Mars". NASA. Accessed December 30, 2007. <a href="https://mars.jpl.nasa.gov/spotlight/porkchopAll.html" target="_blank">https://mars.jpl.nasa.gov/spotlight/porkchopAll.html</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Goldman, Elliot. "Launch Window Optimization: The 2005 Mars Reconnaissance Orbiter (MRO) Mission". Colorado Center for Astrodynamics Research. Archived from the original on 2017-04-13. Retrieved 2007-12-30. <a href="http://ccar.colorado.edu/asen5050/projects/projects_2003/goldman/" target="_blank">http://ccar.colorado.edu/asen5050/projects/projects_2003/goldman/</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Peter J. Westwick (2007). Into the Black: JPL and the American Space Program, 1976-2004. Yale University Press. ISBN 978-0-300-11075-3. <a href="978-0-300-11075-3" target="_blank">978-0-300-11075-3</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
</ol>

Porkchop plot open-in-new

Porkchop plot