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Could all launches be fairly lined up according to one single scalar metric representing how much kinetic energy they impart to their payloads - from launch pad to whatever trajectory the payload ends up in?

Popularly, mass to low Earth orbit or mass to geosynchronous orbit are used to classify rockets. But those figures depend on many assumptions and circumstances because there are always different payloads, orbits, launch sites, launcher configurations, etc. Is there any simple measure, such as how much kinetic energy a launch event ultimately transfers to its payload?

Is there a better idea along these same lines? Rocketry, like all other shipping, is about only three things: relocation, relocation, relocation. What is the bottom line?

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  • $\begingroup$ 1/2mv<sup>2</sup>? $\endgroup$
    – Hobbes
    Feb 22, 2018 at 17:11
  • $\begingroup$ @Hobbes Sure, but how do I figure that out per launch? What I'm looking for is how to avoid the specifics, not having to get intimately into depth with them. $\endgroup$
    – LocalFluff
    Feb 22, 2018 at 17:38

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I don't think you can avoid the specifics and still end up with a better metric than 'mass to low Earth orbit or mass to geosynchronous orbit'.

For one, launcher performance depends on orbit. See for instance this question that compares a few launchers. The difference in payload changes a lot depending on the target orbit. So the orbit has to be part your metric.

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  • $\begingroup$ wouldn't it be mass to LEO or GTO? $\endgroup$
    – user20636
    Feb 22, 2018 at 22:50
  • $\begingroup$ As the linked question indicates, you can't extrapolate from 'payload to LEO' to 'payload to GEO' or 'payload to escape velocity' so you end up with two or three figures instead of one. $\endgroup$
    – Hobbes
    Feb 23, 2018 at 7:26
  • $\begingroup$ I thought most launchers (that do launches for geosynchronous spacecraft quote payload to GTO not GEO $\endgroup$
    – user20636
    Feb 24, 2018 at 1:41

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