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Comment by Thrymr | Hacker News Reader

What a strange way to take a dig at non-metric measurements. The "units" command makes it trivial to get whatever you want:

  You have: (G earthmass / earthradius)**.5
  You want: mph
   * 17693.688
   / 5.6517331e-05
  You have: (G earthmass / earthradius)**.5
  You want: furlongs / fortnight
   * 47560632
   / 2.1025793e-08

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yes, but why would you want that?

the original title said 'at 17000 mph', and as you can see, that's very significantly low, about 4%:

    You have: (G earthmass / earthradius) ** .5 / 17000mph - 1
    You want: %
            * 4.0805157

so if you, like any rational person, want to know how fast the capsule was entering in meters per second, you're better off using units(1) to calculate it from first principles rather than converting it from a 4% wrong quantity in medieval units

Maybe 17000mph was a bit sloppy of a title on my part. It was a weird orbit, with the burns we were doing.

naw, 4% is fine, i'm half joking

i'm pretty much a raw beginner with orbital dynamics but my vague idea was that you'd have to ellipticize the orbit by hundreds of kilometers to change the orbital speed by more than a fraction of a percent, and that would be expensive enough that you'd only do it if you had a really good reason

but the only satellites i've ever troubleshot had only extremely limited maneuverability (though i'm not totally sure how much more than that i can say)

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