I went over the KSP-RO's Discord research notes and found this PDF about the Star kick motors. The OP wrote that the Star-5A had a mass ratio of 0.493, which seems extremely low from a solid motor standpoint. Is there any reason why it doesn't contain as much propellant than any other solid motor?

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    $\begingroup$ Comment instead of answer because I'm not a mechanical engineer, but the Star-5A is extremely small, at 4.6kg. At that size, the usual observed scaling relationships for larger rockets don't apply -- in short, the proportional contribution of the metal casing to the total mass is much higher than it would be for a multi-ton motor. $\endgroup$ Aug 4, 2022 at 4:23
  • $\begingroup$ @RussellBorogove - sounds like a answer! OP - do you have a link to the source of the graphic? You described it verbally, but that meant nothing to me. $\endgroup$ Aug 5, 2022 at 0:01
  • $\begingroup$ @RussellBorogove: Or, in other words: the square-cube law works in both directions! $\endgroup$ Aug 5, 2022 at 12:56


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