Size and design a shear pin system

[joshdboss]

As a shear pin would've likely saved the first Hermes, adding it to the second iteration is critical. This shear pin should be sized so that it doesn't allow the rocket to separate prematurely, while allowing the rocket to separate with either of the ejection charges.

• Calculate the maximum expected tension force caused by drag on the rocket (adding a healthy safety factor)
• Calculate a typical ejection charge's compressive force
• Size the shear pin accordingly
• Integrate the pins into the design