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Comment: Fixed some problems with notation.

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ConstraintDescription
WC,D > RBThe line connecting the top of the main chute canopy to the inside of the deployment bag must be long enough such that the main parachute is not stuck inside the deployment bag upon full line extension.
WA,H > WA,E,F,G + RD + SD + lfcWhen lines between the mission package and fin can are fully extended, the drogue parachute must be within the airstream.
WA,H > lmp + hmp + lfcAssuming full line extension, the mission package and booster section should not hit one another during descent. This neglects the effect of drag on these sections and their respective masses.
WA,E,F,G - lmp > 8.5*FD,D- SDThis constraint reduces the impact of forebody wake on the drogue parachute during drogue descent. Please see the extended note below on the calculation of forebody diameter. We subtract the vertical height of the shroud lines to reach a total canopy distance of ~9 forebody diameters.1
WA,E,F < WA,B + SM + RM + WC,DPrior to firing the tender descender, the load should go through the shorter (TD) path. Note that this is automatically satisfied by virtue of the fact that the main shroud lines alone are significantly longer than the deployment bag. There is no need to check this constraint.
WA,B > lmp + 6*FD,M
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Mathinline
body\sqrt{S_{M}^2-(D_{M}/2)^2}
"[T]he parachute should be ejected to a distance equivalent to more than four times–and preferably six times–the forebody diameter" (Knacke, 5.2.2). Please see the extended note below on the calculation of the forebody diameter. We subtract the vertical length of the shroud lines to reach a total canopy distance of ~6 forebody diameters.
Note on

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Forebody

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Diameters

As noted in Hermes Descent Dynamics, it is difficult to predict the falling orientation of the mission package and booster during drogue descent. For this reason, we evaluate the worst case possibility (supersonic descent is already somewhat of a worst case scenario, so we have multiple methods of redundancy): the booster falls horizontally below the drogue parachute. In this scenario, the actual forebody area (FA,D) is calculated by multiplying the drogue diameter by the booster diameter, yielding approximately 227 in2. The effective forebody diameter is calculated below via the equivalent circle technique presented in Knacke section 5-23 [2]:

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Similarly, the main parachute forebody area (FA,M) is calculated as 684 in2. The effective forebody diameter (FD,M) is calculated:

Mathinline
bodyF_{D,DM} = \sqrt{\frac{4F_{A}}{\pi}}

where FA = 684 in2

FD,DM = 29.5 in

Webbing Length Variable

Length

(in)

Length (ft)Factor of SafetyReasoning
WA,E5.40.451Described above–not a webbing length.
WE,F13.51.131Described above–not a webbing length.
WF,G76.16.341 (Try to keep around 1)Mod 2/25/18: Originally calculated as ~40, we have opted to add an additional 3 feet of webbing here to provide further distance between the parachute and the mission package.
WA,B85.97.161 (Try to keep around 1) 
WC,D756.2510 (Suggested around 10)In subsonic flow, upstream disturbances could disrupt the airflow if there is only minimal length on this webbing.
WA,H467.238.92Mod 2/25/18: Updated to account for increased length of drogue riser.

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