1. Brandon White 3/20/2008 Structures Group Contact Inert Mass Standard Deviation Justification Other Work
AAE 450 Spring 2008

2. Standard Deviation Justification
Value input into Monte Carlo: 2.255%
5 times the Vanguard 1st Stage Std. Dev.
Accounts for small manufacturing tolerances.
High Tech Companies + Small Tolerances  High Costs
Final launch vehicles designed under the assumption of Space grade Aluminum
Cutting tolerances at .01”
Using Non-Space grade Aluminum shows opportunity for 200g and 1kg launch vehicles
Cutting tolerances at 0.125”
Standard Deviations
SB-HA-DA-DA
MB-HA-DA-DA
LB-HA-DA-DA
Monte Carlo
2.255%
Non-Space Grade
2.28%
2.32%
8.94%
Space-Grade
3.13%
2.88%
4.42%
AAE 450 Spring 2008
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3. Inertia Model Geometry assumptions made due to unknown characteristics
Payload, Avionics S
Geometry assumptions made due to unknown characteristics
Payload, Avionics in the 3rd Stage all assumed to be a point mass located at the base of the Nose Cone
LITVC assumed to be a point mass at the base of the 1st stage Nozzle
Avionics in the 1st and 2nd Stage assumed to be wall mounted to the inter-stage skirts
Constant thickness of 10cm
Masses of each are minor in comparison to entire rocket, but this causes small inaccuracies in calculations
Avionics
Skirt
SOLID
Avionics
Skirt
Pressurant Tank
Oxidizer Tank
SOLID
LITVC
AAE 450 Spring 2008
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4. Backup Slides – References
Krando Metal Products,
Luminum,
AAE 450 Spring 2008
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5. Backup Slides – Thickness Tolerances for Aluminum
Thickness (meters)
Tolerance +/-
Greater Than
Less Than
Space Grade
Non-Space Grade
Credit: Molly Kane
AAE 450 Spring 2008
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6. Inertia Matrix Math Model
Calculates Ixx, Iyy, Izz at the center of mass of the launch vehicle
Assumes ALL products of inertia (ex. Ixy) equal to zero (vehicle is symmetric in radial directions)
Outputs values at different time steps.
First Stage: Full Propellant, Empty Propellant
Second Stage: Full Propellant, Empty Propellant
Third Stage: Full Propellant, Empty Propellant
AAE 450 Spring 2008
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7. Evolution of Inertia Code
Payload, Avionics
Payload S
Avionics
Skirt S
Skirt O S
PROP
SOLID F
SOLID
SOLID
PROP O
Avionics F
Skirt
Skirt
Pressurant Tank
Pressurant Tank
PROP
Oxidizer Tank O
Oxidizer Tank
SOLID
SOLID F
SOLID
LITVC
AAE 450 Spring 2008
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