Science Forums 2

[Pyrotex]

Rocket Engineering Lesson 1

I've gone ahead and done a WBS analysis (first pass) on just the piece that goes to the Moon. Now, if you come up with a different way to land or navigate, then your WBS will be different, so be aware.

Lunar Payload
1. Communication System
2. Navigation System
3. Reaction Control System
4. Electrical Power System
5. Thermal Control System
6. Descent Rocket Motor & Controller
7. Lander Attach/Detach System
8. Lander System
8.1 Lander Static Structure
8.2 Lander Airbag System
8.3 Lander Electrical Power System
8.4 Lander Thermal Control System
8.5 Lander Computer System
8.6 Lander Communication System
8.7 Lander Camera System
8.8 Lander Unfolding System
8.9 Rover Attach/Detach System
8.10 Rover System
8.10.1 Rover Static Structure
8.10.2 Rover Electrical Power System
8.10.3 Rover Thermal Control System
8.10.4 Rover Computer System
8.10.5 Rover Communication System
8.10.6 Rover Camera System
8.10.7 Rover Transport System
8.10.7.1 Electrical Motors
8.10.7.2 Motor Controllers
8.10.7.3 Steering Assemblies
8.10.7.4 Wheel Assemblies
8.10.7.4.1 Wheel Rims
8.10.7.4.2 Wheel Spokes
8.10.7.4.3 Wheel Hubs
8.10.7.4.4 Wheel Axle Assemblies
8.10.7.4.5 Wheel Gearing Assemblies

There's a start. But look. I began with 3 computer systems, then I decided to merge the overall Lunar Payload computer with the Lander computer to save weight and complexity. But was this the right decision? What are the pros and cons? Could I have just had one computer on the Rover and have it control all three major sections? (Payload, Lander & Rover) Do I need a kick motor on the the Payload section for either orbital insertion or decelleration? I don't think so, but you consider that. How many wheels? Should the gearing assembly be part of the Motor assembly? On second thought, I'm beginning to change my mind.

Notice that I broke only one 4th level WBS item into its 5th level sub-items. You really need to do this kind of decomposition for EVERY item in the whole WBS.

For example, consider the Lunar Payload Navigation System, WBS#2. What does it break into? Do you need a radar? How about a gyro inertial platform? How about a star tracker? How about a Lunar horizon detector? What are you gonna need to have the payload know where it is and how it is oriented and when things need to happen?

You may find that you're designing something that is NOT in the WBS. Well, it needs to be there!!! But where? At what level? Is your thing part of something else, or is something already in the WBS just a part of what you're designing? You all need to agree on the WBS before you can build the first thing.

GOOD LUCK, DUDES & DUDETTES!!!