Fuselage Manufacturing for Launch Vehicles
An overview by Scienceinsight
Article RE51
Functions
The cylindrical fuselage of a launch vehicle serves functional, structural, and aerodynamic purposes.
Load Distributor: Transfers thrust and gravitational forces across the stages
Structural Framework: Integrates all components (engines, tanks, avionics, etc.)
Aerodynamic Shell: Provides stability and low drag during ascent
Materials
The selection of materials represents an optimal balance of weight, strength, temperature resistance, and manufacturability.
Material
Usage
Properties
Aluminum Alloys (e.g., 2219, 7050, 7075)
Widely used for tanks and outer hull (e.g., SpaceX Falcon 9)
Cost-effective, easily machinable, corrosion-resistant
Titanium Alloys (Ti-6Al-4V)
For critical structural components or connections
Very strong, lightweight, but expensive and difficult to machine
Carbon Fiber Composites (CFRP)
Modern rockets (e.g., Rocket Lab Electron) utilize CFRP fuselages
Extremely lightweight and rigid, but expensive and complex to manufacture
Stainless Steel (SpaceX Starship: 301 & 304L)
Unconventional, but chosen for high temperature and pressure resistance
Robust, but heavier – acceptable for fully reusable systems
Manufacturing Process
1. Raw Material: Sheet metal or prepreg
- Aluminum alloys: large, rolled sheets
- CFRP: prepreg rolls (resin-impregnated fabric)
2. Segment Manufacturing
- The fuselage structure is typically manufactured in cylindrical segments ("barrels" or "cylindrical shells")
- The aluminum sheet is rolled into a cylinder and welded using automated processes (e.g., Friction Stir Welding)
- CFRP fibers are automatically wound onto a rotating mandrel ("Filament Winding") or laid down ("Tape Laying")
3. Integration of Reinforcement Structures
- Stringers (longitudinal stiffeners) and frames (ring frames) are attached for stabilization, either integrally manufactured or bonded/welded on
- For CFRP, these are often co-cured or co-bonded during autoclave curing
4. Assembly of Sections
- Individual barrel sections are joined axially (welding, bolting, or adhesive bonding for CFRP)
- A large autoclave or oven is required for CFRP construction methods
5. Surface Treatment
- Aluminum is often anodized or chemically treated (corrosion protection)
- CFRP requires no external treatment but is usually painted for UV protection