Unibody Pressurized Composite Structure (UPCS)

Microcosm, in collaboration with Scorpius Space Launch Company (SSLC), has developed a unique, low-cost, low-mass, high-utility combined structure/propellant tank for smallsats. The unibody pressurized composite spacecraft structure acts as one unified structure that integrates the propellant tank and does not require additional support elements of any kind, yet still allows easy installation of various payloads and bus subsystems. A representative structure is shown in Fig. 1 that shows the propellant tank, thrusters, and CubeSat channels to accommodate a payload and bus subsystems, and a candidate solar panel configuration.  Key features of the UPCS are:  1)  Provides excellent strength, stiffness, and robustness.  The proposed structure is both stronger and stiffer than a traditional metal structure; 2) Has low thermal sensitivity.  Composite materials have very low coefficient of thermal expansion (CTE) relative to metal structures and tanks; 3) This design eliminates the need for secondary structures (parasitic weight).

Key Advantages of the UPCS:

  • Reduces overall spacecraft mass by 20% to 40%, depending on configuration
  • Exceptionally stiff and strong- very robust design
  • Can have an interface to a standard Planetary Systems LightBand such that loads are carried directly into the launch vehicle support structure
  • Built to your specifications with design help available as needed
  • Rapid development and construction timeline
  • Compatible with hydrazine and most spacecraft propellants
  • Standard sizes can include a bladder made from material that has flown in space for many years


All-Composite Unibody SC Image 1

Figure 1.  Representative Unibody Configuration.

Figure 2 shows an actual prototype combined propellant tank/spacecraft primary structure that SSLC built, with a central structural support cylinder that is the propellant tank wall and 5 external stringers and a small shelf between 2 stringers.  The stringers and shelf can be used for mounting all of the needed spacecraft subsystem components and payload.

All-Composite Unibody SC Image 2

Figure 2.  Prototype Unibody Pressurized Composite Spacecraft Structure (propellant tank visible in the center)