ESA Document - Emits - ESA

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3.4.4 Mechanisms
HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 247 of 422
3.4.4.1 Requirements and design drivers
The HMM science requirements do not state any specific requirements applicable to the
propulsion module mechanisms. As a result of the propulsion module’s configuration, the
following necessary mechanisms and their requirements can de derived:
• TMI, MOI & TEI In-orbit berthing:
o LEO In-orbit assembly operations
• TMI Propulsion Stage Separation System:
o Release & Separation of the Individual Propulsion stage backbone structures:
� Horizontal separation system
• MOI Stage Separation System:
o Release & Separation of the Propulsion stage back-bone structure:
� Horizontal & Vertical Separation System
• TEI Stage Separation System:
o Release & Separation of the propulsion stack:
� Horizontal separation system
3.4.4.2 Assumptions and trade-offs
No system specific assumptions or trade-offs have been made or performed.
3.4.4.3 Baseline design
3.4.4.3.1 Backbone structure berthing
For all berthing I/Fs, the common berthing mechanism shall be implemented. The following I/F
are affected:
• TMI Stage-to-stage I/F
• TMI to MOI I/F
• Node-to-TEI Stack-MOI Backbone
3.4.4.3.2 Horizontal separation system
For release of individual propulsion stages, a clamp-band with ejection springs shall be the
baseline.
3.4.4.3.3 Vertical separation system
The along-axis joints of the two half cylinder parts of the MOI backbone shall be separated by a
system similar to the launcher fairing jettison system. The separation mechanism consists of a