1. 2006/3/22 5-3-1 System Block Diagram Mechanical Interface and Component Layout Power Distribution Major Subsystem Status

2. 2006/3/225-3-2 System Block Diagram

3. 2006/3/22 5-3-3 Component Layout (1/2) MIA HEP-i (1) (4) (5) (2) (3) (6) (7) (8) ENA MEA2 Upper Thruster Module(2 places) SSAS MSA MEA1 HEP-e MAST-SC MAST-MGF X Y Z MSASI Lower Thruster Module(2 places) MGA (after deployment) WPT1 MAST-MGF SSC WPT2 MEFISTO2 MEFISTO1 MAST-SC X Y Z Top View Bottom View

4. 2006/3/22 5-3-4 Component Layout (2/2) Internal Surface of the Upper Deck, Perspective View from +Z direction. THR-M Tank ZX Y DRU EPC TWT SSAS-E SSAS-S X-TRP1 XSW X-TRP2 TWT EPC XDIP SPM APR DMC Internal Surface of the Lower Deck, Perspective View from +Z direction. CNV-1 CNV-2 ZX Y BAT MDP1 MDP2 HEP-e MEA MAST-MGF MAST-SC HEP-i MIA MDM V-M MSA WPT-Pre SSC PCU MSASI MEA ENA MDM-S

5. 2006/3/22 5-3-5 Geometrical Interface for instruments Updating now Upper Deck Bulkhead Substrate Support Fixture Lower Deck Substrate Substrate Support Fixture will be moved to the exposed side. It will mitigate restriction on instruments mounting at the corner. Ref. MMO-NT-D05013

6. 2006/3/22 5-3-6 Power Distribution for payloads Issues and possible resolutions > Motors for MEFISTO, WPT, and MAST require 28V, not 50V.  External PSU to provide 28V power > Centralized vs. Distributed architecture. It would be too complex to have all of switching functions and secondary power supply functions at the MDP.  External PSU for each MPPE and MDM instrument > How to distribute +3.3V to instruments. It would be difficult to provide such a low voltage with good quality from the external PSU.  To generate +3.3V by onboard regulator within instruments

7. 2006/3/22 5-3-7 Alternative Power Distribution Architecture for payloads