System Design Dave Curtis UCBSSL Space Sciences Laboratory

System Design Dave Curtis UCB/SSL Space Sciences Laboratory University of California, Berkeley TRIO-CINEMA 1 UCB, 2/08/2010

System Design Agenda AGENDA Requirements Electrical System Overview Resource Summary Issues TRIO-CINEMA 2 UCB, 2/08/2010

Requirements • System Requirements have been documented in CINEMA_Requirements – Subsystem designers should be familiar with requirements placed on their system and design/test to verify compliance – Deviations from requirements need to be approved by me. • More detailed requirements have been developed in some cases – For example, Flight Software requirements, CINEMA_FSW_002_Requirements TRIO-CINEMA 3 UCB, 2/08/2010

Requirements Verification • For each requirement we need to identify how/when we are going to verify it – Subsystem designers need to propose verification plans for each of their requirements to me before starting tests – Requirements verification for each subsystem shall be reviewed prior to integration • Requirements which can only be verified at a lower level of assembly need to be completed prior to integration • Some requirements need to be verified or re-verified at the system level – plans for these need to be identified prior to integration – Some requirements may have to be verified wholly or partially by analysis • test preferred • A document describing the analysis is desirable – All requirements shall be verified prior to launch TRIO-CINEMA 4 UCB, 2/08/2010

Interface Control Documents • By CDR some form of ICD should exist between all subsystems which interface together – Some ICD are more formal than others – Existing ICDs • • • Cube. Sat Design Specification Purchased hardware manuals such as EPS Users Manual MAGIC ICD Spacecraft Mechanical Layout & Accomodations Model Avionics backplane Specification Harnessing Diagram – Needs connector definitions, pinouts • FPGA Specifications (preliminary) TRIO-CINEMA 5 UCB, 2/08/2010

Electrical Systems Block Diagram TRIO-CINEMA 6 UCB, 2/08/2010

Mechanical Layout [Obsolete] TRIO-CINEMA 7 UCB, 2/08/2010

Harnessing Diagram TRIO-CINEMA 8 UCB, 2/08/2010

Resources - Mass • Somewhat Obsolete [10/09] – +UHF Antennas, deployment system – +UHF Electronics – -Micro. Hard Antennas – -Micro. Hard Electronics – LVPS/Instrument Interface combined into IIB – Updates • Plenty of Margin – 4 kg limit per rev 12 CDS TRIO-CINEMA 9 UCB, 2/08/2010

Resources – Power Generation 3. 22 W Orbit Average, Nominal Attitude 2. 14 W Worst Case Attitude TRIO-CINEMA 10 UCB, 2/08/2010

Resources – Battery Capacity 26% Max DOD (once/day, mostly S-band Transmitter) Assumes no UHF Downlink (or only 1 transmitter on at a time) TRIO-CINEMA 11 UCB, 2/08/2010

Resources – Power Usage 80% Margin, SAFE Mode 25% Margin, ACS, Normal Modes TRIO-CINEMA 12 UCB, 2/08/2010

Resources – Telemetry 9700 bps average science (and stored engineering) rate 9600 baud real time engineering via UHF 27 bps average engineering rate if stored engineering downlinked via UHF 1 pass/day TRIO-CINEMA 13 UCB, 2/08/2010

Issues • Some ICDs/Specifications need work by subsystem designers • Subsystem designers need to start thinking about Verification Plans • Need Mass update • Need more analysis if we plan to use UHF transmitter – – – TRIO-CINEMA Can we simultaneously use S-band (needs power analysis) We need a switch or PIN-D diode Requires simplex operation – software & MOC complications Need GSE (Another UHF card & antennas? ) Ground station receiver/antenna Link margin 14 UCB, 2/08/2010