Subsystems Flashcards
Determines Yaw
IIR - CSS
IIF - ASD
III - SSA
Determines Roll & Pitch
IIR - ESS
IIF - STES
III - ESA
Use during L/EO
IIR - FSS
Measures rates
IIR - RMA
IIF - RGP
III - IMU
Actuators
IIR - MTC
IIF - EMA
III - MTR
Nominal mode
IIR - SNP
IIF - 3A
III - Normal
Lost earth
IIR - SSH
IIF - SSA
III - SAM
Found sun/looking for earth
IIR - SHES/EAH
IIF - ESA
III - EAM
Use for Delta-V
IIR - SK/EHYS
IIF - SK
III- OA
Launch
IIR - Rate nulling
IIF - INIT
III - Standby
RW for
Roll
Pitch
Yaw
1 +3 Roll
2 + 4 Pitch
All
Batteries
IIR - 40 Amp Nickel Hydrogen, no memory effect, no reconditioning. Bus operates at 28.4V
IIF - 40 Amp Nickel Hydrogen, uses battery system cycling (BSC). Bus operates at 28.4V
III - 70 Amp Nickel Hydrogen. Bus operates at 70V, payload and frequency stdrs at 28.28V
Solar Arrays
IIR - SAD controlled by ADE by sending cmds to SPU
IIF - SADA
III - SAWA controlled by the SADA. TFU protects SV electronics against hostile threats and EM disturbances
EPS Regulation
IIR - PRU regulates at 28.4V with modes: Shunt- batteries full, Charge- batteries charging, Discharge- batteries in use during eclipse. PMS in the SPU controls EPS, ADE send cmds to control SADs
IIF - PRE, PCU- regulates distributes, controls power. SDA - dissipate excess power
III - SPRU- regulates voltage during sunlight SAS shuts off SA circuits
Loadshedding
To preserve the SV integrity, systems are powered down.
IIR - determined by the AHD
Level 1 &2 - powers down systems but NAV stays on
Level 3 - powers down all but SV critical systems
IIF - 25 min timer: initiates when SV generating power and discharging (in/out eclipse)
70 Min timer: initiates when batteries are discharging
Level 1 - powers down all non-essential systems except RCS/TCS
Level 2 - powers down all non-essential, SV in sun search, SA at 90 degrees, performs SCP swap
III - Level 1: stops all maneuvers, charges battery at 18Amps, yellow SOH
Level 2: off all non-essetial components, red SOH, SV in sun search. Level 3: turns off GBD, MDU, clock RWA, SA at ideal charging, switches to thruster attitude control
TTC Modes
IIR - ATO- s tones received. CTO - S tones and command. COM - everything is on
III - Normal: day to day mode, analog TLM from all NAV, bus, hosted, antenna. Auxiliary: when selective data on a components is required. Memory Dump: dump stored data from OBC, every contact 1 &2, 3rd
UPLINK
IIR - Antenna - receiver - CDU - KIR (decrypts) - PCE (payload control electronics)
IIF - antenna - RF assembly - Transponder/cardholder (decrypts) - SCP - (NAV to NDU, everything else to RMU remote Multiplexer Unit)
III UPLINK/DOWNLINK Cardholder - decrypts Belshazzar - encrypts UDU - both sides ON, provides TLM, emerg TLM, routes SCCs OBC - RIU - SUT - 1553 Bus/payload
SPU
Spacecraft Processing Unit - HOT 2 sides always on
ROM - permanent copy of FSW non-volatile
RAM - FSW with upgrades volatile
SOFTWARE Watchdog monitor - controls REDMAN, swaps components as needed AHD is -5 coming out of eclipse, SPU takes cmd CMD link priority 1. S-band CNTRL U1 2. S-band CNTRL U2 3. SPU A CNTRL SA 4. SPU B CNTRL SB
CV error: 42 sec timers when processing cmd, all other links blocked out
SCP
Software Processor
UPLINK Modes
Authenticated CMD - SV performs software and hardware checks
Unauthenticated CMD - NAV only ground must cmd
DOWNLINK Modes
Format 1 - TLM
Format 2 - dump/dwell
Types of Commands Real time cmd Store time tagged - up to 200, 16 at a time Cross link cmd - from SCP to NDU Software executed cmd
Watchdog timer - resets SCP at the end of every processing cycle (1/64 sec), after 4 sec, forces same side reboot of SCP
Keep Alive Timer - after 12 sec, forces SCP switch
OBC
Onboard Computer
SRAM - main memory, preserved by OBC hard reset
BOOTSTRAP and Operational FSW - crew can dump operational FSW to support anomaly investigation
STATUS
MEOK - OBC functioning well
NOT MEOK - by watchdog timer, direct FSW cmd, OBC power on reset, hardware reset
REDMAN - corrects failures
UPLINK COMMANDING
SCC - by UDU, allows configuration of critical components in case OBC is off
Bus link cmd - from ground
DOWNLINK TLM
Normal, Auxiliary, Memory Dump
SV SOH FLAGS
G - fully operational
Y - anomaly detected, SV msn capable
A - anomaly detected, SV status cannot be determined
R - anomaly detected, SV cannot return to operational status
Rolling Buffer - records time-stamped defined set of FSW variables, for anomaly resolution
Propellant/Preassurant
IIR - 2 tanks Liquid Hydrazine, P: Gaseous Helium
IIF - 2 tanks Liquid Hydrazine, P: Gaseous Nitrogen
III - 1 tank Diimide N2H2; Oxidizer: N2O4. P: GHe
Valves
IIR - LVA configures RCS, isolates propellant in case of leaks (4)
IIF - 2 latch valves
Thrusters
IIR - 12x 0.2lbf
4x 5lbf
IIF - 12x 1lbf
4x 5lbf
III - 12x 0.2 lbf
6x 5 lbf
LAE 1x 103lbf
TCS maintain temperature limits by
Active - Heaters (batteries, payload), temperature sensor, thermostat OBC heater in Block III
Passive - thermal boublers, battery radiators, insulation blankets, coatings, optical solar reflectors, heat pipes
