Overview of STIS Repair Plans
Charles R. Proffitt
November 16, 2006
STIS History
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Installed during SM2, Feb 14, 1997
Side 1 Failed May 16, 2001 (after ~ 4.5 yrs)
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Short across power input leads
Probably failed tantalum capacitor
Side 1 electronics not accessible w/o removing STIS
Side 2 failed Aug 3, 2004 (after ~ 3 yrs)
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Interpoint converter in low voltage power supply failed
Supplied power to most instrument mechanisms aperture wheel, MSM, CCD shutter, etc.
Can’t get light to the detectors
Need to replace LVPS2 card in MEB1
Can be accessed w/o removing STIS
STIS Repair TIPS Presentation
Nov 16, 2006
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STIS in HST with Location of MEB
+V2
NICMOS
STIS
MEB
Cover
NCC
STIS Repair TIPS Presentation
Nov 16, 2006
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STIS
+V3
Side
MEB-2
Flight STIS Instrument
+V2
Side
MEB-1
EVA Handle
L-Handle
MEB Cover
Extension
STIS Closeup
MEB-1
Cover
MEB Cover
Extension
Clamp
STIS Repair TIPS Presentation
Nov 16, 2006
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STIS Main Electronics Box (MEB)
LVPS-2
LVPS2 Board (Engineering Unit)
MEB1 with Cover Removed
MEB Structure (non-flight)
STIS Repair TIPS Presentation
Nov 16, 2006
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LVPS-2 Interfaces
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Circuit board LVPS-2 has 3 main functions
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Supply Heater Power
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Supply Calibration Lamp Power
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+30 volts to Calibration Lamp Controller
Supply Mechanism Power
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+15 volts to Thermal Control Zone A and B
+5 volts to Mechanism Optical Coupler
+15 volts to Mechanism Drivers
+30 Volts to Mechanism motors
LVPS-2R will connect to MEB motherboard
STIS Repair TIPS Presentation
Nov 16, 2006
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Functional Overview of Repair
Major activities to be performed to repair STIS
HST +V2
STIS Repair TIPS Presentation
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Open the +V2 Aft Shroud doors
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Remove STIS EVA Handrail
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Remove MEB Cover Clamp
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Install the Fastener Capture Plate (FCP) Tool
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Release MEB cover fasteners (111)
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Remove MEB Cover and FCP Tool
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Remove failed LVPS-2 board
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Install replacement LVPS-2R board
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Install replacement MEB cover
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Perform Aliveness Test
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Install the STIS Thermal Interface Kit (STIK)
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Install the STIK Radiator (STIKER)
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Close the +V2 Aft Shroud doors
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EVA Timeline
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Goal from STIS Repair SRR was to get STIS repair
and cooling to fit in one EVA day.
STIS Repair TIPS Presentation
Nov 16, 2006
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STIS Repair - NBL 06.2 Images
STIS Repair TIPS Presentation
Nov 16, 2006
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STIS Aliveness Test
(This is when we find out if it worked)
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To be conducted during EVA
Verify connectivity of LVPS-2R board to MEB motherboard.
Ensure that major functions of LVPS-2R all work
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Less Than 10 minutes in duration.
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Verify heaters enabled
Enable SES telemetry collection
Enable (close) mechanism and lamp relays and verify output voltages
Macro started at beginning of test will ensure auto-shutdown
Isolate any failure to specific pin.
STIS Repair TIPS Presentation
Nov 16, 2006
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Cooling System (SCS) Overview STIS
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The STIS Cooling System (SCS) is intended to conduct heat
away from the MAMA detector radiator and radiate it into the aftshroud.
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Evolved from the STIK interface to the Aft Shroud Cooling
System
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Three part assembly:
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SCS Mounting Bracket (SMB)
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The STIS Thermal Interface Kit (STIK
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An actuator forces STIK pressure
plate against STIS radiator
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Soft thermal interface material on the
pressure plate conducts heat to heat
pipes.
NICMOS
STIK Support
Bracket
The STIK Extended Radiator (STIKER)

Spreader heat pipes on the STIKER
conduct and radiate heat away from
the instrument.
STIS Repair TIPS Presentation
Nov 16, 2006
STIS
NCC
STIKER
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Why install the SCS?
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Without SCS would expect a significant increase in
MAMA tube temperature over previous side-2 values
(~ 4 C).
Substantial increase in MAMA dark rates
New temperature regime for detectors
SCS should keep tube temperatures ~ 2 C lower than
were seen in 2003-2004.
Should reduce MAMA detector dark currents.
STIS Repair TIPS Presentation
Nov 16, 2006
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Challenges of STIS Repair
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STIS repair requires a whole EVA
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Removal of 111 MEB Cover Fasteners
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Tolerances very tight, need all active pins to connect
Need enough force to engage pins, but not enough to break anything
Debris generated by fastener, cover plate, and card removal
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Card Locks may stick - studies indicate card can be removed anyway
Insertion of LVPS-2R
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RFI gasket
Removal of LVPS-2 card
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Need to be prepared to handle stripped or jammed fasteners
Removal of MEB cover
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If fewer EVAs than expected are available, STIS repair will be the first
thing deleted!
Determined to be within acceptable limits
HST PCS analysis of SCS Jitter and STIKER mass control ongoing

Failed SCS installation could cause jitter.
STIS Repair TIPS Presentation
Nov 16, 2006
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Status after PDR
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Hardware shown to meet requirements
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NBL tests successfully demonstrated execution of STIS Repair
with high-fidelity hardware
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10 successful completions of LVPS-2 change-out
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2 successful completions of SCS installation
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Extensive testing and analysis performed to show compliance
with HST Contamination requirements
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Test results for high-risk tasks (Card Extraction and Insertion)
and resulting requirements
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The STIS Repair Team has defined and implemented plans,
processes, tools, and has in place the organization to proceed
to CDR (January 2007).
STIS Repair TIPS Presentation
Nov 16, 2006
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STIS Repair Top-level Schedule
2006
Apr
May
June
July
Aug
Sept
Oct
Nov
2006
2007
Dec
Jan
Feb
March
April
May
June
July
Crew
FAM 1
NBL
06-02
STIS Repair System
SRR
PDR
CDR
PER
STIS Repair Reqts Dev
Contamination Study
Interpoints replaced &
COS testing complete
Card Extraction Study
PWB Flatness
LVPS-2R
EM Manuf
Fl Manuf
Func Test
MEB Replacement Cover
Vibe
Mech
Verif
Amb
Test
Manufacture
Peer
Review
CATS
STIS CATS
PDR
Amb Test
MPT
CDR
Thermal
Vac
Thermal
Acoustic
w/Carriers
Vibe
Mech
Verif
Modal
Vibe
Glove
box
T/V
STIS CATS
CDR
Manufacture
STIS Trainer 1 - STAR
Manufacture
STIS Trainer 2 - JSC
Design
STIS Repair TIPS Presentation
Manufacture
MPT
PDR
SRR
Design
Peer
Review
EMC
Vib
EMI
Modal
Peer
Review 2
STIKER
STIS MEB Sim
Mech
anism
Manufacture
Peer
Review 1
STIK
Func Test
Manufacture
Nov 16, 2006
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