Overview of STIS Repair Plans
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Transcript of Overview of STIS Repair Plans
Overview of STIS Repair Plans
Charles R. Proffitt
November 16, 2006
STIS Repair TIPS Presentation Nov 16, 2006 2
STIS History
Installed during SM2, Feb 14, 1997 Side 1 Failed May 16, 2001 (after ~ 4.5 yrs)
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) 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
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STIS in HST with Location of MEB
STISNICMOS
NCC
+V2
MEB Cover
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STIS
+V2Side
+V3Side
MEB-1
MEB-2
Flight STIS Instrument
MEB-1Cover
L-Handle
EVA Handle
MEB CoverExtension
MEB CoverExtension
Clamp
STIS Closeup
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STIS Main Electronics Box (MEB)
LVPS-2
LVPS2 Board (Engineering Unit)
MEB1 with Cover Removed
MEB Structure (non-flight)
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LVPS-2 Interfaces
Circuit board LVPS-2 has 3 main functions Supply Heater Power
+15 volts to Thermal Control Zone A and B Supply Calibration Lamp Power
+30 volts to Calibration Lamp Controller Supply Mechanism Power
+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 7HST +V2
Functional Overview of RepairMajor activities to be performed to repair STIS
Open the +V2 Aft Shroud doors
Remove STIS EVA Handrail
Remove MEB Cover Clamp
Install the Fastener Capture Plate (FCP) Tool
Release MEB cover fasteners (111)
Remove MEB Cover and FCP Tool
Remove failed LVPS-2 board
Install replacement LVPS-2R board
Install replacement MEB cover
Perform Aliveness Test
Install the STIS Thermal Interface Kit (STIK)
Install the STIK Radiator (STIKER)
Close the +V2 Aft Shroud doors
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EVA Timeline Goal from STIS Repair SRR was to get STIS repair
and cooling to fit in one EVA day.
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STIS Repair - NBL 06.2 Images
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STIS Aliveness Test
To be conducted during EVA Verify connectivity of LVPS-2R board to MEB motherboard. Ensure that major functions of LVPS-2R all work
Verify heaters enabled Enable SES telemetry collection Enable (close) mechanism and lamp relays and verify output voltages
Less Than 10 minutes in duration. Macro started at beginning of test will ensure auto-shutdown
Isolate any failure to specific pin.
(This is when we find out if it worked)
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Cooling System (SCS) Overview STIS
The STIS Cooling System (SCS) is intended to conduct heat away from the MAMA detector radiator and radiate it into the aft-shroud.
Evolved from the STIK interface to the Aft Shroud Cooling System
Three part assembly: SCS Mounting Bracket (SMB) The STIS Thermal Interface Kit (STIK
An actuator forces STIK pressure plate against STIS radiator
Soft thermal interface material on the pressure plate conducts heat to heat pipes.
The STIK Extended Radiator (STIKER) Spreader heat pipes on the STIKER
conduct and radiate heat away from the instrument.
STISNICMOS
NCC
STIKER
STIK Support Bracket
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Why install the SCS?
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.
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Challenges of STIS Repair
STIS repair requires a whole EVA If fewer EVAs than expected are available, STIS repair will be the first
thing deleted! Removal of 111 MEB Cover Fasteners
Need to be prepared to handle stripped or jammed fasteners Removal of MEB cover
RFI gasket Removal of LVPS-2 card
Card Locks may stick - studies indicate card can be removed anyway Insertion of LVPS-2R
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 Determined to be within acceptable limits
HST PCS analysis of SCS Jitter and STIKER mass control ongoing Failed SCS installation could cause jitter.
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Status after PDR
Hardware shown to meet requirements
NBL tests successfully demonstrated execution of STIS Repair with high-fidelity hardware
10 successful completions of LVPS-2 change-out
2 successful completions of SCS installation
Extensive testing and analysis performed to show compliance with HST Contamination requirements
Test results for high-risk tasks (Card Extraction and Insertion) and resulting requirements
The STIS Repair Team has defined and implemented plans, processes, tools, and has in place the organization to proceed to CDR (January 2007).
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STIS Repair Top-level Schedule
SRR
March May JuneApr May June July Aug Sept Oct Nov Dec Jan Feb
NBL06-02
PDR CDR
Contamination Study
Card Extraction Study
STIS Repair Reqts Dev
EM ManufVibe
Func TestLVPS-2R
MEB Replacement Cover ManufactureMech Verif
ThermalVac
EMIMechanism
Vib Modal
ThermalAcoustic
w/Carriers
STIKER Manufacture Amb Test
STIK
Vibe
T/VModalMechVerif
Glove box
April
200720062006
STIS MEB Sim
STIS Trainer 2 - JSC
ManufactureDesign
Manufacture
Manufacture
STIS Trainer 1 - STAR
Design
Crew FAM 1
STIS Repair System
SRRMPT CDR
CATSSTIS CATS
PDR
Peer Review 2
MPT PDR
Peer Review 1
Fl ManufPWB Flatness
Func Test
PeerReview
ManufactureAmb Test
Vibe
July
Interpoints replaced & COS testing complete
PER
PeerReview
EMC
STIS CATS CDR