1. THEMIS Critical Design Review Reaction Control Subsystem
Mike McCullough
THEMIS CDR 6/16/04

2. RCS Agenda RCS Specification Compliance RFA Status
AEROJET Organization
RCS Contract Chronology
Production Schedule Overview
Subsystem Overview
Analysis
Subsystem Verification
Subsystem Safety Features
THEMIS CDR 6/16/04

3. Specification Compliance
Most specifications are met or exceeded
Specifications that are compliant are shown with an “X”
Items where the testing surpasses the requirements are shown with an “S”
Some items are now out of date due to system evolution and re-pressurization upgrade
Items highlighted in yellow
Represent areas where compliance issues exist with the original specification
Most are relatively minor and have been discussed and agreed to with Aerojet
Where Aerojet will meet a revised spec are shown with an “R”
THEMIS CDR 6/16/04

4. Specification Compliance Matrix
THEMIS CDR 6/16/04

5. Specification Compliance Matrix
THEMIS CDR 6/16/04

6. Specification Compliance Matrix
THEMIS CDR 6/16/04

7. Specification Compliance Matrix
THEMIS CDR 6/16/04

8. Specification Compliance Matrix
THEMIS CDR 6/16/04

9. RCS CDR Peer Review RFA StatusID
Action Requested
Reason/Justification
Requested By/ Org
Assigned To
Date Due
Comment / Status
RFA 1
There is currently a disconnect between the perceived requirement for total System external leak rate and the proposed method of verification. The following actions are requested to resolve the conflict:
1. Perform a worst-case analysis assuming that all welds have an external leak rate equal to the capability of the Snoop detection method (1 x 10E-4 sccs) to determine if the resulting loss of pressure is acceptable. If the answer is affirmative, then the proposed verification method is conservative and acceptable.
2. If the above answer is negative, then the proposed verification method must be changed to a more sensitive technique, such as:
a)       bag the entire assembly and perform a total helium mass spectrometer measurement
b)       perform helium mass spectrometer measurements for each of the individual welds
c)       evacuate the inside of the system and measure the internal leak rate when the external environment is surrounded by helium
d)       other?
The current system leak requirement is not being properly validated by the proposed test method. If a worst-case system leakage analysis (assuming all welds leak at the Snoop detection capability limit) produces acceptable pressure losses for the Project, then the Project total system leak requirement should be revised to the higher allowable leak rate. If the pressure loss is unacceptable, then a new verification method must be proposed.
Mike Leeds & Marc Kaylor Swales
Aerojet
5/28/04
6/11/04 - Aerojet has a tent test capability now and will be using this for system leak check. The tent will provide a 10e-6 capability.
5/14/04 - Sent to Swales the External Leak Test Process Instructions
THEMIS CDR 6/16/04

10. RCS CDR Peer Review RFA Status
Re-evaluate case of trapped gas between pyro and check valves after proof testing by:
1)               Check Range Requirement for minimum energy allowed in pressurized systems
2)               Examine possibility of adding latch-valve or solenoid valve to replace check valve.
3)               Add service valve to relieve pressure
In general, flying with proof pressure is unacceptable with respect to EWR requirements
Chuck Zakrzwski NASA/GSFC
Aerojet
5/28/04
6/11/04 If check valve is used, the trapped GN2 will be evacuated. A trade study has reduced candidate check valves to 3 vendors. A solenoid valve may be instituted to mitigate range safety risk.
5/19/04 Swales was notified that Aerojet was investigating adding a service valve in the dead zone. This will facilitate evacuating the zone after leak tests and allow for testing the check valve.
RFA 3
Swales to define a reasonable worst case condition for thruster operation
·                     Number of pulses
·                     Number of preheated starts
·                     Propellant through put
Aerojet will provide a minimum recommended start temperature for non-emergency starts
Self evident
Olwen Morgan Aerojet
Swales Aerojet
6/11/04 Cold Bias - 250F start Temp. 2 elements 60 min., 1 element not recommended. 110F start, 2 elements 20 min., 1 element 50 min.
5/19/04: Conservative estimates from Swales provide. # of Pulses - 60K - 146K
Preheated Starts: 365
Propellant Throughput: 18Kg/Thruster
RFA 4
Need to prove that the system will handle worst case water hammer for opening the latch valve (analysis or test) or else preclude water hammer by design (bypass bleed-in leg or properly sized cavitating Venturi, etc.)
Current system has a potential for water hammer condition from a latch valve opening (even if the lines are filled during loading) that is unknown and must be determined within the component capabilities.
Mike Leeds Swales - West
6/11/04 Analyses shows that there is adequate design pressure capability to withstand surge and waterhammer flow after opening the latch valve.
THEMIS CDR 6/16/04

11. Aerojet's THEMIS Team
THEMIS CDR 6/16/04

12. Contract History
THEMIS CDR 6/16/04

13. Top Level Schedule
THEMIS CDR 6/16/04

14. RCS Overview Two Stage Blow-down System Monopropellant Hydrazine
Propellant Load: 48 kg
Helium Pressurant: 54 g
Three Segments
Pressurant System
MEOP of ºF
Carleton COPV P/N
Propellant Management Assembly
MEOP of ºF
Ardé I-718 Propellant Tanks
Rocket Engine Assembly Manifold
MEOP of ºF
Four MR 111C 4.4N Thrusters
Thermostatically Controlled Heaters
All Welded Construction
Complete Assembly By Aerojet
THEMIS CDR 6/16/04

15. Prepress System Increases Fuel Load
Blow-Down Curve – Pyro Valve Actuation
THEMIS CDR 6/16/04

16. RCS Layout Pyro Valve 1832-243 (Repressurization Subsystem)
Fill/Drain Valve
(Repressurization Subsystem)
REA T1
REA A2
Tube,
Tube,
Tube,
Tube,
THEMIS CDR 6/16/04

17. RCS Layout Pyro-Actuated Valve Service Valve, SV4 Tank 1 Tank 2 REA T1
Tube
Filter, F2
F0D
REA A1
Tube,
2 Places
Latch Valve, LV2
Latch Valve, LV1
THEMIS CDR 6/16/04

18. RCS Layout View into X-Y Plane directed along +Z-axis -Y +X
Tube,
(Cross-over line from
outlet of Latch Valve, LV2
to outlet of LV1)
Propellant Filter, F2
REA T2
REA T1
REA A1
Tank 2 +X
Tank 1
Latch Valve, LV1
Latch Valve, LV2
REA A2
Propellant Filter, F1
View into X-Y Plane directed along +Z-axis
-Bottom Deck Omitted for Clarity
THEMIS CDR 6/16/04

19. Thermal Modeling Overview
Aerojet performed extensive thermal modeling of the RCS subsystem
7 Thermal Control Zones
Both Propellant Tanks
Thruster A1
Thruster A2
Thruster T1
Thruster T2
Fuel Lines & Plumbing Zone 1
Fuel Lines & Plumbing Zone 2
Thermostats: Elmwood 3200 Series
50oF - 70oF Primary Setpoints
Series Redundant in All Zones
41oF - 61oF Secondary Setpoints
Series Redundant on N2H4 tanks only
Boundary conditions supplied by Swales to Aerojet
Swales verifies Aerojet thermal analysis, correlates results and folds into overall bus thermal model
THEMIS CDR 6/16/04

20. Thermal Summary
REAs Have Adequate Thermal Margin in Hot & Cold Environments
Current Design Exceeds 2 Watt Power Usage Target
Swales and Aerojet refining thermal interfaces to reduce heater power both at the component and system level.
May be reduced
THEMIS CDR 6/16/04

21. Plume Impingement Analysis Status
Nearfield/Farfield Plume
Axial Thruster Plume Analysis is Complete
Tangential Thruster Plume Analysis Awaiting More Information
Need spacecraft boom geometric definition (Not included in ICD or STEP files)
Axial Thruster Plume Impingement Analysis
Evaluated Plume Impingement from Axial Thrusters 1 & 2 on Separation Ring
Analyses Shows Plume Impingement Forces are Extremely Small
THEMIS CDR 6/16/04

22. Basic Parameters and Analysis Assumptions
Basic analysis parameters and assumptions
Propellant mass: 24 kg each tank (total 48 kg)
Two tanks for four MR-111C thrusters
Propellant tank internal volume: 1556 in3 each tank
Propellant: high purity hydrazine
Propellant ullage volume charged to 210 psia at 62 °F
thus, MEOP is 400 max temperature of 120 °F
Pressurant gas: GN2
Pressurant tank internal volume: 140 in3
GN2 fill pressure: °F
One pressurant tank for two propellant tanks
Propellant line elasticity modulus: 212 GPa
Hydrazine bulk modulus: 2.19 GPa
THEMIS CDR 6/16/04

23. Performance Analysis Completed to Date
Re-pressurization system
Pressure drop analysis
Surge and Water Hammer Pressure analysis
Check valve leakage analysis
Performance analysis includes thruster performance
THEMIS CDR 6/16/04

24. ‘NISA’ FEA Model Integration of All Lines With a Compliant Support Structure
CENTER
SUPPORT
SPRINGS
FUEL
TANK
MASS
COMPLIANT DECK
Ongoing Analysis
THEMIS CDR 6/16/04

25. Qualification Testing
Hydrazine Tank
Qualification Testing
THEMIS CDR 6/16/04

26. THEMIS System Final Assembly Flow
Install Tank #1 onto Flight structure verify tube endpoint locations with mating tubes secure & torque
Install service valve & thermal spacers verify tube endpoint location with mating tube secure & torque
Install Tank #2 onto Flight structure verify tube endpoint locations with mating tubes secure & torque
Install Re-pressurization manifold and brackets onto Flight structure verify tube endpoint locations with mating tubes secure & torque
Install REA manifold and bracket.Secure corner panel to handling fixture (3) places. Verify tube endpoint location with mating fitting secure & torque
Verify torque of all components and manifold standoff locations
Orbital weld (9) places THEMIS System closeout welds
THEMIS CDR 6/16/04

27. THEMIS System Final Assembly Flow, Con’t
Visual & X-RAY inspect orbital welds (9) places
Proof/Leak test (9) closeout welds
Penetrant Inspect (9) closeout welds. Use poly film sheet blanket to protect adjacent hardware
Finish final placement of propellant line heaters and thermal tape overlap
Complete electrical fabrication per wiring diagram
Verify electrical fabrication.Check each THEMIS component continuity & IR. Heat & cool thermostats heater to verify circuits
REA, Latch & Service Valves functional/leak checks
Verify Thrust alignment and position of REAS to THEMIS structure datum A, B, & D
Remove all GSE, measure THEMIS System weight with handling fixture subtract handling fixture weight. Replace all protective GSE
THEMIS CDR 6/16/04

28. Safety/Quality/Reliability System Level Features
System Is All Welded Design
100% Radiographic Dye Penetrant and Bubble Leak Tested
Proof Test to 1.5 MEOP of Each Section
Periodic Leak Checks Accomplished for Thruster and Latch Valve Seats
¼” x Tubing with Cajon Fittings
Burst Pressure > 15,000 psi (20,000 psi pre-installation)
Material Compatibility in Accordance With
RD-WSTF-0002
MSFC-HDBK-527
AIAA SP
MAPTIS, Marshall Space Flight Center Materials List
Leak Checking Methods are Under Investigation
Snoop Threshold of 1x10-4 Does Not Meet Mission Requirement
Heritage of Leak Check Method Indicates Better Resolution
THEMIS CDR 6/16/04

29. Safety/Quality/Reliability Pressurant System
Carleton PTD P/N 7149, Developed for the ST-5 Program
COPV Is Classified Fracture Critical In Accordance With Carleton PTD Damage Control Plan 5412
Liner: 6061-T6 Aluminum Per AMS QQ-250/11
Fluid Port Boss: Bimetallic 6061-T6 Aluminum To 304L CRES
Overwrap: 791 ksi PBO Fiber
MOP: 2240 Psig At 104°F
Proof Pressure: 3360 psig
Min. Burst Pressure: 4480 psig
Design, Manufacture, and Qualification Of COPV is IAW ANSI/AIAA S
Operational Cycle Life: 8 MEOP Pressure Cycles From 0 To 2240 psig And 6 Proof Cycles From 0 To 3360 psig
THEMIS CDR 6/16/04

30. Safety/Quality/Reliability Pressurant System – Cont’d
Paine Pressure Transducer
P/N
psi Range
Proof 4000 psi
Conax N/C Pyro Valve
P/N
MOP 9400 psi
Actuated by NSI EED with a Booster
Carleton PTD P/N 7149, Developed for the ST-5 Program
Qualified IAW Carleton QTP 1337
Carleton Qualification Test Report 5286
Conax High Pressure Service Valve
1700 psi MEOP, 6800 psi design burst
Requirement for Check Valve is Currently Under Investigation
THEMIS CDR 6/16/04

31. Safety/Quality/Reliability Propellant Feed Assembly
ValveTech Latch Valve
P/N
Proof Pressure 1000 psi
Burst Pressure 2400 psi
Vacco Filter
P/N F0D
Proof Pressure 600 psi
Burst Pressure 800 psi
Vacco Fill/ Drain Valves
P/N V1E
Burst Pressure 2000 psi
Arde Propellant Tank P/N D4899
Inconel I-718 to Meet Magnetics Cleanliness
THEMIS CDR 6/16/04

32. Safety/Quality/Reliability Propellant Feed Assembly
Arde Propellant Tank P/N D4899
Inconel I-718 to Meet Magnetics Cleanliness
MIL-STD-1522 and EWR Compliant Path 2A Leak Before Burst
Radiographic Inspection Post Proof Test Per NAS-1514 Class 1 for Welds and QA10177 for Membrane
Special Level Fluorescent Penetrant Inspection Sensitivity at 0.030” at 90/95% Probability of Detection/Confidence Level
Certification of Inspectors by Boeing Valid through November 2005
Stress Analysis and Fracture Analysis per ANSI/AIAA S-080 Sections and 4.2.6
Analysis Report Ardé EG10399, N/C Being Updated for 48kg Propellant Load
DVT and Qualification Testing Being Conducted by Arde to Meet THEMIS Mission Requirements
THEMIS CDR 6/16/04

33. Safety/Quality/Reliability Rocket Engine Assemblies
Rocket Engine Assembly Manifold
MEOP = 400 psia psia, Latch Valve Reverse Cracking Pressure
Proof Test to 1.5 x 650 psia
Thrusters – Aerojet MR 111C
Nominal 4.4 N Thrust
Mission Average Specific Impulse Estimated 215 s
Dual Coil – Dual Seat Valve with Integral Filter
Proof Test 1500 psi
Design Burst Pressure 2650 psia
THEMIS CDR 6/16/04

34. RCS Hazards Personnel Exposure to Hydrazine
Propellant is Toxic, Flammable and Known Carcinogen
Material Incompatibility with Propellant
Hydrazine Will React Catalytically With a Variety of Materials
Structural Failure of Propulsion System Components
Tanks, Tube Supports, Tube Runs, Components
Fatigue Failure of Propellant or Pressurant Tank
Highly Stressed Components, Limited Cycle Life
Inadvertent Actuation of Thruster or Pyro Valves, Valve Leakage
Release of Hydrazine Plume Constituents (H2, N2 and NH3) at elevated temperature
Over Pressurization of Propellant Management Assembly
Failure of Thermal Control System Elements
Potential to Drive System Pressure Outside Design Limits
THEMIS CDR 6/16/04

35. Safety Inhibits – Propellant Flow
Three Mechanical Inhibits to Prevent Propellant Leakage / Inadvertent Commanding
Dual Coil / Dual Seat Thruster Valves (2 Inhibits)
Thruster Enable Plug Permits Individual Testing of Valve Seats
Latch Valve Closed Immediately Following Propellant Loading (1 Inhibit)
“Wet to the Seat” to Prevent Surge Pressure Rise Upon Opening LV
Minimal Propellant Volume in Manifold and No Driving Force through Thrusters with Latch Valve Closed
Three Electrical Inhibits
Thruster Drive Circuit Grounded until Fairing Separation
Enable Command Processed through Bus Avionics Unit Communications Card (Special Command)
Thruster Commands Processed through Bus Avionics Unit Processor Card and Power Module
Inhibits are Independent and Verifiable
THEMIS CDR 6/16/04

36. Safety Inhibits – Repress
Mechanical Inhibits to Prevent Inadvertent / or Uncommanded Over Pressurization of the RCS
NSI Actuated Pyro Technic Valve (2 Inhibits)
Inlet and Outlet Port Must Both Be Punctured
No credible failure mechanism for both to fail
Failure causes inadvertent pressurization but not catastrophic failure
Three Electrical Inhibits
Pyro Drive Circuit Grounded until Fairing Separation
Enable Command Processed through Bus Avionics Unit Communications Card (Special Command)
Pyro Fire Command Processed through Bus Avionics Unit Processor Card and Power Module
Inhibits are Independent and Verifiable
THEMIS CDR 6/16/04

37. Safety Inhibits – Over Temperature
A “Stuck” Heater on the Propellant Tank Has Been Identified as a Failure that can Lead To Catastrophic Failure
Propellant Tank Heaters can cause over pressure due to the “piston” effect of heated propellant – The Hazard does not come from chemical energy release
Propellant Tanks are Thermally Isolated for reduced Power Consumption
Three Inhibits For Propellant Tank Heaters
Series Redundant Thermostats (2 Inhibits)
Limit Checking Task In BAU to Monitor Tank Temperatures and Disable Propellant Tank Heater Service Upon Reaching 121ºF (1 Inhibit)
THEMIS CDR 6/16/04

38. Safety - RCS GSE GSE for RCS is limited to a pressure panel
Designed, Fabricated and Tested IAW EWR 127-1
Redundant Relief Valves limit pressurization level to MEOP
Pressure Panel used for functional demonstration of RCS
Propellant Load Equipment and GSE is TBD
Anticipate using KSC Propellant Loading Services
Introductory Meeting set for late Summer
THEMIS CDR 6/16/04