Leland D. HillAMS-02 Phase III Safety Review1 Safety Summary of Significant Changes Since Phase II

Leland D. Hill AMS-02 Phase III Safety Review 1

Safety Summary ofSignificant Changes Since Phase II


This Presentation will:

Highlight changes to AMS-02Highlight modifications made to Flight

Hazard reportsWill not detail verification status changes,

those will be presented with hazard reports.

Updates to supporting data not reflected here.


ROEU Folding BracketAs the ROEU extension outside of the

ICD defined envelope for theAMS-02 CAS site is no longer deemed an impact to an adjacent ELC, the EVA operable PIP pins have been removed and replaced with fixed threaded fasteners.Hazard Reports directly impacted

AMS-02-F11AMS-02-F14AMS-02-F18


AMS-02 Magnetic Field Strength

The maximum current supplied by the AMS-02 Cryomagnet Avionics Box (CAB) to the superconducting magnet has been reduced by 7.6%. (459 A → 424 A)New Value established through ground magnet

quench “training.” Associated with this change the ramp rate

for charging and discharging the AMS-02 has been changed, to reduce the probability of a quench during discharge.The number of dump diodes have been reduced

to 9, to provide this reduced discharge rate.Charging and discharging time has gone from 1.5

hours to 2.5 hours.


AMS-02 Cryosystem Modification

To protect the cryosystem during ground operations, a “burp valve” has been installed.Allows for any long periods of quiescent

operations (such as a hurricane rollback) for the AMS-02 to “burp” evolved gases if power is not available to operate the nominally operated vacuum pumps.

This protects from operating burst disks in the event there is a delay in restoring services while preventing air from being ingested into the Cryosystem.

Valve is isolated prior to launch.


AMS-02 TRD Gas Supply

The TRD Gas Supply has been modified to remove the Calibration Tubes (also referred to as Monitoring Tubes) that contain the radioactive Fe55 isotope.The removal of the AMS-02 system’s only

radioactive material removes the need for hazard report AMS-02-F09

AMS-02-F05, Control 1.2 was revised to remove reference to the tubes containing the radioactive material.



The TRD Gas Supply has been modified to add a supply gas link so that alternative gas sources may be used while on the ground to keep the delicate tubes used in the sensing array from being reversed pressurized by atmospheric changes.Supply only used on the ground.Additional plumbing to the low pressure section

of TRD that remains on the AMS-02 meets applicable flight requirements.AMS-02-F05 tables updated for additional components.



The TRD Gas Supply Composite Overwrapped Pressure Vessels were provided with an additional MMOD shield on the inboard side.Constructed of aluminum foam with

aluminum skins.Necessary to meet MMOD susceptibility

requirements.Provides additional protection of COPV to

impact damage.


TRD COPV MMOD Shield

MMOD Shield (Left)

COPV Ground Shield (Below)

AMS-02 TRD Sensor

Low Pressure Gas supply manifold structure changedCreates larger groups of “straws”, uses fewer

and more simplified valve structure for controlling.From 41 segments of straws to 10

M-Structure of TRD equipped with redundant strings of 120 V resistive heaters (70 W) to minimize leakage past manifold flipper valve seats during cold soak.Allows valve operations at cold attitudes.Heaters not considered safety critical.

Each heater has two thermostatic control devices.Leland D. Hill AMS-02 Phase III Safety Review 10


AMS-02 Warm Helium Gas Supply

The Warm Helium Gas Supply Composite Overwrapped Pressure Vessel MMOD shield design finalized. Constructed of aluminum foam and aluminum skins.

Same Construction as new TRD Gas MMOD shield. Check Valves added to relief valves to minimize

helium loss past relief valve seats. Raises relief pressure of the system by 0.35 bar

Hazard Report AMS-02-F03/ F05 reflects this change Pilot Valves replaced with different valve as old

valves consumed too much helium with each operation. New valves do not suffer same reverse pressurization

issue as old valves. Hazard Report 5 updated to remove control for fracture

criticality.


Warm Helium Supply MMOD Shield

Warm Helium Gas Supply

Check Valves added to relief valves to minimize helium loss past relief valve seats.Raises relief pressure of the pressure

relief valves by 0.35 bar (5.07 psi)Hazard Report AMS-02-F03/ F05 reflects

this change


Warm Helium Gas Supply Modification



Pilot Valves replaced with different valve as old valves consumed too much helium with each operation.New valves do not suffer same reverse

pressurization issue as old valves.Hazard Report 5 updated to remove control for fracture

criticality of old valve bodies.

New valves require additional current to drive.New electronics box created to take existing signals

and provide appropriate control power to new valves.Taps into UPS for additional power needs during

ascent. Compliant with active electronic design and thermal limits

for ignition of flammable atmospheres.Leland D. Hill AMS-02 Phase III Safety Review 15


New Valves had different footprint than old valves Redesigned PVVV built and installed.

Additional Plumbing was put in to augment the evacuation of the PVVV during ground operations. Additional Valve (DV09C) put in to control this connection.

Port and valve (MV80) was added so that ground operations could use alternate source of helium gas rather than flight pressure vessel.

Check valves added to feed line to warm pilot valves to limit helium consumption.




New PVVV






New Valves require more power than old valves. Required a new electronics box to “amplify” the power

to the new pilot valves.Cryomagnet Pilot Valve Switch (CPVS) Box.

Box powered by UPS during ascent.Contains no Arcing/Sparking partsDoes not reach autoignition temperaturesMaintains UPS isolation from power distribution

system

Small heaters added to pilot valve base plate.Insufficient power to impact pressure in system

Thermostatic control implemented to limit application to cold attitudes.



AMS-02 UPS

The battery cells of the AMS-02 UPS have been replaced with new cells of the same design and pedigree as a subset of the previous cells were under-performing.Energy content of the original UPS were

still sufficient to fulfill mission objectives.Concerns over life cycle trends dictated

replacement of cells.


AMS-02 Radiators

Edges of the AMS-02 Radiator Panels, Main Ram and Wake and Zenith, were found to have inadequate rounding (full rounding required for thin sheets) of the aluminum surface sheets that faced the radiators. Accessible edges were covered with a

Teflon tape to preclude contact with the non-fully rounded edges.Edges weren’t found to be sharp, only non-

compliant with the NASA standard.


TTCS Line Heaters

Design of TTCS condenser line heaters finalized. Redundant heater “wire” wrapped around tubes as they go to radiators.Additional Control added to AMS-02-F01

to relate potential thermal impact on adjacent composite struts.

Heater control structure consistent with heater philosophy maintaining two fault tolerant control to potential hazardous event (Excessive Heat).Concern adjacent composite struts.


SSRMS Power

Maximum allowable current draw for SSRMS is16.7 Amps for payload power draw as a derated wiring specification. In SSRMS warmest attitude and currents exceeding the

specification, wiring may overheat insulation

AMS-02 has not pursued the fuse described as an option at Phase II from the design and instead took the path of confirming that maximum load (everything that defaults on) can not exceed SSRMS requirement. All heaters on exceedingly unlikely as thermostatic control

implemented on heaters. AMS-02 would have to be in a significant cold position while SSRMS was in

excessively hot position to reach AMS-02 maximum draw and approach SSRMS limit (16.2 to 16.7 Amps.)

AMS-02 active systems implement current protection

RICH Modification

RICH Aerogel volume was previously fitted with relief valves and bladders to minimize atmosphere intrusion during ground processing. In order to make sure the aerogel remains dry, a low

pressure (~1-2 psi) flow was provided for through this volume.

Uses the 1 psi relief vents, T fittings, and a ground source of dry nitrogen gas.

PTFE Piping and quick disconnects mounted to ease access to ports to connect gas supply.

At Phase II the volume of the aerogel and sodium flouride was not considered a pressurized system, and this modification did not change that categorization.


RICH Modification


TTCS

Tracker Thermal Control SystemDifferences in Primary and Secondary

Loops were removedBoth looks now identical, “Experiment” valves

in Primary Loop removed.


TTCS


Location of Removed Valves

Warm Heliomatic Valve Modification

Warm Heliomatic Weka Valves were found to leak past the activation stem that attached to the bellows when transitioning between open and closed. Leakage was small inclusion of atmosphere into the low

pressure cryosystem lines

A low pressure manifold was put in place to place a helium blanket where it would be ingested in lieu of atmosphere. Stainless Steel construction with 1/8” piping that can be

evacuated or filled with a low pressure (1 bar or less) helium blanket.

Nine Weka Warm Valves modified. Anomaly report AMS-02-A26



Hazard Report Modifications

AMS-02-F01 – Structural Failure of Hardware Add control for vented containers (ΦII Instruction)

Add new Cause and associated controls to address rotating equipment (ΦII Instruction)

Numerous small pumps exist in AMS-02 subsystems AMS-02 On-Board Pump will operate on ground only (within payload

bay), but flies with the AMS-02 into space. Verification of Magnet Structure changed from 1.1x test to 2.0

analysis Coordinated with SWG

Specific Verification on Acoustic Analysis/Test removed from verifications

Reference to JSC 23642E changed to JPR 8730.2 for fastener testing.

Under reconfiguration of AMS-02 (i.e. capture bar failed to be returned to nominal location) it was not desired by NASA to make this a planned or contingency EVA, Control adjusted to address method available, not specific EVA.

Folding ROEU Bracket removed from Controls (12.2)



AMS-02-F02 – Toxic Material OffgassingNo modifications



AMS-02-F03 – Rupture of Superfluid Helium Tank, Vacuum Case and/or Pressurized SystemsA modification to the “2 o-rings” on all

non-welded Vacuum Case interfaces provides a caveat for specific electrical connectors a single o-ring is used with a Loctite 1C Hysol Epoxi-Patch potting used as a second sealing method.

Pressure Tables and Schematics updated



AMS-02-F04 – Overpressurization of Orbiter Payload Bay Control 6.1 modified to:

reflect that AMS-02 MLI will not be retained by what the project considers “soft” means of attaching MLI, including the use of hook and loop fasteners.

GFE which have been independently approved in their design and application of hook and loop fasteners to retain their unique MLI/blankets are being used within their certification.

Modification of controls to reflect that only a single burst disk now used on Vacuum Case emergency vent and two burst disks on the Super Fluid Helium Tank emergency vent

Control 5.2 updated with up to date quantity of propylene and specifies that it is in each of 8 tubes, previously the number of tubes was not mentioned in control.

Controls 5.3, 5.5 and 5.7 are updated with the final fill values of ammonia used in heat pipes and heat pipe loops.

All changes within the scope of previous analyses. Schematic updates for TRD, Cryosystem and Warm Helium Gas

Supply.



AMS-02-F05 – Rupture of AMS-02 Pressure Systems: (list) Control 1.2 modified to remove reference to TRD

Monitor/Calibration Tubes. Control 1.3 modified to reflect addition of check valves that

minimize the leakage of gas past the relief valves. This addition makes a minor alteration of the relief pressure of the

system (.3 bar) All components have adequate margin to account for this alteration.

Pilot Valves have been changed out for valves that do not consume as much helium in operation

New valves do not have reverse pressure criticality like previous valves. Control removed that was specific to old valves.

Control 8.6 revised to explain that Ram and Wake heater redundant heater strings only have two thermostatic controls per string as analysis shows that two strings must fail on to drive heat pipe pressure above MDP. Two fault tolerance to hazard does not required each string to be independently two fault tolerant.

Verification added to include Fault/thermal analysis. Schematic and Table updates for TRD and Warm Helium Gas

Supply.



AMS-02-F06 – Excessive Thrust/ Overturning MomentsControl 2.2 was clarified to include not just

cryogenic sources of potential thrust materials, but gaseous sources as well.

Correction made to Control 1.3 to reflect zero-thrust vents and not specifically “T” vents.

Schematic Updates for TRD and Cryosystem (including Warm Helium Gas Supply).



AMS-02-F07 – Excessive Field Strengths: EMI, Magnetic (DC Field) Magnetic field nominally 7930 Gauss included in controls. Maximum Cryomagnet Current now 424 not 459 and changes

made accordingly in Control 1.8 Typographical error in SVM 1.3.4 Control 1.4 and 3.1 removed erroneous statement about switching

of cables by EVA during a launch phase. Verifications modified to account for this as well

Verifications for 1.5 and 3.2 modified to account for Go-No Go call not being an LCC and being an OMRSD

Redundant and poorly worded duplicate verification removed from control

Control 1.6 specifically describes that Hall Effect sensors will detect magnetic field’s presence.

Safety Verification 1.6.9 added to establish EVA keep out zones for excessive magnetic fields as OCAD submittal.

Added Control 1.10 addressing magnetic field impact on visiting vehicles (none) per Phase II Agreement.



AMS-02-F08 – Electric Shock/ DischargeNo Modifications



AMS-02-F09 – Exposure of the Crew to Excessive Ionizing RadiationThe source of radioactive Fe55 has been

removed from the payloadHazard Report Withdrawn for Phase III



AMS-02-F10 – Flammable Materials in the Payload BayAdded Cause 3 and Control 3.1 for ignition of

non-AMS-02 Source flammable materialsControl of potential hotspots, electrical sparking

equipment, etc controlled as per letter NS2/81-MO82 and MLI grounded per ICD 2-19001.

Added verifications for: Thermal Analysis Review of Design Grounding Testing of MLI

All values for Ammonia and Propylene fill quantities changed to final as measured values.



AMS-02-F11 – Mechanism Failure Verification 5.1.4 erroneously referenced

travel limiters which have no impact on control, changed to relevant component, Load Release Screw Locking Mechanism.

Control 6.1 modified to account for ROEU folding bracket no longer folding.Verification 6.1.1 deleted

Control 6.2 deleted in entirety to account for the ROEU folding bracket no longer folding.Four verifications deleted.



AMS-02-F12 – Mate/Demate of ConnectorsControl 1.6 added to account for the need to

deadface T-0 power prior to launch. Verifications confirm ground procedures and required

additional LCC for AMS-02 sourced power. Modification required by KSC operations to protect the

flight vehicle.

Control 1.4 was giving a Review of Design verification (1.4.1) and the Testing Verification became 1.4.2 and the list of EVA accessible connectors was modified to PVGF and ROEU as well.



AMS-02-F13 – Battery FailureDescriptive bullet list attached to hazard

report updated to reflect the SDP text and control 3.2 on stack level monitoring for overdischarge.



AMS-02-F14 – EVA Operational Hazard Control 1.1 modified to clarify that FRGF and PVGF EVA Release have

been approved for both free float and use of the WIF socket. Control 1.2 modified to remove “with a 7/16 inch drive”

“Drive” is the interface between the “socket” and the “tool” not the “socket” and the bolt. Prepositional phrase added nothing to the control and was deleted.

Verification 1.3.3 went from “Crew EVA inspection” to “Crew inspection” as the inspection was to be on flight hardware at KSC, not during an EVA.

Control 4.1 was modified to account for AMS-02 NCR-001 for EVA Touch Temperature violations.

Verification 4.1.2 added for approval of the NCR.. Control 4.2 was modified to clarify that the touch temperature compliance

was limited to areas that were accessible to an EVA crew member. Control 4.2.3 modified to account for the functional testing of the heater

circuitry including the heaters and thermal switches, not just the thermal switches.

Control 5.3 and associated verification deleted as ROEU folding bracket no longer folds.

Control 6.1 removes reference to folding ROEU bracket from list of EVA tasks.

Control 10.2 modified to reflect that the ROEU folding bracket no longer folds, retaining the verifications that the protrusion is documented and not extending to the adjacent payload’s envelope.



AMS-02-F15 – Thermal ExtremesStill Deleted from Phase II



AMS-02-F16 – Shatterable Material ReleaseControl 1.5 and 1.7 modified to reflect that

vents of laser source boxes are unfiltered 50 micron holes and that now interior components are contained within housings or fibers within jackets.



AMS-02-F17 – Electrical Power Distribution Damage Control 1.2 modified to reflect new

consensus on SSRMS Power utilization that allows for the removal of the AMS-02 supplied fuse.

Control 1.3 removes reference to Cryomagnet Avionics Box from control as it is not relevant to the control.

Control 2.4 referenced incorrect control in hazard report AMS-02-F12.



AMS-02-F18 – Rapid Safing/Payload ReconfigurationControl 1.6 added to address the rapid safing

analysis to show that Orbiter can be safed during AMS-02 transfer within1 hour and 35 minutes.

Safety Verification 2.2.2, inspection of hardware, not applicable to control and deleted.

Control 3.3 was rewritten as a repair solution and not an established EVA as it required multiple failures and operational errors to get to that point and it wasn’t considered contingency or nominal EVA.

Control 3.4 deleted as ROEU folding bracket no longer folds.



AMS-02-F19 – Excessive GlareWithdrawn prior to Phase II safety review,

PSRP concurred with this action at Phase II.



AMS-02-F20 – Crew Exposure to Coherent LightNo Modifications



STD-AMS-02-F01 – JSC Form 1230 for AMS-02 Exterior ElementsPer Phase II instructions, the content of

this hazard report have been reassigned to other hazard report.Sub HR 3 moved to AMS-02-F01Sub HR 12 moved to AMS-02-F10Sub HR 13 moved to AMS-02-F01



STD-AMS-02-F02 – JSC 1230 Form for AMS-02 Interior Elements.Safety Verification 10.a.1 redlined for

clarity of the actual activity to be performed, to specify low power application.

Safety Verification 10.a.2 redlined to clarify that originally referenced analysis is a thermal analysis and the goal is to check touch temperatures.


Correction to SDP (Post Phase III Submittal, Prior to Working Group)

Star Trackers are reported in SDP as being attached to Vacuum Case Conical Flange.Star Trackers are attached to the Tracker

Conical Flange.Error entirely in the SDP text description,

specifying vacuum case instead of Tracker, all analyses and installations are according to the design.

Documents

Leland D. HillAMS-02 Phase III Safety Review1 Safety Summary of Significant Changes Since Phase II