HST Replacement Battery Initial Performance Space Flight Center Hubble Space Telescope Program 1 HST Replacement Battery Initial Performance Stan Krol, Greg Waldo Lockheed Martin Information

Goddard Space Flight Center

Hubble Space Telescope Program

1

HST Replacement Battery Initial Performance

Stan Krol, Greg Waldo

Lockheed Martin Information Systems & Global Services

Roger Hollandsworth

Lockheed Martin Space Systems Company

https://ntrs.nasa.gov/search.jsp?R=20100003027 2018-06-16T21:51:15+00:00Z

Presenter

Presentation Notes

Abstract: The original HST batteries, with 19 years of on-orbit life, were replaced by astronauts during the May 2009 HST Service Mission #4. The manufacturing of nickel plaque for the "new" batteries began in 1995, the cells were activated after 4 years of dry storage, in 2000, and assembled into batteries and then battery modules, which were stored wet for 9 years, before being installed onto HST. This paper details the prelaunch capacity verification, and the on-orbit performance of the replacement batteries.


2


Introduction

The Purpose Of This Presentation Is To Highlight The Findings From The Assessment Of The Initial SM4 Replacement Battery Performance

The Assessment Period Starts At SM4 Release On May 18, 2009 And Covers Through November 8, 2009.

The Assessment Examines The Battery Voltage, Current, Thermal, Pressure, State Of Charge And Impedance Performance.

Presenter

Presentation Notes

This paper will describe the condition of the replacement batteries at installation and their subsequent orbital performance providing power for the science preformed by the Hubble Space Telescope.


3


SM4 Battery Replacement

The HST original Nickel-Hydrogen (NiH2) batteries were replaced during the Servicing Mission 4 (SM4) after 19 years and one month on orbit.

The replacement batteries were installed during EVA2 (Bay 2) and EVA5 (Bay 3). – Bay 2 contains battery (SN): 1 (1161), 2 (1162) and 3 (1163)

– Bay 3 contains battery (SN): 4 (1166), 5 (1165) and 6 (1164).

Aliveness Tests and Functional Test were executed successfully with no liens

Presenter

Presentation Notes

The original set of HST batteries were began manufacturing in 1988, were activated in 1989, and deployed with HST on April 25, 1990. They have undergone 19+ years of orbital cycling, with 104,125 orbits at time of replacement during SM4. The batteries were replaced during two separate EVA periods on the 2nd and 5th day of HST EVA activities. There have been no problems with either the installation or subsequent testing on the new batteries.


4


Battery Description

22 Electrically Series Connected RNH 90-3 NiH2 Cells

Wet Slurry Nickel Positive Electrodes & Double Layer Zircar Separator– Nickel Precharge– 1990 Original: Dry Sinter – Hydrogen Precharge

Battery Isolation Switch (BIS) (EVA Operated Only)

Current Sensor

Individual Cell Heaters– 2 Independent Heater Circuits, Primary And Redundant

2 Independent Strain Gauge Pressure Monitoring Circuits

Temperature Monitoring Circuit (Telemetered)

4 Charge Control Thermistors (Not Telemetered)

Individual Cell Voltage Monitoring Test Connector J3 (GSE Only)

Presenter

Presentation Notes

The batteries for the SM4 replacement mission began manufacturing in 1995 and the cells were placed into dry storage in 1996 for four years. The cells were then activated in Sept. 2000 and assembled into two battery modules composed of 3 batteries each. 9 years elapsed from cell activation in 2000 till installation onto HST in May of 2009, resulting in a 9 year wet storage period, five years beyond specifications.


5


Battery Description (continued)

Nameplate capacity: 88AH

Battery IsolationSwitch

Presenter

Presentation Notes

The original set of batteries was composed of 23 cells in each battery, of which 22 cells were electrically connected in series. The replacement set of batteries was modified for astronaut EVA safety during handling by replacing cell #15 with a Battery Isolation switch (BIS) connected in series with the cells and then wiring cell #23. The BIS was turned to the OFF position during launch and EVA installation, and then turned to the “ON” position, activating the battery.


6


Battery Description The Six Batteries Are Housed Within Two Modules (S/N 1032 &

1033). Each Module Consists Of 3 Electrically Independent Ni-h2 Batteries Mounted To A Battery Module Base Plate.

Battery Isolation Switch

• Size: 36” H x 32” W x 15” H• Weight: 475 lbs each module

• Fabrication: January 1995-96 • Dry Stored for 4 Years

• Activatation: September 2000• Passively Stored Until April 2009

• Wet Stored 9 Years

J-Hook – Attach to Bay Door

Presenter

Presentation Notes

Three batteries are enclosed within each Battery Assembly Module. The module is attached to the HST equipment bay door by astronaut operated J-Hooks


7


Battery 0°C Capacity

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4

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2020

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0 10 20 30 40 50 60 70 80 90 100 110 120

Cur

rent

(A)

Bat

tery

Vol

tage

(V)

Discharge Capacity (Ah)

2002 Battery ATP vs. 2009 Can Ops

2002 Battery ATP 2009 Can Ops

2002 Amps 2009 Amps

2nd Plateau

2002 - 96.14 Ah2009 - 91.08 Ah

Presenter

Presentation Notes

This chart details the changes which occurred during 9 years of wet storage to the voltage discharge in the Standard 0°C Capacity Test, following a 149% overcharge. Note that the voltage plateau remains unchanged, however usable capacity above 26.5V is reduced with storage, due to second plateau capacity. Also exhibited here is growth of total capacity, below 20V, which is due to loss of nickel precharge.


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Battery 0°C Capacity Trend

0

10

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60

60

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110

120

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Del

ta C

apac

ity (A

h)

Cap

acity

(Ah)

Date

MaximumCapacity (15V)

BatteryCapacity (26.5 V)

2nd PlateauCapacity (Delta)

Presenter

Presentation Notes

This chart details the decrease in 0°C battery capacity during the 9 years of wet storage, the increase in the 2nd plateau capacity, and the increase in the total capacity. All due to loss of nickel precharge and nickel corrosion processed during storage.


9


Battery 0°C Cell Capacity

0123456789101112131415160.0

0.10.20.30.40.50.60.70.80.91.01.11.21.31.41.51.6

0 10 20 30 40 50 60 70 80 90 100 110 120

Cur

rent

(A)

Cel

l Vol

tage

(V)

Discharge Capacity (Ah)

B1CV1 B1CV2 B1CV3 B1CV4B1CV5 B1CV6 B1CV7 B1CV8B1CV9 B1CV10 B1CV11 B1CV12B1CV13 B1CV14 B1CV16 B1CV17B1CV18 B1CV19 B1CV20 B1CV21B1CV22 B1CV23 Amp1

2nd Plateau

Presenter

Presentation Notes

This chart details the second plateau capacity which appears within all cells after 9 years of wet storage. There is still >20 AH capacity, but it is only available at a voltage below 1.0V/cell or 22 V for the battery.


10


State Of Charge (SOC) Performance

The Table Below Shows The Battery Pressure Based SOC’s At The Time Of Installation, Release And Release +30 Days (DOY 169 / 09) and present (DOY 301/09)

Battery Install SOC (Ah)

Release Full SOC (Ah)

DOY 169/09 Full SOC (Ah)

DOY 301/09 Full SOC (Ah)

1 52.3 67.7 86.2 87.5 2 53.3 66.8 84.9 87.8 3 49.0 62.3 80.4 82.1 4 58.0 73.4 92.2 92.0 5 52.5 66.9 86.4 89.0 6 56.9 67.9 90.4 88.8

Presenter

Presentation Notes

The SOC of the batteries is shown at installation, which was residual from pre-launch charge maintenance. The SOC at release followed the initial Aliveness and Functional Testing, and then the SOC following 30 days of orbital operations shows that good orbital capacity has been achieved.


11


State Of Charge (SOC) Performance At The Time Of HST Release, The Battery SOC Was 484 Ah

SOC Continues To Increase And As Of DOY270 Is Above 525 Ah.

470

480

490

500

510

520

530

540

65

70

75

80

85

90

95

100

139 159 179 199 219 239 259 279 299

Syst

em B

atte

ry S

OC

(Ah)

Indi

vidu

al B

atte

ry S

OC

(Ah)

DOY 2009

Individual Battery and System State Of Charge(DOY 139-301, 2009)

BAT1CAP BAT2CAP

BAT3CAP BAT4CAP

BAT5CAP BAT6CAP

Total SOC

Presenter

Presentation Notes

This chart details the individual battery SOC and the System SOC following HST battery installation and HST release.


12


Battery Voltage Performance

The 1990 Dry Sinter Voltage Profile Differs From The Other Profiles:– Software Step-to-trickle Charge Scheme Was Used vs. The Software Taper-charge

Scheme– Less Powerful SA1 vs. SA3– Battery Temperatures:

• 1990: ~ 0°C• 2008: ~ 0°C• 2009: ~ -2°C

Orbit Day Duration Was Matched For All Profiles

Battery Currents Were Approximately Matched (Within 2A Amps During Discharge) For All Profiles

The Battery Voltage Profiles Indicate That The Replacement Batteries Maintain A Higher Voltage Throughout The Orbit Night Discharge Period Than The Original Batteries Had Just After HST Deploy Mission.

The Plot Also Indicates The Degradation Of The Voltage Profile Between 1990 And 2008 For The Previous Batteries.

At This Time, The On-Orbit Plateau Voltage Is Unknown And Can Only Be Determined By An Extended Discharge Period.

Presenter

Presentation Notes

The chart following this details the voltage differences observed between the new and atteries.aged Original Battery as compared to the new replacement. This chart defines the comparison parameters utilized.


13


Battery Voltage Comparison

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-5

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0:00 0:28 0:57 1:26 1:55 2:24

Load

Cur

rent

(A

)

Volta

ge (V

)

Normalized Time

(Wet Slurry {SM4} vs Dry Sinter {1990 and 2008})

SM4 V 2008 V 1990 V

SM4 I 2008 I 1990 I

SA1 and Step to Trickle (K2 Level 3 {~33V})

SA3 and Taper Charge(K1 Level 4-100mV {~32.6V})

Presenter

Presentation Notes

This chart details the voltage and current traces for the original Dry Sinter batteries in 1990 (red) and 2008 (green) versus the new replacement batteries (blue trace). Note that the new replacement wet slurry batteries have a higher voltage plateau than even the original batteries, even at beginning of life. There have been three sets of solar arrays (SA1 – SA3) during the 19 year life of HST.


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Battery Impedance

The Battery Impedance Is Computed Using The Change In Battery Voltage Divided By The Change In Battery Current During The Night to Day Transition

The Impedance Of The Replacement Batteries Exhibits Lower Impedance Than The Original Batteries At Beginning Of Life And After 18 Years On Orbit

Impedance Includes 22 mohm Harness Resistance


15


Battery Impedance

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Impe

danc

e (O

hms)

Battery

(Dry Sinter {1990 and 2008} and Wet Slurry {2009})

Bat 1 Bat2 Bat3 Bat4 Bat5 Bat6

DS

-19

90

DS

-19

90

DS

-19

90

DS

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90

DS

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08WS

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WS

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WS

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WS

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09

WS

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WS

-20

09

Presenter

Presentation Notes

Using the orbital night to day transition, the change in voltage vs. current change was used to calculate the battery impedance comparing the as installed original batteries, these batteries aged after 18 years, and then the new replacement batteries. The new replacement batteries exhibit impedances lower than the original batteries, at beginning of life.


16


Minimum Voltage Performance

Minimum End Of Orbit Night Battery Voltages (28.2V) Indicate 0.85V Margin Vs. Ground System Limit Of 27.35v.

When Compared To The Bus Voltage Limit Of 26.37V This And Accounting For The 0.8V Diode Drop There Is (28.2 – (26.37 + 0.8) = 1.03V Of Margin Vs. The Bus Voltage Ground Limit.

Ground Limit

27

27.5

28

28.5

29

29.5

30

139 159 179 199 219 239 259 279 299

Bat

tery

Vol

tage

(V)

DOY 2009

Daily Minimum Battery Voltage {End of Orbit Night}(DOY 139 - 308, 2009)

CBAT1V CBAT2V CBAT3V

CBAT4V CBAT5V CBAT6V

NCS Operating

SM4 HST Release

Presenter

Presentation Notes

This chart details the end of eclipse (orbit night) battery voltage of the new replacement batteries for the 30 days following installation. The data indicates adequate margin between operational voltages and ground safety limits.


17


Battery Thermal Performance

The Battery Temperatures Range Between -5°C And -2°C With Excursions To 0°C, When The Redundant Heaters Activate in the Low Load Configuration.

– The Redundant Heaters Typically Cycle Between One And Two Times Within A 24 Hour Period

– The Primary Heaters Remain Disabled To Allow The Batteries To Operate At Reduced Temperatures

In the High Load Configuration, The Daily Average Temperatures Range Between -1°C and 2°C

HST Experienced Solar Beta Peaks On DOY 155 and 200 Which Resulted In A Peak Orbit Day Duration Of 69.3 Minutes and 67.9 Minutes

– Historically, The Batteries Have Tended To Heat-up During And/OrFollowing A Solar Beta Peak

– No Heat-up Was Associated With These Events. The Lack Of Heat-up For This Recent Event May Be Attributed To The Good Condition Of The New Replacement Batteries And The Charge Control System Configuration

– As The SOC Continues To Increase, The Batteries May Become More Sensitive To Such Beta Peaks

Presenter

Presentation Notes

The cells are equipped with individual cell heater strips which are controlled by primary and redundant heater circuits.


18


Battery Thermal Performance

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61

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-4

-3

-2

-1

0

1

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3

4

139 159 179 199 219 239 259 279 299

Orb

it D

ay D

urat

ion

(min

utes

)

Mea

n B

atte

ry T

empe

ratu

res

(deg

C)

DOY 2009

Battery Temperatures {Daily Mean}Orbit Day Duration

(DOY 139 - 308, 2009)

CBAT1TMP

CBAT2TMP

CBAT3TMP

CBAT4TMP

CBAT5TMP

CBAT6TMP

Day_Duration

EPS Configured for High NCS Load

Presenter

Presentation Notes

The mean battery temperature is very stable, even during the solar maximum at DOY 157. The battery thermal distribution is also within 1°C .


19


Battery Current – Loadshare

The Battery Load Share Is Well Balanced And Generally Within 16.2 To 17.2%. (larger transients are due to low load condition)

– Mean Load Share Deviation Among The Batteries Is 16.6 To 16.8%.

14

14.5

15

15.5

16

16.5

17

17.5

18

139 159 179 199 219 239 259 279 299

Bat

tery

Loa

dsha

re (%

)

DOY 2009

Battery Loadshare Since SM4(DOY 139 - 308, 2009)

Bat1 LS Bat2 LS Bat3 LSBat4 LS Bat5 LS Bat6 LS

Mean LoadshareBat1 LS 16.7%Bat2 LS 16.8%Bat3 LS 16.8%Bat4 LS 16.6%Bat5 LS 16.7%Bat6 LS 16.6%

Presenter

Presentation Notes

The distribution of current (load share) between the six replacement batteries is very balanced due to balance battery impedance.


20


Battery System Recharge Ratio

The Mean Battery Recharge Ratios Range From 1.05 To 1.10.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

139 159 179 199 219 239 259 279 299

Rec

harg

e Rat

io (C

/D)

DOY 2009

Battery Recharge Ratios(DOY 139 - 308, 2009)

Bat1 RR Bat2 RR

Bat3 RR Bat4 RR

Bat5 RR Bat6 RR

Lack of system reset due to low load corrupts calculation

Lack of system reset due to low load corrupts calculation

Mean Chg/Dischg

Bat1 RR 1.10Bat2 RR 1.07Bat3 RR 1.06Bat4 RR 1.07Bat5 RR 1.08Bat6 RR 1.05

Presenter

Presentation Notes

This chart details the recharge ratio for the six new replacement batteries, all running about 1.09.


21


Conclusion

Replacement Batteries, Installed Into HST During Servicing Mission 4, Are Performing Well Within Specification.

The Batteries SOC Provides Good Science Margin.

The Voltage Performance Maintains The End User Equipment Well Within The Operational Input Voltage Specification.

Voltage Performance Supported By Favorable Battery Impedance

Charge System Providing Recharge Ratios That Maintain And Improve The Battery SOC While Maintaining Battery Temperatures Below 0°C

Recharge Ratio And Temperatures Are Within Optimal Ranges

Presenter

Presentation Notes

The replacement batteries and charge system are very healthy. Not terribly bad for batteries which were installed 13 years after beginning of manufacture.


22


ACKNOWLEDGEMENTS

• This Work Was Supported by NASA Contract Mod 593 Dated 2 June 1987• Directed LMSC to Design, Develop and Deliver Nickel-hydrogen Battery Modules• For the Hubble Space Telescope Low Earth Orbit Mission

• Per NAS 8-32697 and NAS 5-5000.

Documents

HST Replacement Battery Initial Performance Space Flight Center Hubble Space Telescope Program 1 HST Replacement Battery Initial Performance Stan Krol, Greg Waldo Lockheed Martin Information