Programmable Thermostats for MPLM Shell Heater · PDF fileProgrammable Thermostats for MPLM...
Transcript of Programmable Thermostats for MPLM Shell Heater · PDF fileProgrammable Thermostats for MPLM...
U FC- 400 -66sircd
Programmable Thermostats for MPLM ShellHeater Control ULF1.1 Thermal Performances
ABSTRACT
The Multi-Purpose Logistics Module (MPLM) is the primary carrier for "pressurized" logistics toand from the International Space Station (ISS). The MPLM is transported in the payload bay ofthe Space Shuttle and is docked to the ISS for unloading, and reloading, of contents within theISS shirt sleeve environment. Foil heaters, controlled originally with bi-metallic thermostats, aredistributed across the outside of the MPLM structure and are utilized to provide energy to thestructure to avoid exposure to cold temperatures and prevent condensation.
The existing bi-metallic, fixed temperature set point thermostats have been replaced withProgrammable Thermostats Modules (PTMs) in the Passive Thermal Control Subsystem (PTCS)28Vdc shell heater circuits. The goal of using the PTM thermostat is to improve operationalefficiency of the MPLM on-orbit shell heaters by providing better shell temperature control viafeedback control capability. Each heater circuit contains a programmable thermostat connected toan external temperature sensor, a Resistive Temperature Device (RTD),, which is used to providecontinuous temperature 'monitoring capability. Each thermostat has programmable temperatureset points and control spans. The data acquisition system uses a standard RS-485 serialinterface communications cable to provide digital control capability.
The PTM system was designed by MSFC, relying upon ALTEC support for their integration withinthe MPLM system design, while KSC performed the installation and ground checkout testing ofthe thermostat and RS-485 communication cable on the MPLM FM1 flight module. The PTMswere used for the first time during the STS-121/ULF1.1 mission.
This paper will describe the design, development and verification of the PTM system, as well asthe PTM flight performance and comparisons with SINDA thermal model predictions.
https://ntrs.nasa.gov/search.jsp?R=20090033636 2018-05-10T09:09:27+00:00Z
MS c L oo-- f^^ S-CA y +^
Programmable Thermostats forMPLM Shell Heater Control - ULFlol
Thermal Performances
Shaun Glasgow/ NASA MSFCDallas Clark/NASA MSFCMichele Trichilo/ALTEC
4,0
L T E CThe Italian Gateway to ISS
Outline
n Background
n Hardware Development
n STS-121 Mission Operations
n Flight Performance
(D 2007-01-3028
S102ES095 201.703.110085945
MPLM Description
• Size:• Dry Weight:• Cargo Capacity:• Flight History:
21' long X 15' diameter9800 Ibm20000 Ibm7 ISS missions
MULTI-PURPOSE LOGISTICS MODULE (MPLM) - The MPLM is apressurized module used to transport cargo to/from the InternationalSpace Station (ISS). The Italian Space Agency (ASI)-built MPLM servesas the ISS "moving van", carrying laboratory racks filled with equipment,experiments, and supplies. The MPLM is transported in the Space Shuttlecargo bay and then docked to the ISS for cargo transfer. It can transportup to 16 racks with a maximum payload weight of 20,000 lbs (9,072 kg)in a controlled (human-rated) operating environment.
ALTEC (the Italian Space Agency MPLM sustaining engineering partner)and the Marshall Space Flight Center are responsible for the sustainingengineering activities associated with the MPLM, including support to(D Cargo Element Integration for each flight and real-time mission support.
2007-01-3028
MPLM Shell Heater SystemFwC CONEF-HOT-4t0UGH5
----------------------- ------ -------- ---------- ---tJOT PC—T tt ^
AwG 20 ^^ 28 VOCO Or-^
TH IA
iLj
AA__ i i -_- I I Yy^!' I -W, I I ti 1
I MTRT I I MTRB i I HTA9 1' I HTRII t ^I T I I I 1 I I r
_ l 'YI^fJ I _^ ^' j tVffir
JOB aCCEF' t t
I THtB
t O O
AV.'G 20 ^ '2C Vd:
FCYL i
MPLM Shell Heater System: •------------------ ---------- ------------------------------
n 2 separate circuits: 28V (STS mode) & 120V (ISS mode) Forward Cylinder Electrical Schematic
• 22 fused branches / 66 Kapton strip heater pads
Purpose:• Moisture/condensation prevention• Cargo temperature conditioning (50-90F)• Regulate internal pressure (13.9 -15.2 psi)
2007-01-3028
Issues w/ BimMetalfic Thermostatsn Setpoints were set too high (81 to 95°F) for nominal mission timeline
heater operationsPositive Pressure Relief Assembly (PPRAs) actuation would occur at these temperatures
PPRA actuation exposes a risk of a valve not resenting and resultant venting of theMPLM environment
Loss of MPLM environment prevents ingress/cargo transfer and loss of mission
n Operational workarounds required for heaters ops w/ bi-metallicthermostats
Heaters manually cycled by crew from aft flight deck switch panel
Mission-dependent profile required for shell heater ops
Preflight analyses define approx. heater cycle times and generate trend data
Real-time telemetry required to "fine-tune" and optimize heater operations
Real-time MOD support to coordinate crew activity
n Unnecessary usage of Orbiter cryogenic resources (for powergeneration)
(i) 2007-01-3028
Project Authorization
ISS Program Office formally approved CR3578 in October2000 for developing solid-state Programmable Thermostatsto replace the 28V bi-metallic units
Operational Goals:
• Provide temperature control w/ closed loop feedback• Reduce mission operational impacts &crew interaction• Improve Shuttle cryogenic fuel cell efficiency
C) 2007-01-3028
Project Deliverables
100 Programmable Thermostat Modules (PTMs)
n 6 Data Recorder Modules (DRMs)
GSE Laptop computer & Thermoview software
n RS-485 Serial Communications Cable
n PTM Installation & Cable Layout Drawings
(D 2007-01-3028
Roles &Responsibilitiesn PTM & DRM designed, manufactured, and certified by
MSFC
n GSE software designed and certified by MSFC
n RS-485 communications flight cable designed,manufactured, and certified by Boeing
n Hardware installation, cable routing layout, and MPLMelectrical power harness wiring drawings provided byALTEC
n Installation/
(Dand ALTECsystem checkout testing performed by Boeing
2007-01-3028
Programmable ThermostatDesign Features:
+28 V EXISTING EXISTING
• Size: 2.25" x 1.75" x 0.5 FUSE THERMOSTAT SHELL HEATER
• Weight: < 75 gm (w/o carrier); < 100 gm 412B V RTN
(w/carrier)MODULE TO CARRIERMOUNTING SCREWS
• C&DH: RS-485 serial communication protocolRTD SENSOR
• Software: Graphical Users Interface (GUI)developed for programming and monitoring
COMMUNICATIONS ^^ PROGRAMMABLE• Input Power: +9 to +28 VDC. CONNECT i THERMOSTAT
MODULEI I
I
• External RTD temperature sensorTHERMALPAD
• External Heater : Up to 5A at +28VDC ^il. CARRIER
• Programmable temperature set points and span. EPDXYSetpoint/ span resolution: 0.1 OC
• Data Recorder Module (DRM) available in the MPLM PROGRAMMABLE THERMOSTAT HARDWARE
same housing for recording status and temperaturedata for up to 32 PTM units connected on a singleRS-485 bus.
(D 2007-01-3028
Extensive prototype development testing performed (1 PTM & DRM)• Thermal Cycling/Random Vibration/EMI/EMC• Adhesive bond strength (RTV bonding process validation)• Radiation susceptibility (Radiation-hardened EEE parts waiver)
Lot qualification (10 PTMs & 1DRM) FAcceptance tests (90 PTMs & 5DRMs)
Is0
0
No test failures!
2007-01-3028(D Qualification Test Fixture
PTM18A on MPLM FM1
Flight Certification Process• Environmental Qualification/Acceptance testing conducted per SSP-41172 ISS test
guidelines• Thermostat hardware certified for 25 missions
Continuity/Functional
ThermalVacuum
Continuity/Functional
Qualification Test Flow
StructuralVibration
Continuity/ EMI/EMCFunctional
Continuity/Functional
C) 2007-01-3028
Acceptance Test Flow
Module Continuity/ Structuralburn-in Functional Vibration
Continuity/ Thermal Continuity/Functional Vacuum Functional
C) 2007-01-3028
Thermal Cycle Ranges
Low Temperature High Temperature # of Cycles
Qualification -240F +1560F 24
Acceptance -40F +1360F 8
Environmental Test LevelsRandom Vibration Levels
AcceptanceFrequency (Hz) Qualificatio Level
n Level
20 0.04 g 2 /Hz 0.01g2/Hz
20 to 65+7.6 +7.6
dB/Octave dB/Octave
65 to 180 0.8 g 2 /Hz 0.2g2/Hz
180 to 360 -7.0 dB/Octave7.0
dB/Octave
360 0.16 g 2 /Hz 0.04 g2/Hz
360 to 1400 -2.6 dB/Octave2.6
d B/Octave
1400 0.05 g 2 /Hz 0.0125 g2/Hz
1400 to 2000 - 4.9dB/Octave
-4.9dB/Octave
2000 0.028 g 2 /Hz 0.007 g2/Hz
Composite 16.8 g rms 8.4 firms
(DQualification Duration = 810s in each of 3 mutually perpendicular axesAcceptance Duration = 60s in each of 3 mutually perpendicular axes. 2007-01-3028
Mission Highlights
• STS-121/ULF1.1 mission launched July 4, 2006• 14 day mission duration• 7t" MPLM mission; 1 St flight of new PTM system• MPLM heater ops during downhill mission phase (FD10-13)• MPLM daily pressure checks performed for monitoring• 1St MPLM mission in which shell temperatures recorded during
flight operations
(D 2007-01-3028
Mission Phase Cabin Environment
Flight Phase Cabin P Lower Limit Action RequirementLimits Point
Prior to Transfer to Accounts for MPLM spec, lower limit
ISS (28V Heaters)10 °C (50°F) and PPRA
773.1 mmHg 14.95psiaTransfer to ISS -
Accounts for transfer cool down &
includes vestibule(a) > 18.3°C (65°F) protects against
outfitting (No Heaters)(b) > 12.8°C (55°F) (a) condensation
(b) MPLM spec. lower limit
Ingress (120V MPLM Activation complete w/MPLM ISS
Heaters) AN/A 15.6°C 60°F ) Shell heaters operational
Accounts for transfer cool down &Transfer to PLB (No (a) > 18.3°C (65F) protects againstHeaters) (b) > 12.8°C ( 55°F) (a) condensation
773.1 mmHg 14.95 (b) MPLM spec. lower limit
psia Accounts for transfer cool down &Return to Ground (28V (a) > 15.6°C (60°F) protects againstHeaters) (b) > 10°C (50°F) (a) condensation
(b) MPLM spec. lower limit
De-orbiting (a) >15.6 0C (60°F) To avoid atmosphere entering and
Landing Pground - DPNPRV (b) > 10°C (50°F) contaminating MPLM
(D 2007-01-3028
Mission Setpoint Analysis
• Mission setpoints are loaded during KSC ground processing
• PTM setpoint optimized to maintain MPLM cabin air environment withinpressure range to avoid:
PPRA actuation (on-orbit)NPRV actuation (re-entry)Condensation
. MPLM heater usage remain within allocated STS-121 Shuttle power budget
Relief Valve analysis constraints:95% KSC landing site max pressure variationsNPRV cracking pressure limitPPRV cracking pressure limit
. Final heater control parameters: SP= 25.6 C; Error span= +/- 0.2 C
C) 2007-01-3028
MPLM Pressure Relief Valve ChartSTS-121 MPLM/ ISS Closeout Conditions
78F Setpoint, +/- 0.4 F Control Band
90.00
85.00
NPRV crack limit
80.00camCL
Emw 75.00 —oISS Nominal [T,P] Range..,:*:,:072-74F @ 14.65-14.75psi PPRA crack limitU
MPLM Max. Dewpoint Limit
60.0014.5 14.55 14.6 14.65 14.7 14.75 14.8 14.85 14.9 14.95
P1, MPLM Closeout Pressure (psia)
MPLM/ISS Closeout Conditions 2007-01-3028
ALTEC Thermal Verification ResultsHeaters Dissipation
MPLM ULF1.1 Mission - Beta -2 -ZLV -XVV
30000
25000
c^20000
15000a^
= 10000w
5000
0235 245 255 265 275 285 295 305
Time [h]
(D MPLM Pre-mission Thermal Verification Analysis
2007-01-3028
0.0 (14 .51)
102.0(14.80)
102.5(14.87)
15/20:3
16/11:5
17/09:4
MPLM Cabin Air Pressures
Cabin Temp Cabin Press1 Act (GMT) °C kPa (psi)
> 15.6 °C < 103 kPa
(D
Notes
Environment Check (CFARunning)
Pressure Check (w/oCFA)
Pressure Check (w/oCFA)
2007-01-3028
Shell Heater Summary0 Heater on-time: 60.83 hr
• DRM successfully captured all 20 PTM data channels
0 Data acquisition rate: 1/min; 3647 total samples
• Heater Duty Cycle: 0.387 (on/off cycle counts)
• Heater Power consumption: 23.35 kWH
C) 2007-01-3028
1000
900
800
700
600
m0 500a
0400
300
200
100
0
0.00 4.00 8.00 12.00 16.00 20.00 24.00 28.00 32.00 36.00 40.00 44.00 48.00 52.00 56.00 60.00
MET from PTM Powerup (Hrs)
—TOT PWR
Shell Heater Power ProfileSTS-121 Heater Power Profile
0 Heater Duty Cycle = 38%2007-01-3028
20
15Y_
T
dcW
0 10
5
0
0.00 4.00 8.00 12.00 16.00 20.00 24.00 28.00 32.00 36.00 40.00 44.00 48.00 52.00 56.00 60.00
MET from PTM Powerup (Hrs)
25
— Energy (kWh)
STS-121 Shell Heater PowerSTS-121 Energy Profile
0 23 kwH (actual) vs 30kwH (planned) 2007-01-3028
1 154 307 460 613 766 919 10721225137815311684183719902143229624492602275529083061321433673520
(DNo of Samples
2007-01-3028
30
28
26
24
m 22m
d20M
dCL
E 18H
16
14
12
10
mperature
1
1
1
1
1
1
3tat On/OffStatus
Forward Endcone PTMsFCON PTMs
25
ULA
20
N!
RQ 15Em
Grapple Fixture PTMsGrapple Fixture (+Y/-Y) PTMs
35
30
10
5
0
-Y Port, Sun +Y Stbd, shade
OrbiterSidewall —I
I Sidewall
U
_UAttitude Timeline
ULUULILF ll ^U _JLJ LJI^LJ I1 UL- __
Temperature Control Range: 25.4 - 25.8 C
+Y Stbd
0.0 4.0 8.0 12.0 16.0 20.0 24.0 28.0 32.0 36.0 40.0 44.0 48.0 52.0 56.0 60.0 64.0
MET from PTM on (Hrs)
Illustration of Shuttle flight attitude heating influencf- 07-01-3028s0
Common Berthing Mechanism PTMsCBM PTMs
40
0
35
30
& 25rn
20
E15
10
5
0
0.0 4.0 8.0 12.0 16.0 20.0 24.0 28.0 32.0 36.0 40.0 44.0 48.0 52.0 56.0 60.0
MET from PTM Powerup (Hrs)
2007-01-3028
30
28
26
Lj 24
22
20+r
LCL 18Ea)
14
12
10
^„`^`a`d•^i 13.^'^-.^^ `. - .r—` r^ tr ,rs' +—^ f ^,..^^.°_a^— ^^ _"fit
On/Off Cycle status
^ IU U ... _.
U) OIT- coO M CD O N U) W = d" 1- O M O O N U) M = ;I 1` OCO C^ - f— N f— M M M O ;T O ;;r O U) O M = 0 N
CO I^ O O N M U7 O M O = N 1;T M I- O O N M LO^ T- T- ^ = = ^ N N N N N N co M M M
— PTM7A— PTM8A
PTM9A
PTM10A
— PTM7A
PTM8A
PTM9A
PTM10A
Aft Endcone PTMsACON PTMs
(D No. of Samples
2007-01-3028
On/Off Cycle status
30
28
26
—24
22a^L
20La 18EaD^— 16
- PTM 17A
- PTM 18A
- PTM17A
PTM18A
Stabilizer & Main Fitting PTMsStabilizer & Main Fitting PTMs
14
12
10^- q r- O CO (D O N LO 00 = Iq ti O M (D M N LO 00 ^ 143- rl- O
LO O (D = 0 = r` N r- M M CO O ;T M Iq O LO O (D - 0 NM IT M ti O O N M LO (D 00 O N d (O ti O O N M LO^- r- T- ^ = = N N N N N N CO CO CO CO
No. of samples 2007-01 -3028
35
33
31
29
U27
a^L25L
Q.
23
21
19
17
15
SINDA
—MIDFWD CYL9425
— PTM2-PTM1A rci
PTM
ALTEC Thermal Model ResultsFCYL1 _PTM 2(PTM 1 A)_CO425
230 240 250 260 270 280
290 300 310
Time [h]
IDPTM2 vs SINDA model
Forward Cylinder2007-01-3028
35
33
31
29
U27
aL̂
L 25CL
E 23
21
19
17
15
SIN
PTM22- FWD CONE 9218- PTM23-PTM22A K
ALTEC Thermal Model ResultsFCON4_PTM23(PTM22A)_CO218
230 240 250 260 270 280 290 300 310
Time [h]
PTM22 vs SINDA model2007-01-3028
Forward Endcone