STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
NICMOS/NCS Anomaly and Status
Timeline overview:




NICMOS/NCS was commanded to shutdown on Sep 10 to prepare for
NSSC-I
Subsequent recovery on Sep 11 lasted ~ 6 hours before safing
3 subsequent retries safed
Safings typically indicated above-average current drawn by the circulator
motor
Current status / prognosis



Possibly due to water ice/contaminant interfering with circulator pump
Other anomalous telemetry confirms likelihood of contaminants
No evidence of any permanent damage to the mechanical system
Plans forward



Decision by HST-P to allow system to warm up, thaw contaminants
Cooldown would take a few weeks, similar to SMOV3B
Given SM4 October launch date, remainder of Cyc 15 & 16 NICMOS will
execute in Cycle 17
1
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
Initial NCC restart timeline







255/01:14:05
– Circulator On (1200 Hz)
255/01:27:37
– Compressor On (5000 Hz)
255/02:33:02
– CPL Control
255/003:07:56
– CPL Operate/Compressor Ramp (6000 Hz)
255/03:10:39
– PID Operate (7043 rps + Surge effects)
255/05:44:00
– Exit FSW-defined Surge (7330 rps)
255/07:57:47
– Safing indicating overspeed limit for Circulator pump
– No apparent deviation of the Circulator differential pressure (MNCIDFPR) or
the Circulator frequency (MNCIIFRQ)
2
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
3
NCC Circulator Failure - 2008/255 History Buffer Collection
4500
4000
(52)MNCIDFPR
(54)MNTBAIPR
(62)MNCIINII
(67)MNCOIFRQ
(69)MNCORSPD
(70)MNCIRSPD
(71)MNTBASPD
(72)MNCOINOI
(201)MNCOSLIP
(202)MA3SE03
(55)MNCOCMDI
(61)MNCOINII
(53)MNCOINPR
(74)MNTBALDI
(68)MNCIIFRQ
(60)MNCIINIV
(56)MNCICMDV
3500
Raw Counts
3000
2500
2000
1500
1000
500
0
0
50
100
150
Sample Number
200
250
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
4
NCC Circulator Failure - 2008/255 History Buffer Collection
4500
4000
(52)MNCIDFPR
(54)MNTBAIPR
(62)MNCIINII
(67)MNCOIFRQ
(69)MNCORSPD
(70)MNCIRSPD
(71)MNTBASPD
(72)MNCOINOI
(201)MNCOSLIP
(202)MA3SE03
(55)MNCOCMDI
(61)MNCOINII
(53)MNCOINPR
(74)MNTBALDI
(68)MNCIIFRQ
(60)MNCIINIV
(56)MNCICMDV
3500
Raw Counts
3000
2500
2000
1500
1000
500
0
185
190
195
200
205
210
Sample Number
215
220
225
230
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
5
2008 restart - current and pressure diff.
Circ Current and DP 9/10/08 Restart
250
1
200
0.8
0.6
100
0.4
50
0.2
Current (mA)
150
0
0:00:00
1:00:00
2:00:00
3:00:00
4:00:00
5:00:00
6:00:00
7:00:00
0
8:00:00
delta-p (psid)
MNCIINII EU
MNCIDFPR EU
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
6
2007 restart - current and pressure diff.
120
1.2
100
1
80
0.8
60
0.6
40
0.4
delta-p (psid)
Current (mA)
Circ Current and DP 1/29/07 Restart
MNCIINII
MNCIDFPR
20
0
01/29/07 2000
0.2
01/30/07 0000
01/30/07 0400
01/30/07 0800
01/30/07 1200
01/30/07 1600
01/30/07 2000
0
01/31/07 0000
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
7
2003 Restart - current and pressure diff.
120
1.2
100
1
80
0.8
60
0.6
40
0.4
delta-p (psid)
Current (mA)
Circ Current and DP 8/7/03 Restart
MNCIINII
MNCIDFPR
20
0
08/07/03 1200
0.2
08/07/03 1600
08/07/03 2000
08/08/03 0000
08/08/03 0400
08/08/03 0800
0
08/08/03 1200
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
Differences between 2008 vs 2007/2003
On-Orbit History




2002: Initial start-up after installation during SM3B
2002: NCC Restart following Turboalternator (TBA) failure in SMOV
2003: Restart following DOY 213 SEU corrupting the Circulator
commanded voltage (NCC only)
2007: Restart following 027/2007 NCC Safing event due to Total Pressure
Sensor (TPS) limit violation (NCC only)
Comparison:






Absolute temperature of circulator housing and NICMOS return higher
during prior restarts
dT between circulator housing and NICMOS return higher this time
Circulator current higher during first hour of recent restart
Circulator restart transient appears similar during initial restart but current
is 1.5X after 20 sec
At circulator housing temperatures of nominally 120 K, the circulator
current was higher by 2X during recent restart
Anomalous current event noted during recent restart prior to shutdown
8
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
Contaminant Possibilities

Scenario: Ice particle is dislodged during initial cool down event.
– May be related to the short duration of the stoppage.


Particle runs through circulator turbine.
Higher mechanical load leads to mismatch in phase angle between backEMF and drive signal.
– Causes large rise in Circulator current.
– Slight drop in Circulator voltage consistent with large draw, and is in opposite
phase.
– Current is a good indicator of motor torque.


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Perturbed rotor triggers speed sensor to have additional switches per
revolution, and appears as an erratic increase in speed.
Circulator does NOT drop out of sync.
Creare has study on the size range
– 10 u to 1 mm size range


No good theory on how ice formed
Cannot be explained by change in temperature and partial pressure.
9
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
Subsequent restart attempts
09/14/2008 20:00


Circulator current threshold was lowered from 381 to 130 mA, to avoid
running the system at high current for prolonger period of time
Safed almost immediately due to current threshold limit exceeded
09/15/2008 16:00


Circulator current threshold was raised from 130 to 150 mA
Safed this time due to circulator speed violation limit exceeded
09/15/2008 20:00



Circulator speed limit threshold was raised
Ran for about 20 - 25 minutes
Safed due to likely current limit exceeded (telemetry was lost during the
final minutes)
10
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
11
NCC Circulator Failure on Start (DT 251) - 2008/258 (14 September 2008)
History Buffer Collection
(Sensors 52 54 62 67 69 70 71 72 201 202 55 61 53 74 68 60 56 )
4500
(52)MNCIDFPR
DT 251 Compare1 Value (MNCIINII)
4000
3500
(54)MNTBAIPR
Previous MNCIINII Limit = '0420'X = 1056 dec
New MNCIINII Limit = '0178'X = 376 dec
STB Reported Count = 395 dec (EU = 137 mA)
(62)MNCIINII
DT 251 Compare2 Value (MNCIIFRQ)
1000 Hz Limit = '07B0'X = 1968 dec
(69)MNCORSPD
(67)MNCOIFRQ
(70)MNCIRSPD
3000
Raw Counts
(71)MNTBASPD
(72)MNCOINOI
2500
(201)MNCOSLIP
(202)MA3SE03
2000
(55)MNCOCMDI
(61)MNCOINII
1500
(53)MNCOINPR
1000
(74)MNTBALDI
(68)MNCIIFRQ
500
(60)MNCIINIV
(56)MNCICMDV
0
1
3
5
7
9
11
13
15
17
19
21
23
25
Time (mf)
27
29
31
33
35
37
39
41
43
45
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
12
NCC Circulator Failure on Start (DT 120) - 2008/259 (15 September
2008)
History Buffer Collection
5000
(52)MNCIDFPR
DT 120 Compare2 Value (MNCIRSPD)
1396.1 rps Limit = '0B10'X = 2832 dec
4500
(54)MNTBAIPR
(62)MNCIINII
4000
(67)MNCOIFRQ
(69)MNCORSPD
3500
(70)MNCIRSPD
(71)MNTBASPD
Raw Counts
3000
(72)MNCOINOI
2500
(201)MNCOSLIP
(202)MA3SE03
2000
(55)MNCOCMDI
(61)MNCOINII
1500
(53)MNCOINPR
(74)MNTBALDI
1000
(68)MNCIIFRQ
(60)MNCIINIV
500
(56)MNCICMDV
0
1
2
3
4
5
6
7
8
9
10
Time (mf)
11
12
13
14
15
16
17
18
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
13
NCS System with Temperatures & Parasitics
C ircu a
l tn
i g Loop
T4 MNPTAILT
Supp Brkt
0.04 watts
T6 MNPLINTT
R e cupe ra to r
F el x bi el
M e ta lH o se s
Flexline
l no di
Inlet 0.19 W S o e
Outlet 0.26 W V a v
l es
C ircu al to r
SV 1 SV 3
Total parasitics
expected to
be lower at BOL
T u rboa lte rna to r
T7 MNPNCOLT
B a yone t
C oup el rs
Total
6.395 W
C o dl Load nI te r fa ce
T9 MNRNCILT
Rigid Tubes
Inlet 0.08 W
Outlet 0.065 W
Bayonets
In 0.78 W
Out 1.69 W
Tested
5.105 W
Analysis
1.29 W
E x si tni g N CI MO S
C ryo s ta t
N CI MO S
C oo lni g Loop
C ryocoo e
l r Loop
C ap ilal ry P um p
Loop E vapo ra to r
T1
MNCOINLT
M V2
T3
MNAFTCOT
SV 4
M a ni N eon
F illB o ttel
SV 2
C om p re s so r
M V1
N eon R e f ill
B o ttel
Trej
MNH
TREE
JT
P ow e rC on ve rs oi n
E el c tron ci s and
TA Load R e s si to rs
H ea tR e ej c toi n
nI te r fa ce
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
14
NICMOS Dewar with Temperatures and Parasitics
TEC Radiator
Cryo Valve
Heaters (2)
Cryovalves
2.22 watts
(includes htrs)
Load to tank
0.67 watts
Internal
0.40 watts
Review of MEB/BB
powerdown shows parasitc
change is consistent
with model predictions
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
15
Previous NICMOS Cool-downs
Mar 2002
SMOV3b
Aug 2003
Cool–down of the NICMOS dewar
(from 3 previous NCS start-ups)
Red curve = weighted average of the
Ne inlet and outlet temperatures
Jan 2007
STScI TIPS/JIM
18 September 2008
NICMOS/NCS Anomaly and Status
Anton Koekemoer
Current / Forward Plans
NICMOS / NCS:



Continue warming up to ~270 K, enable contaminants to thaw
Keep TECs running to dewar - essentially retain system in as similar state
as possible to post-cryogen / pre-SMOV3B
Keep to original SM4 plan to commence cooldown after SM4
SMOV & Calibration programs:



May need to defer start of NICMOS SMOV4 by a few weeks, since
cooldown would likely take longer than previously planned
Likely augment NICMOS SMOV4 plan to include more comprehensive
filter wheel tests, PAM/FOM tests, focus (similar to SMOV3B)
Post-SMOV4 Cycle 17 calibration may need additional observations if
there are changes in the properties of the system
GO programs:

All remaining Cycle 15 and 16 programs are being retained and will
execute after SMOV4 along with the Cycle 17 NICMOS program
16