**POLAR Spacecraft Status As of: Thurs 21 Aug 2008, 12:00 EST**

*(Changes* from last week in bold border)

+----------+--------------+--------------+--------------+--------------+
| **Subs   | **NOAA-15K** | **NOAA-16L** | ##           | ##           |
| ystem/** |              |              | ### NOAA-17M | ### NOAA-18N |
|          | AM: 17:49=AN | PM: 15:04=AN |              |              |
| **Com    |              |              | AM: 22:23=AN | PM 13:49=AN  |
| ponent** | GAC data     | GAC data     |              |              |
|          | only         |              | GAC&LAC data | GAC & LAC    |
|          |              |              |              | data         |
+==========+==============+==============+==============+==============+
| **LA     | 05/13/98     | 09/21/00     | 6/24/02      | ####         |
| UNCHED** |              |              |              | ### 5/20/05  |
+----------+--------------+--------------+--------------+--------------+
| **CNTL   | OBP2         | OBP2         | OBP2         | OBP2         |
| OBP**    |              |              |              |              |
+----------+--------------+--------------+--------------+--------------+
| **BUS**  | B-BUS        | B-BUS        | B-BUS        | B-BUS        |
|          |              |              |              |              |
|          | XSU-1        | XSU-2:       | XSU-2: TOAR  | XSU-1        |
|          |              | TOAR472      | 471          |              |
|          |              |              |              |              |
|          |              |              | 1/15/08      |              |
+----------+--------------+--------------+--------------+--------------+
| **BUS    | NO           | NO           | NO           | NO           |
| VETO**   |              |              |              |              |
+----------+--------------+--------------+--------------+--------------+
| *        | [Nominal     | ######       | ###### [N    | [Nominal     |
| *ADACS** | Mode]        | [RGYRO Mode] | ominal Mode] | Mode]        |
|          | {.underline} | {.underline} | {.underline} | {.underline} |
|          |              |              |              |              |
|          | Rg           | Estimate     | Rg           | Gyro-A       |
|          | mode=Monitor | Y-ROLL       | mode=Monitor | MIMU-2       |
|          |              |              |              |              |
|          | Gyro-3 Off   | Rg           | Gyro-3 Off   | Z-wheel      |
|          | 6/26/00 Gyro | mode=PASSIVE | 6/10/04      | -Pitch       |
|          | chans=AAB    |              |              |              |
|          |              | Gyros-1 & 3  | Gyro         | TOAR 447     |
|          | N2 Low PSI   | Inop/Off     | chans=AAB    |              |
|          | invalid      |              | GAS Enabled  | Z-momentum   |
|          |              | Gyro chans   | Dec 05       | transition   |
|          |              | XA-ZB        |              | complete     |
|          |              |              | \*Z Gas      |              |
|          |              | Pitch wheel  | unload =45   | Pitch        |
|          |              | bias 2400    |              | Torquer      |
|          |              |              |              | again active |
|          |              | \*Z gas      |              |              |
|          |              | unload = 145 |              | Gas auto     |
|          |              |              |              | unloading    |
|          |              | Gyro2 safe   |              | enabled      |
|          |              | macro        |              | 8/18/08      |
+----------+--------------+--------------+--------------+--------------+
| **RXO**  | PRI          | PRI          | PRI          | PRI          |
|          |              |              |              |              |
|          | daily bias   | Daily Bias   | Daily Bias   | No daily     |
|          | -8 mS        | --5.5 mS     | --3 mS       | bias         |
|          |              |              |              |              |
|          | -500 mS      | -1500 mS     | -1500 mS     | -1500 mS     |
|          | 12/31/05     | 31Dec05      | 31Dec05      | 31Dec05      |
+----------+--------------+--------------+--------------+--------------+
| **CLOCK  | 2            | 2            | 2            | 2            |
| DIV**    |              |              |              |              |
+----------+--------------+--------------+--------------+--------------+
| **MIRP** | External     | External     | External     | External     |
|          | Synch        | Sync         | Sync         | Synch        |
|          | Rephase 0730 |              |              |              |
|          | daily        | Rephase each | Rephase      | Rephase      |
|          |              | orbit        | Enabled      | Enabled      |
+----------+--------------+--------------+--------------+--------------+
| **TIP    | 2            | 2            | 2            | 1            |
| SIDE**   |              |              |              |              |
|          | (since       | since        | Swapped      | Analog telem |
|          | 4/3/03)      | 4/18/05      | 9/20/06      | drifting     |
|          |              |              |              |              |
|          | 3 channels   | (analog      |              |              |
|          | inop         | drifting?)   |              |              |
+----------+--------------+--------------+--------------+--------------+
| **Rec    | DTRs 1, 2,   | DTRs 1, 2,   | DTR 1,3,4 /  | SSRs         |
| orders** | 3, 4         | 3, 4A        | SSR 2        | 1,2,3,4,5    |
|          | Safestate 1B |              |              |              |
| **(DTR,  | EOT          | Safestate 3A | S            | Safestate=5B |
| SSR)**   |              |              | afestate=SSR |              |
|          |              | 4B STIP only | 2B           | Current      |
|          |              |              |              | spikes       |
|          |              |              | 4A Pressure  |              |
|          |              |              | leak         |              |
+----------+--------------+--------------+--------------+--------------+
| **VTX**  | #1 ON        | OFF / INOP   | #2 ON        | #1 ON        |
|          |              |              |              |              |
| (APT     | As of 19     | since        | 137.62 MHZ   | 137.1 MHZ    |
| data)    | June 07      | 11/15/00     |              |              |
|          |              |              |              | As of 16 Aug |
|          |              |              |              | 07           |
+----------+--------------+--------------+--------------+--------------+
| **BTX**  | #1           | #2           | ####### #2   | #1           |
|          |              |              |              |              |
|          | 137.35 MHZ   | 137.77 MHZ   | 137.77 MHZ   | 137.35 MHZ   |
+----------+--------------+--------------+--------------+--------------+
| **STX**  | 2-Omni HRPT  | 2 -- HRPT    | 1 -- HRPT    | 3 - HRPT     |
|          |              |              |              |              |
| 1 = rcp  | 2 Omni=rcp   | 1-- Playback | TOAR424 low  | 1 - Playback |
| 1698.0   |              |              | power        |              |
| mhz      | Power TOAR   | 4 Standby    |              | 2 - Playback |
|          | 446          |              | 2 & 4        |              |
| 2 = lcp  |              | 3 low power  | Playback     | 4-Test &     |
| 1702.5   | 4-Playback   | INOP -10 Aug |              | Standby      |
| mhz      |              | 2007         | STX-1 Power  |              |
|          | 1,           |              | drop 2.29W   |              |
| 3= rcp   | 2,3-Degraded |              | 3/2/08       |              |
| 1707.0   |              |              |              |              |
| mhz      |              |              | STX-4        |              |
|          |              |              | nominal      |              |
| 4= rcp   |              |              |              |              |
| 2247.5   |              |              | STX-3 Failed |              |
| mhz      |              |              | 2/14/08      |              |
+----------+--------------+--------------+--------------+--------------+
| #        | [Array Off   | [Array Off   | [Array Off.  | [Array Off.  |
| ## POWER | -45]         | -20]         | --40]        | -40]         |
|          | {.underline} | {.underline} | {.underline} | {.underline} |
| (Array   |              |              |              |              |
| offset   | [Since       | [Since       | [Since       | [Since       |
| and CANT | 1/25/01]     | 9/13/]{.     | 1/29/04]     | 6/6/05]      |
| angle,   | {.underline} | underline}07 | {.underline} | {.underline} |
| eclipse  |              |              |              |              |
| states   | Full Sun     | Eclipse all  | Eclipse all  | Eclipse all  |
| and sun  |              | year         | year         | year         |
| angle)   | Sun Angle 13 |              |              |              |
|          |              | Sun Angle 34 | Sun Angle at | Sun Angle 63 |
|          | Uptrend to   |              | 66           | uptrend to   |
|          | 18 early Jan | Steady trend |              | 65 on        |
|          | 07           |              | Steady trend |              |
|          |              | SA CANT=22   |              | 1 Jan 07     |
|          | SA CANT=37   | degs         | SA CANT=37   |              |
|          | degs         |              | degs         | SA CANT=22   |
|          |              | Full sun S/C |              |              |
|          |              | in Sept 07   | BVR Phase    | BVR Phase    |
|          |              |              | Control      | Control      |
|          |              | BVR Phase    | auton swap   | auton swap   |
|          |              | Control      | 9/17/07      | 3/29/06 &    |
|          |              | auton swap   |              | 1/4/07       |
|          |              | 7/19/07      | Swap back    |              |
|          |              |              | 9/18/07      |              |
|          |              |              |              |              |
|          |              |              | SADPOS       |              |
|          |              |              | Enabled      |              |
|          |              |              | 2/12/08      |              |
+----------+--------------+--------------+--------------+--------------+
| *        | Nominal      | Nominal      | ### Nominal  | Nominal      |
| *AVHRR** |              |              |              |              |
|          | Channel 3B   | Recent SM    | 3A-B switch  | Channel 3B   |
|          | only         | current      | enabled      | only         |
|          |              | increases    |              |              |
|          | Occasional   |              | Previous     | Scan motor   |
|          | minor scan   | TCE24 OFF    | scan motor   | current drop |
|          | motor        | 4/14/04      | current mini | 29 Aug 06    |
|          | i            |              | surges       |              |
|          | nstabilities | Channel 3B   |              |              |
|          |              | only         |              |              |
+----------+--------------+--------------+--------------+--------------+
| **A      | Operational  | Operational  | OFF/INOP     | Nominal      |
| MSU-A1** |              |              |              |              |
|          | Ch14         | Primary PLLO | Since        | Full Scan    |
|          | inoperative  | chans 9-14   | 10/30/03     | mode         |
|          |              | bias shift.  |              |              |
|          | Ch11         |              | Survival     |              |
|          | inoperative  | Backup PLLO  | heat on.     |              |
|          |              | inop.        |              |              |
|          |              |              |              |              |
|          |              | Channel 9-14 |              |              |
|          |              | noise        |              |              |
|          |              |              |              |              |
|          |              | Channel 4    |              |              |
|          |              | severely     |              |              |
|          |              | degraded 4   |              |              |
|          |              | Mar 08       |              |              |
+----------+--------------+--------------+--------------+--------------+
| **\`A    | Nominal      | Nominal      | Nominal      | Non-nominal  |
| MSU-A2** |              |              |              |              |
|          |              |              |              | DIG-A Temps  |
|          |              |              |              | erratic      |
|          |              |              |              | 2/7/08       |
|          |              |              |              |              |
|          |              |              |              | Cold Cal Pos |
|          |              |              |              | 2 2/21/08    |
+----------+--------------+--------------+--------------+--------------+
| **       | Operational  | Operational  | Nominal      | ***Replaced  |
| AMSU-B** |              |              |              | by MHS***    |
|          | Bias in All  | Space        |              |              |
|          | Chans.       | Position-3   |              |              |
|          |              |              |              |              |
|          | Degraded     | Chan-8       |              |              |
|          | Chan-3       | degradation  |              |              |
+----------+--------------+--------------+--------------+--------------+
| ### HIRS | NOMINAL      | NOMINAL      | NOMINAL      | ########     |
|          |              |              |              | Operational  |
|          | FW Abrupt    | New all time | 1 Pixel      |              |
|          | return to    | high filter  | cross-track  | Filter Heat  |
|          | nominal      | motor        | m            | OFF.         |
|          | 7/12/05      | current      | isalignment. |              |
|          |              | reached      |              | ########     |
|          | After years  | 9/17/06.     |              |  LW channel  |
|          | of minor and |              |              | 1-12 noise T |
|          | major        | Imagery      |              | OAR 448 Loos |
|          | current      | occasionally |              | e LWIR lens. |
|          | surges       | exhibits     |              |              |
|          |              | high levels  |              | LW imagery   |
|          | FW mode=Hi   | of           |              | erratic.     |
|          | Powr         | radiometric  |              |              |
|          |              | noise        |              | CH 1 Period  |
|          |              |              |              | Monitor      |
|          |              |              |              | event 13 May |
|          |              |              |              | 08           |
+----------+--------------+--------------+--------------+--------------+
| ###      |              |              |              | Nominal      |
|  MHS/MIU |              |              |              |              |
|          |              |              |              | Fly Wheel    |
|          |              |              |              | Motor        |
|          |              |              |              | Current      |
|          |              |              |              | Spiking but  |
|          |              |              |              | not alarming |
|          |              |              |              | since 27 Dec |
|          |              |              |              | 06           |
|          |              |              |              |              |
|          |              |              |              | Entered      |
|          |              |              |              | Motor Spin   |
|          |              |              |              | State on 9   |
|          |              |              |              | May 08       |
|          |              |              |              |              |
|          |              |              |              | H4 gain      |
|          |              |              |              | increased 9  |
|          |              |              |              | May 08       |
|          |              |              |              |              |
|          |              |              |              | H3 gain      |
|          |              |              |              | increased 9  |
|          |              |              |              | May 08       |
+----------+--------------+--------------+--------------+--------------+
| **DCS**  | Nominal      | Nominal      | Nominal      | Nominal      |
|          |              |              |              |              |
| RFI      |              | Pseudo       |              | DRU's 1-7 On |
| inves    |              | message      |              |              |
| tigation |              | turned on    |              | DRU8         |
|          |              | 1/5/06       |              | inop/off     |
+----------+--------------+--------------+--------------+--------------+
| **SARR** | Operational  | Operational  | Nominal      | Nominal      |
|          |              |              |              |              |
|          | B-Side, 13   | Mode =AA     | A-side       | A-Side       |
|          | Dec 07       |              |              |              |
|          |              | A-side, AGC  | All AGC Mode | All AGC Mode |
|          | AGC Mode     | Mode         |              |              |
|          |              |              |              | Since 15 Aug |
|          | Intermittent | (B-side in   |              | 05           |
|          | failures for | FG mode)     |              |              |
|          | 243MHz A&B   |              |              |              |
|          |              | 124 & 243    |              |              |
|          |              | MHz = INOP & |              |              |
|          |              | OFF as of 29 |              |              |
|          |              | Jul 08       |              |              |
|          |              |              |              |              |
|          |              | 406 RCVR ATT |              |              |
|          |              | set to 5dB,  |              |              |
|          |              | PDS ATT set  |              |              |
|          |              | to 0dB       |              |              |
+----------+--------------+--------------+--------------+--------------+
| **SARP** | Nominal      | Nominal      | Nominal      | Nominal      |
|          |              |              |              |              |
|          | RCVR B/W = 2 | RCVR B/W = 2 |              | A-side 23    |
|          |              |              |              | May05        |
+----------+--------------+--------------+--------------+--------------+
| **SEM**  | Nominal      | Nominal      | Nominal      | Nominal      |
|          |              |              |              |              |
|          | E            | E            | E            | El           |
|          | -CDEM-HVPS=2 | -CDEM-HVPS=7 | -CDEM-HVPS=2 | ec-CH-HVPS=1 |
|          |              |              |              |              |
|          | P            | P            | P            | 27 June 06   |
|          | -CDEM-HVPS=0 | -CDEM-HVPS=7 | -CDEM-HVPS=4 | 17:00z       |
|          |              |              |              |              |
|          |              | 11 Jan       | 27 June 06   | Pr           |
|          |              | 0714:47z     | 16:00z       | ot-CH-HVPS=1 |
|          |              |              |              |              |
|          |              |              |              | 11 Jan 07    |
|          |              |              |              | 14:15z       |
+----------+--------------+--------------+--------------+--------------+
| **SBUV** |              | Operational  | Nominal      | Partially    |
|          |              |              |              | -Operational |
|          |              | Degraded     | Anode Mode   |              |
|          |              | Ozone data   |              | Anode mode   |
|          |              |              | Plan sweep   |              |
|          |              | Backup       | mode         | since 6 July |
|          |              | Diffuser     |              | 05 13:30z    |
|          |              | inop         | Standard Ops |              |
|          |              |              |              | Electronics  |
|          |              | Primary      | TOAR 463 sun | turnoff      |
|          |              | Diffuser     | glint        | taken out of |
|          |              | deployment   |              | STESM        |
|          |              | problem TOAR | IBSL test    | safestate    |
|          |              | 426          | performed 12 | table        |
|          |              |              | Sept 06      |              |
|          |              | AMSU EMI     |              | TOAR 462 sun |
|          |              | causing      | Grating      | glint        |
|          |              | erratic      | motor        |              |
|          |              | Behavior in  | i            | Chop Motor   |
|          |              | PMT cathod,  | nvestigation | stalled 22   |
|          |              | range 3      |              | May 08.      |
|          |              |              |              | Currently    |
|          |              |              |              | all motors   |
|          |              |              |              | turned on;   |
|          |              |              |              | not fully    |
|          |              |              |              | operational  |
+----------+--------------+--------------+--------------+--------------+
| **       |              | ON           | ON           | ON           |
| SADPOS** |              |              |              |              |
|          |              | Enabled      | ENABLED      | Enabled      |
|          |              | MFactor50%   |              |              |
|          |              |              | Timer =      | Timer =12    |
|          |              | Timer = 12   | 12mins       | mins         |
|          |              | mins         |              |              |
+----------+--------------+--------------+--------------+--------------+
| **T      | TCE26 & 15H  | Nominal      | TCE3H Batt   | All TCE's    |
| HERMAL** |              |              | 2A heater    | active       |
|          | Telem valid  | TCE24 OFF    | failed ON,   |              |
| Heaters, |              | 4/14/05      | turned off   | HIRS filter  |
| louvers  | TOAR 432     |              | 8/26/03      | heater       |
|          | closed       | (AVHRR H&L)  |              | turned OFF   |
| TCE's    |              |              | AMSU-A1      | 9/28/06      |
|          | TCE24L&25L   | HIRS Filter  | survival     |              |
|          | (HIRS &      | heater       | heaters on   |              |
|          | AVHRR)       | turned OFF   | 10/29/03     |              |
|          | failed       | 1/18/05      |              |              |
|          | 5/13/98      |              |              |              |
|          |              |              |              |              |
|          | RCE          |              |              |              |
|          | thermostat   |              |              |              |
|          | failed       |              |              |              |
|          | 5/13/98      |              |              |              |
|          |              |              |              |              |
|          | Spacecraft   |              |              |              |
|          | in thermal   |              |              |              |
|          | uptrend      |              |              |              |
+----------+--------------+--------------+--------------+--------------+

**COMMENTS/CHANGES:**

MISC:

NOAA-15: There were relatively no changes to the NOAA-15 bus or payload
health situation during the past week.

The #2 gyro is still relatively quiet. Daily monitoring continues.

Summer eclipse season ended on 17 August 08 as expected.  Slight battery
temperature increase and patch current of about 250 mamps (about
pre-summer value).  Bus voltage min and max variation have settled into
average bus voltage.  The load current has decreased due to reduced TCS
demand and no charging of batteries required.

NOAA-16: There was relatively no change in the performance of the
NOAA-16 bus & payload subsystems during the past week.

Summer eclipse season ended on 16 August 08 as expected. Batteries 1 and
2 have had typical temperature increases that have settled in at 12 deg
C and 9.5 deg C, battery 3 had a very slight increase in temperature.
 The patch current is about 210 mamps which is about pre-summer value. 
 Bus voltage min and max variation have settled into average bus
voltage.  The load current has decreased due to reduced TCS demand and
no charging of batteries required.

Per request by USMCC/SARSAT, NOAA-16\'s SARR 406 MHz receiver
attenuators will be set to 5 DB and its PDS channel attenuators to 0 DB
on 20 August 08 (08/233) at 18:10z. CTEC confirmed that they saw the
change in the attenuator settings.

NOAA-17: There was relatively no change in the performance of the
NOAA-17 payload subsystem during the past week.

NOAA-17 continues to have occasional bus voltage spikes. It appears the
shunts are responding to a small change in the load current that causes
a large swing in the bus voltage and then a large swing in the shunt
drive voltage.  This could be a result of the solar array current versus
voltage curve operating near the knee. See Figures 1 & 2.

NOAA-18: There were relatively no changes to the NOAA-18 health
situation during the past week.

The Air Force informed NOAA of a possible close approach with a piece of
debris from the FENGUYN Chinese satellite that was destroyed January
2007 on 18 August at 10:16z. Auto Thruster Firing (Gas) was enabled on
NOAA-18, and no other configuration change was done to the spacecraft
based on the analysis of the size of the object. The spacecraft was over
the South Pole at the time of the predicted close approach. No effects
were seen on the spacecraft.

As a result of the Automatic Thruster Unloading Enable commanding for
the close approach, the automatic momentum unloading system (ATMUL) was
turned on for this encounter and left enabled to guard against future
close encounters. The pitch thruster firing that occurred at 18:14 UT
was determined to be due to nominal operational conditions and not the
result of outside forces i.e. impact from debris or foreign object.
During normal spacecraft operations the momentum carried by the Z
(pitch) RWA ranges from -25 to about -40 inch pound seconds (see Figure
3). The automatic thruster unloading threshold for the pitch axis is set
at ±40 in. lb sec, which is too close to operational levels to avoid
inadvertent thruster firings when automatic thruster momentum unloading
is enabled. ATMUL was disabled to avoid additional inadvertent thruster
firings. The threshold for the Z axis should be increased to 45 in. lb
sec if ATMUL is to be enabled for future close encounters. Once the
investigation is complete and the thresholds are increased, auto
thruster unloading will be re-enabled and remain enabled. During the +
pitch thruster firing the ROLL reasonableness test failed on the NON
control side, which caused the MIMU to switch from MIMU 2 to MIMU 1, and
set MIMU switching to INHIBIT.

The N18 MHS Channel 5 signal has been slowly drifting downward. This is
an anticipated condition resulting from seasonal effects (cyclical
temperatures) and aging hardware. The signal levels in the space view
are near the lower 5% level, 3276 counts. When the signal is below 5%,
the MHS raises flags to indicate the sensor may need adjustment to keep
the signal from saturating. Figure 4 depicts the daily and orbital
cycles in which the signal dips below the 5% level. The plan is to
perform a DC Offset correction that will move the signal level back
towards the center of its range. There are no current concerns of data
loss/degradation or instrument health.

MetOp-A: There were relatively no changes to the health and safety of
the NOAA instruments on MetOp-A this past week.

 

The slightly increasing trend identified last week in the SARR 121.5 MHz
Rx-A AGC Voltage (mean values) did not continue this week and can
therefore be considered insignificant.

![](media/image4.jpeg){width="8.561111111111112in"
height="6.250694444444444in"}

Figure 1 NOAA-17 Shunts (2008/230-231)

![](media/image5.jpeg){width="8.561111111111112in"
height="6.378472222222222in"}

Figure 2 NOAA-15 RWA Speeds (2008/136-232)

![](media/image6.jpeg){width="8.561111111111112in"
height="6.250694444444444in"}

[Figure 3]{.mark} NOAA-18 X,Y,Z Momentum (2008/231)

![](media/image7.png){width="8.560416666666667in"
height="6.003472222222222in"}

[Figure 3]{.mark} NOAA-18 MHS Channel 5 (2008/228-234)