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000
NOUS72 KNES 241648
ADMNES
SUBJECT: ADMINISTRATIVE:  S-NPP SPACECRAFT CONTROL COMPUTER (SCC)
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*TOPIC: *S-NPP SPACECRAFT CONTROL COMPUTER (SCC) CLOCK SLOPE UPDATE:
GPS
DRIFT**

DATE/TIME ISSUED:**JULY 24, 2014 1640 UTC

**

*PRODUCT(S) OR DATA IMPACTED: *ALL S-NPP DATA

*DATE/TIME OF INITIAL IMPACT: *JULY 23, 2014 1844  UTC

*DATE/TIME OF EXPECTED END: *JULY 23, 2014    2351 UTC

*LENGTH OF OUTAGE: *05:07

*DETAILS/SPECIFICS OF CHANGE: *AN UPDATE TO THE SCC CLOCK SLOPE WAS
PERFORMED ON JULY 23, 2014 AT 18:44 UTC AT SVALBARD CONTACT 14179.
THIS
UPDATED SLOPE IS CALCULATED ON THE GROUND AND SENT TO THE SPACECRAFT
WITH AN UPDATED BASETIME AND SLOPE VIA AN UPLOADED SCC TABLE 2.

DURING THE 14179 CONTACT, THIS UPDATED TABLE 2 WAS UPLOADED AND
APPEARED
TO PERFORM NOMINALLY. NO ALARMS WERE OBSERVED. UPON A SUBSEQUENT PASS,
IT WAS OBSERVED THAT THE SCC CLOCK WAS DEMONSTRATING A +13 MS DRIFT
RELATIVE TO THE GPS TIME, WHICH IS GREATER THAN NOMINAL OPERATIONAL
RANGE; A DRIFT OF 0 IS THE TARGETED VALUE.

AT 23:51 UTC SVALBARD CONTACT 14182 THE SCC CLOCK WAS CORRECTED TO
ELIMINATE THE DRIFT BETWEEN THE GPS CLOCK AND THE SCC CLOCK VIA AN
UPDATED BASETIME.

THE AFFECTED TIME WHERE THERE EXISTED A 13 MS DRIFT BETWEEN THE SCC
CLOCK AND GPS CLOCK WAS THUS 18:44 UTC TO 23:51 UTC.  NO FURTHER
ACTIONS
ARE REQUIRED AND SATELLITE IS IN A NOMINAL CONFIGURATION.

**

*CONTACT INFORMATION FOR FURTHER INFORMATION:*ESPC OPERATIONS AT
ESPCOPERATIONS@NOAA.GOV  AT
301-817-3880
 *
*

*WEB SITE(S) FOR APPLICABLE INFORMATION:*N/A

YOU HAVE BEEN SENT THIS AND OTHER NOTIFICATIONS BECAUSE YOU HAVE OPTED
IN TO RECEIVE IT. IF FOR ANY REASON, YOU WISH TO UNSUBSCRIBE, PLEASE
CONTACT ESPC HELP DESK AT ESPCOPERATIONS@NOAA.GOV OR (301) 817-3880.
PLEASE NOTE: IT MAY TAKE UP TO TWO BUSINESS DAYS TO PROCESS YOUR
UNSUBSCRIBE REQUEST.



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TOPIC: S-NPP SPACECRAFT CONTROL COMPUTER (SCC) CLOCK SLOPE UPDATE: GPS DRIFT

DATE/TIME ISSUED:
JULY 24, 2014 1640 UTC

PRODUCT(S) OR DATA IMPACTED: ALL S-NPP DATA

DATE/TIME OF INITIAL IMPACT: JULY 23, 2014 1844 UTC

DATE/TIME OF EXPECTED END: JULY 23, 2014 2351 UTC

LENGTH OF OUTAGE: 05:07

DETAILS/SPECIFICS OF CHANGE: AN UPDATE TO THE SCC CLOCK SLOPE WAS PERFORMED ON JULY 23, 2014 AT 18:44 UTC AT SVALBARD CONTACT 14179. THIS UPDATED SLOPE IS CALCULATED ON THE GROUND AND SENT TO THE SPACECRAFT WITH AN UPDATED BASETIME AND SLOPE VIA AN UPLOADED SCC TABLE 2.

DURING THE 14179 CONTACT, THIS UPDATED TABLE 2 WAS UPLOADED AND APPEARED TO PERFORM NOMINALLY. NO ALARMS WERE OBSERVED. UPON A SUBSEQUENT PASS, IT WAS OBSERVED THAT THE SCC CLOCK WAS DEMONSTRATING A +13 MS DRIFT RELATIVE TO THE GPS TIME, WHICH IS GREATER THAN NOMINAL OPERATIONAL RANGE; A DRIFT OF 0 IS THE TARGETED VALUE.

AT 23:51 UTC SVALBARD CONTACT 14182 THE SCC CLOCK WAS CORRECTED TO ELIMINATE THE DRIFT BETWEEN THE GPS CLOCK AND THE SCC CLOCK VIA AN UPDATED BASETIME.

THE AFFECTED TIME WHERE THERE EXISTED A 13 MS DRIFT BETWEEN THE SCC CLOCK AND GPS CLOCK WAS THUS 18:44 UTC TO 23:51 UTC. NO FURTHER ACTIONS ARE REQUIRED AND SATELLITE IS IN A NOMINAL CONFIGURATION.

CONTACT INFORMATION FOR FURTHER INFORMATION: ESPC OPERATIONS AT ESPCOPERATIONS@NOAA.GOV AT 301-817-3880

WEB SITE(S) FOR APPLICABLE INFORMATION: N/A

YOU HAVE BEEN SENT THIS AND OTHER NOTIFICATIONS BECAUSE YOU HAVE OPTED IN TO RECEIVE IT. IF FOR ANY REASON, YOU WISH TO UNSUBSCRIBE, PLEASE CONTACT ESPC HELP DESK AT ESPCOPERATIONS@NOAA.GOV OR (301) 817-3880. PLEASE NOTE: IT MAY TAKE UP TO TWO BUSINESS DAYS TO PROCESS YOUR UNSUBSCRIBE REQUEST.


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