The following information is being forwarded to you to keep you abreast of
plans to enable further analysis of the AVHRR problem on the NOAA-15
spacecraft. Please review it and send any comments or concerns to me as
soon as possible.
>> After a well attended meeting on Monday, August 21st by representatives
>> of OSD, SAO, IPD, and OSO, the following operating conditons for
>> NOAA-15 were requested for scheduling of tests to begin on September
>> 5th and continue for 2 weeks, through September 18th. This test period
>> is limited to 2 weeks based on: 1) the scheduling software (SOMS) -
>> current software has not been used operationally during a launch and
>> NOAA-L is scheduled to be launched September 20th; also 2) Two passes
>> per day for two weeks (28 passes) will give the equivalent of 2 full
>> days worth of data to analyze.
>> With this reasoning the following actions are requested of the listed
>> Scheduling (SOCC)
>> 1) Select the passes preceding 2 high elevation (>35 degrees) downlink
>> passes each day (preferably day staff passes) and begin a stored-AIP
>> (SAIP) record then command the MIRP into AVHRR sync mode. The normal
>> GAC recording should continue to be routinely scheduled, i.e., the SAIP
>> will "shadow" the GAC record. At the end of each SAIP "shadow" pass,
>> the MIRP should be commanded back to internal sync (current operating
>> 2) On the high elevation pass after the "shadow" SAIP recording, the
>> SAIP and GAC will be "played down" from the spacecraft , and transferred
>> post-pass with the SAIP transferred to IPD first (at their request) for
>> level 1B processing.
>> SOCC engineering
>> 3) For internal analysis, using the new PIDES, produce soft and hard
>> copies of the HRPT and GAC data from the two passes where the MIRP is
>> switched to AVHRR sync. This should include the real-time dataset
>> showing the switch from internal to external sync and the return to
>> internal sync.
>> The objective of this test is to determine what effects the AVHRR
>> re-syncing has on the MIRP dataset production. Currently, whenever the
>> AVHRR re-syncs, it perturbs the MIRP sampling process, and therefore,
>> the GAC dataset production (effecting all AIP data). With the SAIP
>> "shadow" recording, an AVHRR event will NOT effect the SAIP dataset
>> (different processor), therefore, the current anomaly investigation team
>> will have information to use in investigating the cause and effects of
>> the problem and the other operational instrument datasets will not be
>> From an operations standpoint, both CDAs have been functionally tested
>> for receiving and transferring SAIP to IPD and the 13m and IMUX
>> recorders have been "set-up".
>> Should any deviation of the test plan outlined above be required,
>> notification and approval of all members of the investigation team will
>> be required.
Emily D. Harrod
E/SP13 Room 0308 FB#4
5200 Auth Road
Suitland, Md. 20746-4304