- Press Release
- Nov 29, 2022
NASA Hubble Space Telescope Daily Report #4858
HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science
DAILY REPORT #4858
PERIOD COVERED: 5am June 2 – 5am June 3, 2009 (DOY 153/0900z-154/0900z)
Optimizing FGS2R2 Performance with the AMA
Ths proposal satisfies SMOV4 AD OTA/FGSS-054. S-curves with PUPIL and F583W will be obtained at selected locations within the FGS2R2 FOV during SMOV4. These data will be will be used to adjust the AMA so as to align the HST pupil onto the interferometer’s Koesters prisms. The final AMA position will be set to produce an acceptable set of S-curves across the FGS2R2 FOV. The AMA will be adjusted using CCL/instructions from the ground. It is intended that this proposal executes during the SMOV4 BEA and will require several (on the order of 4) iterations to achieve optimal interferometric performance.
FUV MAMA HV Recovery
This proposal addresses the concerns over Cesium migration from the FUV-MAMA photocathode into the pores of the microchannel plate and lays out the procedures necessary to permit a safe and controlled recovery of the FUV-MAMA detector to science. This procedure should only be used during the SMOV4 high voltage recommissioning phase for the FUV-MAMA. After that, the normal ramping procedure should be used. This proposal is loosely based on proposal 10036, STIS MAMA Anomalous Recovery, with the differences summarized below: (1) additional plateaus during voltage commanding, (2) longer dwells after each 50 V step, (3) intermediate ramp re-structured into 2 parts, (4) change in yellow and red limits and the MCP Hi limit, setting new values for the next plateau, and (5) adding a fold test at 300V below the nominal MCP voltage. The recovery consists of four separate and unique procedures (visits) and they must be completed successfully and in order. They are: (1) a signal processing electronics check, (2) 1st high voltage ramp-up to an intermediate MCP voltage of -1500 V with limits modifications and voltage plateaus, (3) 2nd high voltage ramp-up to an intermediate MCP voltage of -1950 V (300 V below the nominal MCP voltage) with limits modifications and voltage plateaus followed by a fold distribution test, and (4) the final high voltage ramp-up to the full operating voltage, again with limits modifications and voltage plateaus, followed by a fold distribution test. During the 1st high voltage ramp-up, diagnostics are performed followed by a dark exposure. During the 2nd and 3rd high voltage ramp-ups, diagnostics are performed followed by a dark, flat field ACCUMs, and a fold analysis test. All required parameters are defined in 07-248 FUV and NUV SMOV Ramp-up Parameters Excel workbook. Supports Activity STIS-17
STIS CCD Hot Pixel Annealing (SMOV4 activity STIS-05)
This purpose of this activity is to repair radiation induced hot pixel damage to the STIS CCD by warming the CCD to the ambient instrument temperature and annealing radiation damaged pixels.
Radiation damage creates hot pixels in the STIS CCD Detector. Many of these hot pixels can be repaired by warming the CCD from its normal operating temperature near -83?C to the ambient instrument temperature (~ +5 deg C) for several hours. The number of hot pixels repaired is a function of annealing temperature. So although the CCD during Safing has been warmer (~ -5 deg C) than its normal operating temperature, the electronics have been off and the CCD has remained cooler than its temperature (+5 deg C) during the annealing procedure.
The effectiveness of the CCD hot pixel annealing process is assessed by measuring the dark current behavior before and after annealing and by searching for any window contamination effects. In addition CTE performance is examined by looking for traps in a low signal level flat. This proposal is a continuation of the Cycle 12 proposal 10022.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
11861 – GSAcq(1,3,3) at 153/21:42:00 results in fine lock backup (1,0,1) using FGS-1
Observations affected: None.
COMPLETED OPS REQUEST:
18469-0 – Clear COS Event Flag 2 after NUV initial turn on Part 2 completes @ 153/1347
18466-0 – Clear STIS Event Flag 2 (MAMA1 Checkout Part 2) @ 153/1428z
18471-1 – Update ACS CEB-R ASIC Offsets @ 153/1755z
18470-0 – 1st AMA Move for FGS2R2 @ 153/2155z
COMPLETED OPS NOTES: (None)
FGS GSAcq 9 9
FGS REAcq 0 0
OBAD with Maneuver 6 6
The 1st FGS2R2 AMA Move was executed 153/21:42-21:55.