! File: 3360C.PROP ! Database: PEPDB ! Date: 19-FEB-1994:04:53:21 coverpage: title_1: FES FINE LOCK GUIDANCE TEST proposal_for: ENG/FGS pi_title: DR. pi_fname: FRANCIS pi_mi: H. pi_lname: SCHIFFER pi_inst: STSCI pi_country: USA pi_phone: 338-4789 keywords_1: ENGINEERING keywords_2: ACQUISITIONS hours_pri: 0.60 num_pri: 1 fgs: Y ! end of coverpage abstract: line_1: The current operational limit for fine lock is 13.0 magnitude, line_2: rather than the planned 14.5 magnitude. This restriction is due line_3: to the OTA spherical aberration and internal FGS effects. line_4: The limitation severly restricts the availability of guide stars line_5: for observations which require fine lock for guidance. line_6: The purpose of this test is to determine whether use of line_7: FES averaging time can allow the capture and guidance on stars line_8: fainter than 13.0, thus recovering the lost capability. line_10: This test will verify that fine lock averaging with NULL-BYPASS line_11: can be used to support pointing control. The discussions with line_12: the flight software engineers suggests that the FGS can be run line_13: with fine lock averaging as large as 100 milli-seconds without line_14: compromising the pointing control system. The probability of lock line_15: and the stability while in lock needs to be verified using the line_16: Spacecraft with an observation which is not scientifically critical line_17: before this method of guidance is used to support scientific line_18: observations. ! ! end of abstract general_form_proposers: lname: SCHIFFER, 3RD fname: FRANCIS title: DR. mi: H. inst: STSCI country: USA ! lname: LUPIE fname: OLIVIA title: DR. mi: L. inst: STSCI country: USA ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: The current limitting magnitude for FGS guiding of 13.0 line_2: is insufficient to allow the location of potential guide line_3: stars in the portions of the sky where stars are not line_4: common. These portions of the sky which are out of the line_5: galactic plane are precisely the directions in which the line_6: important extra-galactic astronomy can be done. The original line_7: mission was planned assuming that stars down to 14.5 would be line_8: usable for guiding in fine lock. By changing the FESAVG time line_9: it should be possible to regain the missing 1.5 magnitudes of line_10: sensitivity and so make it possible to find guide stars in line_11: these interesting regions of the sky. As changing the FESAVG line_12: time requires using the FGS in a mode which was not planned for line_13: in the control system, it is necessary to determine how well line_14: control system will work using this mode. If the test line_15: demonstrates that the pointing stability is better than coarse line_16: track then this approach can be used to extend the range of the line_17: FGSs for guidence. ! question: 3 section: 1 line_1: Acquire one pair fine lock plus Astrometry POS mode observation line_2: with high rate telemetry. Verifies the ability to acquire faint line_3: guide stars and the tracking performance from the PCS. line_5: FGS3 & FGS1 guiding FGS2 Astrometry - long observation at 14.25 line_6: FGS3 & FGS1 guiding FGS2 Astrometry - short obs at 13.25 and 13.75 line_7: FGS3 & FGS2 guiding FGS1 Astrometry - long observation at 13.75 line_8: FGS3 & FGS2 guiding FGS1 Astrometry - short obs at 13.25 and 14.25 line_9: FGS1 & FGS2 guiding FGS3 Astrometry - long observation at 13.25 line_10: FGS1 & FGS2 guiding FGS3 Astrometry - short obs at 13.75 and 14.25 line_11: Each series with one astrometry FGS should be done together. line_12: Each series with different FGSs may be scheduled separately. line_13: Guide stars should be within 0.25 mag of the specified brightness line_14: if possible. line_16: Acquisitions are required for each observation (to change guide line_17: stars) and should be done with one pair in fine lock. line_18: Special commanding is needed for the acquisitions as they must line_19: set the FESAVG parameter to 100 msec. The astrometry is standard. line_21: High rate (FN) telemetry is desirable during the acquisitions in line_22: order to analyze acquisition failures, however, it is not required line_23: in order to carry out the test. ! question: 3 section: 2 line_1: In order to maximize the return on the test the largest collection line_2: of guide stars should be used. This goal implies that the test line_3: needs two (2) guide stars in each magnitude range (for a total of line_4: 6 stars) in each FGS. ! question: 4 section: 1 line_1: Tests of the Pointing Control System telemetry can only be performed line_2: by the actual space hardware. All of the available ground system line_3: simulations have been completed successfully. ! question: 5 section: 1 line_1: This test is a verification of the systems capability to track line_2: faint guide stars with adequate stability to perform science line_3: observations. As the performance of each FGS is different, the line_4: ability to locate and acquire stars must be checked in each FGS line_5: independently. By checking a range of guide star brightnesses, line_6: and trying more than one star, we can gain some confidence as to line_7: the faintest stars which can be acquired reliabily. In addition line_8: one pair in each sequence is observed for a long enough time to line_9: allow a reliable measurment of the guiding performance. This line_10: measurement should be the same for each FGS but may vary with line_11: guide star brightness. Thus it is done for each of the guide line_12: star brightness ranges. ! question: 6 section: 1 line_1: Each observation must be in a separate observation set in order line_2: to allow a different guide star pair to be used for each line_3: measurement. line_5: All acquisitions should be scheduled using a 1 pair fine lock line_6: acquisition scenario. line_8: The guide star acquisitions must use special commanding which line_9: sets the FESAVG time for the guiding FGSs to 100 milliseconds line_10: and uses the NULL BYPASS mode. line_12: The guide stars in each pair must be matched in brightness and line_13: selected within the brightness range specified by the line_14: appropriate exposure logsheet line. Using guide stars outside line_15: the magnitude range will compromise the test. The accuracy in line_16: the magnitude matching is the same as the magnitude ranges line_17: specified in the exposure logsheet line. (ie, both stars must be line_18: in the range specified.) line_20: Although the target is part of the NGC-188 special targets and line_21: the field is covered by a special guide star catalog, the guide line_22: stars used by this test should be taken from the standard guide line_23: star catalog for this region. ! question: 7 section: 1 line_1: The data from OMS will be examined to determine the success/failure line_2: of each acquisition. For those acquisitions which were successful line_3: and for which there is an successful astrometry observation, the line_4: position data from the astrometer will be examined to determine line_5: the position stability of the S/C. Particular attention will be line_6: paid to the peak-to-peak and RMS deviations from a stable position. ! question: 8 section: 1 line_1: None. ! question: 9 section: 1 line_1: None. ! question: 10 section: 1 line_1: OMS, Computational power to analyze the data. ! !end of general form text general_form_address: lname: SCHIFFER, 3RD fname: FRANCIS mi: H. category: PI inst: STSCI ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: GS-ID3888900204 name_2: VID-998 name_3: LID-14 descr_1: BRIGHT STAR IN NGC188 pos_1: RA = 0H 42M 43.32S +/- 0.04S, pos_2: DEC=+85D 14' 13.6" +/- 0.1" equinox: J2000 pm_or_par: Y pos_epoch_bj: J pos_epoch_yr: 2000.00 ra_pm_val: 0.002905 ra_pm_unct: 0.000067 dec_pm_val: -0.0068 dec_pm_unct: 0.0010 comment_1: USED BY HDOS IN FINE LOCK fluxnum_1: 1 fluxval_1: V=9.58 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 10.000 targname: GS-ID3888900204 config: FGS opmode: POS aperture: 2 sp_element: PUPIL num_exp: 1 time_per_exp: 10M priority: 01 param_1: DATA-RATE=32 req_1: SEQ 10-12 NO GAP; req_2: CYCLE 0 / 10-32; comment_1: GUIDE WITH 100 MSEC AVERAGING; comment_2: GUIDE STARS 14.0-14.5 MAG; comment_3: USE 1 PAIR ACQUISITION; ! linenum: 11.000 targname: GS-ID3888900204 config: FGS opmode: POS aperture: 2 sp_element: PUPIL num_exp: 1 time_per_exp: 1M priority: 01 param_1: DATA-RATE=32 comment_1: GUIDE WITH 100 MSEC AVERAGING; comment_2: FORCE NEW GUIDE STAR ACQ; comment_3: GUIDE STARS 13.0-13.5 MAG; comment_4: USE 1 PAIR ACQUISITION; ! linenum: 12.000 targname: GS-ID3888900204 config: FGS opmode: POS aperture: 2 sp_element: PUPIL num_exp: 1 time_per_exp: 1M priority: 01 param_1: DATA-RATE=32 comment_1: GUIDE WITH 100 MSEC AVERAGING; comment_2: FORCE NEW GUIDE STAR ACQ; comment_3: GUIDE STARS 13.5-14.0 MAG; comment_4: USE 1 PAIR ACQUISITION; ! linenum: 20.000 targname: GS-ID3888900204 config: FGS opmode: POS aperture: 1 sp_element: PUPIL num_exp: 1 time_per_exp: 10M priority: 01 param_1: DATA-RATE=32 req_1: SEQ 20-22 NO GAP; comment_1: GUIDE WITH 100 MSEC AVERAGING; comment_2: GUIDE STARS 13.5-14.0 MAG; comment_3: USE 1 PAIR ACQUISITION; ! linenum: 21.000 targname: GS-ID3888900204 config: FGS opmode: POS aperture: 1 sp_element: PUPIL num_exp: 1 time_per_exp: 1M priority: 01 param_1: DATA-RATE=32 comment_1: GUIDE WITH 100 MSEC AVERAGING; comment_2: FORCE NEW GUIDE STAR ACQ; comment_3: GUIDE STARS 13.0-13.5 MAG; comment_4: USE 1 PAIR ACQUISITION; ! linenum: 22.000 targname: GS-ID3888900204 config: FGS opmode: POS aperture: 1 sp_element: PUPIL num_exp: 1 time_per_exp: 1M priority: 01 param_1: DATA-RATE=32 comment_1: GUIDE WITH 100 MSEC AVERAGING; comment_2: FORCE NEW GUIDE STAR ACQ; comment_3: GUIDE STARS 14.0-14.5 MAG; comment_4: USE 1 PAIR ACQUISITION; ! linenum: 30.000 targname: GS-ID3888900204 config: FGS opmode: POS aperture: 3 sp_element: PUPIL num_exp: 1 time_per_exp: 10M priority: 01 param_1: DATA-RATE=32 req_1: SEQ 30-32 NO GAP; comment_1: GUIDE WITH 100 MSEC AVERAGING; comment_2: GUIDE STARS 13.0-13.5 MAG; comment_3: USE 1 PAIR ACQUISITION; ! linenum: 31.000 targname: GS-ID3888900204 config: FGS opmode: POS aperture: 3 sp_element: PUPIL num_exp: 1 time_per_exp: 1M priority: 01 param_1: DATA-RATE=32 comment_1: GUIDE WITH 100 MSEC AVERAGING; comment_2: FORCE NEW GUIDE STAR ACQ; comment_3: GUIDE STARS 14.0-14.5 MAG; comment_4: USE 1 PAIR ACQUISITION; ! linenum: 32.000 targname: GS-ID3888900204 config: FGS opmode: POS aperture: 3 sp_element: PUPIL num_exp: 1 time_per_exp: 1M priority: 01 param_1: DATA-RATE=32 comment_1: GUIDE WITH 100 MSEC AVERAGING; comment_2: FORCE NEW GUIDE STAR ACQ; comment_3: GUIDE STARS 13.5-14.0 MAG; comment_4: USE 1 PAIR ACQUISITION; ! ! end of exposure logsheet ! No scan data records found