! File: 3247C.PROP ! Database: PEPDB ! Date: 18-FEB-1994:23:44:34 coverpage: title_1: SA FEATHERING TEST II proposal_for: ENG pi_fname: J pi_lname: DECKER pi_inst: CODE 440 pi_country: USA num_pri: 1 ! end of coverpage abstract: line_1: During the initial execution of the Solar Array Feathering line_2: test, an unplanned control system gain change resulted in a line_3: failure to achieve some of the critical goals of this test. line_4: In particular, data required to identify the differences line_5: between stick-slip and thermal bending phenomena, and data line_6: required to assess the validity of analytical model predictio line_7: were suppressed. A partial repeat of this test is necessary t line_8: to obtain these data and will consist of reconfiguration of line_9: the solar arrays to a series of off-nominal configurations line_10: and observing/recording the resulting vehicle disturbances. ! ! end of abstract general_form_proposers: lname: DECKER fname: J. inst: GFSC country: USA esa: X ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: This test will provide data concerning the behavior of the line_2: vehicle throughout the orbit with the arrays line_3: in off-nominal configurations. The data will be used to line_4: identify differences between stick-slip and thermal bending line_5: phenomena and to assess the validity of analytical model line_6: predictions of thermally induced vehicle disturbances. This line_7: information cannot be obtained by any means other than an line_8: on-orbit test involving off-nominal SA config's. line_9: The data will be used to determine any modifications to the line_10: design of the replacement SAs which are required to minimize line_11: the SA induced disturbances. ! question: 3 section: 1 line_1: This test will be conducted with the HST in Normal Mode line_2: using gyros for attitude reference. The +V1 will be pointed line_3: toward the SEP, and the +V3 axis towards the sun. line_4: The battery Rate of Charge (ROC) safemode line_5: test must be disabled during the entire test; the SA normal line_6: Sun Angle Safemode test will be disabled during specific line_7: parts of the test by real time commands and then enabled line_8: by Stored Program Commands. All other safemode tests must line_9: remain enabled during the test. line_10: All critical data e.g format PN data, will be downlinked in line_11: realtime when possible, recorded on the ETR as a backup, line_12: and dumped to the STOCC to insure that all critical line_13: data are available for either real time or near-real time line_14: analysis. line_15: The nominal orientation of th SAs for this test is an angle line_16: of +90 degs. This test consists of series of SA positioning line_17: slews that a) place the the -V2 wing 'edge-on' to the sun; line_18: b) place the +v2 wing 'edge-on' to the sun. At least one line_19: 15-min forward link contact is required during the time line_20: that each wing is in the 'edge-on' configuration to enable line_21: the wing to be commanded back to the nominal ! question: 3 section: 2 line_1: orientation in the event that the any problems are en- line_2: countered; these are designated as critical forward link line_3: service. Each SA slew to an edge-on configuration will be line_4: accomplished using real-time commands. line_5: Two opportunities will be provided for sending the real- line_6: time commands to accomplish these slews in order to insure line_7: that the edge-on coinfigurations are established and settled line_8: prior to a night-day transition. Each edge-on configuration line_9: will be maintained for one full orbit of PN data collections. line_10: After each test configuration, the SA wings will be slewed line_11: back to their nominal positions using stored commands. A line_12: recovery period is required between the 2 edge-on configurati line_13: to allow the battery test SOC to return to the level that line_14: prevailed at the beginning of the test. ! question: 4 section: 1 line_1: Acquisition of the on-orbit data which is necessary both to line_2: identify differences between slip-stick and themal bending line_3: phenomena contributing to jitter, and to assess the validity line_4: of analytical model predictions of thermally induced vehicle line_5: disturbances, cannot be accomplished via any other means line_6: other than on-orbit testing w/off-nominal SA configurations. line_7: The required data are not available during normal operations, line_8: and are not acquired from any other planned test. ! question: 7 section: 1 line_1: HST Rate Gyro Assembly (RGA) data will be anaylzed in both line_2: realtime and frequency domains using PSDs. These results will line_3: be correlated to the SA configurations wrt to the vehicle, line_4: and to the vehicle configuration wrt the sun. This data will line_5: be compared to the predicted behavior of each array. ESA, line_6: GSFC, MOC, and LMSC-W will process and test the data and line_7: issue reports. ! !end of general form text general_form_address: lname: DECKER fname: J category: PI inst: CODE 440 ! lname: DECKER fname: J. category: PI inst: GFSC ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: SEP descr_1: S.ECLIPTIC POLE pos_1: RA = 90.0D +/- .1", pos_2: DEC = -66.500D +/- .01" equinox: 1990 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: SEP config: S/C opmode: POINTING aperture: V1 num_exp: 1 time_per_exp: 1S fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO req_1: SEQ 1- 10 NO GAP; req_2: CRIT OBS / 1-10; req_3: CYCLE 0 / 1-10; comment_1: SLEW TO TARGET SEP comment_2: WITH +V3 TO SUN, VIA comment_3: SPC. ! linenum: 2.000 targname: SEP config: S/C opmode: DATA aperture: V1 num_exp: 1 time_per_exp: 30M fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO, param_2: FORMAT=PN req_1: RT ANALYSIS; req_2: REQ UPLINK; comment_1: DEACTIVATE SAGA. INSTALL, comment_2: PCS MANEUVER GAINS, AND SA comment_3: BLANKET TENSION IN "TLMDIAG" comment_4: DISABLE SA/SUN ANGLE TEST, comment_5: BATTER ROC TEST, AND PATCH comment_6: ONNRLM TO 18DEGS VIA RTC ! linenum: 3.000 targname: SEP config: S/C opmode: DATA aperture: V1 num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO, param_2: FORMAT=PN req_1: RT ANALYSIS; req_2: REQ UPLINK; comment_1: START 25 MINS PRIOR TO EON. comment_2: SLEW -V2 WING TO 0 DEGS VIA comment_3: RTC. BEGIN COMCON 25 MINS comment_4: PRIOR TO SHADOW ENTRY (EON). ! linenum: 4.000 targname: SEP config: S/C opmode: DATA aperture: V1 num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO, param_2: FORMAT=PN req_1: AFTER 3 BY 20M+/-0M; req_2: RT ANALYSIS; req_3: REQ UPLINK; comment_1: LAST OPPORTUNITY TO SLEW comment_2: -V2 WING TO 0 DEGS. ! linenum: 5.000 targname: SEP config: S/C opmode: DATA aperture: V1 num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO, param_2: FORMAT=PN req_1: RT ANALYSIS; req_2: REQ UPLINK; comment_1: START ENTER ORBIT DAY. comment_2: CONTINGENCY FORWARD comment_3: LINK. ! linenum: 6.000 targname: SEP config: S/C opmode: DATA aperture: V1 num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO, param_2: FORMAT=PN req_1: AFTER 5 BY 105M+/-15M; req_2: RT ANALYSIS; req_3: REQ UPLINK; comment_1: TAPE RECORDER DUMP comment_2: IN PN FORMAT. ! linenum: 7.000 targname: SEP config: S/C opmode: DATA aperture: V1 num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO, param_2: FORMAT=PN req_1: RT ANALYSIS; req_2: REQ UPLINK; comment_1: START 25 MINS PRIOR TO comment_2: ENTER ORBIT NIGHT. COMMAND comment_3: TO DISABLE SA SUNANGLE comment_4: TEST AND TO SLEW +V2 comment_5: WIND TO 0 DEGS. PERFORM comment_6: DURING NEXT SUNLITE ORBIT ! linenum: 8.000 targname: SEP config: S/C opmode: DATA aperture: V1 num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO, param_2: FORMAT=PN req_1: AFTER 7 BY 20M +/- 0M; req_2: RT ANALYSIS; req_3: REQ UPLINK; comment_1: LAST OPPORTUNITY TO comment_2: SLEW SA +V2 WING TO comment_3: 0 DEGS. ! linenum: 9.000 targname: SEP config: S/C opmode: DATA aperture: V1 num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO, param_2: FORMAT=PN req_1: RT ANALYSIS; req_2: REQ UPLINK; comment_1: START AT EOD. comment_2: CONTACT REQ'D FOR comment_3: CONTINGENCY. ! linenum: 10.000 targname: SEP config: S/C opmode: DATA aperture: V1 num_exp: 1 time_per_exp: 30M fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO, param_2: FORMAT=PN req_1: AFTER 9 BY 105M +/- 10M; req_2: RT ANALYSIS; req_3: REQ UPLINK; comment_1: COMMANDING TO INSTALL PCS comment_2: ACQ GAINS, AND TO REACTIVATE comment_3: SAGA AND PATCH ONNRLM TO comment_4: 9 DEGS. DUMP TAPE RECORDER. ! ! end of exposure logsheet ! No scan data records found