! File: 4021C.PROP ! Database: PEPDB ! Date: 20-FEB-1994:04:06:45 coverpage: title_1: SAGA II ON-ORBIT TEST proposal_for: ENG/SC pi_fname: MIKE pi_lname: URBAN pi_inst: GSFC/CODE 441 pi_country: USA num_pri: 1 ! end of coverpage abstract: line_1: This proposal test will acquire data to demonstrate the line_2: health and safety of the SAGA-II software. Data gathered line_3: during this test will also be used to compare the SAGA-II line_4: performance to that of the existing SAGA-GA software. line_5: SAGA-II software modifies the SAGA-GA software addition to line_6: the Pointing Control System (PCS) control law. The SAGA-GA line_7: modificatin attenuates attitude transients produced by solar line_8: array disturbance torques. SAGA-II modifies the attenuation line_9: to further reduce vehicle response to a 0.6 Hz mode. line_10: The test will consist of five orbits of activity. During the line_11: first four orbits the vehicle attitude will point V3 to the line_12: sun. Data will be gathered in fine lock, gyro hold, course line_13: track, and fine lock modes respectively. During the fifth line_14: orbit the vehicle slews -V1 to the sun and acquires guide line_15: stars in fine lock. All data will be gathered in P format. line_16: SAGA-GA will be used for the first orbit. SAGA-II will be line_17: used for the last four orbits. After the data gathering line_18: interval SAGA-GA will be restored and the vehicle will be line_19: reconfigured for normal operations. ! ! end of abstract general_form_proposers: lname: URBAN fname: MIKE inst: GFSC/CODE 441 country: USA esa: X ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: The SAGA-II software modifications are expected to attenuate line_2: the vehicle attitude response to solar array disturbance line_3: torques beyond the attenuation provided by SAGA-GA. The line_4: additional attenuation will reduce the succeptibility to line_5: FGS loss of lock due to the 0.6 Hz component of the solar line_6: array disturbance, thereby reducing science losses. ! question: 3 section: 1 line_1: The test will be performed per the following schedule. line_2: ORBIT 1: Slew to target normal to the sunline (+V3 pointing line_3: to the sun within 5 deg). Earth cannot occult the target line_4: through entire orbit to allow uninterrupted data take.up line_5: Select P format. The TLMDIAG slots will be configured to read line_6: out the V1 attitude error parameter THETAPO. line_7: Acquire the guide star pair in fine lock. Guide star choice line_8: should yield the brightest pair possible to minimize the line_9: possibility of loss of lock during experiment. The acquistion line_11: period is to be from at least 5 minutes prior to EOD to at line_12: least 10 minutes after EON. ! question: 3 section: 2 line_1: ORBIT 2: Select Gyro hold mode. Select SAGA-II. The acq. line_2: period is to be from at least 5 minutes prior EOD to at line_3: least 10 minutes after EON. line_4: ORBIT 3: Acquire guide stars in FGS Course Track. The acq. line_5: period is to be at least 5 minutes prior EOD to 10 minutes line_6: after EON. line_7: ORBIT 4: Acquire guide stars in FGS Fine Lock. The acq. line_8: period is to be at least 5 minutes prior to EOD to 10 line_9: minutes after EON. line_10: ORBIT 5: At 10 minutes after orbit 4 EON, slew to new line_11: target that points -V1 to the sun within 5 deg. NOTE: EOD line_12: crossing and target occultation are expected to occur before line_13: the spacecraft completes the slew. ASAP after the target line_14: leaves earth accultation, acquire the guide stars in FGS line_15: fine lock. Maintain fine lock until next target occultation. line_16: Restore SAGA-GA. (Need foreward link). Reconfigure the line_17: spacecraft for normal operations. ! question: 5 section: 1 line_1: This test must be scheduled at least two weeks (preferably line_2: four) prior to the MINI-OFAD Calibration Test in April. This line_3: schedule allows at least two weeks for data analysis before line_4: the SAGA-II software is comitted to full time operation. The line_6: MINI-OFAD Calibration Test requires the reduced frequency of line_7: loss of lock expected with SAGA-II. ! question: 6 section: 1 line_1: The uninterrupted guide star lock during the first target line_2: attitude is necessary in order to observe system response at line_3: all terminators. No terminator may be missed if both EOD and line_4: EON are to be observed for each control mode and vehicle line_5: attitude. ! question: 7 section: 1 line_1: All data will be gathered and analyzed through the MOC ESS line_2: or with the aide of MOC strip-chart recorders. ! question: 8 section: 1 line_1: P format must be scheduled for all observations after the line_2: maneuver to the first target. ! !end of general form text general_form_address: lname: URBAN fname: MIKE category: PI inst: GSFC/CODE 441 addr_1: GSFC city: GREENBELT state: MD zip: 20771 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: SEP descr_1: S. ECLIPTIC POLE (NOMINAL) WITH +V3 TO SUN pos_1: RA = 270.0D +/- .1", pos_2: DEC = -66.500D +/- .01" equinox: 1991 ! ! 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: CYCLE 1/ 1-9; req_2: SEQ 1-9 NO GAP; comment_1: SLEW TO TARGET +V3 SUNPOINT WITHIN comment_2: 5 DEG. (NOMINAL ROLL) ! linenum: 2.000 targname: SEP config: S/C opmode: DATA aperture: V1 num_exp: 1 time_per_exp: 20M fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO req_1: RT ANALYSIS; req_2: REQ UPLINK; comment_1: ETR AND TLMDIAGS CONFIGURED VIA RTC comment_2: P FORMAT SELECTED VIA MOC MERGE, comment_3: FORWARD LINK MUST BEGIN 25 MINUTES comment_4: PRIOR TO EOD. ORBIT 1 ! linenum: 3.000 targname: SEP config: S/C opmode: POINTING aperture: V1 num_exp: 1 time_per_exp: 1S fluxnum_1: 1 priority: 1 param_1: CONTROL=FGS comment_1: FINE LOCK ACQ. 5M PRIOR TO EOD AND comment_2: REMAIN IN LOCK UNINTERRUPTED UNTIL comment_3: 10M AFTER EON VIA SPC (ORBIT 1) ! linenum: 4.000 targname: SEP config: S/C opmode: DATA aperture: V1 num_exp: 1 time_per_exp: 20M fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO req_1: REQ UPLINK; req_2: RT ANALYSIS; req_3: AFTER 3 BY 1M +/- 1M comment_1: SELECT SAGA-II VIA RTC comment_2: FORWARD LINK MUST BEGIN comment_3: 20M PRIOR TO EOD (ORBIT 2) ! linenum: 5.000 targname: SEP config: S/C opmode: POINTING aperture: V1 num_exp: 1 time_per_exp: 1S fluxnum_1: 1 priority: 1 param_1: CONTROL=FGS comment_1: COURSE TRACK ACQ. 5M PRIOR TO comment_2: EOD AND REMAIN IN TRACK UNINTER- comment_3: RUPTED UNTIL 10M AFTER EON VIA comment_4: SPC (ORBIT 3). ! linenum: 6.000 targname: SEP config: S/C opmode: POINTING aperture: V1 num_exp: 1 time_per_exp: 1S fluxnum_1: 1 priority: 1 param_1: CONTROL=FGS comment_1: FINE LOCK ACQ. 5M PRIOR EOD AND comment_2: REMAIN UNINTERRUPTED 10M AFTER comment_3: EON VIA SPC (ORBIT 4). ! linenum: 7.000 targname: ANTI-SUN 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: AFTER 6 BY 0.5M +/- 0.5M comment_1: SLEW TO -V1 SUNPOINT WITHIN 5 comment_2: DEG. SLEW MUST BEGIN 10M AFTER comment_3: EON (ORBIT 4). ! linenum: 8.000 targname: ANTI-SUN config: S/C opmode: POINTING aperture: V1 num_exp: 1 time_per_exp: 1S fluxnum_1: 1 priority: 1 param_1: CONTROL=FGS comment_1: FINE LOCK ACQ. ASAP AFTER V1 comment_2: LEAVES EARTH OCCULTATION AND comment_3: REMAIN UNINTERRUPTED UNTIL V1 comment_4: OCCULTS VIA SPC (ORBIT 5). ! linenum: 9.000 targname: ANTI-SUN config: S/C opmode: DATA aperture: V1 num_exp: 1 time_per_exp: 20M fluxnum_1: 1 priority: 1 param_1: CONTROL=GYRO req_1: REQ UPLINK; req_2: RT ANALYSIS; req_3: AFTER 8 BY 0.5M +/- 0.5M comment_1: RESTORE SAGA-GA, RECONFIGURE comment_2: S/C FOR NORMAL OPERATIONS comment_3: (ORBIT 5) ! ! end of exposure logsheet ! No scan data records found