16712( 6) - 11-Nov-2021 15:21:50 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16712 Version: 6 Check-in Time: 11-Nov-2021 15:21:50 STScI Edit Number: 2 Title Constraining the Orbit of Eurybates' Satellite, Queta ------------------------------------------------------------------------------------ Type Cycle GO 29 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Keith S. Noll NASA Goddard Space Flight Center Y CoI: Dr. Michael E Brown California Institute of Technology N CoI: Dr. Harold F. Levison Southwest Research Institute N CoI: Dr. Harold A. Weaver The Johns Hopkins University Applied N Physics Laboratory CoI: Dr. Catherine Olkin Southwest Research Institute N CoI: Dr. Simone Marchi Southwest Research Institute N CoI: Dr. Will M. Grundy Lowell Observatory N CoI: Dr. John R. Spencer Southwest Research Institute N CoI: Dr. Thomas Statler NASA Headquarters N CoI: Dr. Richard P. Binzel Massachusetts Institute of Technology N CoI: Dr. Marc W. Buie Southwest Research Institute N CoI: Dr. S. Alan Stern Southwest Research Institute N ------------------------------------------------------------------------------------ Abstract (3548) Eurybates will be the first Trojan asteroid to be explored in situ when the Lucy spacecraft flies by it in August 2027. The possibility of close-up study of Eurybates' satellite, Queta, offers a unique opportunity to test whether Eurybates' unusual properties are tied to its collisional history and, more broadly, how collisional evolution shapes small body populations. It is critical to reduce the orbital uncertainty and improve knowledge of the relative position of Queta as soon as possible to understand if there could be an impact to Lucy's encounter concept of operations and to optimize planning for the best angular resolution and lighting conditions in the brief window when observations can be made. By establishing a tighter constraint on the current orbit, it will be possible to accelerate searches for non-Keplerian motion should there be an additional satellite or satellites interior to Queta (as are commonly found in other collisional-family satellite systems). Additionally, we will use astrometric information from trailed stars in the full UVIS aperture to improve predictions for future stellar occultations. HST is required because Queta is 8.7 magnitudes fainter than Eurybates and will be observed at a separation of 0.5 arcsec - an observational regime that is unique to Hubble. ------------------------------------------------------------------------------------ Observations Description ------------------------ This proposal is two orbits of astrometric observations of the satellite of Eurybates. It is intended to execute the orbits at known orbital phase to maximize the improvement in orbit determination needed to validate spacecraft pointing on approach. Each one - orbit visit will be identical 5 exposure sequence using the full WFC3 UVIS FOV to enable absolute astrometry with field stars as well as relative astrometry determined by measuring the positions of 16712( 6) - 11-Nov-2021 15:21:50 - [ 2] Eurybates and Queta. ------------------------------------------------------------------------------------ 16712( 6) - 11-Nov-2021 15:21:50 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 TARGET NAME: EURYBATES ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: ASTEROID Queta is a satellite of Eurybates ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 TYPE=ASTEROID, A=5.194825660909952, E=0.08892019463262771, I=8.05897310596958 , O=43.53959194136358, W=27.42986950746389, M=279.393486820639, EQUINOX=J2000, EPOCH=05-AUG-2019:00:00:00, EpochTimeScale=TDB ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 16.6 +/- 0.4 Ephemeris Center: EARTH ------------------------------------------------------------------------------------------------------------------------------------ 16712( 6) - 11-Nov-2021 15:21:50 - [ 4] Visit: 01 Visit Requirements: BETWEEN 16-DEC-2021:12:00:00 AND 18-DEC-2021:12:00:00; VISIBILITY INTERVAL NO GYRO BIAS UPDATE ON MOVING TARGET On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 EURYBATES WFC3/UVI ACCUM UVIS2 F350LP 1 370 S (370 POS TARG 0.6544, 0.6796; S S) SEQ 1-5 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 2 EURYBATES WFC3/UVI ACCUM UVIS2 F350LP 1 370 S (370 POS TARG 0.4760, 0.5286 S S) ------------------------------------------------------------------------------------------------------------------------------------ 3 EURYBATES WFC3/UVI ACCUM UVIS2 F350LP 1 370 S (370 POS TARG 0.3437, 0.3674 S S) ------------------------------------------------------------------------------------------------------------------------------------ 4 EURYBATES WFC3/UVI ACCUM UVIS2 F350LP 1 370 S (370 POS TARG 0.1719, 0.1837 S S) ------------------------------------------------------------------------------------------------------------------------------------ 5 EURYBATES WFC3/UVI ACCUM UVIS2 F350LP 1 370 S (370 S S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ EURYBATES 1 WFC3/UVI ACCUM UVIS2 F350LP none none none none 1 N/A S EURYBATES 2 WFC3/UVI ACCUM UVIS2 F350LP none none none none 1 N/A S EURYBATES 3 WFC3/UVI ACCUM UVIS2 F350LP none none none none 1 N/A S EURYBATES 4 WFC3/UVI ACCUM UVIS2 F350LP none none none none 1 N/A S EURYBATES 5 WFC3/UVI ACCUM UVIS2 F350LP none none none none 1 N/A S 16712( 6) - 11-Nov-2021 15:21:50 - [ 5] Visit: 02 Visit Requirements: BETWEEN 24-NOV-2021:12:00:00 AND 26-NOV-2021:12:00:00; VISIBILITY INTERVAL NO GYRO BIAS UPDATE ON MOVING TARGET On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 EURYBATES WFC3/UVI ACCUM UVIS2 F350LP 1 370 S (370 SEQ 1-5 NON-INT S S) ------------------------------------------------------------------------------------------------------------------------------------ 2 EURYBATES WFC3/UVI ACCUM UVIS2 F350LP 1 370 S (370 POS TARG 0.1719, 0.1837 S S) ------------------------------------------------------------------------------------------------------------------------------------ 3 EURYBATES WFC3/UVI ACCUM UVIS2 F350LP 1 370 S (370 POS TARG 0.3437, 0.3674 S S) ------------------------------------------------------------------------------------------------------------------------------------ 4 EURYBATES WFC3/UVI ACCUM UVIS2 F350LP 1 370 S (370 POS TARG 0.4760, 0.5286 S S) ------------------------------------------------------------------------------------------------------------------------------------ 5 EURYBATES WFC3/UVI ACCUM UVIS2 F350LP 1 370 S (370 POS TARG 0.6544, 0.6796 S S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ EURYBATES 1 WFC3/UVI ACCUM UVIS2 F350LP none none none none 1 N/A S EURYBATES 2 WFC3/UVI ACCUM UVIS2 F350LP none none none none 1 N/A S EURYBATES 3 WFC3/UVI ACCUM UVIS2 F350LP none none none none 1 N/A S EURYBATES 4 WFC3/UVI ACCUM UVIS2 F350LP none none none none 1 N/A S EURYBATES 5 WFC3/UVI ACCUM UVIS2 F350LP none none none none 1 N/A S 16712( 6) - 11-Nov-2021 15:21:50 - [ 6] Summary Form for Proposal 16712 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures UVIS2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC3/UVIS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements BETWEEN 16-DEC-2021:12:00:00 AND 18-DEC-2021:12:00:00, BETWEEN 24-NOV-2021:12:00:00 AND 26-NOV-2021:12:00:00, POS TARG 0.1719, 0.1837, POS TARG 0.3437, 0.3674, POS TARG 0.4760, 0.5286, POS TARG 0.6544, 0.6796, SEQ 1-5 NON-INT, VISIBILITY INTERVAL NO GYRO BIAS UPDATE ON MOVING TARGET ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F350LP ------------------------------------------------------------------------------------------------------------------------------------ Target Names EURYBATES ------------------------------------------------------------------------------------------------------------------------------------