16770( 11) - 27-Oct-2021 18:16:37 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 16770 Version: 11 Check-in Time: 27-Oct-2021 18:16:37 STScI Edit Number: 6 Title The return of Rosetta's comet 67P/Churyumov-Gerasimenko ------------------------------------------------------------------------------------ Type Cycle GO 29 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Dennis Bodewits Auburn University Y CoI: Dr. Jian-Yang Li Planetary Science Institute Y CoI: John W Noonan University of Arizona Y CoI: Dr. Kathleen Mandt The Johns Hopkins University Applied N Physics Laboratory CoI: Dr. Davide Farnocchia Jet Propulsion Laboratory N CoI: Dr. Walter M. Harris University of Arizona N CoI: Dr. Kumar Venkataramani Auburn University N CoI: Zexi Xing University of Hong Kong N ------------------------------------------------------------------------------------ Abstract We request 4 orbits of HST STIS and COS observations of comet 67P/Churyumov-Gerasimenko (hereafter 67P) during its close approach to Earth to obtain large-scale coma measurements for direct comparison with the localized Rosetta spacecraft results. We will measure the bulk production rates (mol/s) of the main volatiles (H2O, CO2, and CO), search for extended sources of volatiles in the coma, and investigate the sulphur chemistry of 67P. HST's sensitivity and spectroscopic abilities in the Far Ultraviolet make it uniquely capable to simultaneously measure the Far-Ultraviolet atomic and molecular emission of chemically coupled or otherwise interdependent species in the 100-15, 000 km of the coma (i.e. CS, S, and S2 ; CO, CO2+ and OH). Observations that can connect the results for the inner coma with that of fragment species more typically observed at scales of 1000s of km (A'Hearn 2017) are essential to interpret large surveys of chemical abundances of comets. The details of how comets formed still need to be worked out by the modellers, but we need to make sure that the inputs for those models have had observational biases removed. The observation should be executed between October 14 and December 20, 2021, which brackets the close approach of the comet to Earth on November 2 at 0.42 au. We plan to dedicate two consecutive orbits for exposures with STIS G230L exposures, and two consecutive orbits for exposures with COS G160M. The STIS exposures and COS exposures should be executed within one week. For the STIS observations, we request that the slit orientation is aligned within 30 deg perpendicular to the sun-comet direction, which is allowed by the HST roll angle range during our observing window. ------------------------------------------------------------------------------------ Observations Description ------------------------ We plan to observe comet 67P/Churyumov-Gerasimenko for a total of 4 orbits, split between the STIS and COS instruments. Timing requirements: We request that the observations are acquired around 16770( 11) - 27-Oct-2021 18:16:37 - [ 2] closest approach at 0.42 AU on UT Nov. 2, 2021, but allow for a window of 2 months because the 2021 apparition of the comet is very favorable and the comet remains within 0.45 AU from Earth between Oct. 14 - Dec. 20, 2021, during which the brightness only varies between v ~ 10.14 to 10.85 mag. Although we request that the exposures are acquired close in time to each other so that we can add them together to improve the SNR, we do not require that all exposures are acquired in consecutive orbits, conforming to the limit of 2 consecutive orbits for observations of moving targets for Cycle 29. Instead, we request that the 2 STIS exposures are acquired back-to-back and that the 2 COS exposures are also acquired back-to-back within a week of the STIS exposures. VIsibility: While 67P is relatively nearby during its closest approach at 0.4 au, it's apparent motion on the sky is about 136 arcsec/motion, which is well within HST's tracking capabilities. During the window UT Oct. 14, 2021 - Dec. 20, 2021, the comet is far outside the solar constraint with a solar elongation between 110-136 degrees. The comet is within the lunar constraint of 9 degrees on Oct. 26 - 27, 2021, and Nov. 24 - 25, and these days should be avoided. Observation design: A: We will use 2 orbits of STIS G230L/NUV-MAMA centered at 2376 A with a 52x0.5 arcsec aperture to get OH at 2835 A and 3085 A; CS at 2576 A; CO2+ at 2890 A, and S2 between 2830-3050 A. We would like to orient the STIS long slit close to the perpendicular direction with respect to the sun-comet line, in order to create a spatial profile of the gas distribution. Based on the ephemeris of 67P in October 2021 and the APT Phase II planning tool, the permitted range of roll angles for HST when pointing at 67P is about 230 - 290 deg, allowing the slit to be oriented within 30 deg of our desired orientation, which is about 185 deg position angle (east of north). Each orbit will consist of an ACQ image, a spectroscopic exposure, and finished by direct imaging for context. Because we do not need more than two consecutive orbits, we will disable moving target gyro bias update to maximize visibility time. B: 2 orbits of COS/FUV G160M center 1623 A, to detect the SI multiplets at 1667 A and 1479 A; to detect the CO Fourth Positive Group emission features (1400 - 1700 A), and to detect the CI features at 1561 A and 1657 A. Each orbit will consist of an ACQ and two exposures with two different FP-POS. We will disable moving target gyro bias update to maximize visibility time for these two orbits as well. Target aquisition: The 3-sigma ephemerise uncertainty of target during our observing window is up to 1.2" based on JPL Horizons, which is well within the target acquisition region for both STIS and COS. There is no need to use ACQ/SEARCH for COS. ------------------------------------------------------------------------------------ 16770( 11) - 27-Oct-2021 18:16:37 - [ 3] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 TARGET NAME: 67P-CHURYUMOV-GERASIMENKO ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: COMET Comet 67P/Churyumov-Gerasimenko ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 TYPE=COMET, Q=1.210613814968979, E=0.649713733698611, I=3.871753825377044 , O=36.33518841638918, W=22.13089737728478, T=02-NOV-2021:01:28:47, TTimeScale=TDB, EQUINOX=J2000, EPOCH=18-OCT-2021:00:00:00, EpochTimeScale=TDB ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 11 +/- 1 Ephemeris Center: EARTH Extended: YES ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 TARGET NAME: 67P-CHURYUMOV-GERASIMENKO-V5 ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: COMET Comet 67P/Churyumov-Gerasimenko ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 TYPE=COMET, Q=1.210613663849778, E=0.649700834587701, I=3.871699730539964 , O=36.33530311531698, W=22.13248241862631, T=02-NOV-2021:01:31:23, TTimeScale=TDB, EQUINOX=J2000, EPOCH=15-NOV-2021:00:00:00, EpochTimeScale=TDB ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 11 +/- 1 Ephemeris Center: EARTH Ephemeris Uncertainty: 3000 KM Extended: YES 16770( 11) - 27-Oct-2021 18:16:37 - [ 4] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------------------------------------------ 16770( 11) - 27-Oct-2021 18:16:37 - [ 5] Visit: 01 (STIS G230L) Visit Requirements: ORIENT 220D TO 260 D; BETWEEN 14-OCT-2021:00:00:00 AND 20-DEC-2021:00:00:00; 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 67P-CHURYUM STIS/CCD ACQ F28X50LP MIRROR 1 2 S (2 S) SEQ 1-3 NON-INT OV-GERASIME NKO ------------------------------------------------------------------------------------------------------------------------------------ 2 67P-CHURYUM STIS/NUV ACCUM 52X0.5 G230L 2376 1 1600 S OV-GERASIME -MAMA (1600 S) NKO ------------------------------------------------------------------------------------------------------------------------------------ 3 67P-CHURYUM STIS/CCD ACCUM F28X50LP MIRROR 1 2 S (2 S) OV-GERASIME NKO ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 67P-CHURYUMOV-GERAS 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A IMENKO 67P-CHURYUMOV-GERAS 2 STIS/NUV ACCUM 52X0.5 G230L 2376 none none none none 1 N/A IMENKO -MAMA 67P-CHURYUMOV-GERAS 3 STIS/CCD ACCUM F28X50LP MIRROR none none none 1 1 N/A IMENKO 67P-CHURYUMOV-GERAS 3 STIS/CCD ACCUM F28X50LP MIRROR none none none 2 1 N/A IMENKO 16770( 11) - 27-Oct-2021 18:16:37 - [ 6] Visit: 02 (STIS G230L) Visit Requirements: SAME ORIENT AS 01; AFTER 01 BY 0.8 Orbits TO 1.2 Orbits; BETWEEN 14-OCT-2021:00:00:00 AND 20-DEC-2021:00:00:00; 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 67P-CHURYUM STIS/CCD ACQ F28X50LP MIRROR 1 2 S (2 S) SEQ 1-3 NON-INT OV-GERASIME NKO ------------------------------------------------------------------------------------------------------------------------------------ 2 67P-CHURYUM STIS/NUV ACCUM 52X0.5 G230L 2376 1 1600 S OV-GERASIME -MAMA (1600 S) NKO ------------------------------------------------------------------------------------------------------------------------------------ 3 67P-CHURYUM STIS/CCD ACCUM F28X50LP MIRROR 1 2 S (2 S) OV-GERASIME NKO ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 67P-CHURYUMOV-GERAS 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A IMENKO 67P-CHURYUMOV-GERAS 2 STIS/NUV ACCUM 52X0.5 G230L 2376 none none none none 1 N/A IMENKO -MAMA 67P-CHURYUMOV-GERAS 3 STIS/CCD ACCUM F28X50LP MIRROR none none none 1 1 N/A IMENKO 67P-CHURYUMOV-GERAS 3 STIS/CCD ACCUM F28X50LP MIRROR none none none 2 1 N/A IMENKO 16770( 11) - 27-Oct-2021 18:16:37 - [ 7] Visit: 03 (COS G160M) Visit Requirements: AFTER 02 BY 0.01 D TO 7 D; BETWEEN 14-OCT-2021:00:00:00 AND 20-DEC-2021:00:00:00; 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 67P-CHURYUM COS/NUV ACQ/IMA PSA MIRRORA 1 20 S (20 SEQ 1-3 NON-INT OV-GERASIME GE S) NKO ------------------------------------------------------------------------------------------------------------------------------------ 2 67P-CHURYUM COS/FUV TIME-TA PSA G160M 1623 BUFFER-TIME=10000, FP-POS=1 1 885 S (885 OV-GERASIME G S) NKO ------------------------------------------------------------------------------------------------------------------------------------ 3 67P-CHURYUM COS/FUV TIME-TA PSA G160M 1623 BUFFER-TIME=10000, FP-POS=2 1 885 S (885 OV-GERASIME G S) NKO ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 67P-CHURYUMOV-GERAS 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A IMENKO GE 67P-CHURYUMOV-GERAS 2 COS/FUV TIME-TA PSA G160M 1623 none none none none 1 N/A IMENKO G 67P-CHURYUMOV-GERAS 3 COS/FUV TIME-TA PSA G160M 1623 none none none none 1 N/A IMENKO G 16770( 11) - 27-Oct-2021 18:16:37 - [ 8] Visit: 04 (COS G160M) Visit Requirements: AFTER 03 BY 0.8 Orbits TO 1.2 Orbits; BETWEEN 14-OCT-2021:00:00:00 AND 20-DEC-2021:00:00:00; 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 67P-CHURYUM COS/NUV ACQ/IMA PSA MIRRORA 1 20 S (20 SEQ 1-3 NON-INT OV-GERASIME GE S) NKO ------------------------------------------------------------------------------------------------------------------------------------ 2 67P-CHURYUM COS/FUV TIME-TA PSA G160M 1623 BUFFER-TIME=10000, FP-POS=3 1 885 S (885 OV-GERASIME G S) NKO ------------------------------------------------------------------------------------------------------------------------------------ 3 67P-CHURYUM COS/FUV TIME-TA PSA G160M 1623 BUFFER-TIME=10000, FP-POS=4 1 885 S (885 OV-GERASIME G S) NKO ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 67P-CHURYUMOV-GERAS 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A IMENKO GE 67P-CHURYUMOV-GERAS 2 COS/FUV TIME-TA PSA G160M 1623 none none none none 1 N/A IMENKO G 67P-CHURYUMOV-GERAS 3 COS/FUV TIME-TA PSA G160M 1623 none none none none 1 N/A IMENKO G 16770( 11) - 27-Oct-2021 18:16:37 - [ 9] Visit: 05 (STIS G230L) Visit Requirements: ORIENT 220D TO 260 D; BETWEEN 14-OCT-2021:00:00:00 AND 20-DEC-2021:00:00:00; 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 67P-CHURYUM STIS/CCD ACQ F28X50LP MIRROR 1 2 S (2 S) REQ EPHEM CORR 000001; OV-GERASIME SEQ 1-3 NON-INT NKO-V5 ------------------------------------------------------------------------------------------------------------------------------------ 2 67P-CHURYUM STIS/NUV ACCUM 52X0.5 G230L 2376 1 1600 S REQ EPHEM CORR 000001 OV-GERASIME -MAMA (1600 S) NKO-V5 ------------------------------------------------------------------------------------------------------------------------------------ 3 67P-CHURYUM STIS/CCD ACCUM F28X50LP MIRROR 1 2 S (2 S) REQ EPHEM CORR 000001 OV-GERASIME NKO-V5 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 67P-CHURYUMOV-GERAS 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A IMENKO-V5 67P-CHURYUMOV-GERAS 2 STIS/NUV ACCUM 52X0.5 G230L 2376 none none none none 1 N/A IMENKO-V5 -MAMA 67P-CHURYUMOV-GERAS 3 STIS/CCD ACCUM F28X50LP MIRROR none none none 1 1 N/A IMENKO-V5 67P-CHURYUMOV-GERAS 3 STIS/CCD ACCUM F28X50LP MIRROR none none none 2 1 N/A IMENKO-V5 16770( 11) - 27-Oct-2021 18:16:37 - [ 10] Visit: 06 (STIS G230L) Visit Requirements: SAME ORIENT AS 05; AFTER 05 BY 0.8 Orbits TO 1.2 Orbits; BETWEEN 14-OCT-2021:00:00:00 AND 20-DEC-2021:00:00:00; 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 67P-CHURYUM STIS/CCD ACQ F28X50LP MIRROR 1 2 S (2 S) REQ EPHEM CORR 000001; OV-GERASIME SEQ 1-3 NON-INT NKO-V5 ------------------------------------------------------------------------------------------------------------------------------------ 2 67P-CHURYUM STIS/NUV ACCUM 52X0.5 G230L 2376 1 1600 S REQ EPHEM CORR 000001 OV-GERASIME -MAMA (1600 S) NKO-V5 ------------------------------------------------------------------------------------------------------------------------------------ 3 67P-CHURYUM STIS/CCD ACCUM F28X50LP MIRROR 1 2 S (2 S) REQ EPHEM CORR 000001 OV-GERASIME NKO-V5 ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ 67P-CHURYUMOV-GERAS 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A IMENKO-V5 67P-CHURYUMOV-GERAS 2 STIS/NUV ACCUM 52X0.5 G230L 2376 none none none none 1 N/A IMENKO-V5 -MAMA 67P-CHURYUMOV-GERAS 3 STIS/CCD ACCUM F28X50LP MIRROR none none none 1 1 N/A IMENKO-V5 67P-CHURYUMOV-GERAS 3 STIS/CCD ACCUM F28X50LP MIRROR none none none 2 1 N/A IMENKO-V5 16770( 11) - 27-Oct-2021 18:16:37 - [ 11] Summary Form for Proposal 16770 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.5, F28X50LP, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV, STIS/CCD, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=10000, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 0.8 Orbits TO 1.2 Orbits, AFTER 02 BY 0.01 D TO 7 D, AFTER 03 BY 0.8 Orbits TO 1.2 Orbits, AFTER 05 BY 0.8 Orbits TO 1.2 Orbits, BETWEEN 14-OCT-2021:00:00:00 AND 20-DEC-2021:00:00:00, ORIENT 220D TO 260 D, REQ EPHEM CORR 000001, SAME ORIENT AS 01, SAME ORIENT AS 05, SEQ 1-3 NON-INT, VISIBILITY INTERVAL NO GYRO BIAS UPDATE ON MOVING TARGET ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G160M, G230L, MIRROR, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names 67P-CHURYUMOV-GERASIMENKO, 67P-CHURYUMOV-GERASIMENKO-V5 ------------------------------------------------------------------------------------------------------------------------------------