0 Assigned ID: 3246 ----- Attempting Submission 1 (Fri Mar 25 14:36:01 GMT 2022) ----- HST Phase I Proposal 3246 successfully submitted. Receipt: # 3246-1 ----- Attempting Submission 2 (Fri Mar 25 19:58:19 GMT 2022) ----- HST Phase I Proposal 3246 successfully submitted. Receipt: # 3246-2 ----- Attempting Submission 3 (Fri Mar 25 21:27:39 GMT 2022) ----- Modified dither patterns to adopt standard parameters -522465070 ----- Attempting Submission 1 (Tue Jul 12 17:29:21 GMT 2022) ----- ----- Attempting Submission 2 (Tue Aug 02 20:13:18 GMT 2022) ----- We propose to obtain high spatial resolution imaging polarimetry of the surface of Europa to localize features in the polarization phase curve which are diagnostic of fresh deposition, sintering and aging, allowing identification of regions of recent cryovolcanism and subsurface activity. We will seek a relationship between polarization and global thermal inertia maps, and between polarization and spectroscopically distinct compositional units. Polarization and thermal inertia probe regolith porosity, surface transparency, composition and topography, while spectroscopically distinct regions relate to absorbing chemical admixtures. The overall global polarization pattern will constrain the systematic ice scattering characteristics. This polarimetric suite of high-resolution HST images, with its unique emphasis on surface physics, will complement the wide variety of upcoming observations from major flagship missions JWST, Europa Clipper, JUICE and Juno as well as thermal ALMA imaging. With Europa and its global saline ocean at the forefront of strategic planning for NASA and ESA as a target of exceptional astrobiological importance, it is essential to advance our understanding of the Europa surface to the maximum. We will acquire ACS polarization images of both the leading and trailing hemispheres of Europa at two different phase angles using the F435W filter. Each visit comprises two orbits. The first pair of visits will be obtained as close as possible and the second at a phase angle within 5-10 degrees. Dr. William Sparks is P.I. on several successful HST programs aimed at seeking plumes on Europa including a major program in a dedicated HST Europa plume campaign currently in analysis. He has extensive experience of HST instrumentation and was deputy head of the Instrument Division at STScI. As a member of the ACS Science Definition team, his primary responsibility was the implementation of the polarimetric capability. Now at the SETI Institute (STScI emeritus), he continues research on Europa and instrumentation for polarimetry. Dr. Ludmilla Kolokolova is Principal Research Scientist at the Small Bodies group, University of Maryland. She is an expert in light scattering by surfaces and dust particles. Her principal experience is in the computer modeling of photometric and polarimetric characteristics of the solar system objects with a focus on comets and satellites of giant planets, which are required for the interpretation of the observations. Dr. Melissa McGrath is an internationally recognized expert on the Galilean satellite exospheres and aurora. She was a co-investigator and author on the Europa plume discovery paper (Roth et al. 2014a), and has led and participated in numerous space- and ground-based mission and observing programs to study the Io, Europa, Ganymede and Callisto exospheres. She has first-authored two major review book chapters (McGrath et al. 2004; McGrath et al. 2009) and is a co-I on the Ultraviolet Spectrometer instrument on the ESA JUICE mission to Ganymede, as well as a Co-investigator on two instruments selected for NASA's Europa Multiple Flyby Mission (UVS and MASPEX), Europa Clipper. Dr. McGrath will participate and advise throughout. Dr. Kevin Hand, Deputy Chief Scientist for Solar System Exploration at JPL, is a planetary scientist working on laboratory investigations, numerical modeling and ground based observations relating to the physics and chemistry of icy moons in the outer solar system. His specialty is the spectroscopy and spectrometry of radiation processed ices that simulate the surfaces of ice-covered moons of the outer solar system. Hand has served on the Science Definition Teams for Europa Flagship mission studies and is leading studies of the Europa lander option for NASA. He is a co-author on Keck compositional mapping papers. Dr. John Grunsfeld is an astrophysicist and a former NASA astronaut. He is a veteran of five Space Shuttle flights and has served as NASA Chief Scientist and Associate Administrator for Science. He is strongly committed to furthering exploration of Europa and its ocean, and contributes his in-depth knowledge of Europa, its context and implications of our observations for NASA strategic planning. He also developed and implemented on-orbit the EVA fix for the failed power supply on ACS, and previously led the mission that installed ACS. Dr. Olivier Poch, CNRS researcher at IPAG, studies the composition and evolution of surfaces of Solar System bodies, to understand their origin, evolution and possible habitability, using spectroscopic and polarimetric observations. He develops laboratory experiments and protocols aiming at simulating the compositional and textural complexity of extra-terrestrial surfaces, such as small bodies and icy satellites, made of mixtures of ices, salts, as well as organic and mineral compounds. These empirical measurements will be an important asset in interpreting our results (Poch et al., 2018). Dr. Thomas Germer, is a physicist at the National Institute of Standards and Technology. His research interests focus on optical properties of materials, especially bidirectional reflectance distribution function (BRDF) measurements and modeling. Current research interests include the exploration of optical scattering techniques for evaluating and characterizing surfaces; the development of Mueller matrix light scattering methods; development and application of theoretical methods for determining the polarization of scattered light; and instrument design. He authored the SCATMECH library, which catalogues a wide variety of light scattering theories and models with an emphasis on polarization prediction. Louis (Eddie) Bergeron is a highly skilled member of the STScI technical staff, with exceptional knowledge of the HST systems including scheduling and tracking. He has previously worked with the P.I. in both technical and scientific capacity, on polarimetry analysis from NICMOS and the VLT/FORS, and observations aimed at seeking evidence of plumes on Europa. Dr. Daniel Cotton is a Research Astronomer specializing in precision polarimetry and radiative transfer modelling of planets. He contributed to the development of the world's most precise optical astronomical polarimeters (HIPPI/-2), and was responsible for the development of its reduction software. He will contribute his expert knowledge to data processing and interpretation, and contribute to acquisition and provision of precision ground-based disk integrated polarimetry to complement the HST observations. Dr. Jeremy Bailey is a world-renowned expert in polarimetry, astrobiology and planetary and stellar atmospheric modelling. He designed and built HIPPI (Bailey, et al. 2015), the world's most sensitive stellar polarimeter. He has authored 270+ scientific papers including a seminal paper using polarimetry to reveal the handedness of molecules in star forming regions and the implications for life (Bailey et al. 1998). He will contribute his expert knowledge to the data acquisition, processing and interpretation, and guide efforts to acquire ground-based disk integrated precision polarimetry to complement the HST observations. Dr. Kimberly Bott is an expert in polarized reflected light modelling with VSTAR, a model capable of computing the full Stokes radiative transfer of icy surfaces, including mixed composition icy surfaces under thin atmospheres. She has used VSTAR previously to model terrestrial and gaseous worlds, and is currently improving the treatment for icy and other solid surfaces to be more precise, incorporating recent advancements in the description of their polarized reflectance behaviour. She has experience with observations of Solar System objects, and polarimetric observations. Solar System Astronomy 6 false false false false false false false AVAILABLE SOLAR SYSTEM SATELLITE Europa STD=JUPITER STD=EUROPA NOT OCC OF EUROPA-L BY JUPITER FROM EARTH, SEP OF EUROPA-L IO FROM EARTH GT 10", SEP OF EUROPA-L GANYMEDE FROM EARTH GT 10", SEP OF EUROPA-L CALLISTO FROM EARTH GT 10", OLG OF EUROPA-L FROM EARTH BETWEEN 30 150 EARTH SOLAR SYSTEM SATELLITE Europa STD=JUPITER STD=EUROPA NOT OCC OF EUROPA-T BY JUPITER FROM EARTH, SEP OF EUROPA-T IO FROM EARTH GT 10", SEP OF EUROPA-T GANYMEDE FROM EARTH GT 10", SEP OF EUROPA-T CALLISTO FROM EARTH GT 10", OLG OF EUROPA-T FROM EARTH BETWEEN 210 330 EARTH ACS/WFC Imaging No Yes F435W ACS/WFC Imaging No Yes F435W ACS/WFC Imaging No Yes F435W ACS/WFC Imaging No Yes F435W POS-TARG DITHER 0.17 LINE false false 3 47.23 ACS-WFC-DITHER-LINE 1 false POS-TARG DITHER 0.149 LINE false false 2 34.25 ACS-WFC-DITHER-LINE 2 false 1659470880404 Using ephemeris for target 17163-01-EUROPA-L The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. 1663621704000 287.409430674386 (Tic-Visit :proposal-id 17163 :visit-id "01" :proposal-version -1 :trans-version "20220516" :date "02-Aug-2022 16:07:59.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1279376 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17163 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17163 :visit-id "01" :orbit-number 1 :pcs-time 393 :si-vis-utilization 1906 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17163 :visit-id "01" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2368 :al-overhead-at-end 0 :internal-dur-at-end 269 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) true 2 0 1659470882746 Using ephemeris for target 17163-02-EUROPA-T The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. 1663193411000 258.13562173237494 (Tic-Visit :proposal-id 17163 :visit-id "02" :proposal-version -1 :trans-version "20220516" :date "02-Aug-2022 16:08:02.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1279376 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17163 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17163 :visit-id "02" :orbit-number 1 :pcs-time 393 :si-vis-utilization 1906 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17163 :visit-id "02" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2368 :al-overhead-at-end 0 :internal-dur-at-end 269 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) true 2 0 1659470884945 Using ephemeris for target 17163-03-EUROPA-L The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. 1667032666000 59.184446218848706 (Tic-Visit :proposal-id 17163 :visit-id "03" :proposal-version -1 :trans-version "20220516" :date "02-Aug-2022 16:08:04.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1279376 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17163 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17163 :visit-id "03" :orbit-number 1 :pcs-time 393 :si-vis-utilization 1906 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17163 :visit-id "03" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2368 :al-overhead-at-end 0 :internal-dur-at-end 269 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) true 2 0 1667333569620 Using ephemeris for target 17163-53-EUROPA-L ephemeris data for target 17163-53-EUROPA-L does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 22.226 to 24.182. ephemeris interval: 22.304 to 24.306 The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. /private/var/folders/8t/mg1bkfyj20xf2vfc_9vyhfs80006z1/T/OPVisit16392080292340654943.xml Duplicate of visit 03 which failed (Tic-Visit :proposal-id 17163 :visit-id "53" :proposal-version -1 :trans-version "20220630" :date "01-Nov-2022 16:12:49.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1279376 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17163 :visit-id "53" :obset-id "53" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17163 :visit-id "53" :orbit-number 1 :pcs-time 393 :si-vis-utilization 1906 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17163 :visit-id "53" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2368 :al-overhead-at-end 0 :internal-dur-at-end 269 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) true 2 0 1659470887600 Using ephemeris for target 17163-04-EUROPA-T The scheduling data was generated by CASM 30.3. CASM was run in Phase II mode. 1666609947000 61.29219669483339 (Tic-Visit :proposal-id 17163 :visit-id "04" :proposal-version -1 :trans-version "20220516" :date "02-Aug-2022 16:08:07.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "27" :si-bright-earth-limb-angle 20.0 :data-volume 1279376 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 17163 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 17163 :visit-id "04" :orbit-number 1 :pcs-time 393 :si-vis-utilization 1906 :al-overhead-at-end 0 :internal-dur-at-end 347 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) (Tic-Orbit :proposal-id 17163 :visit-id "04" :orbit-number 2 :pcs-time 392 :si-vis-utilization 2368 :al-overhead-at-end 0 :internal-dur-at-end 269 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2782 :pcs-gap 0 ) true 2 0