! File: 4353C.PROP ! Database: PEPDB ! Date: 20-FEB-1994:23:00:15 coverpage: title_1: HUBBLE SPACE TELESCOPE IMAGING OF IO: CYCLE3 HIGH sci_cat: SOLAR SYSTEM sci_subcat: SATELLITES proposal_for: GO pi_fname: MELISSA pi_mi: A. pi_lname: MCGRATH pi_inst: STSCI pi_country: USA hours_pri: 5.00 num_pri: 1 foc: Y funds_length: 12 off_fname: HERVEY off_mi: S. off_lname: STOCKMAN off_title: DEPUTY DIRECTOR off_inst: 3470 off_addr_1: 3700 SAN MARTIN DRIVE off_city: BALTIMORE off_state: MD off_zip: 21218 off_country: USA off_phone: 410-338-4700 ! end of coverpage abstract: line_1: Ultraviolet and visible disk-resolved images of Io are requested in line_2: cycle 3. The highest-priority goal is to obtain complete surface line_3: coverage of Io at ~2300 and 2600A for the purpose of determining line_4: the abundance and distribution of both surface and atmospheric line_5: constituents, especially sulfur dioxide (SO2). Images at 2600A line_6: will spectrally resolve the SO2 component to as great a degree line_7: as possible, while images at 2300A have been specifically chosen line_8: to aid in interpretation of spectroscopic measurements by dis- line_9: entangling the competing optical effects due to surface SO2 frost line_10: and possible patchy regions of thick atmospheric SO2 gas. These line_11: will also be used to search for evidence of recent or ongoing line_12: volcanic outburts such as active plumes on the limb or new line_13: surface patterns, or other significant long-term changes in line_14: surface albedo since the Voyager disk-resolved images line_15: in 1979. A critical component of the proposed program is the line_16: request for visible images in bandpasses as closely matching those line_17: of the Voyager UV and visible filters as possible, which will line_18: provide critical information about the relative calibration required line_19: to make quantitative comparisons. Our results will be made available line_20: to the Galileo team members for possible help in misson planning. ! ! end of abstract general_form_proposers: lname: MCGRATH fname: MELISSA title: PI mi: A. inst: STSCI country: USA ! lname: SARTORETTI fname: PAOLA inst: STSCI country: USA esa: Y ! lname: PARESCE fname: FRANCESCO inst: STSCI country: USA esa: Y ! lname: CLARKE fname: JOHN mi: T. inst: UNIVERSITY OF MICHIGAN country: USA ! lname: SPENCER fname: JOHN mi: R. inst: LOWELL OBSERVATORY country: USA ! lname: MCEWEN fname: ALFRED mi: S. inst: US GEOLOGICAL SURVEY country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: We request one set of Faint Object Camera images of Io using each of four line_2: filter combinations (F275W+F253M, effective wavelength 2600A; line_3: F220W+F231M, effective wavelength 2300A; F346M,F8ND, effective line_4: wavelength 3500A; F410M+F8ND, effective wavelength 4100A) line_5: near each of four orbital longitudes 45, 135, 225 and 315 degrees to insure line_6: complete surface coverage. At each longitude we would take one 15 minute line_7: exposure with each of three filters, and two second 15 minute exposures with line_8: the 2300A filter. ! question: 4 section: 1 line_1: The Hubble Space Telescope is the only instrument capable of providing line_2: disk-resolved imaging of Io ($\sim$1$''$ diameter) in the visible and UV line_3: at the present time. Until the first HST images were taken the Voyager line_4: encounters provided the only disk-resolved information on the distribution line_5: of surface components. However, the wavelength range of the Voyager images line_6: (3400-6000A) does not cover below the diagnostic \sot absorption edge at line_7: 3000\AA. Furthermore, this wavelength region will not be covered by the Galileo line_8: mission, so HST presents the only possibility for disk-resolved UV imaging line_9: for the forseeable future. line_11: Disk-integrated spectroscopic and photometric studies in both the UV line_12: and visible have been pursued extensively from the ground (Caldwell 1975; line_13: McFadden et al\. 1980; Clark and McCord 1980; Nelson et al\. 1987), line_14: and have provided a major framework for the present studies. However, line_15: disk-integrated studies allow major ambiguities to exist in interpretation of line_16: the data. For example, based on the disk-integrated geometric albedo line_17: derived from ground-based and IUE observations, two quite different models line_18: currently exist to explain the surface composition one which contends line_19: that elemental sulfur is a major surface constituent (Nash et al\. 1980), and line_20: (Hapke 1989). While the disk-integrated properties of these two quite line_21: different models are similar, their disk-resolved properties are quite line_22: different. Similarly, it is difficult to identify optically thick line_23: patches of atmosphere using disk-integrated measurements. ! question: 4 section: 2 line_1: Knowledge of the FOC filter responses, detector quantum efficiency, and the line_2: known spectrum of Io have been combined to accurately estimate the required line_3: exposure times. Preliminary cycle 0 and 1 imaging observations with the FOC line_4: have given us confidence that these estimates are accurate, and will provide line_5: count rates within the linear regime of the instrument. The 2300A image line_6: requires twice the amount of total integration time (30 min) to obtain a S/N line_7: of 6, which we recommend be done in two 15 minute integrations. For the line_8: visible images, we have chosen the FOC as opposed to the PC primarily based line_9: on the desire for a consistent data set using the same instrument at line_10: the same resolution (PC images would give ~1/2 the pixel size of the FOC line_11: images). While using the PC would result in far shorter integration times line_12: in the visible (of order seconds), much of the integration time saved would line_13: be wasted in overhead time required to switch instruments between exposures. line_14: It is therefore our judgement that the scientific advantages of a consistent line_15: data set, one of whose primary purposes is intercomparison, far outweigh line_16: the advantage of shorter visible integration times using the PC. ! question: 5 section: 1 line_1: Due to current health and safety restrictions on the FOC requiring verification line_2: of filter placement before exposing on a bright target, we have been forced to line_3: add special exposures and real time contacts before each new filter com- line_4: bination for each set of images. ! question: 6 section: 1 line_1: None ! question: 7 section: 1 line_1: We have assembled what we believe to be a highly qualified team to tackle line_2: the scientific objectives outlined in this proposal. We have represented on line_3: this team expertise in all aspects of the physical processes we are trying line_4: to understand, including volcanic activity (Spencer)m, surface composition and line_5: distribution of surface components (McEwen), the atmsphere and the torus line_6: (Clarke and McGrath). Furthermore, we have two co-Is who are expoert in use line_7: of the FOC (Paresce and Sartoretti) and have extensive previous experience line_8: in acquiring, reducing and publishing FOC data. Among us we have at our line_9: disposal SUN workstations, the extensive software libraries of STScI, line_10: previously developed software used to reduce and analyze FOC Io images, line_11: and existing models for the atmosphere and surface which will be thoroughly line_12: tested by the proposed observing program. We believe we are in a very line_13: strong position to produce some outstanding scientific results in a line_14: relatively short time after acquisition of the data. Finally, we have line_15: demonstrated by our previous cycle 0 and 1 observations the remarkable line_16: progress which can be made using HST to achieve the scientific objectives line_17: outlined above. line_19: Acquisition and reduction of the data will be handled primarily by Sartoretti line_20: at STScI, with the direct support and assistance of Paresce and McGrath. line_21: Detailed analysis, which will require careful coordination of the existing line_22: expertise and previous modeling, will be directed by the PI line_23: from STScI. ! question: 7 section: 2 line_1: Finally, we intend that our HST discoveries, from both the early line_2: observations as well as any in cycle 3, are considered in future mission line_3: planning, in particular that for the Galileo mission. HST discovery of active line_4: volcanic plumes or locations of atmospheric patchiness would surely influence line_5: observation decisions as well as data analysis. We have a direct connection line_6: with the Galileo SSI team through A. McEwen, who will also act line_7: as liason with other Galileo teams, especially NIMS. ! question: 8 section: 1 line_1: None ! question: 9 section: 1 line_1: {1.} GO 2627 - Io's Atmosphere and its Interaction with the Plasma Torus line_2: M. McGrath Co-I, related. line_4: {2.} GO 2625 - Excitation Processes for the Outer Planet UV Emissions, M. line_5: McGrath and J. Clarke Co-Is, unrelated. line_7: {3.} GO 3616 - The Upper Atmospheres of Uranus and Neptune, line_8: M. McGrath PI, unrelated. line_10: {4.} GO 3617 - The UV Emissions of Titan, M. McGrath PI, unrelated. line_12: {5.} GO 3618 - Excitation Processes for the Outer Planet UV Emissions-- line_13: Cycle 2 Continuation, M. McGrath PI, unrelated. line_15: {6.} DD 4005 - HST UV Imaging of Jupiter to Support the Interpretation line_16: of Ulysses Xray Measurements, M. McGrath Co-I, unrelated. line_18: {7.} GO 2602 - The Excitation of the Atmospheres of Planetary Satellites, line_19: J. Clarke PI, related. line_21: {8.} GO 2603 - Parallel Observations of H Ly alpha Emission from the line_22: Local ISM, J. Clarke PI, unrelated. ! question: 9 section: 2 line_1: {9.} GO 2393 - D/H Ratio of Venus and Mars from Lyman alpha Emission, line_2: J. Clarke, Co-I, unrelated. line_4: {10.} GO 3511 - H Ly alpha Dayglow Emission Line Profiles from the Outer line_5: Planets, J. Clarke PI, unrelated. line_7: {11.} GO 3862 - The Excitation of the Atmospheres of Planetary Satellites, line_8: J. Clarke PI, related. line_10: {12.} GTO 1253 - High Resolution Observations of Cataclysmic Variables, line_11: F. Paresce, unrelated. line_13: {13.} GTO 1269 - Far UV Observations of the Giant Planets, line_14: F. Paresce, related. ! question: 10 section: 1 line_1: Workstations, salary support for the PI and all the co-Is except one, line_2: clerical support, and line_3: extensive software and technical support are provide by all our home line_4: institutions. The major funding request for this proposal is graduate line_5: student support for Sartoretti, which is not covered by the home line_6: institution of the PI. ! !end of general form text general_form_address: lname: MCGRATH fname: MELISSA mi: A. category: PI inst: STScI addr_1: 3700 SAN MARTIN DRIVE city: BALTIMORE state: MD zip: 21218 country: USA phone: 410-338-4545 ! ! end of general_form_address records ! No fixed target records found solar_system_targets: targnum: 1 name_1: IO1-OFFN descr_1: SATELLITE IO lev1_1: STD = JUPITER lev2_1: STD = IO lev3_1: TYPE = POS_ANGLE, lev3_2: RAD = 30, lev3_3: ANG = 0, lev3_4: REF = NORTH wind_1: OLG OF IO BETWEEN 230 310, wind_2: SEP OF IO CALLISTO FROM EARTH GT 10", wind_3: SEP OF IO EUROPA FROM EARTH GT 10", wind_4: SEP OF IO GANYMEDE FROM EARTH GT 10", wind_5: OLG OF JUPITER BETWEEN 315 45 fluxnum_1: 1 fluxval_1: SURF(V)=5.02 ! targnum: 2 name_1: IO2-OFFN descr_1: SATELLITE IO lev1_1: STD = JUPITER lev2_1: STD = IO lev3_1: TYPE = POS_ANGLE, lev3_2: RAD = 30, lev3_3: ANG = 0, lev3_4: REF = NORTH wind_1: OLG OF IO BETWEEN 50 130, wind_2: SEP OF IO CALLISTO FROM EARTH GT 10", wind_3: SEP OF IO EUROPA FROM EARTH GT 10", wind_4: SEP OF IO GANYMEDE FROM EARTH GT 10", wind_5: OLG OF JUPITER BETWEEN 315 45 fluxnum_1: 1 fluxval_1: SURF(V)=5.02 ! ! end of solar system targets ! No generic target records found exposure_logsheet: linenum: 1.000 targname: DARK config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F275W,F253M num_exp: 1 time_per_exp: 17S priority: 1 req_2: CYCLE 3 / 1-16; req_3: SEQ 1-2 NON-INT; req_4: SEQ 1-8 NO GAP; ! linenum: 2.000 targname: IO1-OFFN config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F275W,F253M num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 req_1: REQ UPLINK ! linenum: 3.000 targname: DARK config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F220W,F231M num_exp: 1 time_per_exp: 17S priority: 1 req_2: SEQ 3-4 NON-INT; ! linenum: 4.000 targname: IO1-OFFN config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F220W,F231M num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 req_1: REQ UPLINK ! linenum: 4.100 targname: IO1-OFFN config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F220W,F231M num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 req_1: REQ UPLINK; req_2: NON-INT; ! linenum: 5.000 targname: DARK config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F346M,F8ND num_exp: 1 time_per_exp: 17S priority: 1 req_2: SEQ 5-6 NON-INT; ! linenum: 6.000 targname: IO1-OFFN config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F346M,F8ND num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 req_1: REQ UPLINK ! linenum: 7.000 targname: DARK config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F410M,F8ND num_exp: 1 time_per_exp: 17S priority: 1 req_2: SEQ 7-8 NON-INT; ! linenum: 8.000 targname: IO1-OFFN config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F410M,F8ND num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 req_1: REQ UPLINK ! linenum: 9.000 targname: DARK config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F275W,F253M num_exp: 1 time_per_exp: 17S priority: 1 req_2: SEQ 9-10 NON-INT; req_3: SEQ 9-16 NO GAP; ! linenum: 10.000 targname: IO2-OFFN config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F275W,F253M num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 req_1: REQ UPLINK ! linenum: 11.000 targname: DARK config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F220W,F231M num_exp: 1 time_per_exp: 17S priority: 1 req_2: SEQ 11-12 NON-INT; ! linenum: 12.000 targname: IO2-OFFN config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F220W,F231M num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 req_1: REQ UPLINK ! linenum: 12.100 targname: IO2-OFFN config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F220W,F231M num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 req_1: REQ UPLINK; req_2: NON-INT; ! linenum: 13.000 targname: DARK config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F346M,F8ND num_exp: 1 time_per_exp: 17S priority: 1 req_2: SEQ 13-14 NON-INT; ! linenum: 14.000 targname: IO2-OFFN config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F346M,F8ND num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 req_1: REQ UPLINK ! linenum: 15.000 targname: DARK config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F410M,F8ND num_exp: 1 time_per_exp: 17S priority: 1 req_2: SEQ 15-16 NON-INT; ! linenum: 16.000 targname: IO2-OFFN config: FOC/96 opmode: IMAGE aperture: 512X512 sp_element: F410M,F8ND num_exp: 1 time_per_exp: 15M fluxnum_1: 1 priority: 1 req_1: REQ UPLINK ! ! end of exposure logsheet ! No scan data records found