! File: 3862C.PROP ! Database: PEPDB ! Date: 19-FEB-1994:22:09:23 coverpage: title_1: THE EXCITATION OF THE ATMOSPHERES OF PLANETARY SATELLITES sci_cat: SOLAR SYSTEM proposal_for: GO pi_title: DR. pi_fname: JOHN pi_mi: T. pi_lname: CLARKE pi_inst: MICHIGAN, UNIVERSITY OF pi_country: USA pi_phone: 313-747-3540 keywords_1: PLANETARY SATELLITE, PLASMA TORUS, AURORA hours_pri: 4.11 num_pri: 1 fos: X hrs: X time_crit: X funds_length: 12 funds_date: SEP-92 off_fname: MARTIN off_mi: H. off_lname: TOBIN off_title: ASSISTANT DIRECTOR off_inst: THE UNIVERSITY OF MICHIGAN off_addr_1: DIV. OF RESEARCH DEVELOPMENT AND ADMINISTRATION off_addr_2: 245 W. ENG. BLDG. off_addr_3: 550 E. UNIV. STREET off_city: ANN ARBOR off_state: MI off_zip: 48109 off_country: USA ! end of coverpage abstract: line_1: We will observe Io at near and far UV wavelengths in a set of observa- line_2: tions designed to study the excitation of Io's atmosphere. The distin- line_3: guishing element of this program is the design of the observations to line_4: separate the following processes: resonant scattering of solar emission, line_5: charged particle excitation by magnetospheric plasma, and the decay in line_7: surface. Io will be observed with the FOS/HST in the near-UV over a line_8: period of time centered Io emerging from eclipse to separate the solar line_9: emissions (sunlit) from particle excited emissions (while in shadow) and line_10: the near UV SO2 aurora will be observed while Io is in shadow. Two far-UV line_11: multiplets of O and S will be observed with GHRS as Io goes into eclipse line_12: to determine the light curve by which these lines rapidly decrease in line_13: intensity when Io is in shadow, discovered in Cycle 1. The far UV line_14: lines of atomic sulfur and oxygen come from an extended atmosphere, and line_15: are produced by a combination of ionospheric currents and torus plasma line_16: impact relatively high in the atmosphere. The near-UV bands of SO reflect line_17: particle impact on SO2, the parent molecule believed to be driven by line_18: sublimation vapor pressure from the surface, and may be excited relatively line_19: closer to Io's surface (due to three times smaller scale height) by line_20: incident plasma and/or ionospheric processes. ! ! end of abstract general_form_proposers: lname: CLARKE fname: JOHN title: PI mi: T. inst: MICHIGAN, UNIVERSITY OF country: USA ! lname: LUHMANN fname: JANET inst: CALIFORNIA, UNIVERSITY OF, LOS ANGELES country: USA ! lname: AJELLO fname: JOE inst: JET PROPULSION LABORATORY country: USA ! lname: SCHNEIDER fname: NICK inst: UNIVERSITY OF COLORADO country: USA ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: ! question: 3 section: 1 line_1: The proposed observations are: i) two GHRS G160M LSA exposures of Io line_2: (at 1300 and 1910 A) with 1 minute readouts roughly centered on the time of line_3: eclipse disappearance for a period of 40 min. (or as long as possible in one line_4: dark orbit), ii) one FOS G270H 4.3 arc sec aperture exposure of Io with 1 line_5: minute readout time centered on the time of eclipse re-appearance for one dark line_6: orbit: the total is 3 dark orbits. Because we will be using large apertures, line_7: we request coarse track only (no fine lock) to decrease the acquisition time line_8: and avoid any chance of loss of lock. Acquisition will be accomplished by: line_9: GHRS - on-board acq. of Io, and FOS - acquiring a satellite in sunlight line_10: (listed as Ganymede, but could be any), interactive acq. of that sat., and line_11: then blind offset to Io in shadow. ! question: 4 section: 1 line_1: The line emissions excited by the impact of magnetospheric plasma at line_2: Io are radiated chiefly in the FUV, and require a space-based instrument line_3: with high sensitivity and angular resolution to be detected. Ground-based line_4: instruments today have great difficulty in detecting atmospheric line line_5: emissions from Io. Emissions from the extended atmosphere of Io line_6: are just detectable with the IUE, but higher sensitivity and angular resolution line_7: will be required to determine the source region and spatial distribution. We line_8: have successfully performed observation (ii) above with the IUE, although the line_9: low sensitivity of IUE did not permit a positive detection of SO emission. Only line_10: the HST is fast enough to detect changes in emission brightness through the line_11: eclipse events. Io is believed to be the initial source of the plasma in line_12: Jupiter's magnetosphere, and we are proposing to observe the source region of line_13: that plasma localized in the atmosphere of Io. ! question: 5 section: 1 line_1: The observations of Io must be centered (+/- 15 min.) on the time of eclipse line_2: re- or dis- appearance, and must occur at the time of year when the orbital line_3: longitude of Jupiter 30 to 70 degrees for the GHRS (ingress) spectra, and 250 line_4: to 300 degrees for the FOS (egress) spectra. These constraints can be relaxed line_5: somewhat if necessary to allow scheduling. ! question: 6 section: 1 line_1: None. ! question: 7 section: 1 line_1: J. Ajello has recently performed laboratory studies of electron excita- line_2: tion of SO2 and N2 gases, measuring the electron impact induced fluorescence line_3: spectrum of SO2 in the UV (400-2000 A). The results of these studies show that line_4: the strongest features in the wavelength range of GHRS occur between 1200-1500A line_5: and include resonance lines of SI, SII, SIII, and OI. For these features we line_6: have measured excitation functions from 0-400 eV for modelling the excitation line_7: rates at Io. The analysis of the HST spectra will be greatly aided by our line_8: laboratory studies of electron excitation of SO2 and N2 gases. The relative line_9: strengths of the various lines will allow us to estimate the bulk composition line_10: and vertical thickness of Io's atmosphere, and the absolute intensity of the line_11: observed emission can be related to the total ionization rate and therefore the line_12: mass supply rate into the plasma torus. Through the measurements of solar line_13: scattering, particle excitation, and the several time scales for atmospheric line_14: collapse, we hope to obtain a definitive picture of the production and line_15: excitation of Io's atmosphere. Through comparison of leading and trailing face line_16: spectra, we hope to determine the process by which Titan's atmosphere is line_17: excited. line_18: The UV spectra will be reduced using standard routines. The temporal line_19: variation of the emission features in the Io data before and after eclipse re- line_20: appearance will be interpreted in terms of a model for the various emission line_21: processes discussed above. We hope to separate the strengths of the different line_22: processes by fitting components with different time scales to the measured line_23: variation in brightness of each individual line, and then compare the different ! question: 8 section: 1 line_1: None. ! question: 9 section: 1 line_1: GO 2602 - "The Excitation of the Atmospheres of Planetary Satellites", J. line_2: Clarke PI - directly related to the proposed observations. Observations were line_3: performed on 17 January 1992 with FOS G270H and 4.3 aper. as Io entered into line_4: eclipse shadow, and on 26 January 1992 with FOS G130H and 4.3 aper. as Io line_5: entered into eclipse shadow. ! question: 10 section: 1 line_1: Complete computing facilities are in place and available within the Space line_2: Physics Research Lab. at the University of Michigan for use on this project. line_3: Two VAX 750's and a VAX 8600 are accessible via a local area network, in line_4: addition to the Michigan network MERIT, SPAN, and Internet. A SUN 4/110 line_5: workstation with IDL is available for use, and a SUN IPX with IDL has been line_6: procured with cycle 1 GO funding. All Co-I's also have complete computing line_7: facilities at their institutions for use on this project. In addition, N. line_8: Schneider has proposed undertaking ground-based observations of Io in eclipse, line_9: to study the O[I] 6300 A emission changes for comparison with the line_10: HST UV data. ! !end of general form text general_form_address: lname: CLARKE fname: JOHN mi: T. title: PROF. category: PI inst: UNIVERSITY OF MICHIGAN addr_1: AOSS DEPT. city: ANN ARBOR state: MI zip: 481092143 country: USA ! ! end of general_form_address records ! No fixed target records found solar_system_targets: targnum: 1 name_1: IO-ACQ-GHRS descr_1: SATELLITE IO lev1_1: STD = JUPITER lev2_1: STD = IO comment_1: IO-ACQ-GHRS = IO IN SUNLIGHT FOR comment_2: ON-BOARD ACQUISITION WITH GHRS. ! targnum: 2 name_1: IO-INGRESS descr_1: SATELLITE IO lev1_1: STD = JUPITER lev2_1: STD = IO wind_1: OLG OF JUPITER BETWEEN 30 70, wind_2: ECL U OF IO BY JUPITER, wind_3: SEP OF EUROPA IO FROM EARTH GT 10", wind_4: SEP OF GANYMEDE IO FROM EARTH GT 10", wind_5: SEP OF CALLISTO IO FROM EARTH GT 10" comment_1: OBSERVE IO GOING INTO ECLIPSE comment_2: BEHIND JUPITER; BEGIN GHRS SERIES comment_3: 10-15 MIN. BEFORE ECLIPSE comment_4: DISAPPEARANCE AND SCHEDULE comment_5: WHEN ORBITAL LONGITUDE OF JUPITER comment_6: IS 30 TO 70 DEGREES (~FEB-MARCH 1993). comment_7: PLEASE NOTE THAT THE WINDOWS CAN comment_8: BE EXPANDED IF NEEDED TO SCHEDULE. fluxnum_1: 1 fluxval_1: SURF(V) = 5.8 +/- 0.5 fluxnum_2: 2 fluxval_2: SIZE = 1.0 +/- .2 fluxnum_3: 3 fluxval_3: SURF-CONT(2700) = 2 +/- 1 E-13 ! targnum: 3 name_1: IO-ACQ-FOS descr_1: OFFSET EUROPA lev1_1: STD = JUPITER lev2_1: STD = EUROPA comment_3: STRATEGY IS TO ACQUIRE EUROPA comment_4: AND THEN BLIND OFFSET TO IO, BOTH comment_5: IN 4.3 APERTURE. TO ACQUIRE EUROPA comment_6: WITH FOS, TAKE A SET OF 5 SPECTRA comment_7: AT DIFFERENT Y-DEFLECTIONS TO comment_8: DETERMINE CENTERING IN X AND Y comment_9: (FROM OBSERVED WAVELENGTH) THEN comment_10: UPLINK HST POINTING CORRECTION. fluxnum_1: 1 fluxval_1: SURF(V) = 5.5 +/- 0.5 fluxnum_2: 2 fluxval_2: SIZE = 2.0 +/- .2 fluxnum_3: 3 fluxval_3: SURF-CONT(2700) = 2 +/- 1 E-13 ! targnum: 4 name_1: IO-EGRESS descr_1: SATELLITE IO lev1_1: STD = JUPITER lev2_1: STD = IO wind_1: OLG OF JUPITER BETWEEN 250 300, wind_2: ECL U OF IO BY JUPITER, wind_3: SEP OF EUROPA IO FROM EARTH GT 10", wind_4: SEP OF GANYMEDE IO FROM EARTH GT 10", wind_5: SEP OF CALLISTO IO FROM EARTH GT 10", wind_6: SEP OF EUROPA IO FROM EARTH LT 2' comment_1: OBSERVE IO COMING OUT OF ECLIPSE comment_2: BEHIND JUPITER; BEGIN FOS SERIES comment_3: 10-15 MINUTES BEFORE IO ECLIPSE comment_4: REAPPEARANCE AND SCHEDULE comment_5: WHEN ORBITAL LONGITUDE OF JUPITER comment_6: IS 250 TO 300 DEGREES. comment_7: PLEASE NOTE THAT THE WINDOWS CAN comment_8: BE EXPANDED IF NEEDED TO SCHEDULE. fluxnum_1: 1 fluxval_1: SURF(V) = 5.8 +/- 0.5 fluxnum_2: 2 fluxval_2: SIZE = 1.0 +/- .2 fluxnum_3: 3 fluxval_3: SURF-CONT(2700) = 2 +/- 1 E-13 ! ! end of solar system targets ! No generic target records found exposure_logsheet: linenum: 1.000 targname: IO-ACQ-GHRS config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 10S fluxnum_1: 3 priority: 1 param_1: SEARCH-SIZE=5, param_2: BRIGHT=RETURN req_1: CYCLE 2 / 1-14; req_2: PCS MODE C /1-14; req_3: ONBOARD ACQ FOR 4; req_4: SEQ 1-4 NO GAP comment_1: ON-BOARD ACQ OF IO WITH N2. comment_2: PLEASE USE INFO. FROM EARLIER comment_3: IO ACQ'S FOR STEP-TIME: I comment_4: ESTIMATE STEP-TIME = 0.4. ! linenum: 2.000 targname: IO-ACQ-GHRS config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 40.8S fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 4 comment_1: STEP-TIME=0.4; comment_2: NEED 0.25 ARC SEC comment_3: CENTERING OF IO IN LSA. comment_4: PLEASE ADJUST TIME_PER_EXP comment_5: IF NECESSARY. ! linenum: 3.000 targname: IO-ACQ-GHRS config: HRS opmode: IMAGE aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 96.8S fluxnum_1: 3 priority: 1 comment_1: IMAGE OF IO IN LSA AFTER comment_2: CENTERING. I ESTIMATE comment_3: 100 COUNTS/DWELL POINT comment_4: FROM IO DISK. ! linenum: 4.000 targname: IO-INGRESS config: HRS opmode: RAPID aperture: 2.0 sp_element: G160M wavelength: 1301.0 num_exp: 1 time_per_exp: 25M fluxnum_1: 1 priority: 1 param_1: SAMPLE-TIME = 12.75 req_1: DARK TIME comment_1: BEGIN GHRS SPECTRA AFTER IMAGE comment_2: AND 10-15 MINUTES BEFORE IO comment_3: PASSES INTO JUPITER'S SHADOW. comment_4: SCHEDULE IN DARK TIME DUE TO comment_5: 1304 AIRGLOW. ! linenum: 5.000 targname: IO-ACQ-GHRS config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 10S fluxnum_1: 3 priority: 1 param_1: SEARCH-SIZE=5, param_2: BRIGHT=RETURN req_1: ONBOARD ACQ FOR 8; req_2: SEQ 5-8 NO GAP; req_3: PCS MODE C comment_1: ON-BOARD ACQ OF IO WITH N2. comment_2: PLEASE USE INFO. FROM EARLIER comment_3: IO ACQ'S FOR STEP-TIME: I comment_4: ESTIMATE STEP-TIME = 0.4. ! linenum: 6.000 targname: IO-ACQ-GHRS config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 40.8S fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 8 comment_1: STEP-TIME=0.4; comment_2: NEED 0.25 ARC SEC comment_3: CENTERING OF IO IN LSA. comment_4: PLEASE ADJUST TIME_PER_EXP comment_5: IF NECESSARY. ! linenum: 7.000 targname: IO-ACQ-GHRS config: HRS opmode: IMAGE aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 96.8S fluxnum_1: 3 priority: 1 comment_1: IMAGE OF IO IN LSA AFTER comment_2: CENTERING. I ESTIMATE comment_3: 100 COUNTS/DWELL POINT comment_4: FROM IO DISK. ! linenum: 8.000 targname: IO-INGRESS config: HRS opmode: RAPID aperture: 2.0 sp_element: G200M wavelength: 1910.0 num_exp: 1 time_per_exp: 25M fluxnum_1: 1 priority: 1 param_1: SAMPLE-TIME = 12.75 comment_1: BEGIN GHRS SPECTRA AFTER IMAGE comment_2: AND 10-15 MINUTES BEFORE IO comment_3: PASSES INTO JUPITER'S SHADOW. ! linenum: 9.000 targname: IO-ACQ-FOS config: FOS/BL opmode: IMAGE aperture: 4.3 sp_element: G270H num_exp: 1 time_per_exp: 300 S fluxnum_1: 3 priority: 1 param_1: Y-SIZE=5, param_2: Y-SPACE=128, param_3: COMB=YES, param_4: SUB-STEP=4 req_1: SEQ 9-11 NO GAP; req_2: RT-ANALYSIS; comment_1: SPECTRA OF EUROPA FOR INT. ACQ. comment_2: REQUIRES REAL-TIME UPLINK FOR comment_3: S/C MOTIONS IN X AND Y DURING comment_4: EARTH OCCULTATION. AFTER comment_5: CENTERING ON EUROPA, OFFSET TO comment_6: IO, WHICH IS IN SHADOW. ! linenum: 10.000 targname: IO-EGRESS config: FOS/BL opmode: RAPID aperture: 4.3 sp_element: G270H num_exp: 1 time_per_exp: 30 M fluxnum_1: 1 priority: 1 param_1: STEP-PATT=DEF, param_2: READ-TIME=60. req_1: REQ UPLINK; comment_1: FOS EXPOSURES OF IO: BEGIN comment_2: 10-15 MINUTES BEFORE IO comment_3: REAPPEARS IN SUNLIGHT FROM comment_4: ECLIPSE. ! linenum: 11.000 targname: IO-EGRESS config: FOS/BL opmode: IMAGE aperture: 4.3 sp_element: G270H num_exp: 1 time_per_exp: 4.0 S fluxnum_1: 1 priority: 2 param_1: STEP-TIME=1.0, param_2: SUB-STEP=1, param_3: Y-SIZE=4, param_4: Y-SPACE=64, param_5: COMB=NO comment_1: IMAGE OF 4.3 APERTURE comment_2: FOR POST-UPLINK POINTING comment_3: INFORMATION, PERFORMED comment_4: AFTER IO COMES BACK INTO comment_5: SUNLIGHT. ! linenum: 12.000 targname: IO-ACQ-FOS config: FOS/BL opmode: IMAGE aperture: 4.3 sp_element: G270H num_exp: 1 time_per_exp: 300 S fluxnum_1: 3 priority: 1 param_1: Y-SIZE=5, param_2: Y-SPACE=128, param_3: COMB=YES, param_4: SUB-STEP=4 req_1: SEQ 12-14 NO GAP; req_2: RT-ANALYSIS; comment_1: SPECTRA OF EUROPA FOR INT. ACQ. comment_2: REQUIRES REAL-TIME UPLINK FOR comment_3: S/C MOTIONS IN X AND Y DURING comment_4: EARTH OCCULTATION. AFTER comment_5: CENTERING ON EUROPA, OFFSET TO comment_6: IO, WHICH IS IN SHADOW. ! linenum: 13.000 targname: IO-EGRESS config: FOS/BL opmode: RAPID aperture: 4.3 sp_element: G190H num_exp: 1 time_per_exp: 30 M fluxnum_1: 1 priority: 1 param_1: STEP-PATT=DEF, param_2: READ-TIME=60. req_1: REQ UPLINK; comment_1: FOS EXPOSURES OF IO: BEGIN comment_2: 10-15 MINUTES BEFORE IO comment_3: REAPPEARS IN SUNLIGHT FROM comment_4: ECLIPSE. SAME AS OTHER comment_5: SET, BUT WITH G190H. ! linenum: 14.000 targname: IO-EGRESS config: FOS/BL opmode: IMAGE aperture: 4.3 sp_element: G270H num_exp: 1 time_per_exp: 4.0 S fluxnum_1: 1 priority: 2 param_1: STEP-TIME=1.0, param_2: SUB-STEP=1, param_3: Y-SIZE=4, param_4: Y-SPACE=64, param_5: COMB=NO comment_1: IMAGE OF 4.3 APERTURE comment_2: FOR POST-UPLINK POINTING comment_3: INFORMATION, PERFORMED comment_4: WHEN IO IS IN SUNLIGHT. ! ! end of exposure logsheet ! No scan data records found