This proposal is to make STIS E140H long aperture observations of Venus near elongation to measure the D and H Ly apha emissions to determine the D/H ratio in the upper atmosphere, with implications for the historic escape of water into space. It is important to determine the actual D Ly alpha brightness in Venus' upper atmosphere, and also to measure the center-to-limb variation of the H Ly alpha emission, to understand the radiative transfer of these emissions and derive accurate values for the densities of both H and D and thus the D/H ratio. The combination of one long-slit STIS spectrum of Venus and the coordinated sounding rocket data can put to rest uncertainties about the D/H ratio and escape of water that have lingered since Pioneer Venus orbited Venus in the late 1980's. The next Venus opposition periods are August 15, 2012 at western elongation and November 1, 2013 at eastern elongation. While these bracket either side of cycle 20, we prefer the latter observing period for the line of sight Doppler shift. The requirement is to have a sufficient Doppler shift from the combined line of sight orbital motions of Venus and the Earth to separate the terrestrial and cytherian emissions. We place a limit of 14 km/sec (the spectral resolution of STIS E140H with the 0.5 aperture) to cleanly separate the lines. The detection of D Ly alpha also imposes the requirement that Venus appear blue-shifted with respect to the geocoronal emissions, to prevent the geocoronal H line from overlapping with the Venus D line. Observations in late September 2013 satisfy this criterion (all evening apparitions of Venus are OK). With the STIS 52 x 0.5 arc sec aperture and 0.057 Angstrom resolution, equal to 14 km/sec velocity resolution, we will just resolve the Venus lines from the geocoronal lines with the Doppler shift from the combined orbital motion near elongation. In addition, we will have sky measurements of the geocoronal H and D lines through the rest of the aperture, providing a higher S/N ratio than in the Venus spectrum for an accurate subtraction. This would give a limiting detection brightness of roughly 100 R at 3 sigma in a 300 sec. observation, limited by a combination of photon counting statistics and the grating scattered light from the H line plus the subtraction of the geocoronal emission. This limiting brightness is factor of 3 below the IUE limit and an order of magnitude lower than theoretical estimates, and thus sufficient to place strong constraints on the D abundance in the upper atmosphere of Venus. As stated above, the combined goal of this proposal is to detect the D emission and to obtain the intensity profile of the H emission across the Venus disc to help to model the H density with a radiative transfer code. From prior STIS E140H observations we know that we will get 0.4 cts/sec-arcsec2 from a 1 kR emission. In a 5 min integration (limited by the technique of observing Venus after it rises but before the Sun rises) covering 8 x 0.5 arc sec of the Venus sunlit disc, we would get a total of 48 counts from a 100 R D Ly alpha emission and 250 counts per 0.2 arc sec resolution element from the 20 kR H Ly alpha emission. We request 2 orbits to observe Venus each visit to build the S/N ratio, plus one orbit for sky background. The combined 600 sec exposure time on Venus is what was obtained in the recent GO 12433. From that program we assume that 5 min observing time can be obtained each orbit, and this should be confirmed by STScI staff. If 600 sec total observing time requires more than 8 orbits, we would restrict the integration time on Venus to this number. The count rate from the D emission would be limited, but the H intensity profile across Venus would be well sampled. We will schedule the HST observations with similar observing conditions as NASA sounding rocket 36.261. The observations do not have to be simultaneous for a fruitful comparison of the data, e.g. models can account for differences in geometry and field of view, and we can scale the intensities by the measured solar Ly alpha flux at the times of both observations corrected for the angle between the Earth and Venus. The rocket experiment are expected to have a higher sensitivity to D Ly alpha emission than HST, but much lower angular resolution. The STIS data will have high angular resolution to obtain the spatial profile of H Ly alpha emission across the Venus disc, in addition to the line profile, so that we can model the H abundance with a radiative transfer code. The Venus Express UV spectrometer (PI J-L. Bertaux, co-I J-Y. Chaufray) observes the dayside H Lyman-alpha emission routinely in limb mode (Chaufray et al. 2012). Dayside limb observations by SPICAV-VEX will be performed at the same time to support HST observations. Paxton et al. (1988) show that disc and limb observations are complementary to study H in the upper atmosphere of Venus. Limb observations are useful to constrain H density above the exobase but are not sensitive to thermospheric H density (Chaufray et al. 2012), while disc observations are mostly sensitive to thermospheric H but not sensitive to exospheric H distribution. Because the thermospheric H density is controlled by escape, only disc observations can provide constrains on H escape. Therefore, SPICAV-VEX and HST observations will be complementary and will be used to derive the full H density profile in the Venusian thermosphere and exosphere. Observations will be of Venus near eastern elongation. Phase 2 proposal is being entered by PI, not knowing exact conditions at time of observations (HST orbit, etc.). Observations will observe Venus just after sunset, and pointing at Venus must occur from a nearby location just after the sun sets, due to Venus at angle less than 50 deg. from the Sun. SOLAR SYSTEM 12 false false 0.0 0.0 false false false AVAILABLE UNIDENTIFIED UNDESIGNATED A pointing at which to perform a guide star acquisition test for guide star S8G1000134. J2000 UNIDENTIFIED UNDESIGNATED A pointing at which to perform a guide star acquisition test for guide star S8G1000147. J2000 SOLAR SYSTEM PLANET Venus-Disc-Center STD=VENUS SEP OF VENUS SUN FROM EARTH GT 46.5D EARTH SOLAR SYSTEM PLANET Venus-Offset-7D STD=VENUS TYPE=POS_ANGLE,RAD=25200,ANG=180,REF=SUN F-LINE(1216)=3 +/- 3 E-13 EARTH SOLAR SYSTEM PLANET Venus-Offset-7D STD=VENUS TYPE=POS_ANGLE,RAD=24840,ANG=180,REF=SUN F-LINE(1216)=3 +/- 3 E-13 EARTH STIS/FUV-MAMA Spectroscopic No No E140H 1234 STIS/FUV-MAMA Spectroscopic No No E140H 1234 Using ephemeris for target 13047-01-VENUS-OFFSET-7D ephemeris data for target 13047-01-VENUS-OFFSET-7D does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 12.212 to 14.213. ephemeris interval: 13.212 to 15.213 Using ephemeris for target 13047-01-VENUS ephemeris data for target 13047-01-VENUS does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 12.212 to 14.213. ephemeris interval: 13.212 to 15.213 The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13047 :visit-id "01" :proposal-version -1 :trans-version "20130722" :date "10-Sep-2013 11:54:35.0" :trans-errors '(:WARNINGS 2 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 278240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13047 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 13047 :visit-id "01" :obset-id "A1" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 13047 :visit-id "01" :obset-id "B1" :pcs-mode "GYRO" ) (Tic-Orbit :proposal-id 13047 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3539 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset 2529 :dark-utilization 469 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 1 1 buffer-time estimate based on 52 x 0.2 aperture spectra of Mars and sky near Mars in GO 12538, max. count rate then was 240 cts/sec, for brighter emission from Venus and sky it is assumed count rate may be as high as 1000 cts/sec buffer-time estimate based on 52 x 0.2 aperture spectra of Mars and sky near Mars in GO 12538, max. count rate then was 240 cts/sec, for brighter emission from Venus and sky it is assumed count rate may be as high as 1000 cts/sec (Tic-Visit :proposal-id 13047 :visit-id "02" :proposal-version -1 :trans-version "20130722" :date "10-Sep-2013 11:54:39.0" :trans-errors '(:WARNINGS 2 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 278240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13047 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 13047 :visit-id "02" :obset-id "A2" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 13047 :visit-id "02" :obset-id "B2" :pcs-mode "GYRO" ) (Tic-Orbit :proposal-id 13047 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3629 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset 2619 :dark-utilization 469 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 1 1 (Tic-Visit :proposal-id 13047 :visit-id "03" :proposal-version -1 :trans-version "20130722" :date "10-Sep-2013 13:04:07.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 156544 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13047 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13047 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2173 :al-overhead-at-end 0 :internal-dur-at-end 440 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) true 1 0 Using ephemeris for target 13047-02-VENUS-OFFSET-7D ephemeris data for target 13047-02-VENUS-OFFSET-7D does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 12.212 to 14.213. ephemeris interval: 13.212 to 15.213 Using ephemeris for target 13047-02-VENUS ephemeris data for target 13047-02-VENUS does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 12.212 to 14.213. ephemeris interval: 13.212 to 15.213 The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13047 :visit-id "04" :proposal-version -1 :trans-version "20130722" :date "10-Sep-2013 11:55:47.0" :trans-errors '(:WARNINGS 2 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 278240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13047 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 13047 :visit-id "04" :obset-id "A4" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 13047 :visit-id "04" :obset-id "B4" :pcs-mode "GYRO" ) (Tic-Orbit :proposal-id 13047 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3689 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset 2679 :dark-utilization 469 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 1 1 buffer-time estimate based on 52 x 0.2 aperture spectra of Mars and sky near Mars in GO 12538, max. count rate then was 240 cts/sec, for brighter emission from Venus and sky it is assumed count rate may be as high as 1000 cts/sec buffer-time estimate based on 52 x 0.2 aperture spectra of Mars and sky near Mars in GO 12538, max. count rate then was 240 cts/sec, for brighter emission from Venus and sky it is assumed count rate may be as high as 1000 cts/sec (Tic-Visit :proposal-id 13047 :visit-id "05" :proposal-version -1 :trans-version "20130722" :date "10-Sep-2013 11:55:51.0" :trans-errors '(:WARNINGS 2 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 278240 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13047 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 13047 :visit-id "05" :obset-id "A5" :pcs-mode "FGS" ) (Tic-Obset :proposal-id 13047 :visit-id "05" :obset-id "B5" :pcs-mode "GYRO" ) (Tic-Orbit :proposal-id 13047 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3689 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset 2679 :dark-utilization 469 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 1 1 (Tic-Visit :proposal-id 13047 :visit-id "06" :proposal-version -1 :trans-version "20130722" :date "10-Sep-2013 12:50:47.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 173968 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13047 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13047 :visit-id "06" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2413 :al-overhead-at-end 0 :internal-dur-at-end 626 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) true 1 0 Guide star acquisiton test for guide star S8G1000134. 1379444065000 95.74517532217169 false -1 -1 Guide star acquisiton test for guide star S8G1000147. 1379541642000 95.67903507498158 false -1 -1