! File: 2393C.PROP ! Database: PEPDB ! Date: 17-FEB-1994:05:55:19 coverpage: title_1: D/H RATIO OF VENUS AND MARS FROM LYMAN ALPHA EMISSION sci_cat: SOLAR SYSTEM sci_subcat: INNER PLANETS proposal_for: GO pi_title: DR. pi_fname: JEAN-LOUP pi_lname: BERTAUX pi_inst: CNRS, DEPARTMENT OF AERONOMY pi_country: FRANCE pi_phone: 311.64.47.42.51 keywords_1: VENUS, MARS, ATMOSPHERE, EVOLUTION, UV SPECTROSCOPY hours_pri: 3.00 num_pri: 2 hrs: X funds_amount: 11531 funds_length: 12 funds_date: SEP-90 pi_position: CHEF DE DEPARTEMENT off_fname: P. off_lname: BAUER off_title: DIRECTOR off_inst: SERVICE D'AERONOMIE DU CNRS off_addr_1: BP 3 off_city: VERRIERES LE BUISSON off_zip: 91371 off_country: FRANCE off_phone: 331.62.47.42.45 off_telex: 602 400 ! end of coverpage abstract: line_1: It is proposed to measure with HRS the D/H ratio of Lyman alpha intensities line_2: from the visible disks of Venus and Mars in order to have a key clue on the line_3: evolution of water on these two planets. Whereas the D/H ratio for Earth is line_4: 1.6x10-4, indicating no substantial water escape since origin, one single line_5: measurement (through in situ mass spectrometry) for Venus indicated a ratio of line_6: 1.6 x 10-2 (enrichment 100). However, IUE La observations pushed to IUE line_7: ultimate capabilities failed to show the D La emission at 1.5 x 10^-2 of the H line_8: La emission, implying a D/H radio significantly smaller than previously line_9: reported (factor 8). This important finding needs to be confirmed with a line_10: positive detection at a lower level. On Mars, HDO has been detected, showing line_11: an enrichment of about 6 in the lower atmosphere. HST observation in the upper line_12: atmosphere would bring strong constraints on differentiation and escape of D line_13: probably valid for both planets. Even with the Earth's ratio of 1.6x 10^-4, D line_14: La can be detected both on Venus and Mars with HST/HRS. line_16: The two lines D and H are separated by 0.33 A and well resolved with HRS line_17: Echelle A. The D/H ratio in the bulk lower atmosphere transfers into a line_18: different D/H La emission ratio because of atmospheric processes, different line_19: solar excitation rates, and radiative transfer. All these effects require line_20: modellings which are well mastered by the proposers, with computer codes used in ! ! end of abstract general_form_proposers: lname: CLARKE fname: JOHN title: DR. mi: T. inst: MICHIGAN, UNIVERSITY OF country: USA ! lname: OWEN fname: TOBIAS title: DR. inst: SUNY, STONY BROOK country: USA ! lname: BERTAUX fname: JEAN-LOUP title: P.I. inst: CNRS, DEPARTMENT OF AERONOMY country: FRANCE esa: X ! lname: MUMMA fname: MIKE title: DR. mi: M. inst: NASA, GODDARD country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: WE PROPOSE TO PERFORM TWO OBSERVATIONS USING THE HST/HRS line_2: COMBINATION WITH THE HRS ECHELLE A GRATING, WAVELENGTH CENTERED AT line_3: 1215.5 A, AND THE LARGE SCIENCE APERTURE (LSA) CENTERED ON THE line_4: VISIBLE DISKS OF MARS AND VENUS . IN THIS CASE WE WILL ACHIEVE A line_5: SPECTRAL RESOLUTION OF 0.10 ANGSTOM, A WAVELENGTH COVERAGE OF 6.2 line_6: ANGSTROM,AND A COUNT RATE ROUGHLY 1.1 COUNT PER SEC FOR 1 KILORAY- line_7: LEIGH SPREAD OVER 8 DIODES. THE LSA IS CHOSEN TO ACHIEVE THE line_8: HIGHEST SENSITIVITY FOR UNAMBIGUOUS MEASUREMENT OF THE DEUTERIUM line_9: LYMAN ALPHA LINE.THE INTRINSIC SPECTRAL RESOLUTION OF THE ECHELLE line_10: A IS ROUGHLY 0.013 ANGSTROM AND THE LSA SPREADS THE EMISSION line_11: OVER 8 DIODES (WITH SHARPLY DEFINED EDGES) SO THAT THE D LINE AT line_12: 1215.34 ANGSTROM IS WELL RESOLVED FROM H LYMAN ALPHA LINE AT line_13: 1215.67 ANGSTROM. THE SCATTERING OF ECHELLE A AT 0.33 ANGSTROM line_14: FROM LINE CENTER IS 0.0013 OF THE LINE CENTER INTENSITY, line_15: COMPARABLE TO THE EXPECTED D EMISSION FROM MARS AND FAR BELOW line_16: THAT FROM VENUS. THE RED WING OF THE H LINE CAN BE REFLECTED line_17: ABOUT LINE CENTER AND USED TO SUBTRACT THE LEVEL OF SCATTERED line_18: EMISSION. line_19: THE MEASURED BRIGHTNESSES OF THE H LYMAN ALPHA EMISSIONS FROM line_20: VENUS AND MARS ARE 20 KR AND 4 KR,RESPECTIVELY, FROM IUE OBSERVA- line_21: TIONS. ASSUMING D/H LYMAN-ALPHA RATIOS OF ROUGHLY 0.01 FOR VENUS line_22: AND MARS, WE WOULD ANTICIPATE D LY ALPHA EMISSIONS OF 200 R FROM line_23: VENUS AND 40 R FROM MARS, YIELDING SIGNAL-TO-NOISE RATIOS ( FOR ! question: 3 section: 2 line_1: 30 MINUTE EXPOSURES ) OF 15 AND 6 RESPECTIVELY FOR THE TWO D LINES. line_2: EVEN WITH THE EARTH'S RATIO OF 1.6E-4, D-LYMAN ALPHA CAN BE line_3: DETECTED BOTH ON VENUS AND MARS WITH HST/HRS. IN A SINGLE 30 MINUTE line_4: DARK ORBIT EXPOSURE A LIMITING SENSITIVITY OF ~8 CNTS WOULD BE line_5: ACHIEVED FOR AN EMISSION OF 4 R, THUS ALLOWING STRONG SCIENTIFIC line_6: CONCLUSIONS TO BE DRAWN. line_8: N.B. VENUS DEFINITELY CANNOT NOW WE OBSERVED IN CYCLE 1 SO HAS line_9: BEEN DROPPED FROM THE TARGET LIST. HOWEVER CONSIDERATIONS line_10: FOR OBSERVING VENUS ARE RETAINED IN SECTIONS 5 AND 6 FROM THE line_11: FIRST SUBMITTED PHASE 2 PROPOSAL. ! question: 4 section: 1 line_1: Previous to HST, the only space instruments which had the necessary line_2: spectral resolution to resolve the D Lyman Alpha line at 1215.33 A line_3: technical drawback of IUE is that the short wavelength camera has line_4: some tail sensitivity at long wavelengths. Therfore, for exposures line_5: on the Venus bright disc, longer than 45 minutes, the stary light line_6: ( Rayleigh back-scattered solar UV radiation ) is a very serious line_7: problem precluding sensitive measurements. line_9: We have coadded all IUE archived good spectra taken on Venus with line_10: the large aperture and arrived at a useful upper limit of 300 R, line_11: since it translates into a D/H ratio lower than previously line_12: reported. It is now impossible to do better, because of low power line_13: conditions on IUE when observing at 45 degrees from the sun. line_14: The disc of Mars is smaller than the IUE large aperture, causing line_15: a loss of signal. line_17: From the ground, HDO has been succesfully measured in the IR on line_18: Mars, but not on Venus ( probably because of a much smaller line_19: H2O content ). Therefore a positive Venus measurement still needs line_20: to be done, independent of the in situ mass spectroscopy line_21: measurement which seems now in conflict withy the IUE result. line_22: Mars HST Lyman Alpha results when compared to the lower atmosphere line_23: D/H ratio, would put important constraints on the models of ! question: 4 section: 2 line_1: fractionation and differential escape of D versus H, of general line_2: relevance for planetary physics, including Earth and Venus. ! question: 5 section: 1 line_1: Two observations are foreseen with the LSA, one for Mars and line_2: one for Venus on the bright disc. For best resolution the GHRS line_3: Echelle-A will be selected. each of the D and H Lyman Alpha images line_4: will cover 8 diodes, seperated by 25 diodes ( centre-to-centre ). line_6: The number of detected counts per second, Nc, for an extended source line_7: of 1 kilo Rayleigh is 1.1 per second. line_9: In one single dark orbit exposure of 30 minutes, the Dark count line_10: is 8 counts for 8 diodes and the noise is ~3 counts. S/N ratio line_11: will be limited by counting statistics down to an intensity of line_12: ~ 5 Rayleigh. line_14: Counting in 30 min exposure line_15: Intens. Signal S/N(8 diodes) line_16: Venus H Ly-alpha 20 kR 39600 122.0 line_17: Venus D Ly-alpha 200 R 396 14.6 line_18: Mars D Ly-alpha 40 R 80 6.4 line_19: Geocorona H Ly-alpha 5 kR 9900 69.7 line_20: Lowest D Ly-alpha 4 R 8 1.6 ! question: 6 section: 1 line_1: MARS line_2: The disc of Mars has a diameter of between 10 and 19 arcsec line_3: during the window of Cycle 1. We wish to observe the illuminated line_4: part of the disc, somewhere between the centre of the planet and line_5: the sub-solar point. Therefore the selected point will be defined line_6: by an offset from the centre of the planet in the direction of the line_7: sun. Provision has to be made for pointing errors in the case of line_8: blind pointing to avoid pointing outside the planetary disc. line_9: With the worst pointing error of 3 arcsec, an offset of 1 - 3 arcsec line_10: ( value of offset depends on actual date of observation ), ensures line_11: that the GHRS 2.0 aperture will be entirely on the illuminated line_12: disc. line_13: If the Doppler shift between Earth and Mars is smaller than 7 km/s , line_14: one exposure will be required completely offset from the disc line_15: ( 30 arcsec ) in order to record the pure Geocoronal emission. line_17: VENUS line_18: Venus must be observed at the greatest elongation, when HST is line_19: in Earth shadow. In this case there is a large enough Doppler line_20: shift between Earth and Venus so that no pure Geocoronal line_21: observation is required. The required offset from the centre line_22: of the planet towards the sun is 7.8 arcsec. A blind pointing line_23: error of upto 3 arcsec is acceptable. ! question: 7 section: 1 line_1: The planetary D Lyman-alpha is rather straightforward to obtain, line_2: by summing the signal over 8 diodes covering the 2.0 aperture line_3: field of view. Many adjacent diodes are void of signal and can line_4: be used to estimate the background and subtract from the signal. line_6: The planetary H Ly-alpha, thought much more intense, presents one line_7: difficulty: it will be partially contaminated by geocoronal line_8: Ly-alpha, which intensity depends on HST orbital position ( 1 - line_9: 5 kR for dark orbit ). For Venus observations, likely to be done line_10: near maximum elongation, there is a 16 km/s Doppler shift between line_11: geocoronal and Venus Ly-alpha, corresponding to a shift of 5 line_12: diodes. Therefore, 5 diodes will contain only geocoronal Ly-alpha, line_13: allowing to correct for contamination the three Venus diodes line_14: containing some geocoronal signal. For Mars, the same procedure line_15: will apply; in the case the observation is near opposition, with line_16: a low Doppler shift, the geocoronal Ly-alpha will be measured line_17: with a specific observation, slightly off the planet. line_19: There is no Earth D Ly-alpha ( Deuterium is confined below 150 km ) line_20: and no interplanetary Ly-alpha, because the line of sight to the line_21: planet is comnpletely inside the ionization cavity. The D and H line_22: Ly-alpha measurements will be compared with theoretical line_23: predictions produced in advance by computer codes ( equation ! question: 7 section: 2 line_1: of diffusion for the vertical profile of H and D, radiative line_2: transfer programs, and models of D escape ), ensuring prompt line_3: publication of the results. ! question: 10 section: 1 line_1: Service d'Aeronomie personnel includes 5 computer science line_2: engineers. The Laboratory has its own VAX 8350 and is connected to line_3: three big computers. This ensures that all radiative transfer models line_4: will be ready in time for fast interpratation of the results. line_5: Travel money will come from CNRS, through the special HST programme. line_6: Service d'Aeronomie is associated to Universite Paris 6 where line_7: students are available if necessary. line_8: The Department of Atmosphere and Ocean Sciences at University of line_9: Michigan has also access to computers and students. ! !end of general form text general_form_address: lname: BERTAUX fname: JEAN mi: L. title: DR. category: PI inst: SERVICE D'AERONOMIE DU CNRS addr_1: BP 3 city: VERRIERES LE BUISSON zip: 91371 country: FRANCE ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: MARS-1 descr_1: PLANET MARS pos_1: RA = 8H 6M 53.19S +/- 0.01S, pos_2: DEC = 21D 47' 22.0" +/- 0.1" equinox: 2000 pm_or_par: N comment_1: TIME ESTIMATE 1991 MAY 25 00:00:00 comment_2: POINT AT MARS fluxnum_1: 1 fluxval_1: SURF(V) = 3.3 +/- 0.6 fluxnum_2: 2 fluxval_2: W-LINE(1215) = 0.01 +/- 0.003 fluxnum_3: 3 fluxval_3: SURF-LINE(1215) = 12 +/- 3 E-12 ! targnum: 2 name_1: MARS-2 descr_1: PLANET MARS pos_1: RA = 8H 7M 3.05S +/- 0.01S, pos_2: DEC = 21D 46' 50.7" +/- 0.1" equinox: 2000 pm_or_par: N comment_1: TIME ESTIMATE 1991 MAY 25 01:36:36 comment_2: POINT AT MARS fluxnum_1: 1 fluxval_1: SURF(V) = 3.3 +/- 0.6 fluxnum_2: 2 fluxval_2: W-LINE(1215) = 0.01 +/- 0.003 fluxnum_3: 3 fluxval_3: SURF-LINE(1215) = 12 +/- 3 E-12 ! targnum: 3 name_1: MARS-3 descr_1: PLANET MARS pos_1: RA = 8H 7M 12.92S +/- 0.01S, pos_2: DEC = 21D 46' 19.3" +/- 0.1" equinox: 2000 pm_or_par: N comment_1: TIME ESTIMATE 1991 MAY 25 03:13:12 comment_2: POINT AT MARS fluxnum_1: 1 fluxval_1: SURF(V) = 3.3 +/- 0.6 fluxnum_2: 2 fluxval_2: W-LINE(1215) = 0.01 +/- 0.003 fluxnum_3: 3 fluxval_3: SURF-LINE(1215) = 12 +/- 3 E-12 ! targnum: 4 name_1: MARS-4 descr_1: PLANET MARS pos_1: RA = 8H 7M 22.78S +/- 0.01S, pos_2: DEC = 21D 45' 47.9" +/- 0.1" equinox: 2000 pm_or_par: N comment_1: TIME ESTIMATE 1991 MAY 25 04:49:48 comment_2: POINT AT MARS fluxnum_1: 1 fluxval_1: SURF(V) = 3.3 +/- 0.6 fluxnum_2: 2 fluxval_2: W-LINE(1215) = 0.01 +/- 0.003 fluxnum_3: 3 fluxval_3: SURF-LINE(1215) = 12 +/- 3 E-12 ! targnum: 5 name_1: MARS-5 descr_1: PLANET MARS pos_1: RA = 8H 7M 32.64S +/- 0.01S, pos_2: DEC = 21D 45' 16.4" +/- 0.1" equinox: 2000 pm_or_par: N comment_1: TIME ESTIMATE 1991 MAY 25 06:26:24 comment_2: POINT AT MARS fluxnum_1: 1 fluxval_1: SURF(V) = 3.3 +/- 0.6 fluxnum_2: 2 fluxval_2: W-LINE(1215) = 0.01 +/- 0.003 fluxnum_3: 3 fluxval_3: SURF-LINE(1215) = 12 +/- 3 E-12 ! targnum: 6 name_1: MARS-6 descr_1: PLANET MARS pos_1: RA = 8H 7M 42.50S +/- 0.01S, pos_2: DEC = 21D 44' 44.9" +/- 0.1" equinox: 2000 pm_or_par: N comment_1: TIME ESTIMATE 1991 MAY 25 08:03:00 comment_2: POINT AT MARS fluxnum_1: 1 fluxval_1: SURF(V) = 3.3 +/- 0.6 fluxnum_2: 2 fluxval_2: W-LINE(1215) = 0.01 +/- 0.003 fluxnum_3: 3 fluxval_3: SURF-LINE(1215) = 12 +/- 3 E-12 ! targnum: 7 name_1: MARS-OFFSET descr_1: PLANET MARS pos_1: RA = 8H 7M 52.36S +/- 0.01S, pos_2: DEC = 21D 44' 13.4" +/- 0.1" equinox: 2000 pm_or_par: N comment_1: TIME ESTIMATE 1991 MAY 25 09:39:36 comment_2: POINT AT MARS +2 ARCMIN TOWARD SUN fluxnum_1: 1 fluxval_1: SURF(V) = 3.3 +/- 0.6 fluxnum_2: 2 fluxval_2: W-LINE(1215) = 0.01 +/- 0.003 fluxnum_3: 3 fluxval_3: SURF-LINE(1215) = 12 +/- 3 E-12 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: MARS-1 config: HRS opmode: ACCUM aperture: 2.0 sp_element: ECH-A wavelength: 1215.50 num_exp: 1 time_per_exp: 20M s_to_n: 50 s_to_n_time: 900S fluxnum_1: 3 fluxnum_2: 2 priority: 1 param_1: STEP-PATT = 6, param_2: DOPPLER = ON, param_3: FP-SPLIT=STD req_1: SPATIAL SCAN SINGLE-EXP; req_2: REQ UPLINK; req_3: CYCLE 1/1-7 comment_1: ESTIMATED S/N IN 8 DIODES IN 900S comment_2: FOR HYDROGEN LYMAN ALPHA. comment_3: DEUTERIUM MUCH WEAKER BY ~100. comment_4: SHORT EXPOSURES TO FOLLOW CHANGES comment_5: IN GEOCORONAL LY-ALPHA ALONG HST comment_6: ORBIT. ! linenum: 2.000 targname: MARS-2 config: HRS opmode: ACCUM aperture: 2.0 sp_element: ECH-A wavelength: 1215.50 num_exp: 1 time_per_exp: 20M s_to_n: 50 s_to_n_time: 900S fluxnum_1: 3 fluxnum_2: 2 priority: 1 param_1: STEP-PATT = 6, param_2: DOPPLER = ON, param_3: FP-SPLIT=STD req_1: SPATIAL SCAN SINGLE-EXP; req_2: REQ UPLINK; ! linenum: 3.000 targname: MARS-3 config: HRS opmode: ACCUM aperture: 2.0 sp_element: ECH-A wavelength: 1215.50 num_exp: 1 time_per_exp: 20M s_to_n: 50 s_to_n_time: 900S fluxnum_1: 3 fluxnum_2: 2 priority: 1 param_1: STEP-PATT = 6, param_2: DOPPLER = ON, param_3: FP-SPLIT=STD req_1: SPATIAL SCAN SINGLE-EXP; req_2: REQ UPLINK; ! linenum: 4.000 targname: MARS-4 config: HRS opmode: ACCUM aperture: 2.0 sp_element: ECH-A wavelength: 1215.50 num_exp: 1 time_per_exp: 20M s_to_n: 50 s_to_n_time: 900S fluxnum_1: 3 fluxnum_2: 2 priority: 1 param_1: STEP-PATT = 6, param_2: DOPPLER = ON, param_3: FP-SPLIT=STD req_1: SPATIAL SCAN SINGLE-EXP; req_2: REQ UPLINK; ! linenum: 5.000 targname: MARS-5 config: HRS opmode: ACCUM aperture: 2.0 sp_element: ECH-A wavelength: 1215.50 num_exp: 1 time_per_exp: 20M s_to_n: 50 s_to_n_time: 900S fluxnum_1: 3 fluxnum_2: 2 priority: 1 param_1: STEP-PATT = 6, param_2: DOPPLER = ON, param_3: FP-SPLIT=STD req_1: SPATIAL SCAN SINGLE-EXP; req_2: REQ UPLINK; ! linenum: 6.000 targname: MARS-6 config: HRS opmode: ACCUM aperture: 2.0 sp_element: ECH-A wavelength: 1215.50 num_exp: 1 time_per_exp: 20M s_to_n: 50 s_to_n_time: 900S fluxnum_1: 3 fluxnum_2: 2 priority: 1 param_1: STEP-PATT = 6, param_2: DOPPLER = ON, param_3: FP-SPLIT=STD req_1: SPATIAL SCAN SINGLE-EXP; req_2: REQ UPLINK; ! linenum: 7.000 targname: MARS-OFFSET config: HRS opmode: ACCUM aperture: 2.0 sp_element: ECH-A wavelength: 1215.50 num_exp: 1 time_per_exp: 20M s_to_n: 50 s_to_n_time: 900S fluxnum_1: 3 fluxnum_2: 2 priority: 1 param_1: STEP-PATT = 6, param_2: DOPPLER = ON, param_3: FP-SPLIT=STD req_1: SPATIAL SCAN SINGLE-EXP; req_2: REQ UPLINK; ! ! end of exposure logsheet scan_data: line_list: 1-7 fgs_scan: N cont_dwell: C dwell_pnts: 0 dwell_secs: 0.00 scan_width: 0.0000 scan_length: 30.3540 sides_angle: 0.0000 number_lines: 1 scan_rate: 0.0228 first_line_pa: 101.9881 scan_frame: CEL len_offset: 0.0 wid_offset: 0.0 ! ! end of scan data