6692( 8) - 06/17/96 10:47 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6692 Version: 8 Check-in Date: 17-Jun-1996 10:43:32 1.Proposal Title: The abundance and distribution of deuterium on Saturn ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle SOLAR SYSTEM GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: LOTFI BEN JAFFEL INSTITUT D'ASTROPHYSIQUE, CNRS CoI: Darrell Strobel Johns Hopkins University N CoI: Randall Gladstone Southwest Research Institute N CoI: Alfred Vidal-Madjar Institut d'Astrophysique de Paris N CoI: Paul Feldman Johns Hopkins University N CoI: Warren Moos Johns Hopkins University N CoI: Claude Emerich Institut d'Astrophysique Spatiale N CoI: John Clarke University of Michigan N ------------------------------------------------------------------------------------ 6. Abstract We propose to obtain high resolution profiles of the D Lyman alpha line emitted by the limb of the upper atmosphere Saturn, using the GHRS Echelle A and the LSA. Our technique consists in a radial drift of the LSA slit across the limb of the planet. This is much like the very efficient occultation technique although we record reflected instead of transmitted light. As the deuterium emission is optically thin, the analysis of the resulting profiles will provide, through our photochemistry models and radiative transfer calculations, the possibility for the first time to retrieve the deuterium scale height and abundance at least in four locations of the upper atmosphere of Saturn. Scale heights at different locations derived from the D Ly-alpha emission, and the analysis of the H Ly-alpha profile, obtained with each limb observation, will accurately provide the H total column density. A precise estimate of the D/H ratio will therefore be inferred. Recently, we successfully applied the technique to observe the limb of Jupiter with the medium resolution grating G160M. The inferred D/H ratio ~ 6+/- 1 * 10^-5 seems to support the measurements made through HD/H2 rather than CH3D/CH4. The uncertainty on this value could be reduced if high resolution observations with Echelle A are conducted. This should confirm the newly derived ratio and check the D/H ratio for Saturn. Ultimately, this will help to refine the scenario on the formation and the evolution our Solar System 4.5 billions years ago. ------------------------------------------------------------------------------------ 6692( 8) - 06/17/96 10:47 - [ 2] Observations Description ------------------------ 1. A new technique of observation, On the basis of the available estimates of the H total content and the D/H ratio, one can readily show that the D Ly-alpha line is optically thin and that the Saturn planetary disk averaged D Ly-alpha emissions cannot exceed few tens Rayleigh. We propose a new technique of observation with the side one echelle to derive the deuterium abundance and scale height at least at four locations in the upper atmosphere of the planet. For instance, let's consider, from a theoretical point of view, the situation where the LSA is 100\\% filled by the bright limb as depicted in Fig. 2.a. We also consider an atmospheric model where the deuterium constituent extends between the CH4 absorbing level (located say at R_0) and an upper level (located say at Rmax). Ignoring for the moment the H Ly-alpha emission, one should obtain for the Ech-A resolution, a D Ly-alpha line profile as depicted in Fig. 2.b. Here appears the strength of GHRS. Because the line is optically thin, for each position of the slit across the limb, there is a direct correspondence between each 0.22" spatial region in the dispersion direction and each of the eight diodes on which the LSA projects. The result is that the spatial limb variation is directly converted into clear and simple spectral variation from the blue to the red wing of the line (see Fig. 2.b,c). Indeed, the line being optically thin, it is not difficult to show that the D Ly-alpha line intensity can be approximatively written as follows:, I_D = sum\\limits_i=1^8 J_i* w_i where w_i=(n_0.H_0+n_1.H_1)/(2.cos(Psi_i)) with i=1,5, w_6=2*(n_0.H_0)/(2.cos(Psi_6)) (the path is double for that position), w_7=2*(n_1.H_1)/(2.cos(Psi_7)), w_8=2*(n_2.H_1)/(2.cos(Psi_8)), with Psi_1 to Psi_8 the observing angles, and where n_0, n_1, and n_2 are the deuterium number densities at respectively R_0, R_1, and R_2. J_1 to J_8 are each of the eight 0.22" region contribution to the total signal. For a seek of clarity, we consider the simple case where only the D scale height H_0 for the layer embedded between R_0 and R_1 is different from H_1 the D scale height for the region above R_1. Comparison between theoretical models and observation will surely provide at least the three quantities D_0 = (n_0.H_0+n_1.H_1), D_1=n_1.H_1, and D_2=n_2.H_1 corresponding respectively to the deuterium total column density, column density between R_1 and R_2, and between R_2 and Rmax. Considering an exponential variation for the D number density, it is straightforward to show that:, H_0 = (R_1-R_0)/ln( (D_0 - D_1)/D_1), H_1 = (R_2 -R_1)/ln( D_2/D_1), n_0 = (D_0 - D_1)/H_0, n_1 = D_1/H_1, and n_2 = D_2/H_1., Observing with LSA and Echelle A will provide for a thin line a signal extending over 8 diodes which may help to derive at least 4 parameters of the model. When using Ech-A, the isotopic D-H spectral separation (~ 80 km/s) is large enough to avoid contamination from the planet's H Ly-alpha line and the Earth geocorona. For Jupiter, the H Ly-alpha intensity at mid- latitude from recent GHRS data is ~ 8 kR (Clarke et al., ApJ Lett., 430, L76 1994), and the Earth geocoronal emission is ~ 2-3 kR during dark time. We expect a 2.5 kR D Ly -alpha line due to the limb brightening. Observing the approaching limb will enhance even more the D Ly-alpha emission as the incident solar D Ly-alpha photons are blue-shifted placing the deuterium resonance close to the solar Ly- alpha blue emission peak. This will enhance by nearly a factor 2 the planet's D Ly-alpha line. Using the limited resolving power of the HRS/G160M grating, the technique showed to be very efficient even observing the dark approaching limb of Jupiter as shown in Fig.3. The case of Saturn is somewhat more complicated due to the absorption by the interplanetary medium that separates the planet from Earth. During cycle 6, we will have solar activity not too far from minimum conditions, so that, after correction for the IPM absorption, the Saturn H Ly-alpha emission will not exceed 1 to 2 kR (integrated over the entire disk). Recent observations we made, using IUE (Prange et al., IUE program 1991) and the GHRS (Clarke et al., program ID 2556), revealed a 1.5 kR to 2 kR brightness. Near 1996 observational conditions, the interplanetary medium will absorb in the red wing of the H Ly -alpha line very far from the D Ly-alpha resonance wavelength (the H-D lines separation is 80 km/s). It follows that the D Ly-alpha line will not be disturbed by the IPM. Considering a ratio D/H = 1.7* 10^-5 (Noll and Larson, 1991), we derive for Saturn a sunlit limb emission at D Ly-alpha of 500 to 700 Rayleighs which corresponds to a disk integrated intensity of 50 to 70 R., 2. Technical description of the observations, We propose to point the approaching limb as a reference target as depicted in Fig. 2a. To accurately locate the Ly- alpha planet's limb, we use the procedure proposed by the STI Moving Target Programs team for extended targets. We thus propose to use the Onboard HRS acquisition to locate the Saturnian satellite Rhea, shift to Saturn, and get the planetary limb. This will lead to a total error on the limb location of 0.1 arc-sec. These estimates have been derived by K. Noll based on already completed programs. The problem with the last acquisition technique is that the planetary Ly-alpha limb is not accurately defined. To handle this difficulty, we use a well known atmospheric level (the 1 bar level, and estimate the distance between the two planetary limbs through our radiative transfer calculation. From our analysis, we derived that this distance is known with an error of +/- 150 km. This corresponds 0.03 arc-sec for Saturn. Given the ~ 2 arc-sec LSA width, we are sure to get the planet's Ly-alpha limb within the LSA field of view with an error smaller than 0.12 arc-sec. The whole technique previously presented has been successfully used for cycle 3 observation of Jupiter and there are no inherent obstacles (Ben Jaffel et al., 1994). We therefore require 9 dark orbits, 7 for the LSA position across the expected planetary limb, and the last 2 orbits for sky background. The approaching limb is selected. The ORIENTATION of the Telescope for planetary targets is bimodal. Before opposition the orientation of the U3 axis from the North is approximatively 270 degrees, and after opposition it is approximatively 90 degrees. Based on this, the position angle of the spin axis of Saturn, and the orientation of the GHRS aperture, it is possible to determine what position on the disk perimeter to point at to align the aperture Y axis parallel to the planetary limb. Therefore, our observation will not really constrain the spacecraft operation, but will use the default orientation instead. However, to ensure any departure from the nominal angle used to determine the planetary limb, we include an ORIENT constraint, though it corresponds to the expected orientation of the spacecraft. 3. Time exposures calculation 1 kR at 1216 Angstrom within a 2"* 0.25" solid angle (one of our spatial-spectral bin) roughly corresponds to 1.53* 10^-14 ergs/cm^2-sec. We expect the D Ly-alpha line to be ~ 0.04 Angstrom large which gives a peak level of 3.83* 10^-13 ergs/cm^2-sec-Angstrom. For Echelle A and LSA the sensitivity at 1216 Angstrom is ~ 0.87* 10^11 (counts/sec-diode)/(erg/cm^2-sec-Angstrom). It follows that for 1 kR we expect a peak rate of roughly 0.031 counts/sec- diode. For a 60 min integration time, we derived a signal to noise S/N > 10 per kR per spectral bin i.e. S/N > 28 per kR for the LSA. Real Time Justification ----------------------- We desire to obtain the maximum doppler shift between the planetary and geocoronal emissions, and if possible to minimize the geocoronal background Ly- alpha emission. This is accomplished using the Earth motion, and observing Saturn no later than July 31, 1996. Also, from our experience using the HST/GHRS during the last years, we stress out the importance to measure the sky -background signal in the same conditions of observation (same range of the targets zenith angles and sun zenith angles) than the planet. This means that the sky-background and the planet's observations should be simultaneous and starting with the same position of HST on its orbit. Calibration Justification ------------------------- As we request to acquire the limb of Saturn from the acquisition of its satellite Rhea, we request a WAVE exposure at the beginning of the observation of Saturn. The WAVE should be recorded on the same position of the carrousel as when starting the planetary observation. It is intended to monitor wavelength drifts. We ask a WAVE for each exposure. Indeed, given the particular geometry of observation, we cannot use the H Ly-alpha center line as a reference. Moreover, Doppler shifts induced by thermospheric wind may occur and we would like to avoid the confusing situation where a wavelength drift may be interpreted as a real Doppler shift. As we request our own wave calibration, no SPYBAL is necessary. Additional Comments ------------------- The success of this program is completely based on the following conditions : - At the time of observation, the Y axis of LSA should be parallel to the approaching limb of the planet. The latitude of the only region that satisfy that condition is equal to : LATITUDE = 225D - (HST/Roll angle) with a corresponding radius RAD = 59438 + 3929*(COS(LAT))**2 - The doppler shift between Saturn and Earth lines should be maximum in order to not affect the weak H and D lyman-alpha lines of Saturn. This is accomplished by observing Saturn before July 31 1996. ------------------------------------------------------------------------------------ 6692( 8) - 06/17/96 10:47 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: Software-Version (Controller= 6.0) Preprocessor (Er, ------------------------------------------------------------------------------------ 6692( 8) - 06/17/96 10:47 - [ 4] TARGET LIST b)Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 | TARGET NAME: RHEA-ACQUISITION ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: Satellite Rhea ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=SATURN | STD=RHEA | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | SEP OF RHEA SATURN FROM EARTH LT 60", | SEP OF RHEA SATURN FROM EARTH GT 30", | SEP OF RHEA TETHYS FROM EARTH GT 10", | SEP OF RHEA DIONE FROM EARTH GT 10", SEP | OF RHEA MIMAS FROM EARTH GT 10", SEP OF | RHEA TITAN FROM EARTH GT 10", SEP OF | RHEA ENCELADUS FROM EARTH GT 10" | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | V = 9.7 | HRS ACQUISITION OF RHEA FOR PEAKUP B-V = 0.78 | ON SATELLITE CENTER. LSA IS | REQUIRED. FIRST STEP OF THE | TECHNIQUE TO ACCURATELY ACQUIRE THE | LIMB OF SATURN DESCRIBED IN TARGNUM | 2,3 | ------------------------------------------------------------------------------------------------------------------------------------ 6692( 8) - 06/17/96 10:47 - [ 5] TARGET LIST b)Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 2 | TARGET NAME: SATURN-LIMB ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: FEATURE SATURN ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=SATURN | TYPE=TORUS,LONG=270,LAT=- | 22,RAD=64534.,POLE_LAT=90 | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | SURF(V) = 7.0 | THE APPROACHING LIMB IS REQUIRED. SURF-LINE(1216)=2+/-1e-13 | IF, AT THE DATE OF OBSERVATION, THE W-LINE(1216)=0.04+/-0.02 | HST ROLL ANGLE CHANGES, PLEASE | CHANGE THE LATITUDE AND THE RADIUS | AS FOLLOWS : LAT = 225 D - ROLL ; | RAD (KM) = 59438 + | 5929*(COS(LAT))**2 IN ORDER TO | ALWAYS HAVE THE Y AXIS OF LSA // TO | THE LIMB | ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 3 | TARGET NAME: SKY-BACKGROUND ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: OFFSET SATURN ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 | TARGET POSITION LEVEL 2 | STD=SATURN | TYPE=TORUS,LONG=270,LAT=- | 22,RAD=12000000.,POLE_LAT=90 | ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 | WINDOWS | | ------------------------------------------------------------------------------------------------------------------------------------ DATA | COMMENTS | SURF-LINE(1216)=10+/-5e-13 | SKY BACKGROUND ROUGHLY 3 ARCMIN OFF W-LINE(1216)=0.1+/-0.02 | SATURN. PLEASE SCHEDULE IMMEDIATELY | AFTER SATURN OBSERVATION IN ORDER TO | AVOID SOLAR FLUX VARIATION AT 1216 | A. THE SKY OBSERVATION SHOULD START | WITH HST IN THE SAME POSITION ON ITS | ORBIT AS FOR THE PLANETARY | OBSERVATION. | ------------------------------------------------------------------------------------------------------------------------------------ 6692( 8) - 06/17/96 10:47 - [ 6] Visit: 01 Visit Requirements: GUIDing TOLerance 0.13" ORIENTation 246D TO 248D BETWEEN 1-JUL-96 AND 31- JUL-96 SEQ 1-2 WITHIN 48H On Hold Comments: Additional Comments: THE ORIENT REQUIREMENT ABOVE IS NOT A CONSTRAINT. WE NEED TO CONSTRAIN THE LATITUDE FOR WHICH THE Y AXIS OF THE LSA IS PARALLEL TO THE PLANETARY APPROACHING LIMB. THIS LATITUDE IS DEFINED BY : LAT = 225D - ROLL AND RAD (KM) = 58438 + 5929*(COS(LAT))**2 WE RECOMMAND TO USE THE DEFAULT ROLL BUT TO MODIFY THE PLANETARY LAT ACCORDING TO THE FORMULAS PROVIDED ABOVE; Visit should be completed in SEVEN consecutive orbits. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 RHEA-ACQUIS HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN,LOCATE=EXTENDED 1 18 S ONBOARD ACQ FOR 20 ITION Comments: STEP-TIME=2.0 sec ------------------------------------------------------------------------------------------------------------------------------------ 20 RHEA-ACQUIS HRS ACQ/PEA 2.0 MIRROR-N2 EXTENDED=YES 1 204 S ONBOARD ACQ FOR 25-81 ITION KUP Comments: step-time= 2.0 sec ------------------------------------------------------------------------------------------------------------------------------------ 25 SATURN-LIMB HRS IMAGE 2.0 MIRROR-N2 precision=high 1 51.2 S SEQ 20-26 NON-INT Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 26 SATURN-LIMB HRS ACCUM 2.0 G160M 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 326.4 S DOPPLER=DEF,COMB=FOUR ------------------------------------------------------------------------------------------------------------------------------------ 30 WAVE HRS ACCUM SC2 ECH-A 1216 1 54.4 S SEQ 30-33 NON-INT Comments: WAVE CALIBRATION FOR EXPOSURE 31. ------------------------------------------------------------------------------------------------------------------------------------ 31 SATURN-LIMB HRS ACCUM 2.0 ECH-A 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 761.6 S DOPPLER=DEF,COMB=FOUR,SPYBAL=NO Comments: Please start on same position of carrousel used for wave 30. ------------------------------------------------------------------------------------------------------------------------------------ 32 WAVE HRS ACCUM SC2 ECH-A 1216 1 54.4 S Comments: WAVE CALIBRATION FOR EXPOSURE 33. ------------------------------------------------------------------------------------------------------------------------------------ 33 SATURN-LIMB HRS ACCUM 2.0 ECH-A 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 652.8 S DOPPLER=DEF,COMB=FOUR,SPYBAL=NO Comments: Please start on same position of carrousel used for wave 32. ------------------------------------------------------------------------------------------------------------------------------------ 40 WAVE HRS ACCUM SC2 ECH-A 1216 1 54.4 S SEQ 40-43 NON-INT Comments: WAVE CALIBRATION FOR EXPOSURE 41. ------------------------------------------------------------------------------------------------------------------------------------ 41 SATURN-LIMB HRS ACCUM 2.0 ECH-A 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 761.6 S DOPPLER=DEF,COMB=FOUR,SPYBAL=NO Comments: Please start on same position of carrousel used for wave 40. ------------------------------------------------------------------------------------------------------------------------------------ 42 WAVE HRS ACCUM SC2 ECH-A 1216 1 54.4 S Comments: WAVE CALIBRATION FOR EXPOSURE 43. ------------------------------------------------------------------------------------------------------------------------------------ 6692( 8) - 06/17/96 10:47 - [ 7] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 43 SATURN-LIMB HRS ACCUM 2.0 ECH-A 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 652.8 S DOPPLER=DEF,COMB=FOUR,SPYBAL=NO Comments: Please start on same position of carrousel used for wave 42. ------------------------------------------------------------------------------------------------------------------------------------ 50 WAVE HRS ACCUM SC2 ECH-A 1216 1 54.4 S SEQ 50-53 NON-INT Comments: WAVE CALIBRATION FOR EXPOSURE 51. ------------------------------------------------------------------------------------------------------------------------------------ 51 SATURN-LIMB HRS ACCUM 2.0 ECH-A 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 761.6 S DOPPLER=DEF,COMB=FOUR,SPYBAL=NO Comments: Please start on same position of carrousel used for wave 50. ------------------------------------------------------------------------------------------------------------------------------------ 52 WAVE HRS ACCUM SC2 ECH-A 1216 1 54.4 S Comments: WAVE CALIBRATION FOR EXPOSURE 53. ------------------------------------------------------------------------------------------------------------------------------------ 53 SATURN-LIMB HRS ACCUM 2.0 ECH-A 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 652.8 S DOPPLER=DEF,COMB=FOUR,SPYBAL=NO Comments: Please start on same position of carrousel used for wave 52. ------------------------------------------------------------------------------------------------------------------------------------ 60 WAVE HRS ACCUM SC2 ECH-A 1216 1 54.4 S SEQ 60-63 NON-INT Comments: WAVE CALIBRATION FOR EXPOSURE 61. ------------------------------------------------------------------------------------------------------------------------------------ 61 SATURN-LIMB HRS ACCUM 2.0 ECH-A 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 761.6 S DOPPLER=DEF,COMB=FOUR,SPYBAL=NO Comments: Please start on same position of carrousel used for wave 60. ------------------------------------------------------------------------------------------------------------------------------------ 62 WAVE HRS ACCUM SC2 ECH-A 1216 1 54.4 S Comments: WAVE CALIBRATION FOR EXPOSURE 63. ------------------------------------------------------------------------------------------------------------------------------------ 63 SATURN-LIMB HRS ACCUM 2.0 ECH-A 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 652.8 S DOPPLER=DEF,COMB=FOUR,SPYBAL=NO Comments: Please start on same position of carrousel used for wave 62. ------------------------------------------------------------------------------------------------------------------------------------ 70 WAVE HRS ACCUM SC2 ECH-A 1216 1 54.4 S SEQ 70-71 NON-INT Comments: WAVE CALIBRATION FOR EXPOSURE 81. ------------------------------------------------------------------------------------------------------------------------------------ 71 SATURN-LIMB HRS ACCUM 2.0 ECH-A 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 1414.4 DOPPLER=DEF,COMB=FOUR,SPYBAL=NO Comments: Please start on same position of carrousel used for wave 70. ------------------------------------------------------------------------------------------------------------------------------------ 80 WAVE HRS ACCUM SC2 ECH-A 1216 1 54.4 S SEQ 80-81 NON-INT Comments: WAVE CALIBRATION FOR EXPOSURE 81. ------------------------------------------------------------------------------------------------------------------------------------ 81 SATURN-LIMB HRS ACCUM 2.0 ECH-A 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 1414.4 DOPPLER=DEF,COMB=FOUR,SPYBAL=NO Comments: Please start on same position of carrousel used for wave 80. ------------------------------------------------------------------------------------------------------------------------------------ 6692( 8) - 06/17/96 10:47 - [ 8] Visit: 02 Visit Requirements: GUIDing TOLerance 0.13" ORIENTation 246D TO 248D BETWEEN 1-JUL-96 AND 31- JUL-96 SEQ 1-2 WITHIN 48H On Hold Comments: Additional Comments: The main reason to have the observations within 48H is to avoid lyman-alpha solar flux variation (particularly the solar line shape) that could be catastrophic for the isotopic D/H ratio. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 14 RHEA-ACQUIS HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN,LOCATE=EXTENDED 1 18 S ONBOARD ACQ FOR 15 ITION Comments: STEP-TIME=2.0 sec ------------------------------------------------------------------------------------------------------------------------------------ 15 RHEA-ACQUIS HRS ACQ/PEA 2.0 MIRROR-N2 EXTENDED=YES 1 204 S ONBOARD ACQ FOR 16-19 ITION KUP Comments: step-time= 2.0 sec ------------------------------------------------------------------------------------------------------------------------------------ 16 SATURN-LIMB HRS IMAGE 2.0 MIRROR-N2 precision=high 1 51.2 S SEQ 16-17 NON-INT Comments: STEP-TIME=0.2 ------------------------------------------------------------------------------------------------------------------------------------ 17 SATURN-LIMB HRS ACCUM 2.0 G160M 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 326.4 S DOPPLER=DEF,COMB=FOUR ------------------------------------------------------------------------------------------------------------------------------------ 18 WAVE HRS ACCUM SC2 ECH-A 1216 1 54.4 S SEQ 18-19 NON-INT Comments: WAVE CALIBRATION FOR SKY-BACKGROUND 19. ------------------------------------------------------------------------------------------------------------------------------------ 19 SKY-BACKGRO HRS ACCUM 2.0 ECH-A 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 761.6 S UND DOPPLER=DEF,COMB=FOUR,SPYBAL=NO Comments: Please start on same position of carrousel used for wave 18. ------------------------------------------------------------------------------------------------------------------------------------ 20 WAVE HRS ACCUM SC2 ECH-A 1216 1 54.4 S SEQ 20-21 NON-INT Comments: WAVE CALIBRATION FOR SKY-BACKGROUND 19. ------------------------------------------------------------------------------------------------------------------------------------ 21 SKY-BACKGRO HRS ACCUM 2.0 ECH-A 1216 FP-SPLIT = STD,STEP-PATT= DEF, 1 761.6 S UND DOPPLER=DEF,COMB=FOUR,SPYBAL=NO Comments: Please start on same position of carrousel used for wave 18. ------------------------------------------------------------------------------------------------------------------------------------ 6692( 8) - 06/17/96 10:47 - [ 9] Summary Form for Proposal 6692 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAKUP IMAGE ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN LOCATE=EXTENDED EXTENDED=YES precision=high COMB=FOUR SPYBAL=NO DOPPLER=DEF STEP-PATT= DEF FP-SPLIT = STD ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category SOLAR SYSTEM ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GUIDing TOLerance 0.13" ORIENTation 246D TO 248D BETWEEN 1-JUL-96 AND 31-JUL-96 SEQ 1-2 WITHIN 48H ONBOARD ACQ FOR 20 ONBOARD ACQ FOR 25-81 SEQ 20-26 NON-INT SEQ 30-33 NON-INT SEQ 40-43 NON-INT SEQ 50-53 NON-INT SEQ 60-63 NON-INT SEQ 70-71 NON-INT SEQ 80-81 NON-INT ONBOARD ACQ FOR 15 ONBOARD ACQ FOR 16-19 SEQ 16-17 NON-INT SEQ 18-19 NON-INT SEQ 20-21 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G160M ECH-A ------------------------------------------------------------------------------------------------------------------------------------ Target Names RHEA-ACQUISITION SATURN-LIMB WAVE SKY-BACKGROUND ------------------------------------------------------------------------------------------------------------------------------------