13803( 5) - 13-Feb-2015 18:59:13 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13803 Version: 5 Check-in Time: 13-Feb-2015 18:59:13 STScI Edit Number: 1 Title Europa's Composition as Revealed by its Atmosphere ------------------------------------------------------------------------------------ Type Cycle GO 22 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Melissa A. McGrath SETI Institute Y CoI: Dr. John R. Spencer Southwest Research Institute N CoI: Dr. William B. Sparks Space Telescope Science Institute N ------------------------------------------------------------------------------------ Abstract The two main sources of Europa's tenuous atmosphere, surface sputtering and plumes, imply that Europa's surface and sub-surface composition are directly reflected by the composition of its atmosphere. Recent detection of water vapor plumes at Europa makes it more likely that the atmosphere contains important trace species that are diagnostic of the sub-surface ocean composition. We will perform a sensitive search for trace species via electron excited emissions in the far-ultraviolet with the Cosmic Origins Spectrograph, in order to constrain the composition of the ice-ocean-rock system and better understand the potential habitability of the satellite. HST spectroscopic measurement of trace species is one of the only techniques presently available to meaningfully constrain Europa's composition. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will perform deep spectroscopic integrations of Europa using COS gratings G130M and G160M to search for trace species in Europa's atmosphere. To minimize contamination from Earth's geocoronal emission, we request that the observations be performed near Jupiter opposition. We are targeting the Europa trailing hemisphere, which potentially has a higher abundance of trace species contaminating the surface than the leading hemisphere. We will cycle through the four FP-POS positions with both gratings. Precise centering is not required, so we will utilzie only an acq/search. The acq/search exposure time pf 3 s is based on the well known trailing hemisphere albedo of Europa at 2700 A (about 10%), and the counts obtained in the COS acq/search and acq/peakd acquitisions of Europa in program 11353. ------------------------------------------------------------------------------------ 13803( 5) - 13-Feb-2015 18:59:13 - [ 2] TARGET LIST Solar System Targets ------------------------------------------------------------------------------------------------------------------------------------ TARGET NUMBER: 1 TARGET NAME: EUROPA-TRAILING ------------------------------------------------------------------------------------------------------------------------------------ TARGET DESCRIPTION: SATELLITE Europa's trailing hemisphere ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 1 TARGET POSITION LEVEL 2 STD=JUPITER STD=EUROPA ------------------------------------------------------------------------------------------------------------------------------------ TARGET POSITION LEVEL 3 WINDOWS SEP OF EUROPA-TRAILING JUPITER FROM EARTH GT 30", SEP OF EUROPA-TRAILING CALLISTO FROM EARTH GT 10", SEP OF EUROPA-TRAILING IO FROM EARTH GT 10", SEP OF EUROPA-TRAILING GANYMEDE FROM EARTH GT 10", OLG OF EUROPA-TRAILING BETWEEN 240 300, OLG OF JUPITER BETWEEN 330 20 ------------------------------------------------------------------------------------------------------------------------------------ DATA COMMENTS V = 5.7 +/- 1 Ephemeris Center: EARTH ------------------------------------------------------------------------------------------------------------------------------------ 13803( 5) - 13-Feb-2015 18:59:13 - [ 3] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 EUROPA-TRAI COS/NUV ACQ/SEA PSA G285M 2617 SCAN-SIZE=3, 1 3 S (3 S) GS ACQ SCENARIO BASE1B3 LING RCH CENTER=FLUX-WT-FLR ------------------------------------------------------------------------------------------------------------------------------------ 2 EUROPA-TRAI COS/FUV TIME-TA PSA G130M 1327 BUFFER-TIME=860, FP-POS=1 1 970 S (970 LING G S) ------------------------------------------------------------------------------------------------------------------------------------ 3 EUROPA-TRAI COS/FUV TIME-TA PSA G130M 1327 FP-POS=2, BUFFER-TIME=860 1 970 S (970 LING G S) ------------------------------------------------------------------------------------------------------------------------------------ 4 EUROPA-TRAI COS/FUV TIME-TA PSA G130M 1327 BUFFER-TIME=510, FP-POS=ALL 1 620 S LING G (2480 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 EUROPA-TRAI COS/FUV TIME-TA PSA G130M 1327 FP-POS=1, BUFFER-TIME=480 1 585 S (585 LING G S) ------------------------------------------------------------------------------------------------------------------------------------ 6 EUROPA-TRAI COS/FUV TIME-TA PSA G130M 1327 FP-POS=2, BUFFER-TIME=480 1 585 S (585 LING G S) ------------------------------------------------------------------------------------------------------------------------------------ 7 EUROPA-TRAI COS/FUV TIME-TA PSA G160M 1589 FP-POS=1, BUFFER-TIME=480 1 585 S (585 LING G S) ------------------------------------------------------------------------------------------------------------------------------------ 8 EUROPA-TRAI COS/FUV TIME-TA PSA G160M 1589 FP-POS=2, BUFFER-TIME=480 1 585 S (585 LING G S) ------------------------------------------------------------------------------------------------------------------------------------ 9 EUROPA-TRAI COS/FUV TIME-TA PSA G160M 1589 FP-POS=ALL, BUFFER-TIME=510 1 620 S LING G (2480 S) ------------------------------------------------------------------------------------------------------------------------------------ 10 EUROPA-TRAI COS/FUV TIME-TA PSA G160M 1589 FP-POS=ALL, BUFFER-TIME=510 1 620 S LING G (2480 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ EUROPA-TRAILING 1 COS/NUV ACQ/SEA PSA G285M 2617 none none none none 1 N/A RCH EUROPA-TRAILING 2 COS/FUV TIME-TA PSA G130M 1327 none none none none 1 N/A G EUROPA-TRAILING 3 COS/FUV TIME-TA PSA G130M 1327 none none none none 1 N/A G 13803( 5) - 13-Feb-2015 18:59:13 - [ 4] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ EUROPA-TRAILING 4 COS/FUV TIME-TA PSA G130M 1327 none none none 1 2 N/A G EUROPA-TRAILING 4 COS/FUV TIME-TA PSA G130M 1327 none none none 2 2 N/A G EUROPA-TRAILING 4 COS/FUV TIME-TA PSA G130M 1327 none none none 3 2 N/A G EUROPA-TRAILING 4 COS/FUV TIME-TA PSA G130M 1327 none none none 4 2 N/A G EUROPA-TRAILING 5 COS/FUV TIME-TA PSA G130M 1327 none none none none 3 N/A G EUROPA-TRAILING 6 COS/FUV TIME-TA PSA G130M 1327 none none none none 3 N/A G EUROPA-TRAILING 7 COS/FUV TIME-TA PSA G160M 1589 none none none none 3 N/A G EUROPA-TRAILING 8 COS/FUV TIME-TA PSA G160M 1589 none none none none 3 N/A G EUROPA-TRAILING 9 COS/FUV TIME-TA PSA G160M 1589 none none none 1 4 N/A G EUROPA-TRAILING 9 COS/FUV TIME-TA PSA G160M 1589 none none none 2 4 N/A G EUROPA-TRAILING 9 COS/FUV TIME-TA PSA G160M 1589 none none none 3 4 N/A G EUROPA-TRAILING 9 COS/FUV TIME-TA PSA G160M 1589 none none none 4 4 N/A G EUROPA-TRAILING 10 COS/FUV TIME-TA PSA G160M 1589 none none none 1 5 N/A G EUROPA-TRAILING 10 COS/FUV TIME-TA PSA G160M 1589 none none none 2 5 N/A G EUROPA-TRAILING 10 COS/FUV TIME-TA PSA G160M 1589 none none none 3 5 N/A G EUROPA-TRAILING 10 COS/FUV TIME-TA PSA G160M 1589 none none none 4 5 N/A G 13803( 5) - 13-Feb-2015 18:59:13 - [ 5] Summary Form for Proposal 13803 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/SEARCH, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=480, BUFFER-TIME=510, BUFFER-TIME=860, CENTER=FLUX-WT-FLR, FP-POS=1, FP-POS=2, FP-POS=ALL, SCAN-SIZE=3 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GS ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, G160M, G285M ------------------------------------------------------------------------------------------------------------------------------------ Target Names EUROPA-TRAILING ------------------------------------------------------------------------------------------------------------------------------------