Resubmitted with correct PI email address 577892993 Assigned ID: 1024 ----- Attempting Submission 1 (Fri Apr 08 23:34:16 GMT 2016) ----- HST Phase I Proposal 1024 (Cassini_impact_apt) successfully submitted. Receipt: # 1024-1 ----- Attempting Submission 2 (Fri Apr 08 23:45:57 GMT 2016) ----- Visit Planner returned the warning: Target SATURN: There is no need or capability to test the scheduling of observations of moving targets in Phase I. Sensitive exposures should have an ETC run number provided. 0 ----- Attempting Submission 1 (Mon Jul 18 21:28:37 GMT 2016) ----- This target (Saturn) has been observed with STIS FUV-MAMA and 25MAMA filter many times before. The Cassini spacecraft's mission at Saturn will end after over 13 years in orbit, on September 15th, 2017. The spacecraft will be disposed of by impacting Saturn and its atmospheric entry will be that of an artificial meteor. The resulting bolide will be observable in the far ultraviolet using Hubble Space Telescope's STIS instrument. We propose to observe this event using STIS-FUV MAMA, in TIME-TAG imaging mode. The goal of this observation is to determine the luminous efficiency of hypervelocity impacts on gas giants. Recent observations of meteor flashes on Jupiter could be used to determine the flux and size distribution of meteors in the outer solar system, but only if the luminoius efficiency is known. With a well-known mass (2186 kg) and impact velocity (34.9 km/s), the Cassini impact will provide this information. An additional goal is the validate and improve the existing model of Saturn's atmosphere, between 1 nanobar and a few microbars. This region is of particular interest to the interpretation of aurora observations and to the development of future missions involving atmospheric probes. The Cassini spacecraft's mission at Saturn will end after over 13 years in orbit, on September 15th, 2017. The spacecraft will be disposed of by impacting Saturn and its atmospheric entry will be that of an artificial meteor. The resulting bolide will be observable in the far ultraviolet using Hubble Space Telescope's STIS instrument. We propose to observe this event using STIS-FUV MAMA, in TIME-TAG imaging mode. The goal of this observation is to determine the luminous efficiency of hypervelocity impacts on gas giants. Recent observations of meteor flashes on Jupiter could be used to determine the flux and size distribution of meteors in the outer solar system, but only if the luminoius efficiency is known. With a well-known mass (2186 kg) and impact velocity (34.9 km/s), the Cassini impact will provide this information. An additional goal is the validate and improve the existing model of Saturn's atmosphere, between 1 nanobar and a few microbars. This region is of particular interest to the interpretation of aurora observations and to the development of future missions involving atmospheric probes. Solar System 3 false true false false false false SUPPORTED SOLAR SYSTEM YES PLANET Planet Saturn STD=SATURN NOT ECL P PARTIAL OF SATURN BY TITAN FROM EARTH, SEP OF SATURN RHEA FROM EARTH GT 10", SEP OF SATURN TITAN FROM EARTH GT 10" EARTH STIS/FUV-MAMA Imaging No No 25MAMA 1468875130315 /Users/frcr6658/Saturn/Cassini/MAG_TWT/MAG_293/HST_observation/OP-cache/HST_14795-v01.xml The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14795 :visit-id "01" :proposal-version -1 :trans-version "20160601" :date "18-Jul-2016 14:52:09.0" :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 1739552 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14795 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14795 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2694.0 :al-overhead-at-end 0 :internal-dur-at-end 440.0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3210 :pcs-gap 0 ) true 1 0