! Proposal 6817, submission 1 ! PI: Keith Noll ! Received Mon Feb 5 19:08:00 EST 1996 ! From: noll@stsci.edu ! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! $Id: 6817,v 4.1 1996/07/08 16:58:27 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Lubenow ! Phone: 410-338-4928 , E-mail: lubenow@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Name of Phase I Proposal: archive-1094.noll.prop ! Date generated: Fri Dec 22 16:24:30 EST 1995 ! Proposal_Information ! Section 4 Title: The Ultraviolet Spectrum of Callisto Proposal_Category: GO Scientific_Category: SOLAR SYSTEM Cycle: 6 Investigators PI_name: Keith Noll PI_Institution: Space Telescope Science Institute CoI_Name: Arthur Lane CoI_Institution: Jet Propulsion Laboratory Contact: ! Y or N (designate at most one contact) CoI_Name: Deborah Domingue CoI_Institution: Lunar and Planetary Institute Contact: ! Y or N (designate at most one contact) CoI_Name: Robert Johnson CoI_Institution: University of Virginia Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) Ultraviolet spectra of Jupiter's icy satellites Europa and Ganymede have revealed the presence of contaminants in surface ices produced by ion irradiation. \SOt\ ice has been identified on the trailing hemisphere of Europa at 280 nm and \oz\ on the trailing hemisphere of Ganymede in a broad band at 260 nm. Recalibrated IUE spectra now suggest the presence of a broad absorption band on Ganymede's trailing hemisphere. We will complete our survey of the ultraviolet spectra of these objects by measuring the UV spectrum of Callisto with the HST FOS. Questions ! Free format text (please update) Observing_Description: In our cycle 5 FOS observations of Europa and Ganymede we used a novel target acquisiton technique that allowed us to complete a UV spectroscopic observation of these satellites in 1 orbit. We plan to use the same observing sequence for this observation. Acquisition with the FOS is normally problematic for the Galilean satellites. However, the GHRS has a mode, LOCATE=EXTENDED designed specifically for acquisition of bright objects up to 2 arcsec in diameter. Including overheads, this procedure allows an pointing accurate to 0.1 arcsec in 11 minutes. The relative position of the GHRS and FOS apertures are also known to this precision. This accuracy is more than sufficient since Callisto will overfill the FOS 0.86 arcsec diameter aperture. In the remaining portion of the orbit we will obtain a 130 second exposure in the G270H grating and a 1080 second exposure in the G190H grating. The resultant S/N will be comparable to that of Ganymede shown in figure 1. This is more than sufficient to identify surface contaminants in the spectrum. Real_Time_Justification: Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Solar_System_Targets ! Section 5.2 Target_Number: 1 Target_Name: Callisto Description: satellite Callisto Level_1: STD = Jupiter Level_2: STD = Callisto Level_3: Ephem_Uncert: ! Needed for REQ EPHEM CORR sp req Acq_Uncert: ! Needed for SAVE and USE OFFSET sp reqs Window: OLG of Callisto from Earth between 250 290 Flux: V = 5.65 B-V = 0.86 Comments: HRS acq for FOS science ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number: 1 Visit_Requirements: ! Section 7.1 ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling ! PCS MODE [Fine | Gyro] ! GUIDing TOLerance ! DROP TO GYRO IF NECESSARY [NO REACQuisition] ! ORIENTation TO ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! SCHEDulability ! AFTER [BY [TO ]] ! AFTER ! BEFORE ! BETWEEN AND ! GROUP WITHIN