For G160M observations, please consult Chapter 9 of the COS Instrument Handbook to estimate overheads and the number of exposures per orbit, and consequently the correct lifetime position. Use of LP4 with G160M requires justification in the "Special Requirements" section of the Phase I PDF. Use of the default LP6 with G160M requires no justification. Proposals can be submitted with the warning present. For G160M observations, please consult Chapter 9 of the COS Instrument Handbook to estimate overheads and the number of exposures per orbit, and consequently the correct lifetime position. Use of LP4 with G160M requires justification in the "Special Requirements" section of the Phase I PDF. Use of the default LP6 with G160M requires no justification. Proposals can be submitted with the warning present. For G160M observations, please consult Chapter 9 of the COS Instrument Handbook to estimate overheads and the number of exposures per orbit, and consequently the correct lifetime position. Use of LP4 with G160M requires justification in the "Special Requirements" section of the Phase I PDF. Use of the default LP6 with G160M requires no justification. Proposals can be submitted with the warning present. 0 Assigned ID: 7488 ----- Attempting Submission 1 (Thu Apr 16 17:09:22 GMT 2026) ----- HST Phase I Proposal 7488 successfully submitted. Receipt: # 7488-1 ----- Attempting Submission 2 (Thu Apr 16 22:01:51 GMT 2026) ----- These errors are related to the use of COS G160M, which we understand. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. For the best data quality, it is generally required to use all four FP-POS positions at a given COS cenwave (or 2 positions for certain exception cases). See extended explanation in the diagnostic browser. Version 1: Generic ISO target, ideal 3 epoch observing strategy used. Upon discovery of 4I we will rapidly assess the observing strategy best fit to the object's orbit, HST's observing constraints, and guide star availability. -1526616416 ----- Attempting Submission 1 (Mon Aug 17 20:56:34 GMT 2026) ----- All associated warnings are related to the COS instrument settings. We have used all four FP's for the COS observations and understand the risk to be mitigated. Testing The Refractory Sulfur Reservoir Hypothesis with the Next Interstellar Object Comets are the leftovers of the era of solar system formation and, as such contain some of the most primitive materials available for study. Interstellar comets allow us to probe the volatile and organic composition of a protoplanetary disk's cold midplane, where sub-mm and IR observations cannot penetrate. Within those disks, sulfur reservoirs are currently a major source of interest in the astrophysics community as less than 0.1% of the cosmic abundance of sulfur can be traced in gas species. Recent studies imply that the missing sulfur is trapped in refractory components, but which minerals are not yet clear. Ejected icy planetesimals offer unique opportunities to investigate sulfur-bearing species that would be locked in ice or dust in the midplane of these protoplanetary disks, revealed by an interstellar object's heating as it enters our solar system. With the first light of LSST it is highly anticipated that several more will be discovered in the next few years. The time domain observations measured with HST COS and JWST during the apparition of 2I/Borisov and 3I/ATLAS resulted in a more complete picture of the chemical composition of those volatiles present in another planetary system, but did not provide conclusive results on sulfur-bearing species. We propose a Target of Opportunity program to observe the next active interstellar object, which has yet to be discovered. We will quantify its CO, CS, S2, and atomic sulfur reservoirs, a combination of species that is unique to HST's far-ultraviolet (FUV) capability, and measure the sulfur-to-oxygen ratio while providing unparalleled sensitivity to the commonly occurring cometary species OH. 1. Overall observational strategy We plan to observe the next active interstellar object with V<15 with two instrument settings, COS G160M CENWAVE 1589 A and STIS G230L, in two temporally separated epochs. The FOV will be centered at the comet. Therefore, we will use the same 4 visit (7 orbit) observing sequence (3 COS visits and one STIS visit) for each epoch. The sequence in each 2-orbit COS visit is: ACQ/IMAGE in NUV MIRROR A with PSA setting, 30 s exposure G160M FP-POS# 1794 s G160M FP-POS# 1794 s ACQ/IMAGE in NUV MIRROR A with PSA setting, 30 s exposure We will alternate the FP positions to cycle through all four FP-POS in each epoch. The first 2 visits in an epoch will cycle through FP-POS 1-4, one FP per orbit. For the third COS visit in each epoch the sequence is: ACQ/IMAGE in NUV MIRROR A with PSA setting, 30 s exposure G160M FP-POS1 897 s G160M FP-POS# 897 s The 3rd visit cycles FP-POS=1 and FP-POS=2 in a single orbit. The trailing ACQ/IMAGE used in for the first and second COS visits is eliminated to improve science overhead. This leads to a total exposure time in FP 1 and 2 each of 2691 s and 1794 s for each FP 3 and 4, for a total exposure time of 8970 s over 5 orbits. The exposure time is based on COS ETC run #COS.sp.1928787. The sequence for each 2-orbit STIS G230L visit is: ACQ in MIRROR with F28X50LP, 3 s exposure G230L with 52X0.5, 1900 s exposure IMAGE in MIRROR with F28X50LP, 3 s G230L with 52X0.5, 19000 s exposure IMAGE in MIRROR with F28X50LP This leads to a total exposure time of 3800s over two orbits. The exposure time is based on STIS ETC run #STIS.sp.1928799 2. Comet position uncertainty and acquisition: Upon discovery the next active interstellar object we will work rapidly to improve the ephemerides uncertainties. If it becomes clear that we should expect a 3-sigma uncertainty in RA or DEC in the range of 1.5" we will replace the primary ACQ/IMAGE in each COS visit with an ACQ/SEARCH pattern to ensure detection. Our team has extensive experience with HST and consists of expert observers, modelers, and data analysts, who have developed sophisticated techniques for measuring and interpreting comet activity and composition. All team members will aid in integrating the results from the COS and STIS data and will be involved in the preparation of scientific publications. The PI and team leader John Noonan (Auburn U.) is an assistant research professor with Far Ultraviolet (FUV) comet observation experience with both Rosetta Alice UVS and HST, and is an expert in the analysis and interpretation of cometary spectra. Dennis Bodewits (Auburn U.) is an expert on comet activity and coma physics and brings experience with the Rosetta and EPOXI comet missions. He has led several comet observing campaigns for space-based telescopes, including comet observations with HST, Chandra, XMM-Newton, and the Neil Gehrels-Swift Observatory. He is a co-investigator of the approved JWST TOO program to observe an interstellar object. Martin Cordiner (GSFC/Catholic University of America) is an expert in observing and modeling both bound and unbound planetary atmospheres with infrared and sub-mm observatories. He will assist in the coordination with JWST and in analysis and interpretation of the data. Nathan Roth (GSFC/American University) is an early career scientist and expert in cometary near-IR/radio spectroscopy. He will assist with observations, analysis and interpretation of the data. Davide Farnocchia (JPL) is an expert in characterizing and modeling the orbits of small bodies in the solar system and has provided critical support in the past HST observations of comets for the ephemerides updates. Marco Micheli (ESA NEOCC) is an expert observational astronomer and has vast experience extracting astrometry and characterizing small body orbits. The team's successful campaigns to characterize the atomic and molecular abundances of interstellar comet 2I/Borisov and 3I/ATLAS with HST (GO-16049, GO-17780), JWST, and ALMA give them a unique experiential advantage to observe the next interstellar object while implementing the lessons learned from their previous ISO campaigns. Solar System Astronomy Exoplanets and Exoplanet Formation 6 false true false false false false false SUPPORTED SOLAR SYSTEM COMET We will trigger our ToO upon the detection of an active ISO, that is, with an hyperbolic orbit with a barycentric eccentricity significantly greater than unity as reported by the JPL Small-body Database, that has a perihelion within 2 au and reaches at least V=15. Activity will be defined as having a distinct coma upon detection that manifests as a nonstellar point spread function in discovery images and that persists in all follow-up observations. We will coordinate with the JWST ToO team to trigger on the same object and focus HST's capability near perihelion, where JWST may not be able to observe depending on the object's path through the solar system. Active Interstellar Comet COS/FUV Spectroscopic No No G160M 1589 COS/FUV Spectroscopic No No G160M 1589 COS/FUV Spectroscopic No No G160M 1589 STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Imaging No No F28X50LP STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Imaging No No F28X50LP STIS/NUV-MAMA Spectroscopic No No G230L 2376 STIS/CCD Imaging No No F28X50LP Timing link suitability includes constraints ([Group (01 02 03 04 05 06 07) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "01" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:40.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "01" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (01 02 03 04 05 06 07) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "05" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:13.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "05" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (01 02 03 04 05 06 07) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "02" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:41.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "02" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (01 02 03 04 05 06 07) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "03" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:41.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "03" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (01 02 03 04 05 06 07) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "04" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:41.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "04" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (01 02 03 04 05 06 07) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "06" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:42.0" :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 1167952 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "06" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2504 :al-overhead-at-end 0 :internal-dur-at-end 340 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (01 02 03 04 05 06 07) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "07" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:43.0" :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 1167952 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "07" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2504 :al-overhead-at-end 0 :internal-dur-at-end 340 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (08 09 10 11 12 13 14) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "08" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:43.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "08" :obset-id "08" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "08" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (08 09 10 11 12 13 14) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "09" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:43.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "09" :obset-id "09" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "09" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (08 09 10 11 12 13 14) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "10" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:44.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "10" :obset-id "10" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "10" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (08 09 10 11 12 13 14) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "11" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:44.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "11" :obset-id "11" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "11" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (08 09 10 11 12 13 14) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "12" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:44.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "12" :obset-id "12" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "12" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (08 09 10 11 12 13 14) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "13" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:45.0" :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 1167952 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "13" :obset-id "13" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "13" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2504 :al-overhead-at-end 0 :internal-dur-at-end 340 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (08 09 10 11 12 13 14) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "14" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:45.0" :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 1167952 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "14" :obset-id "14" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "14" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2504 :al-overhead-at-end 0 :internal-dur-at-end 340 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (15 16 17 18 19 20 21) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "15" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:46.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "15" :obset-id "15" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "15" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (15 16 17 18 19 20 21) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "16" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:46.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "16" :obset-id "16" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "16" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (15 16 17 18 19 20 21) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "17" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:46.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "17" :obset-id "17" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "17" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (15 16 17 18 19 20 21) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "18" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:47.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "18" :obset-id "18" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "18" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (15 16 17 18 19 20 21) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "19" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:47.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "31" :si-bright-earth-limb-angle 20.0 :data-volume 34896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "19" :obset-id "19" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "19" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2116 :al-overhead-at-end 0 :internal-dur-at-end 357 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2867 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (15 16 17 18 19 20 21) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "20" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:48.0" :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 1167952 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "20" :obset-id "20" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "20" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2504 :al-overhead-at-end 0 :internal-dur-at-end 340 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17. Timing link suitability includes constraints ([Group (15 16 17 18 19 20 21) Within 7.0 days]) The scheduling data was generated by CASM 34.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 18397 :visit-id "21" :proposal-version -1 :trans-version "20260618" :date "17-Aug-2026 14:54:48.0" :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 1167952 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 18397 :visit-id "21" :obset-id "21" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 18397 :visit-id "21" :orbit-number 1 :pcs-time 380 :si-vis-utilization 2504 :al-overhead-at-end 0 :internal-dur-at-end 340 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 2979 :pcs-gap 0 ) true 1 0 We are on hold to activate for an active ISO that is observable by HST and will reach a minimum magnitude of 17.