0Assigned ID: 1502
----- Attempting Submission 1 (Wed Aug 02 17:33:14 GMT 2017) -----
HST Phase I Proposal 1502 (Phaethon.apt) successfully submitted.
Receipt: # 1502-1
----- Attempting Submission 2 (Wed Aug 02 17:44:59 GMT 2017) -----
HST Phase I Proposal 1502 (Phaethon.apt) successfully submitted.
Receipt: # 1502-2Cycle 25 has been specified, but STScI records indicate that program 15379 is assigned to cycle 24. Please change the cycle selection; or if you believe that STScI has recorded the wrong cycle number, then contact your program coordinator.
Ephemeris Center: HUBBLE is recommended only when observing a target closer than 3.8 million kilometers. If the target is farther than that, Ephemeris Center: EARTH is recommended.
Ephemeris Center: HUBBLE is recommended only when observing a target closer than 3.8 million kilometers. If the target is farther than that, Ephemeris Center: EARTH is recommended.
Could not find ephemeris for target 15379-51-PHAETHON-NEW0----- Attempting Submission 1 (Tue Sep 12 18:23:10 GMT 2017) -----
HST Phase II Proposal 15379 (Phaethon_phase2.apt) successfully submitted.
Receipt: # 15379-1
----- Attempting Submission 2 (Wed Nov 08 17:54:07 GMT 2017) -----
HST Phase II Proposal 15379 (phaethon_nov30_v2.apt) successfully submitted.
Receipt: # 15379-2
----- Attempting Submission 3 (Thu Nov 16 00:34:08 GMT 2017) -----
----- Attempting Submission 4 (Tue Dec 05 14:57:22 GMT 2017) -----
HST Phase II Proposal 15379 (phaethon_dec5.apt) successfully submitted.
Receipt: # 15379-4
----- Attempting Submission 5 (Wed Dec 13 20:01:32 GMT 2017) -----I have run the orbit planner. I get errors in the visit planner.Characterizing Enigmatic Phaethon in the UV(3200) Phaethon is a curious object: just 5 km in diameter, it is a near-Earth asteroid that shows signs of being active and is the parent body of the Geminid meteor stream. Phaethon is a B-class asteroid, as is Bennu, the target of the upcoming NASA OSIRIS-REx mission. As a B-class asteroid, Phaethon is linked with carbonaceous species and phyllosilicates; both of these types of materials exhibit diagnostic spectral features in the UV, yet Phaethon has not been observed deep in the UV. Phaethon's UV-visible observations (near 400 nm) suggest spectral variability, spatially and/or temporally. In December 2017, Phaethon will be at its closest approach to Earth in decades. We propose 2 orbits of DD time to observe Phaethon for the first time using STIS deep in the UV to investigate the 400 nm region (potentially diagnostic of phyllosilicates), characterize its spectral shape deeper in the UV (to look for carbon signatures) and to understand the spectral character of Phaethon for better understanding of OSIRIS-REx target Bennu. UV-visible laboratory measurements of candidate materials will be made through our recently-selected NASA SSERVI program, for comparison with Phaethon STIS data.Our goal is to observe Phaethon using the STIS G140L (115-174 nm), G230L (157-318 nm) and
G430L (290-570 nm) gratings to obtain full spectral coverage in the ~100-570 nm range, gaining
new insights into Phaethon's surface composition and possible activity, investigating its UV
absorption edge and spectral shape, and ensuring spectral overlap with existing ground-based data.
We will employ the strategies we used for our Ceres program (13693), observing Phaethon in 2 HST
orbits.
On Dec 9 2017, Phaethon will be 0.043arcsec in diameter and the solar phase angle will be ~19.6deg;
the apparent size increases with time up until Dec 17, when it reaches 0.1arcsec; the phase angle also
increases in this period as Phaethon approaches periapsis, to 65.7deg on Dec 17. Ideally our STIS
observations would occur at a sweet spot between angular size and phase angle. In our ETC
calculations, we find that the best opportunities to maximize UV SNR, while not getting close to
saturating the CCD, are on Dec 14-15.
We have run ETC based on our experience observing Ceres, which has a similar albedo (Ceres'
albedo is ~0.08 compared to Phaethon's of ~0.11, but the Phaethon phase angle will be higher than
Ceres'). Though we don't expect Phaethon's spectral shape to match Ceres', we expect that using
Ceres' spectral shape in ETC is a good enough approximation to make sure that the CCD isn't
saturated and MAMA count rates are not exceeded.
As with the Cycle 22 Ceres observations, we will combine the spectra from each grating into a
composite spectrum. The G140L data will be critical for testing whether a Ceres-like bump near
160 nm is observed; the G430L data will be used to confirm the spectral shape in this contentious
region and possibly look for spatial variations if the timing of the two HST orbits occurs
such that different hemispheres of Phaethon are observed (Phaethon's rotational period is 3.6 hr); the
G230L spectra are important for connecting the G140L and G430L regions and understanding the
overall spectral shape.
We can achieve the required spectral coverage using 2 2-sec G430L exposures, along with 2
700-sec G230L exposures on one orbit; on the second orbit we will do one ~2000-sec G140L
exposure plus 2 more 2-sec G430L exposures. We will use the 0.1arcsec slit. Our ETC estimates indicate
that the G140L SNR will be even higher for Phaethon than for Ceres, demonstrating the excellent
quality of this observing opportunity.Solar System0AVAILABLESOLAR SYSTEMYESASTEROIDAsteroid 3200 PhaethonTYPE=ASTEROID,A=1.271276492594683,E=0.890010915974444,I=22.19847903363508,O=265.3465654874296,W=322.0555020924195,M=139.754587559709,EQUINOX=J2000,EPOCH=17-JUN-2011:00:00:00,EpochTimeScale=TDBEARTHSOLAR SYSTEMYESASTEROIDAsteroid 3200 PhaethonTYPE=ASTEROID,A=1.271276492594683,E=0.890010915974444,I=22.19847903363508,O=265.3465654874296,W=322.0555020924195,M=139.754587559709,EQUINOX=J2000,EPOCH=17-JUN-2011:00:00:00,EpochTimeScale=TDBHUBBLESOLAR SYSTEMASTEROID3200 PHAETHONTYPE=ASTEROID,A=1.271276492594683,E=0.890010915974444,I=22.19847903363508,O=265.3465654874296,W=322.0555020924195,M=139.754587559709,EQUINOX=J2000,EPOCH=17-JUN-2011:00:00:00,EpochTimeScale=TDBHUBBLESTIS/CCDSpectroscopicNoNoG430L4300STIS/NUV-MAMASpectroscopicNoNoG230L2376STIS/CCDSpectroscopicNoNoG430L4300STIS/FUV-MAMASpectroscopicNoNoG140L1425Using ephemeris for target 15379-01-PHAETHONephemeris data for target 15379-01-PHAETHON does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 17.213 to 19.091. ephemeris interval: 17.304 to 19.305The scheduling data was generated by CASM 25.2.CASM was run in Phase II mode.1512002069000250.4055318488929(Tic-Visit
:proposal-id 15379
:visit-id "01"
:proposal-version -1
:trans-version "20170613"
:date "15-Nov-2017 17:31:31.0"
: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 267456
:tdrss-contact-duration 0
:coron NIL
)
(Tic-Obset
:proposal-id 15379
:visit-id "01"
:obset-id "01"
:pcs-mode "FGS"
)
(Tic-Orbit
:proposal-id 15379
:visit-id "01"
:orbit-number 1
:pcs-time 333
:si-vis-utilization 2828
:al-overhead-at-end 0
:internal-dur-at-end 434
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3202
:pcs-gap 0
)false10Using ephemeris for target 15379-02-PHAETHONephemeris data for target 15379-02-PHAETHON does not cover planning interval. Physical constraints are assumed to be unschedulable outside of the ephemeris data. Planning interval: 17.213 to 19.091. ephemeris interval: 17.304 to 19.305The scheduling data was generated by CASM 25.2.CASM was run in Phase II mode.1512007718000261.7589085233637(Tic-Visit
:proposal-id 15379
:visit-id "02"
:proposal-version -1
:trans-version "20170613"
:date "15-Nov-2017 17:33:26.0"
: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 87440
:tdrss-contact-duration 0
:coron NIL
)
(Tic-Obset
:proposal-id 15379
:visit-id "02"
:obset-id "02"
:pcs-mode "FGS"
)
(Tic-Orbit
:proposal-id 15379
:visit-id "02"
:orbit-number 1
:pcs-time 333
:si-vis-utilization 2819
:al-overhead-at-end 0
:internal-dur-at-end 394
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 3202
:pcs-gap 0
)false10(Tic-Visit
:proposal-id 15379
:visit-id "51"
:proposal-version -1
:trans-version "20171009"
:date "13-Dec-2017 16:11:55.0"
: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 258096
:tdrss-contact-duration 0
:coron NIL
)
(Tic-Obset
:proposal-id 15379
:visit-id "51"
:obset-id "51"
:pcs-mode "FGS"
)
(Tic-Orbit
:proposal-id 15379
:visit-id "51"
:orbit-number 1
:pcs-time 333
:si-vis-utilization 2496
:al-overhead-at-end 0
:internal-dur-at-end 439
:dark-offset NIL
:dark-utilization 0
:max-dark-utilization 1920
:low-sky "N"
:pcs-visibility 2978
:pcs-gap 0
)false10