Mars Reconnaissance Orbiter Observa3on Plan for Comet Siding Spring Encounter Leslie Tamppari, MRO Deputy Project Scien3st Jet Propulsion Laboratory, California Ins3tute of Tehcnology 8/11/14 (c) 2014 California Ins3tute of Technology. Government sponsorship acknowledged Mars Reconnaissance Orbiter (MRO) Background •
Mars orbiter (2006-present) to characterize the surface and atmosphere of
Mars (http://mars.jpl.nasa.gov/mro/)
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Orbit characteristics
–  112 min orbit period (~300 km altitude; varies 250-320 km)
–  Near-circular, near-polar orbit, sun-synchronous (3 a.m./3 p.m LMST)
–  Nadir pointed with +/- 30° roll capability for precise targeting
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Investigations
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HiRISE (High-Resolution Imaging Spectrometer, VIS, 30 cm/pixel)
CRISM (Compact Reconnaissance Imaging Spectrometer, VIS-NIR, 18 m/pixel)
CTX (Context camera, 6 m/pixel)
MARCI (Mars Color Imager, weather camera, 1 km/pixel)
MCS (Mars Climate Sounder, atmospheric profiles( T, p, τ), 5 km altitude res’n)
SHARAD (Shallow Radar, also total electron density in ionosphere)
Gravity
(c) 2014 California Ins3tute of Technology. Government sponsorship acknowledged (c) 2014 California Ins3tute of Technology. Government sponsorship acknowledged The MRO team is excited by the unique opportunity and challenge of observing Comet Siding Spring! •  MRO will be phased to be “behind” Mars from the perspective of any
potential incoming particles
•  MRO will be able to observe CSS at closest approach
•  The MRO team and collaborators have been working hard to make
these observations happen
–  6 sequences devoted to observing CSS (outside of our normal observing)
•  MRO will prioritize comet related observations over Mars observations for +/-2.5 days around
closest approach
–  The pace of observations is set by our ability to acquire them (e.g., workload,
testing, data return, power, thermal)
–  These kinds of sequences and S/C motions have been designed before (e.g.,
Comet ISON, Phoenix and MSL EDL, Phobos, Deimos, Jupiter observations)
(c) 2014 California Ins3tute of Technology. Government sponsorship acknowledged MRO ObservaCons of Siding Spring •  There are 3 main science objectives for MRO during the encounter:
–  Observations of the comet near closest approach
•  Nucleus size, rotation, shape (estimate => 0.6-1.5 km diameter)
–  HiRISE (best resolution ~131 m/pixel)
–  CTX (> 3 km/pixel) and CRISM (>10 km/pixel) with also observe
–  Observations of the coma and tail:
•  Composition –HiRISE (color), CRISM (water ice and vapor, minerals, gases)
•  Morphology --HiRISE, CTX, CRISM
–  Observations the Mars atmosphere and ionosphere:
•  Atmospheric Heating—MCS, MARCI (temperatures, clouds)
•  Electron Density Peak –SHARAD (total electron column density)
•  Planning items being discussed
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-10 day observation to refine comet trajectory
Integrating in rover data return
Details of SHARAD plans
MCS observations near closest approach
(c) 2014 California Ins3tute of Technology. Government sponsorship acknowledged 5 High-­‐level schemaCc of MRO ObservaCon Timeline Key: C = CRISM H = HiRISE M = MARCI 6-­‐AUG-­‐2014, CRISM/HiRISE stellar scan to check boresite (1 orbit dura3on) MCS/M/S nadir observa3ons of atmosphere to determine background atmospheric state -­‐2 -­‐1 MCS/M/S nadir observa3ons of atmosphere to determine comet par3cle effect on atm Days from C/A -­‐60 (2.5 d) to -­‐5 hours: 2 observa3ons every other orbit using ~75% of orbit. H/C observa3ons to determine rota3on rate; X R/A X = CTX S = SHARAD C/A = Closest Approach CSS = Comet Siding Spring R/A = Ride Along 0 C/A (5 orbits, 1 sequence): 19-­‐OCT-­‐2014 See next slide +1 +2 +5 to +60 (2.5 d) hours: 2 observa3ons every other orbit using ~75% of orbit. H/C observa3ons to determine rota3on rate; X R/A Possible C/A -­‐10 day observa3on to refine CSS ephemeris (9-­‐OCT-­‐2014) (c) 2014 California Ins3tute of Technology. Government sponsorship acknowledged SchemaCc of MRO Closest Approach ObservaCon Timeline C/SS Nucleus Closest Approach
- 2 days
Possible Encounter with C/SS Debris
- 1 day
+ 1 day
Periodic C/SS Observa3ons each 2hr orbit C/A
+ 2 days
Periodic C/SS Observa3ons on each 2hr orbit 3 closest approach orbits
C/A – 1 orbit: 2 CRISM + 4 HiRISE scans Various line 3mes to provide different exposures; CTX R/A 19:47:25 19:58:21 18:14:30 17:12:14 16:42:26 C/SS C/A 18:33 UT C/A orbit: 2 CRISM + 6 HiRISE scans + CTX R/A Various line 3mes for different exposures; CTX R/A Key: C/A = Closest Approach; R/A = Ride-­‐Along 20:16:48 Center 3me for C/SS par3cle encounter with Mars: 20:07 ± 10 min UT Most likely 3me to see atmospheric effects C/A + 1 orbit: 2 CRISM + 4 HiRISE scans Various line 3mes to provide different exposures, CTX R/A Nadir observa3ons (MCS, M, and/or S) C/SS observa3ons (c) 2014 California Ins3tute of Technology. Government sponsorship acknowledged 7