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
Mars Reconnaissance Orbiter (MRO) Background Mars orbiter (2006-present) to characterize the surface and atmosphere of Mars (http://mars.jpl.nasa.gov/mro/) 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 Investigations 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
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)
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 -10 day observation to refine comet trajectory Integrating in rover data return Details of SHARAD plans MCS observations near closest approach 5
High- level schemacc of MRO ObservaCon Timeline 6- AUG- 2014, CRISM/HiRISE stellar scan to check boresite (1 orbit dura3on) Key: C = CRISM H = HiRISE M = MARCI X = CTX S = SHARAD C/A = Closest Approach CSS = Comet Siding Spring R/A = Ride Along MCS/M/S nadir observa3ons of atmosphere to determine background atmospheric state MCS/M/S nadir observa3ons of atmosphere to determine comet par3cle effect on atm - 2-1 Days from C/A 0 +1 +2-60 (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 Possible C/A - 10 day observa3on to refine CSS ephemeris (9- OCT- 2014) C/A (5 orbits, 1 sequence): 19- OCT- 2014 See next slide +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
SchemaCc of MRO Closest Approach ObservaCon Timeline - 2 days - 1 day C/SS Nucleus Closest Approach Possible Encounter with C/SS Debris + 1 day + 2 days Periodic C/SS Observa3ons each 2hr orbit C/A Periodic C/SS Observa3ons on each 2hr orbit 16:42:26 17:12:14 18:14:30 3 closest approach orbits C/SS C/A 18:33 UT 19:58:21 19:47:25 Center 3me for C/SS par3cle encounter with Mars: 20:07 ± 10 min UT 20:16:48 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 C/A orbit: 2 CRISM + 6 HiRISE scans + CTX R/A Various line 3mes for different exposures; CTX R/A 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) Key: C/A = Closest Approach; R/A = Ride- Along C/SS observa3ons 7