MMS SWG 27 March 2014 1 MMS SWG –27 March 2014 MMS Mission Design March Launch Comparison (slides for the Telecon on 4 April 2014) Stephen A. Fuselier Southwest Research Institute Steven M. Petrinec , Lockheed Martin Advanced Technology Center Karlheinz J. Trattner LASP thanks to Vassilis and his team for providing the and to Steve Petrinec for quickly completing the an
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MMS SWG 27 March 2014 1 MMS SWG –27 March 2014 MMS Mission Design March Launch Comparison (slides for the Telecon on 4 April 2014) Stephen A. Fuselier.
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MMS SWG 27 March 2014 1
MMS SWG –27 March 2014MMS Mission Design
March Launch Comparison(slides for the Telecon on 4 April 2014)
Stephen A. FuselierSouthwest Research Institute
Steven M. Petrinec, Lockheed Martin Advanced Technology Center
Karlheinz J. Trattner LASP
Special thanks to Vassilis and his team for providing the ephem files and to Steve Petrinec for quickly completing the analysis
MMS SWG 27 March 2014
Agenda and Results• Side-by-side comparison of the 15 March 2015 launch
date– Nominal mission– THEMIS coordination mission (using the “Peak” mission”If you don’t want to look at the following slides, here are the results
• Compare the number of diffusion region encounters at the dayside MP– Result: THEMIS coordination has ~400 more magnetopause
encounters, and therefore ~4-8 more diffusion region encounters
• Compare the number of hours near the tail neutral sheet– Result: both missions have similar number of hours
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MMS SWG 27 March 2014
Analysis of 15 March 2015 Launches• Nominal Mission: Orbit Ephem. provided by GSFC Flight
Dynamics – Predicted number of magnetopause crossings for phase 1a, 1b
• Predicted number of diffusion region encounters
– Number of hours within 0.5 RE of the Fairfield tail neutral sheet
• THEMIS coordination mission: Orbit Ephem. provided by Vassilis/UCLA/UCB– 2 different RAANs – picked the “peak” mission (RAAN = 76 deg)– Predicted number of magnetopause crossings for phases 0a, 1a, 1b
• Predicted number of diffusion region encounters
– Number of hours within 0.5 RE of the Fairfield tail neutral sheet
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Steve Petrinec used an identical process to analyze these missions Analysis includes a random element – IMF data from 1 solar cycle prior to the orbits used to determine number of dayside diffusion region encounters
Conclusions (1)• Side-by-side comparison of the Nominal Mission
and THEMIS Coordination Mission– Similar probabilities of encounter of diffusion region at the
dayside magnetopause– ~250 more magnetopause crossings for the THEMIS
Coordination Mission• ~12 more diffusion region encounters
– Nearly the same dwell time in the tail neutral sheet (299 versus 264 hours, respectively)
– Similar, lower dwell times in the tail neutral sheet for the second tail pass in the extended mission
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MMS SWG 27 March 2014
Conclusions (2)• This comparison for the “Peak” THEMIS Coordination
Mission (RAP=255.6, RAAN=76,AOP=179.6)• Results for the “Center” THEMIS Coordination Mission
(RAP=255.6, RAAN=71.1,AOP=184.5):– 90 diffusion region encounters at dayside– Only 214 hours dwell time near the neutral sheet– Similar, lower numbers (114 hours) for the dwell time in the second
pass
• The “Peak” mission is preferred– Distinctly better dwell time near the tail neutral sheet