MMS-THM coordination 1 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS MMS-THEMIS coordination: Optimal Option (and alternatives) Vassilis Angelopoulos (UCLA); Robertson, Brent P. (GSFC-4610); Giles, Barbara (lead) (GSFC-6730); Sibeck, David G. (GSFC-6740); Moore, Thomas Earle (GSFC-6700); BURNS, R D (GSFC- 4440); Klumpar, David M. (HQ-DJ000)[NASA IPA]; KNAPP, DEBORAH (GSFC- 5840); 'Stephen Fuselier,‘ ; Talaat, Elsayed Rasmy. (HQ-DJ000)[NASA IPA]; 'Torbert, Roy B’; Williams, Trevor W. (GSFC-5950); Phan, Tai (UCB); Cindy Russell (UCLA); Sabine Frey (UCB) --- Tooley, Craig R. (GSFC-4610); Spidaliere, Peter D. (GSFC-5990); 'Black, Ron'(swri); Hughes, Kevin C. (GSFC-5430); Hall, James L. (KSC-VAC00)

MMS-THM coordination 2 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS In Sep several perigee reduction maneuvers prepared THEMIS to match MMS, assuming an Oct-Nov 2014 launch (THM would have been within ~6 o of the MMS line of apsides during Phase 1b, and in resonant orbits with MMS during Phase 2b). MMS launch delay to ~Mar results in MMS nominal apogee opposite to THM. A THM-MMS coordination team discussed three options on how to deal with this. Option 1: similar to a Fall-like MMS launch (at 21LT); and Options 2 & 3: similar to Spring-like MMS launch scenarios received preliminary study. Option 1 (launch at 21LT) achieves Phase 2b matching but with reduced commissioning time (2.5mo.). Also good for extended phase studies of Tail Rx. Options 2/3 added ~4-6mo. to the nominal MMS mission duration but achieved good, or excellent Phase 1a, 1b and 2b matching and satisfied most/all other req’s. During the last 2 weeks these have been consolidated, science-optimized and refined to produce launch elements. They are presented as the “Optimized” option herein. Team work during past 6 months

MMS-THM coordination 3 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS MMS nominal launch for Mar 7, 2015 (R p xR a =1.2x12 Re, inc=28 o ): Line of apsides drifts back: 25.5 o /yr (counter clockwise) LT 12 LT Circle at 12Re Nominal orbit projections on XY GSE plane. How to address this large local time difference? X gse Y gse Magnetopause Bow shock Magnetotail …on Mar 7, 2015 Apparent orbit motion: clockwise ~1 o per day Apparent motion: ~1 o per day THM on Mar 7, 2014 (R p xR a =1.145x R E, inc=8 o ) Line of apsides drifts back: 51 o /yr (counter clockwise)

MMS-THM coordination 4 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS “Nominal” MMS launch for Mar. 7, MMS Launch: Mar. 7, 2015 THM: ~16LT MMS: LAUNCH 6 18 MMS 55Re P1 P2 Tail #2 (Phase 2b); Jul. 14, 2017 Dayside #1 (Phase 1a); Dec. 11, 2015: Solid Dayside #2 (Phase 1b); Jan. 7, 2017: Dashed … end of MMS commissioning (18LT) occurs on Sep. 4, 2015 (at L+6mo) MMS end of mission (EOM): in 2 yrs occurs on Sep. 4, 2017 (20.6LT) MMS: EOM MMS: 18LT, by end of Phase0

MMS-THM coordination 5 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS Option #1. Phase2b THM-MMS alignments possible, but MMS gets 2.5mo of commissioning Dayside #2 (Phase 1b, Aug. 28, 2016) Lines of apsides still ~45 o apart 12 MMS Launch: Mar. 7, 2015 ~16LT 6 18 Tail#2 (Phase 2b, Mar. 4, 2017) Within 25 o ; THM apogees: 12-16Re; Get THM resonant orbits w/MMS 55Re P1 P2 P3 P4 P5 MMS MMS on May 22 (2.5 mo. later, at Phase 1a start)

MMS-THM coordination 6 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS Given the time-critical nature of the decision, the team focused on optimizing one solution: Launch of MMS with an extended commissioning phase (Phase0) and raise THM perigee (to slow down precession) after MMS launch optimizing the THM-MMS fleet. Solution is given in terms of RAP, the Right Ascension of Perigee: RAP=RAAN+AOP. For Mar. 7 18LT this is RAP=255 o ; RAAN=72 o +/- 5 o, AOP= 183 o -/+ 5 o. Pros: – Solution consistent with launch window and dispersions; meets all requirements (except Phase 0 length) – Optimal THM-MMS matching during Phase 1a, 1b, Phase 2b (doubles dayside tetrahedral formations compared to what was originally proposed) – Phase 1a, 1b have complementary nested tetrahedral formations (shown below) – Phase 0 gets an extra 1mo. of nominal MMS observation time – can be used for training ops and science team and learn instruments (with time to adjust and optimize prime mission), or for add’l science, better PhaseE funds utilization. – Robust solution, immune to further MMS launch delays and to inadvertent (beyond 3  ) insertion errors – Phase 0x has ~80 hrs of additional near-earth neutral sheet conjunctions – In Phase2b in winter: takes advantage of THEMIS GBOs and other US assets (radars) for global science – Once THM-MMS are together they can “stay” together, improving the extended phase science for HSO Cons: – Adds 6 months to MMS mission profile compared to nominal for this date (as seen next). – Delays minimum mission by 6mo. (from 12mo. to 18mo.) but gets some prime data early-on. Optimal THM-MMS solution (consolidated and optimized Options 2/3)

MMS-THM coordination 7 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS Optimal solution: the first year. Phase 0 acquires a 6mo. addition rel. to “nominal” Tail #0 (Phase 0x), Dec. 28, 2015 Separation: -20 o to -11 o THM could be string of pearls MMS near NS at 7-10R E 12 MMS Launch: Mar. 7, 2015 MMS perigee <1200km is desired (not required). THM: ~16LT MMS: 6 18 Dayside #0 (Phase 0); Jul. 7, 2015 MMS conducts 1mo. prime observations THM could be string of pearls Unique science, HSO-calibration 4 mo. later: 10.4LT …end of MMS commissioning (18LT) occurs on Apr. 3, 2016 The 1 mo. of prime observations at Phase0 counts towards nominal mission. Net addition to Phase 0 (-1mo) is 6 mo. MMS: 18LT, by end of Phase0

MMS-THM coordination 8 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS Optimal solution: prime mission. Duration: 2yrs (1mo. from Phase0 + 23mo.) Dayside #2 (Phase 1b); Aug. 9, 2017 Separation: +4 to +9 o (optimal) THM-MMS nested tetrahedra Tail#2 (Phase 2b); Feb. 13, 2018 Separation: o (optimal coordination) THM apg: 12-16Re. Resonant orbits MMS 55Re P1 P2 P3 P4 P5 Dayside #1 (Phase 1a); Jul. 11, 2016 Separation: -9 to -4 o (optimal) THM-MMS nested tetrahedra MMS end of mission (EOM): in 2 yrs-1mo = 23mo. occurs on Mar. 7, 2018 (22.56LT) MMS: EOM Y gse (apogee)=9.5R E

MMS-THM coordination 9 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS An optimizer (.xlsx) was used to find RAP, mission profile for different insertion errors… … as well as for all launch dates within new launch window

MMS-THM coordination 10 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS Optimized Solution: LongShadows: Left; NS Conjunctions: Middle; LongShadows+Conjunctions: Right; vs RAAN, AOP Phase2b shadows RAP= 255 Optimal region ( ) Shadows (min) in red and conjunctions (hrs) in blue Optimal window for Mar 7 th launch at 18LT (RAP=255 o ): RAAN= 72 o +/- 5 o, AOP= 183 o -/+ 5 o ( ) Neutral Sheet Conjunctions (hrs)Max Long Term Shadows (min)

MMS-THM coordination 11 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS Additional benefits: Phases 1a, 1b have complementary tetrahedral formations ~1-2R E ~0.5R E ~ R E THM MMS THM MMS One of P3,4,5 is out-of-plane

MMS-THM coordination 12 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS Additional benefits: Phase 0x has significant neutral sheet conjunctions E Y gsm Z gsm Can be further optimized varying mean anomaly. E X gsm Y gsm Cartoon depicting THEMIS-MMS separation From orbit integration (one track/day)

MMS-THM coordination 13 Iowa 3/25/14 ARTEMIS THEMIS ARTEMIS THEMIS The timescale for action has to be days not weeks. Is FDOA in agreement with these results? What are the ULA costs for checking out the revised launch elements? Can KSC help bring costs down? What are the operations costs / risks from the additional 6mo. in orbit; can these be minimized? We need a unified front (if there is agreement); associated costs must be less than the perceived costs of an extended phase… What next?