mms-thm coordination 1 iowa 3/25/14 artemis themis artemis themis mms-themis coordination: optimal...

MMS-THM coordination 1 Iowa 3/25/14

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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);

[email protected]; 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)


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• In Sep. 2013 several perigee reduction maneuvers prepared THEMIS to match MMS, assuming an Oct-Nov 2014 launch (THM would have been within ~6o of the MMS line of apsides during Phase 1b, and in resonant orbits with MMS during Phase 2b).

• MMS launch delay to ~Mar. 2015 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


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MMS nominal launch for Mar 7, 2015(RpxRa=1.2x12 Re, inc=28o): Line of

apsides drifts back: 25.5o/yr(counter clockwise)

6

18

0 LT12 LT

10

8

14

16 20

22

2

Circle at 12Re

Nominal orbit projections on XY GSE plane.How to address this large local time difference?

Xgse

Ygse

MagnetopauseBow

shock

Magnetotail

…on Mar 7, 2015

Apparent orbit

motion: clockwise

~1 o per day

Appa

rent

moti

on: ~

1o p

er d

ay

THM on Mar 7, 2014(RpxRa=1.145x11.455 RE, inc=8o) Line of apsides drifts back: 51o/yr(counter clockwise)


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THEMIS“Nominal” MMS launch for Mar. 7, 2015

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MMS Launch: Mar. 7, 2015

THM

:~1

6LT

MM

S: 5

LT@

LAU

NCH

6

18

MMS

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P1

P2

Tail #2 (Phase 2b); Jul. 14, 2017Dayside #1 (Phase 1a); Dec. 11, 2015: SolidDayside #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 yrsoccurs on Sep. 4, 2017 (20.6LT)

MM

S: 20.6LT @ EOM

MM

S: 1

8LT,

by

end

of P

hase

0


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THEMIS Option #1. Phase2b THM-MMS alignmentspossible, but MMS gets 2.5mo of commissioning

Dayside #2 (Phase 1b, Aug. 28, 2016)Lines of apsides still ~45o apart

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MMS Launch: Mar. 7, 2015

THM@ ~16LT MMS@21LT

6

18

Tail#2 (Phase 2b, Mar. 4, 2017)Within 25o; THM apogees: 12-16Re;Get THM resonant orbits w/MMS

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P1

P2

P3P4

P5 MMS

MM

S on

May

22

(2.5

mo.

late

r, at

Phas

e 1a

star

t)


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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 2015 @ 18LT this is RAP=255o; RAAN=72o +/- 5o, AOP= 183o -/+ 5o.• 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 3s) 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)


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THEMIS Optimal solution: the first year. Phase 0acquires a 6mo. addition rel. to “nominal”

Tail #0 (Phase 0x), Dec. 28, 2015Separation: -20o to -11o

THM could be string of pearlsMMS near NS at 7-10RE

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MMS Launch: Mar. 7, 2015MMS perigee <1200kmis desired (not required).

THM

:~1

6LT

MM

S: 1

8LT

@La

unch

6

18

Dayside #0 (Phase 0); Jul. 7, 2015MMS conducts 1mo. prime observations

THM could be string of pearlsUnique science, HSO-calibration

4 mo. later:MMS @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.

MM

S: 1

8LT,

by

end

of P

hase

0


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THEMIS Optimal solution: prime mission. Duration: 2yrs (1mo. from Phase0 + 23mo.)

Dayside #2 (Phase 1b); Aug. 9, 2017Separation: +4 to +9o (optimal)THM-MMS nested tetrahedra

Tail#2 (Phase 2b); Feb. 13, 2018Separation: 17-25o (optimal coordination)THM apg: 12-16Re. Resonant orbits

MMS

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P1

P2

P3P4P5

Dayside #1 (Phase 1a); Jul. 11, 2016Separation: -9 to -4o (optimal)THM-MMS nested tetrahedra

MMS end of mission (EOM): in 2 yrs-1mo = 23mo.occurs on Mar. 7, 2018 (22.56LT)

MMS: 22.5LT@ EOMY

gse (apogee)=9.5RE


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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


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THEMISOptimized Solution: LongShadows: Left; NS Conjunctions: Middle; LongShadows+Conjunctions: Right; vs RAAN, AOP

Phase2b shadows

RAP= 255

Optimalregion

Optimal

region

Optimalregion

( )

Shadows (min) in red and conjunctions (hrs) in blue

Optimal window for Mar 7th launch at 18LT (RAP=255o): RAAN= 72o +/- 5o, AOP= 183o -/+ 5o

( )

( )

Neutral Sheet Conjunctions (hrs) Max Long Term Shadows (min)


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THEMIS Additional benefits: Phases 1a, 1b havecomplementary tetrahedral formations

~1-2RE~0.5RE

~0.1-0.2RE

THM

MMS

THMMMS

One of P3,4,5 is out-of-plane


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THEMIS Additional benefits: Phase 0x hassignificant neutral sheet conjunctions

EY gs

m

Z gsm

Can be further optimized varying mean anomaly.

EXgsm

Ygsm

Cartoon depicting THEMIS-MMS separation

From orbit integration(one track/day)


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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?

mms-thm coordination 1 iowa 3/25/14 artemis themis artemis themis mms-themis coordination: optimal...

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