THEMIS-ARTEMIS (THEMIS Extended Phase)Financial Feasibility Review Science Vassilis Angelopoulos ESS/IGPP UCLA and SSL/UCB
Overview • Overview • Science Background • Mission Concept • Science Objectives • L1 Requirements • Lunar Mission Phases • Science Instrument Utilization
THEMIS: 5 satellites, Launched February 17, 2007 To Solve the Mystery of what Triggers Auroral Substorms Simulation: J. Raeder, UNH Visualization: Tom Bridgman,GSFC/SVS
: Ground Based Observatory THEMIS Mission elements Five probe conjunctions along Sun-Earth line recur once per 4 days over North America. … while THEMIS’s space-based probes determine onset of Current Disruption and Reconnection each within <10s. Ground based observatories completely cover North American sector; determine auroral breakup within 1-3s …
EFIs EFIa SCM ESA BGS SST Operations UCB FGM Tspin=3s Instrument I&T UCB Ground Mission overview D2925-10 @ CCAS Release Probe instruments: ESA: ElectroStatic Analyzer(coIs: Carlson and McFadden)SST: Solid State Telescopes (coI: Larson)FGM: FluxGate Magnetometer(coIs: Glassmeier, Auster & Baumjohann)SCM: SearchCoil Magnetometer (coI: Roux) EFI: Electric Field Instrument (coI: Bonnell) Encapsulation & launch Mission I&T UCB
P1 P2 P3 P4 P5 TH-B TH-C TH-D TH-E TH-A 2007-03-23 2007-06-03 Launch=2007-02-17 YGSE 2007-07-15 XGSE 2007-08-30 2007-12-04 First 10 months: Commissioning andCoast Phase Observations Angelopoulos, 2008 Space Sci. Rev.
TH-B TH-C TH-D TH-E TH-A P1 P2 P3 P4 P5 First year baseline orbit (FY08) YGSE Tail 12008-02-02 Dayside 12008-08-08 XGSE Second year baseline orbit (FY09) YGSE Dayside 22009-09-16 Tail 22009-02-18 XGSE Angelopoulos, 2008 Space Sci. Rev.
Inside-Out model Outside-In model Reconnection Aurora 2nd 1st 1st 2nd 2nd 1st Current Disruption 3rd 3rd 3rd THEMIS Finds: Reconnection DirectlyConnected to Substorm Onset THEMIS on SCIENCE Magazine Cover Story Article, Aug 15, 2008
THEMIS Other Media Successes www.pbs.org/wgbh/nova/sciencenow/0304/02.html
Tornadoes in Space Upcoming Press Releases European Geophysical Union meeting [April 23, 2009, 10:00 am, Vienna, Austria] “Giant Electrical Tornadoes in Space”: NASA’s THEMIS spacecraft discovered plasma vortices generating Hundreds of Thousands of Amps in space, seen as bright auroras on the ground. These results suggest that a significant portion of the stored magnetic energy in Earth’s environment is dissipated by vorticity-generated electrical currents heating the upper atmosphere. They resemble atmospheric tornadoes which dissipate thermal energy stored in the atmosphere, only move at speeds of a million miles an hour, creating dynamic auroral curls.[By: Andreas Keiling, Karl-Heinz Glassmeier and Olaf Amm]
Science paper press release [May 2009, to co-incide with Science paper] Van-Allen Belt Altering Waves Understood: The source of plasmaspheric hiss, electromagnetic noise that permeates near Earth space and modulates radiation belt electrons by scattering them into the ionosphere has finally been explained. NASA’s multi-spacecraft THEMIS mission in a dedicated mode designed to look for the origin of these waves has identified that leakage of another electromagnetic emission, “chorus”, is the culprit. Chorus is generated by injections of radiation belt particles. The results allow modelers to predict more accurately radiation belt intensity to protects humans, satellites in space.[By: Jacob Bortnik, Richard Thorne and Wen Li] TH-E (Chorus) Origin of Hiss: Chorus TH-D (Hiss)
GRL Cover Recent Discoveries, Cover Stories GRL Highlight First Unequivocal Proof of Magnetic Field Line Resonances in Space: Multipoint Observations. [Sarris et al.] Discovery of Quiet Time,Dayside Chorus Waves, ProvidesClues for Wave Generation [Li et al.] Dayside, quiet time Dawn, active time
All instruments functioning nominally Cross calibration, inter-calibration performed during coast-phase Team discoveries are changing the field, excite the public Science discoveries piling up 100 science papers during the last year Space Science Reviews volume in print (>20 papers) >20 GRL papers in special issue on THEMIS >20 JGR papers in special issue on THEMIS THEMIS in the news every AGU meeting Data collected per plan, widely disseminated First tail season showed thinner tail than expected Adjusted 2nd tail season orbit to account for it Second tail season results are a resounding success A dozen substorms collected: unique features Provide further insight into last years’ observations Media releases capture public attention on NASA discoveries Anticipate mission completion on time, on budget by September 2009 Constellation available in good health for extended mission: FY10-12 Extended Phase Approved in Senior Review (Jun 09) thru Sep 2012 THEMIS and ARTEMIS comprise the THEMIS Extended Phase Extended Phase Contract expected to be signed March 2009 Three ARTEMIS reviews (2 peer, one formal) conducted already Expect an additional mini-review to discuss progress in May 2009 Instruments checked out especially for low field conditions ARTEMIS technical implementation is a “go”pending contingency runs Assuming progress as planned by end of May 2009 THEMIS Status
Data Processing and Community Support • All data/plots available, calibrated 1 day after downlink (http://sprg.ssl.berkeley.edu) • Routine data distribution in 4 ways • CDF downloads from SPDF, UCB, 4 mirror sites • HTTP and FTP socket connection through software (seemless) • Bundled downloads via UCB site (per instrument, spacecraft, product) • On-line at VMOs, and PDS and SPASE compatible. • Free, powerful software distribution • IDL-based, platform independent • Software trainings once per 6 months at major meetings (GEM, AGU) • On-line documentation and tutorials on products, software • On-line Support (THEMIS_Science_Support@ssl.berkeley.edu)
Unsolicited Community Feedback “…I was amazed by the quality of the THEMIS IDL software and the way it interacts with the database. I believe all the community should be really grateful for what you have done. Marius Mihai Echim, Researcher “…I am really enjoying using the themis gui so far. I have had very little problems loading in my own data, and everything is easy and intuitive to me as a current splash user. Congrats to you and the rest of the themis gui team!” Marissa Vogt, Graduate Student “…The new THEMIS GUI is really impressing. We are sure it's going to be quite useful to us. Thank you very much for the thorough presentation. We are looking forward to trying the software ourselves as soon as it is released.” Ferdinand Plaschke and Dragos Constantinescu, Graduate Students
THEMIS = THEMIS baseline + ARTEMIS Extended Phase Proposal:Mission Concept
ARTEMIS (P1,P2) in FY10,11,12: Mission Concept • FY10: Translunar injection • FY11-12: 6mo in Lissajous orbits + 17 mo in Lunar orbits
ARTEMIS Science Objectives, #1 • In the Magnetosphere, study: • Particle acceleration: X-line or O-line? • Reconnection: 3D character; global effects • Turbulence: Drivers and effects • Result: • Reveal 3D distant tail, dynamics • In conjunction with: • Solar wind monitors: • ACE, WIND, STEREO • Inner magnetosphere monitors: • Cluster, Geotail, FAST • Using the first: • Two point: dX, dY measurements • …at scales from ion gyroradius to several RE • Even single point measurementsare critical in this region
ARTEMIS Science Objectives, #2 • In the Solar Wind, study: • Particle acceleration at shocks • Nature and extent of elusive low-shear reconnection • Properties of inertial range of turbulence • Result: • Advance our understanding of particle acceleration and turbulence in Heliosphere • In conjunction with: • Other solar wind monitors: • ACE, WIND, STEREO • ARTEMIS is: • High-fidelity solar wind monitor • In beacon mode if requested • Using first of a kind: • …two point measurementsat scales 1-10 RE, ideal for study of particle evolution in shocks, at foreshock and inertial range of turbulence • WIND can replace one of twoprobes in this study
ARTEMIS Science Objectives, #3 • At the Moon/Wake: • Study 3D structure and evolution of wake • Understand particle acceleration at wake • Understand wake refilling under various SW conditions • Result: • Advance our understanding of wakes at planetary moons, plasma void refilling around large objects (Shuttle, ISS, Hubble) • Using first of a kind: • …two point measurementsat scales 0.1-10 RE, ideal for two-point correlations within wake and between wake and solar wind • Comprehensively instrumentedsatellites have never studied wake from various vantage points, thus even single pointmeasurements are critical.
ARTEMIS Science ObjectivesSummary Acceleration, Reconnection and Turbulence and Electrodynamics of Moon’s Interaction with the Sun (ARTEMIS) will be the first Heliophysics missionto study with comprehensive instrumentation: • Particle acceleration, reconnection and turbulence • In the solar wind • In the magnetosphere • Wake formation and refilling • In the solar wind (supersonic) • In the magnetosheath (subsonic) ARTEMIS requires one probe (minimum) plus a solar wind monitor(ACE, WIND), but will reach full mission potential with both probes,as baselined. ARTEMIS will benefit concurrent lunar missions LADEE and LRO. ARTEMIS will also advance our understanding of planetary processesand is in-line with as well
ARTEMIS Level 1 Requirements • … • 4. Baseline Mission • Full success requires: collection of a 50% aggregate interval from a 24 month period of particles and fields observations on two probes; select fast rate data captures from key intervals (10% time); and a total of 10 wake crossings by one ARTEMIS probe with simultaneous observations by the other ARTEMIS probe at separation distances ranging from 0.1 to 20 RE. • Adherence: Data collection will be adjusted to match nominal downlink capability by reducing cadence. Data collection will include continuous, low resolution (~ once per 3 spins) Slow Survey data, 2hrs per orbit of Fast Survey data with one burst each. Wake crossings will be part of Fast Survey schedules. This volume can be accommodated in the memory and downlinked once per 2 days. This can be accomplished in 24 months with a factor of 2 margin. • 5. Minimum Success • Minimum success requires collection of a 50% aggregate interval from a 6 month period of particles and fields observations on one probe, including at least 5 wake crossings by one ARTEMIS probe with simultaneous observations of the solar wind by one or more Heliophysics missions (e.g. ACE, the other ARTEMIS spacecraft, Geotail, or Cluster). • Adherence: Same as above, but for one ARTEMIS probe plus another Heliophysics mission during a 6 month period. This can be accomplished in 6 months with a factor of 2 margin.
ARTEMIS Phases Lissajous Phase(Oct ’10 – Apr ’11) Note: First 3 months: opposite sides, Next 3 months: same side Translunar injection phase (Oct ’09 – Oct ’10)No Science, just get there. Note: Orbit Raise Maneuvers (ORMs)start: July 2009, in parallel withTHEMIS 2nd dayside operations(THEMIS dayside requirementsmet already since 1st dayside season) Lunar Orbit Phase(May ’11 – Sep ’12) Note: P1 retrograde, and P2 prograde, such that orbitalseparations and separationvectors cover full parameter space
ARTEMIS: ScienceInstrument Utilization • All instruments will be utilized in their standard Survey and Burst Modes • Magnetometer will be in most sensitive range to resolve lower field strengths than those at Earth. • Search coil will be in nominal operation, which offers sufficient sensitivity • ESA will be in solar wind mode to resolve the SW beam • SST will be in its nominal mode • If Planetary decides to fund ARTEMIS to study Planetary objectives then: • SST energy bins will be adjusted to provide better dE/E in the relevant smaller E-range • Instrument operations will be similar (if not identical) to present because: • The near-equatorial, 26hr period orbits during lunar phase and the planned downlink schedule of once per 2 days provides the same shadow, power, data through-put and thermal environment as at Earth • Instruments have already operated in and been tuned to the solar wind, magnetosheath and magnetotail environments and are known to perform nominally • Science operations (modes) will be similar (if not identical) to now since: • Slow Survey will accomplishing science requirements at low cadence • Fast Survey can accomplish pre-planned, time-based “conjunction” science • peri-selene, wake crossings, or 2-probe wake crossings • Opportunity science, when in SW • Bursts can accomplish high cadence science in interesting times • Current triggers (Bz, Ni) expected to work to capture reconnection, wake events • Sufficient flexibility exists in triggers to capture other event types if necessary (shocks, CMEs).
ARTEMIS: Summary • ARTEMIS is a robust mission, extending P1, P2’s life in a familiar environment • ARTEMIS orbits are benign and science optimization has already been done • Current L1 minimum requirements drive minimally mission design and operations • Current L1 baseline requirements benefit from 3 years of mission optimization, and have been built into a “natural” baseline design that is also operationally optimal • ARTEMIS instruments can do the job • Have been studying the same environment successfully for just over 2 years • Can be commanded to perform Survey and Burst captures in familiar methods • ARTEMIS rates and volumes are commensurate with proposed science • Expecting 1/4 of data volume per data downlink capabilityand a Survey cadence that can fit continuous coverage,there is a factor of 2 margin that can be used to benefitlow cost operations.