© The Aerospace Corporation 2011

AIM-1

Bill Lotko and Jim Clemmons

The Aerospace Corporation8 March 2011

SCIENCE GOAL

Resolve Energetics, Sources and

Couplings of Atmosphere-Plasma ESCAPE

SBU – Heliophysics Decadal Survey Internal Use Only

AIM-1 (Atmosphere-Plasma Outflows)

• Determine how ionospheric outflows are energized, the processes controlling their fluxes and distributions, and how they affect the AIM systemPlasma and energy sources Coupling between thermosphere and ionospheric upflow, outflow Conversion of EM energy to charged-particle energy Altitude distribution of ion energization, outflow

• Observations/measurements– Electromagnetic and particle drivers– Thermal (3D), superthermal (2D) electron/ion phase-space densities– Local neutral gas density, composition, velocity (3D)– Auroral context from FUV images, plasma density sounding

• Field Instruments– Vector electric, magnetic fields: dc to 8 MHz (fpe)

– Langmuir probe – local electron density and temperature– Plasma density sounder – ionospheric density profiles

• Thermal Electron/Ion Spectrometers – Quasi-3D electron and ion velocity distributions – 0.1 to 20 eV

• Superthermal Electron/Ion Spectrometer– Energy-pitch angle distributions (e-, H+, He+, O+) – 5 eV to 30 keV

• Wind Sensor – 3D neutral gas velocity

• Mass Spectrometer – neutral gas composition

• Ionization Gauge – neutral gas density

• FUV imager – 1356, LBH-S,L emissions

• Optimize orbits and s/c phasing for magnetic conjunctions in outflow regions– In cusp region, near nightside convection throat, auroral regions

• Connect low-altitude source regions with outflows observed near apogee– Ion dispersion mixes convective and field-aligned motions– O+ transit time between s/c (> 1 minute)

• Differentiate ion energization processes– Stochastic, resonant, convective pick-up energization processes– Influence of neutral gas properties on outflow fluxes– Scale couplings: Meso/micro cavitation, upwelling, energization

Mission Science Objectives

Key Instrument Parameters 117 kg, 96 W, 510 kbps Key Challenges

2

• 2 identical s/c, 3-axis stabilized• Launch mass: XXXX kg per s/c• Launch date: Near solar maximum• 2 Taurus 3110 launches• 84 inclination, coplanar orbits

– Maintain common line of apsides– Apogees 180 out of phase– Topside, bottomside phases

1. 500 km 2500 km (1 yr)2. 200 km 2500 km (1 yr)3. 275 km 2500 km (25-yr decay)

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Top Risks and Challenges

• Dual-satellite mission– Early failure of one s/c or instrumentation would diminish scientific return

– New types of single-point measurements would continue to provide novel scientific results, but lack of magnetically conjugate measurements would impede the goal of understanding connections between outflows observed at higher altitude and their generation in the ionosphere and coupling to thermospheric processes

• Dual-phase mission– Resolving both bottomside and topside processes contributing to outflow requires 2

mission phases: Diminished scientific return if one s/c or instrumentation fails prior to 2nd phase

– Topside (phase 1) measurements in the energization region are a higher priority in understanding outflow processes

• Possible interference issues between soundings and other measurements

• Radiation exposure may limit instrument performance during an extended mission

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Unique Investments and Technologies

• First topside sounder since ISIS-2 (1971)

• Two-point in-situ measurements along a single magnetic flux tube

• FUV images with 7 km auroral resolution,10 sec/frame, 900 km FOV

• Leverages Heliophysics System Observatory with in-situ measurements and images in a critical region of geospace

• No new technologies are required, but the science would benefit from instrument developments in measuring low-density neutral gas properties near mission apogee (e.g., neutral polar wind)

Measurements of the ionospheric plasma den-sity profile, combined with SOA measurements of EM fields, charged particles, neutral gas and auroral emissions, provide unique opportunities to determine how ionospheric structure controls and is influenced by ionospheric outflows.

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Operational Strategy

• Minimal delay between launches and commissioning of 2 s/c

• Nominal 2 year mission in 2 phases– Topside: 500 km x 2500 km (1 year)– Bottomside: 200 km x 2500 km (1 year)– EOL orbit at 275 km x 2500 km would allow a useful extended mission and

critical observations for the Heliophysics System Observatory

• Orbit maintenance– Maintain coplanarity of orbits and common line of apsides– Orbital phase to maximize measurements in primary outflow regions (cusp,

auroral) during magnetic conjunctions

• Burst-mode data acquisition would be desirable for campaigns, e.g. coordination with ground-based instruments and intervals of active management of magnetic conjunctions

• Choice of perigee may depend on solar-cycle phase at launch

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Package Instrument Measured Parameters Heritage

Fields

Double probe Vector E, dE DE-2, San Marco, Polar, C/NOFS

Magnetometer Vector B, dB DMSP, MGS, ACE, NEAR, WIND, STEREO, CHAMP

Langmuir probe Plasma density, temperature FAST, C/NOFS, MAVEN

Plasma

Thermal electron/ion spectrometers

Electron, ion distributions0.1 eV – 20 eV

Freja, SCIFER, DE, JOULE, Polar, Akebono, GEODESIC, SWARM

Superthermal electron/ ion spectrometer

Electron, H+, He+, He++, O+ distributions 5 eV – 30 keV RBSP, MMS, JUNO, ROSETTA

Gas

Ionization gauge Neutral density AE, Streak

Wind sensor Vector winds C/NOFS

Mass spectrometer Ion, neutral composition OGO, AE, PVI, Cassini

Remote

FUV imager1356, LBH-S, LBH-L

Images of auroral Q, E0; O/N2; TEC

IMAGE, FORMOSAT-2

Ionospheric sounder Electron density profile Alouette, ISIS, IMAGE

Instrument Heritage and Analogies

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Spacecraft Heritage and Analogies

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Schedule Matrix

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SBU - Astro2010 Internal Use Only

Mission Name - Cost Analogies

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Analogies PM/SE/MA Instrument Spacecraft MOS/GDS Phase E

Mission 1 X X X

Mission 2 X

Mission 3 X X

Mission 4 X X

Mission 5 X X X

Mission 6 X X

Mission 7 X

Mission 8 X X X X X

Mission 9 X

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Cost Box – Summary Chart

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