1 MAVEN PFP ICDR May 23-25, 2011 Mars Atmosphere and Volatile EvolutioN (MAVEN) Mission Particles and Fields Science Critical Design Review May , 2011 Dave Mitchell SWEA Lead

2 MAVEN PFP ICDR May 23-25, 2011 MAVEN Science Questions MAVEN will determine the role that loss of volatiles to space has played through time, providing definitive answers about Mars climate history: What is the current state of the upper atmosphere and what processes control it? What is the escape rate at the present epoch and how does it relate to the controlling processes? What has the total loss to space been through time?

3 MAVEN PFP ICDR May 23-25, 2011 MAVEN Mission Architecture In situ and semi-global remote sensing measurements are made from the MAVEN elliptical orbit. Measurements are obtained down to the well-mixed lower atmosphere through five “deep dip” campaigns. Coverage of all local solar times and most latitudes, along with broad geographical coverage, results from precession of the MAVEN high-inclination orbit.

4 MAVEN PFP ICDR May 23-25, 2011 IUVS NGIMS Neutral Processes MAVEN Measures Drivers, Reservoirs, and Escape Rates SEP SWEA MAG Solar Inputs EUV SWIA LPW MAG SWEA Plasma Processes IUVS SWIALPW STATIC

5 MAVEN PFP ICDR May 23-25, 2011 The MAVEN Payload Makes the Essential Measurements NGIMS IUVS LPW integrated analysis STATIC MAG, SWEA, SWIA, LPW SEP LPW - EUV

6 MAVEN PFP ICDR May 23-25, 2011 STATIC Measurement Requirements STATIC measures low- and medium-energy ion composition, energy, and direction: –Densities, velocities, and temperatures of suprathermal H+, O+, O2+, and CO2+ above the exobase with the ability to spatially resolve magnetic cusps Derived Level 3 measurement requirements: IDTitleParent IDDescription PF55STATIC Flux Range 1MRD61STATIC shall measure energy fluxes from 1E7 to 1E10 eV/cm2-sec-ster-eV with 20 second resolution and 25% accuracy and precision PF56STATIC Flux Range 2MRD62STATIC shall measure energy fluxes from 1E4 to 1E8 eV/cm2-sec-ster-eV with 30 minute resolution and 25% accuracy and precision PF57STATIC Mass RangeMRD63STATIC shall measure ions from at least 1-44amu PF58STATIC Mass ResolutionMRD64STATIC shall have mass resolution m/dm of at least 2 (m/dm) PF59STATIC Energy RangeMRD65STATIC shall measure ions from 1 eV to 10 keV PF60STATIC Energy ResolutionMRD65STATIC shall have energy resolution dE/E of at least 30% PF61STATIC Angular ResolutionMRD65STATIC shall have angular resolution of at least 30 degrees PF62STATIC FOVMRD66STATIC shall have a FOV at least 60 degrees by 180 degrees PF63STATIC Time Resolution 1MRD61STATIC shall have time resolution of 20 seconds or better for Flux range 1 PF64STATIC Time Resolution 2MRD62STATIC shall have time resolution of 30 minutes or better for Flux range 2

7 MAVEN PFP ICDR May 23-25, 2011 SWEA Measurement Requirements SWEA measures properties of solar wind electrons that can drive escape: –Energy distributions of solar wind, magnetosheath, and ionospheric electrons to determine the electron impact ionization rate, with an energy resolution sufficient to distinguish ionospheric photoelectrons from solar wind electrons –Electron angular distributions to determine magnetic topology, with the ability to spatially resolve magnetic cusps. Derived Level 3 measurement requirements: IDTitleParent IDDescription PF65SWEA Flux RangeMRD68SWEA shall measure energy fluxes from 1E4 to 1E8 eV/cm2-sec-ster-eV PF66SWEA SensitivityMRD69SWEA shall have a geometric factor > cm2-ster PF67SWEA Energy RangeMRD70SWEA shall measure electrons from eV PF68SWEA Energy ResolutionMRD70SWEA shall have energy resolution dE/E of at least 25% PF69SWEA Time ResolutionMRD71SWEA shall have time resolution of 20 seconds or better PF70SWEA Angular ResolutionMRD72SWEA shall have angular resolution of at least 45 degrees PF71SWEA FOVMRD73SWEA shall have a FOV which covers at least 50% of the sky

8 MAVEN PFP ICDR May 23-25, 2011 SWIA Measurement Requirements SWIA Measures properties of solar wind ions that can drive escape: –Density and velocity distributions of solar wind and magnetosheath ions to determine the charge exchange rate and the bulk plasma flow from solar wind speeds down to stagnating magnetosheath speeds Derived Level 3 measurement requirements: IDTitleParent IDDescription PF72SWIA Flux RangeMRD75SWIA shall measure energy fluxes from 1E7 to 1E10 eV/cm2-sec-ster-eV PF73SWIA Flow VelocityMRD76SWIA shall measure ion flow velocities from km/s PF74SWIA Energy ResolutionMRD77SWIA shall have energy resolution dE/E at least 15% PF75SWIA Angular ResolutionMRD78SWIA shall have angular resolution of at least 30 degrees (10 degrees in Sun direction) PF76SWIA Time ResolutionMRD79SWIA shall have time resolution of 1 minute or better PF77SWIA FOVMRD80SWIA shall have a FOV of 180 x 40 degrees or better

9 MAVEN PFP ICDR May 23-25, 2011 Cross Calibration of STATIC/SWEA/SWIA The angular and energy responses and the geometric factor (minus detection efficiency) for all three instruments are determined on the ground to within ~10% by calibrations and electrostatic optics simulations. Detection efficiency depends on MCP efficiency, which varies during the mission  need a procedure to measure and track this efficiency for all three instruments. IDTitleParent IDDescription PF105STATIC AccuracyMRD35, MRD52 STATIC shall have an in-flight calibration procedure to determine its absolute sensitivity to within 25%. PF106SWIA AccuracyMRD35, MRD52 SWIA shall have an in-flight calibration procedure to determine its absolute sensitivity to within 25%. PF107SWEA AccuracyMRD35, MRD52 SWEA shall have an in-flight calibration procedure to determine its absolute sensitivity to within 25%. New Level 3 Requirements Response to RFAs 9 and 10

10 MAVEN PFP ICDR May 23-25, 2011 Cross Calibration of STATIC/SWEA/SWIA Detection efficiency for STATIC: –Determine START and STOP efficiencies by measuring event ratios: (START with STOP) Valid and (STOP with START) Valid START Valid STOP Valid –This can be done anywhere that the ion composition is dominated by a single species (e.g., H + in the outer sheath, O 2 + in the ionosphere). –For cross calibration of SWIA and SWEA, efficiencies for H + are needed.  STATIC can meet requirement without cross calibration. –Consistency check: Measure total plasma density near periapsis and compare with calibrated LPW measurements. Response to RFAs 9 and 10

11 MAVEN PFP ICDR May 23-25, 2011 Cross Calibration of STATIC/SWEA/SWIA Absolute sensitivity of SWIA determined by cross calibration with STATIC in the outer sheath –Instruments have the same analyzer optics and overlapping energy and angle ranges, so measurements of ion flux are sufficient for comparison. Absolute sensitivity of SWEA determined by cross calibration with SWIA and STATIC in the outer sheath and with SWIA in the solar wind. –Modeling of total density needed in the sheath for all three. –Modeling of total density needed for SWEA in the solar wind. Response to RFAs 9 and 10

12 MAVEN PFP ICDR May 23-25, 2011 SEP Measurement Requirements SEP Measures solar energetic particle input into upper atmosphere: –Solar energetic particles that can interact with the upper atmosphere, with a time resolution sufficient to capture SEP events. Derived Level 3 measurement requirements: IDTitleParent IDDescription PF78SEP Flux RangeMRD87SEP shall measure energy fluxes from 10 to 1E6 eV/cm2-sec-ster-eV PF79SEP Energy RangeMRD88SEP shall measure ions from 50keV to 5 MeV PF80SEP Energy ResolutionMRD89SEP shall have energy resolution dE/E of at least 50% PF81SEP Time ResolutionMRD90SEP shall have time resolution of 1 hour or better

13 MAVEN PFP ICDR May 23-25, 2011 MAG Measurement Requirements MAG measures solar-wind interactions and “mini-magnetospheres” –Vector magnetic field in the unperturbed solar wind, magnetosheath, and crustal magnetospheres, with the ability to spatially resolve crustal magnetic cusps. Derived Level 3 measurement requirements: IDTitleParent IDDescription PF82MAG Dynamic RangeMRD82MAG shall measure magnetic fields from 3 to 3000nT PF83MAG AccuracyMRD83MAG shall have an accuracy of better than 1% over its dynamic range PF84MAG ResolutionMRD84MAG shall have resolution of better than 1% over its dynamic range PF85MAG Time ResolutionMRD85MAG shall have time resolution of 20 seconds or better (5 seconds below 400km)

14 MAVEN PFP ICDR May 23-25, 2011 LPW Measurement Requirements LPW shall measure electron temperature and number density measured in situ: –Thermal electron density and temperature from the ionospheric main peak to the nominal ionopause with a vertical resolution of one O2+ scale height. LPW shall measure electric field wave power –at frequencies important for ion heating. Derived Level 3 measurement requirements: IDTitleParent IDDescription PF86LPW Density RangeMRD53LPW shall measure electron densities from 1E2 to 1E6 cm-3 PF87LPW Density AccuracyMRD53LPW shall have density (n) precision of 20% and a relative (dn/n) precision of at least 5% below the ionopause PF88LPW Temperature RangeMRD54LPW shall measure electron temperatures from 500 to 5000 K below the ionopause PF89LPW Temperature AccuracyMRD54LPW shall have temperature precision dT/T of at least 20% below the ionopause PF90LPW Frequency RangeMRD55LPW shall measure waves from 0.05 to 10Hz PF91LPW Wave Power SensitivityMRD55LPW shall have wave power sensitivity of at least 1E-8 (V/m)2/Hz PF92LPW Spatial ResolutionMRD56LPW shall have time resolution of 15 seconds or better

15 MAVEN PFP ICDR May 23-25, 2011 LPW/EUV Measurement Requirements EUV shall measure solar EUV input into upper atmosphere: –Solar EUV irradiance at wavelengths important for ionization, dissociation, and heating of the upper atmosphere with a time resolution sufficient to capture solar flares. Derived Level 3 measurement requirements: IDTitleParent IDDescription PF93LPW/EUV Saturation CurrentMRD57LPW/EUV shall have saturation current resolution dl/l of at least 15% PF94LPW/EUV Photodiode CurrentMRD58LPW/EUV shall have photodiode current resolution dl/l of at least 15% PF95LPW/EUV Time ResolutionMRD59LPW/EUV shall have time resolution of 10 minutes or better

16 MAVEN PFP ICDR May 23-25, 2011 PF Instrument Backups InstrumentPrimary BackupsSecondary Backups NGIMSIUVSSTATIC, LPW IUVSNGIMSEUV LPWNGIMS (N e )STATIC (T e ), MAG (waves) EUVLPWSWEA, Earth-based STATICSWIA SWEASWIASTATIC, LPW SWIASTATIC, SWEA SEPSWEA, SWIA, STATIC MAG SWEA PF

17 MAVEN PFP ICDR May 23-25, 2011 PF Measurement Resiliency Objective 1Objective 2Objective 3 InstrumentCurrent StateProcessesEscape RatesProcessesEvolution NGIMSN-NNN IUVSNNNPN STATIC-NSSN SEP-N-NN SWEANNNNN SWIA-NNNN LPWNNNNN EUV-NNNN MAGNNNNN If we lose any one instrument, do we lose any high-level objectives? (Y = Yes, S = Substantial, P = Partial, N = Not significant, - = Minimal contribution) PF