Bruce Jakosky, University of Colorado Mars Express ASPERA Team Meeting 7-8 December, 2009 Mars Atmosphere and Volatile EvolutioN (MAVEN) Mission

CU/LASP, GSFC, UCB/SSL, LM, JPL Potential Importance of the Role of Loss to Space The history of liquid water and of the atmosphere determine Mars’ potential for life throughout time. There is abundant evidence for climate change and atmospheric evolution. Loss of atmospheric CO 2, N 2, and H 2 O to space has been an important mechanism for atmospheric evolution, and may have been the dominant mechanism. Only by understanding the role of escape to space will we be able to fully understand the history of the atmosphere, climate, and water, and thereby understand Martian habitability.

CU/LASP, GSFC, UCB/SSL, LM, JPL What Science Questions Will MAVEN Address? 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?

CU/LASP, GSFC, UCB/SSL, LM, JPL MAVEN Will Measure the Drivers, Reservoirs, and Escape Rates MAVEN will determine the present state of the upper atmosphere and today’s rates of loss to space. Essential measurements allow determination of the net integrated loss to space through time.

CU/LASP, GSFC, UCB/SSL, LM, JPL The MAVEN Science Instruments Mass Spectrometry Instrument Remote-Sensing Package Particles and Fields Package The MAVEN instruments are all closely based on similar instruments that have flown on previous missions.

Neutral Gas and Ion Mass Spectrometer (NGIMS) Paul Mahaffy, GSFC Measurement Objectives: - Neutral and ion structure from homopause to above exobase. - Stable isotope ratios, and variation from homopause to exobase. Technical details and heritage: - Quadropole mass spec, with open and closed source. - Mass range from 1 to 60 a.m.u. - 3 km vertical resolution - Heritage from Pioneer Venus, CASSINI INMS, Contour NGIMS Similar measurements from Pioneer Venus: CU/LASP, GSFC, UCB/SSL, LM, JPL

Imaging Ultraviolet Spectrometer (IUVS) Nick Schneider, LASP Measurement objectives: - Vertical profiles of neutrals and ions through limb emissions and stellar occultations. - Mapping column abundances over visible disk. - D/H ratio through upper atmopshere. Technical details and heritage: -Imaging spectroscopy from nm, with resolution of 0.5 nm. - Vertical resolution of 6 km, horizontal resolution of 200km - Most recent heritage from AIM CIPS. Simulated IUVS data shows how abundances and profiles will be derived: CU/LASP, GSFC, UCB/SSL, LM, JPL

Measurement objectives: - Energetic ion composition, energy, and pitch angle determines ion escape processes and rates. - Key ions H +, O +, O 2 +, CO Energies from thermal to suprathermal to moderate-energy Technical details and heritage: - Energies from 0.5 to 30 keV, velocities from 1-25 km/s. - Oriented to measure either upwelling or downwelling ions. - Heritage from Cluster CODIF. - Considering adding second unit for redundancy and to provide 4π sr coverage. Laboratory spectrum obtained from the EDU: Suprathermal and Thermal Ion Composition (STATIC) Jim McFadden, SSL CU/LASP, GSFC, UCB/SSL, LM, JPL

Langmuir Probe and Waves (LPW) Bob Ergun, LASP Stacer boom to be used for deployment Measurement Objectives: - Electron temperature and number density profiles throughout upper atmosphere. - Electric field wave power at frequencies important for ion heating. Technical details and heritage: - Electron density up to 3 x 10 5 cm -3, and temperatures up to 5000 K. - Electric field wave power ( Hz) with a sensitivity of 10-8 (V/m)2/Hz. - Heritage from very similar instruments on THEMIS and RBSP CU/LASP, GSFC, UCB/SSL, LM, JPL

LPW – EUV Monitor Frank Eparvier, LASP Measurement Objectives: - Solar EUV irradiance at wavelengths important for ionization, dissociation, and heating of the upper atmosphere (wavelengths shortward of H Ly-α nm). Technical details and heritage: -Two diode measurements at key wavelengths and Ly-α from LPW probe - Third diode for Ly-α recently added. - EUV hardware is part of LPW instrument - Full spectrum derived from measurements using Flare Irradiance Spectral Model (FISM). CU/LASP, GSFC, UCB/SSL, LM, JPL

Solar Energetic Particle (SEP) Davin Larson, SSL Measurement objectives: - Solar energetic particles that can interact with the upper atmosphere (energies up to a few MeV). - Time resolution adequate to capture major SEP events (~1 hour). Technical details and heritage: -Solar protons and heavier ions from ~30 keV to 12 MeV (and electrons from ~ keV), with ~30% energy resolution. - Identical to SST on THEMIS. Measured response of Mars upper atmosphere to a solar event: CU/LASP, GSFC, UCB/SSL, LM, JPL

Solar Wind Ion Analyzer (SWIA) Jasper Halekas, SSL Measurement objectives: - 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 (~350 to ~1000 km/s) down to stagnating magnetosheath speeds (tens of km/s). Technical details and heritage: - Proton and alpha velocity distributions from 2000 km/s, density from 0.1 to >100 cm -3. Energy resolution (ΔE/E) of ~6% and angular resolution of ~5°. Time resolution of 5 s. - Heritage from Wind, FAST, and THEMIS. Similar measurements provided by Wind: CU/LASP, GSFC, UCB/SSL, LM, JPL

Solar Wind Electron Analyzer (SWEA) David Mitchell, SSL Measurement objectives: - Energy distributions of solar wind, magnetosheath, and ionospheric electrons from 10 to 1000 eV to determine the electron impact ionization rate, with an energy resolution (~25%) sufficient to distinguish ionospheric photoelectrons from solar wind electrons. Technical details and heritage: - Electrons with energies from 5 eV to 6 keV imaged over ~80% of the sky with 22° angular resolution. Energy fluxes up to 10 9 eV/cm 2 -s-ster-eV. - Identical to STEREO SWEA. MGS measurements of auroral electrons: CU/LASP, GSFC, UCB/SSL, LM, JPL

Magnetometer (MAG) Jack Connerney, GSFC Measurement objectives: - Vector magnetic field in the unperturbed solar wind (B ~ 3 nT), magnetosheath (B ~ nT), and crustal magneto- spheres (B < 3000 nT), with the ability to spatially resolve crustal magnetic cusps (horizontal length scales of ~100 km). Technical details and heritage: - Magnetic field over a dynamic range of ~ 0.1 nT to ~ 60,000 nT, with 1 sec time resolution (4 km spatial resolution), 1° angular determination, and 5% precision on scalar value. -Heritage: MGS, Voyager, AMPTE,, GIOTTO, CLUSTER, Lunar Prospector, MESSENGER and others; identical to MAG on STEREO. MGS MAG measurements: CU/LASP, GSFC, UCB/SSL, LM, JPL

The MAVEN Science Team Overall science leads: Bruce Jakosky (PI) Bob Lin (DPI) Joe Grebowsky (PS) Janet Luhmann NGIMS: Paul Mahaffy Wayne Kasprzak IUVS: Nick Schneider Bill McClintock Erik Richard Ian Stewart John Clarke MAG: Mario Acuna (dec’d.) Jack Connerney SEP: Davin Larson Jasper Halekas Rob Lillis AAG: Richard Zurek Bob Tolson Darren Baird IDS: Steve Bougher Tom Cravens Xiaohua Fang Jane Fox Roger Yelle SWEA: David L. Mitchell Christian Mazelle Jean-Andre Savaud Dominique Toublanc SWIA: Jasper Halekas Davin Larson STATIC: Jim McFadden David Brain Bill Peterson Francois Leblanc LPW: Bob Ergun Greg Delory Laila Andersson Frank Eparvier Tom Woods Phil Chamberlin

CU/LASP, GSFC, UCB/SSL, LM, JPL Launch: November 18, 2013 Ten Month Ballistic Cruise to Mars Orbit Insertion: 16 Sept 2014 One Year of Science Operations MAVEN Mission Architecture

CU/LASP, GSFC, UCB/SSL, LM, JPL The MAVEN Spacecraft

CU/LASP, GSFC, UCB/SSL, LM, JPL Elliptical Orbit Allows Measurement of All Relevant Regions of Upper Atmosphere Nominal periapsis near 150 km. Five “deep-dip” campaigns with periapsis near 125 km.

CU/LASP, GSFC, UCB/SSL, LM, JPL Aerodynamic Stability for Periapsis Passes in the Upper Atmosphere

CU/LASP, GSFC, UCB/SSL, LM, JPL MAVEN Orbit and Primary Mission Elliptical orbit to provide coverage of all altitudes The orbit precesses in both latitude and local solar time One-Earth-year mission allows thorough coverage of near-Mars space

CU/LASP, GSFC, UCB/SSL, LM, JPL Latitude and Local Time Coverage One-Earth-year mission provides coverage of all local solar times and most latitudes. Figure shows periapsis regions. Apoapsis is, of course, on the opposite side of the planet. h < 170 km h < 300 km

CU/LASP, GSFC, UCB/SSL, LM, JPL MAVEN’s Timing in the Solar Cycle

CU/LASP, GSFC, UCB/SSL, LM, JPL MAVEN Schedule We are here

MAVEN’s Ability As A Relay MAVEN is required by NASA to carry an Electra relay for surface assets (esp. MSL extended mission and ExoMars primary mission). MAVEN nominally is the backup, with MRO and ODY (and MEx?) being primary. There’s an inherent trade-off for us between being an effective relay and doing MAVEN science. MAVEN is not an ideal relay, due to its elliptical orbit. We’re anticipating (hoping?) that 2016 orbiter will have relay capability and take some of the pressure off of us. CU/LASP, GSFC, UCB/SSL, LM, JPL

MAVEN – Mars Express – ASPERA Potential Interactions Potential for simultaneous Mars Express and MAVEN observations? Joint MVN – Mars Express – ASPERA science team meeting? Potential for some joint team members? Identify missing measurements that could become a component of the 2016 joint ESA-NASA orbiter? CU/LASP, GSFC, UCB/SSL, LM, JPL

The MAVEN Mission Is On Track MAVEN science goals are tightly focused on understanding atmospheric loss to space through time. The mission architecture, spacecraft design, and instruments and capabilities were selected specifically to provide the desired science. MAVEN and Mars Express are highly complementary, and we hope to have significant scientific interactions across missions. MAVEN will provide a comprehensive understanding of Martian volatile escape and atmospheric evolution. Interim MAVEN web site: MAVEN Facebook page – Search on “MAVEN Mars Atmosphere”