1 Mars Micro-satellite Mission Japanese micro-satellite mission to Mars to study the plasma environment and the solar wind interaction with a weakly-magnetized planet in response to Call for ideas of additional payload in Phobos-Soil mission for the investigation of Mars

2 Motivation Nozomi (Japanese Mars Orbiter) had to give up its injection into orbit around Mars due to unrecoverable malfunction. No other spacecraft has performed the original scientific objectives of Nozomi. Therefore, numerous scientific questions are still unresolved. Recent discoveries of water on Mars surface increase our interest in the atmospheric evolution and the loss process. Existence of the crustal magnetic field provides a unique situation of the space plasma phenomena. (Shinagawa, 2000) Nozomi (Planet-B)

3 Mission Scenario Payload Zone After arriving at Mars, the micro-satellite will be separated from the mother ship at the Martian orbit, and it starts observing the upper atmosphere, ionosphere and the interaction region with the solar wind. A micro-satellite for Mars orbiter will be developed in Japan so that it can fit for the additional payload zone on Phobos main bus.

4 Scientific Objectives The solar wind interaction with “mini” magnetosphere  The interaction with a weakly-magnetized planet  Reconnection, particle acceleration  Magnetospheric convection  Induced atmospheric escape 2. Atmospheric (plasma) escape  Potential influence on the atmospheric evolution  Comparative study with the escape from Earth  Diversity of the escape process and the flux variation  Where did the atmospheric particle go?

5 Scientific Objectives - 2 (Lundin, 1989) 3. Dynamics and structure of the ionosphere  Potential role of the crustal magnetic field  Altitude profile of N e and N i, and a role of the heat flux  Hole, cloud, streamer, tail ray – exist? 4. Ion pickup and magnetotail  Quantitative measurement of pickup ions  Asymmetric distribution of energetic ions and the ionospheric plasma  Acceleration of escaping ions in the magnetotail 5. Ionopause  Pressure balance  Momentum transfer and convection  Role of plasma wave in the mass loading  Turbulence, K-H instability

6 Scientific instruments InstrumentBasic descriptionMeasurement range PSA Ion energy & mass analyzer Energy: 5 eV – 40 keV Mass: 1 – 50 amu Electrostatic analyzerEnergy: 1 eV – 15 keV PWATwo pairs of antennaFrequency : DC – 10 MHz MGFTri-axial fluxgate Range :  2000 nT TPA Ion mass & energy analyzer Energy: < 30 eV Drift velocity, T i and N i FLPLangmuir probeT e and N e

7 Core Institute and Member Institute / UniversityNamePI of Kyoto Univ.S. MachidaPSA Tohoku Univ.T. OnoPWA ISAS/JAXAA. MatsuokaMGF Univ. of Calgary, CanadaA. YauTPA ISAS/JAXAT. AbeFLP Nagoya Univ. STELH. Shinagawa Theory and Modeling

8 Spacecraft configuration and orbit Planned Orbit (To be revised)  Elliptical orbit (<4000 km x km from Mars center) Preferable to reduce the periapsis height below 300 km for the observation of Mars ionosphere  Inclination – TBD (depends on the orbit control ability) Preferable a mid-inclination orbit for the crustal magnetic field observation  Mission life : > 1 Mars year Baseline Configuration (To be revised)  Spinning platform  Control system for orbit and attitude maneuvers  Telemetry link with mother spacecraft by omni-directional antenna (Downlink via main bus)  Two booms for magnetometer and thermal plasma measurement  Two pairs of antenna for plasma wave measurement