Supra-Thermal and Thermal Ion Composition Instrument

The Supra-Thermal And Thermal Ion Composition (STATIC) instrument is designed to measure the ion composition and distribution function of the cold Martian ionosphere, of the heated suprathermal tail of this plasma in the upper ionosphere, and the pickup ions accelerated by solar wind electric fields. STATIC operates over an energy range of 0.1 eV up to 30 keV, with a base time resolution of 4 seconds. The instrument consists of a toroidal “top hat” electrostatic analyzer with a 360 degree x 90 degree field-of-view, combined with a time-of-flight (TOF) velocity analyzer with 22.5 degree resolution in the detection plane. The TOF combines a -15 kV acceleration voltage with ultra-thin carbon foils to resolve H+, He++, He+, O+, O2+, and CO2+ ions. Secondary electrons from carbon foils are detected by microchannel plate detectors and binned into a variety of data products with varying energy, mass, angle, and time resolution. To prevent detector saturation when measuring cold RAM ions at periapsis (~10**11 eV/cm**2-s-sr-eV) while maintaining adequate sensitivity to resolve tenuous pickup ions at apoapsis (~10**3 eV/cm**2-s-sreV), the sensor includes both mechanical and electrostatic attenuators that increase the dynamic range by a factor of 10**3. The STATIC sensor is mounted on the APP boom, along with NGIMS and IUVS, so that it can be pointed in the ram direction during periapsis passes. During apoapsis, pointing of the APP is alternated between optimal viewing for IUVS and STATIC, both of which depend on orbit parameters and local time.

The Supra-Thermal And Thermal Ion Composition (STATIC) instrument is designed to measure the ion 
         composition and distribution function of the cold Martian ionosphere, of the heated suprathermal 
         tail of this plasma in the upper ionosphere, and the pickup ions accelerated by solar wind electric 
         fields. STATIC operates over an energy range of 0.1 eV up to 30 keV, with a base time resolution of 
         4 seconds. The instrument consists of a toroidal “top hat” electrostatic analyzer with a 360 degree x 
         90 degree field-of-view, combined with a time-of-flight (TOF) velocity analyzer with 22.5 degree 
         resolution in the detection plane. The TOF combines a -15 kV acceleration voltage with ultra-thin 
         carbon foils to resolve H+, He++, He+, O+, O2+, and CO2+ ions. Secondary electrons from carbon foils 
         are detected by microchannel plate detectors and binned into a variety of data products with varying 
         energy, mass, angle, and time resolution. To prevent detector saturation when measuring cold RAM ions 
         at periapsis (~10**11 eV/cm**2-s-sr-eV) while maintaining adequate sensitivity to resolve tenuous 
         pickup ions at apoapsis (~10**3 eV/cm**2-s-sreV), the sensor includes both mechanical and electrostatic 
         attenuators that increase the dynamic range by a factor of 10**3. The STATIC sensor is mounted on the 
         APP boom, along with NGIMS and IUVS, so that it can be pointed in the ram direction during periapsis 
         passes. During apoapsis, pointing of the APP is alternated between optimal viewing for IUVS and STATIC,
         both of which depend on orbit parameters and local time.

MAVEN Supra-Thermal and Thermal Ion Composition

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