Instrument Overview
        ===================
        The ROMAP sensors (fluxgate magnetometer, electrostatic 
        analyser and Faraday cup) measure the magnetic field from
        0 to 32Hz, ions up to 8.0 keV and electrons up to 4.2 keV. 
        High integration level of sensors and electronics is the basic
        for a combined field/plasma measurement instrument with less
        than 1 Watt power consumption and 1 kg mass. 
        Additional two pressure sensors are included in the ROMAP 
        sensor arrangement.
        The sensors are moved from COSAC to ROMAP to optimise long
        term operation of pressure sensors. Data of both pressure
        sensors are transmitted within the housekeeping frame and
        are handled / archived as housekeeping values.
  
        Scientific Objectives
        =====================
        Main scientific goals of ROMAP are
        (1) long term measurements on the surface to study the
            cometary activity as function of the distance from the Sun
        and
        (2) magnetic measurements during the descent phase of the
            Lander to investigate the structure of the remnant
            magnetization of the nucleus.
  
        Calibration
        ===========
        MAG : Data are precalibrated by nominal scaling. Offsets can 
              not be corrected automatically. This will be done by
              sequence specific cal files (L3). 
              Finally corrected data (includes the removal of
              spacecraft disturbances) are only available for selected
              data of scientific interest (L5).
        SPM : Instrument calibration will be done preliminary (L3) and
              finally for derived data products (L5).
  
  
        Operational Considerations
        ==========================
        Main measurement sequences are:
        - During Flybys
        - During Descent
        - On cometary Surface
       Common operation with Instruments generating magnetic
       interferences shall be avoided.
       Common operation with RPC-MAG onboard the orbiter is highly
       desirable
  
        Electronics
        ===========
       The ROMAP electronics consists of two boards placed inside the
       common electronics box. The central part of the near sensor
       electronics on the first board is a FPGA which controls AD and
       DA-converters. The 16-bit AD converters are digitising science
       and housekeeping data from all three sensors. Typical analogue
       parts of fluxgate magnetometers like filters or phase-sensitive
       integrators are substituted by fast digitalization of the sensor
       AC-signal and the following data processing in FPGA's (which
       overtakes the functions of the former analogue parts). In this
       way mass is saved without any loss of accuracy. The resolution
       is still restricted by sensor noise (less than 5pT/sqrt(Hz)
       at 1Hz), not by electronics. Compensation fields for the magnetometer
       and high voltage steps for electrostatic analyser and Faraday cup
       are controlled via DA-converters (dashed lines). The near sensor
       electronics is developed by Magson GmbH Berlin The high voltage
       generator (developed by the KFKI) is in a separate shielded box
       on the front panel of the common electronics box. The controller
       is located on the second ROMAP board.
       It controls MAG and SPM, stores their data output and implements
       the interface to the Lander Command and Data Management System 
       (CDMS). It triggers the measurement cycle of the magnetometer,
       implements the digital magnetometer algorithm, controls the 
       magnetometer feedback and generates data frames. For the SPM
       sensors the controller has implemented the counting logic for
       electrons and ions, samples Faraday cup data, generates SPM data
       frames, controls the high voltage parameters (energy,
       elevation), controls the channeltron HV-supply and computes the
       plasma parameters. In the parameter mode only the sums of the
       rows and columns of the sampled ion and ion-current arrays are
       transmitted.
       The controller is based on a RTX2010. Address decoder, reset
       logic, clock generators, control signals generator, watchdog
       logic and CDMS interface are integrated within a FPGA. Hard- and
       software are developed by the IWF Graz.
  
        Sensor / Sensor Location
        ========================
       The magnetometer sensor consists of two ringcores (crossed in to
       each other) as well as pick-up coils and Helmholtz coils for
       each sensor axis. The coil system design without mechanical
       support allows the compensation of the external field on the
       ringcore position with high homogeneity and low weight (the
       overall sensor weight is 30g). Dynamic feedback fields as well
       as offset fields up to 2000nT can be generated in order to
       compensate Lander and/or Orbiter DC stray fields. The main part
       of the SPM-sensor is a hemispherical electrostatic analyzer with
       two channeltrons (CEM's) for ions measurement and one for
       electrons measurement. The entry of the ion channels is equipped
       with deflection plates to realize the spatial resolution. 
       Despite the small size of the sensor, the sensitivity and
       resolution of the instrument are high and its field of view wide
       (appr. 100 degree).
       The E/q-range extends from 0 to 8 kV. Using CEMs in counting
       mode the electrostatic analyzer measures electron and ion
       distribution in a wide energy range. Hemisherical deflection
       plates analyze the energy in 32 or 64 steps. All major plasma
       parameters as bulk velocity, density and isotropic temperature
       of protons and electrons can be derived.
       A retarding-grid Faraday cup sensor is implemented to measure
       currents due to fluxes of low energy charged particles on a
       collector plate. The Faraday cup measures the 'reduced' velocity
       distribution of the plasma due to its inherent integration over
       velocities contained in a plane of differential thickness
       perpendicular to the axis of the sensor. The combined
       magnetometer / SPM sensor is mounted on a 60 cm boom which is
       fixed with a hinge on the upper edge of the Lander structure
       and with a launch lock on the Lander balcony. After opening the
       launch lock, the boom will be deployed by two springs inside
       the hinge. 
       Two pressure sensors are selected to cover the whole pressure
       range from 10^-8 mbar to 10 mbar. For the range from 10^-8 mbar
       to 10^-3 mbar an ionising system (Penning) is deployed while for
       the range from 10^-3 mbar to 10 mbar a heat conduction sensor
       (Minipirani) is available.
  
  
        Operational Modes
        =================
        ROMAP can be basically operated in 3 modes:
        - Slow Mode
        - Fast Mode
        - Surface Mode
  
        Subsystems
        ==========
        The sub-systems are described in Auster et al, 2005.
  
  
        Measured Parameters
        ===================
        Magnetic field; resolution 10 pT
        Electrons: 0.35 ... 4200 eV
        Ions: 40 ... 8000 eV
        Pressure; 10^-8 mbar to 10 mbar.