Instrument Host Overview         ========================          The Galileo spacecraft consists of two parts, an orbiter         (SPACECRAFT_ID = 'GO') and a probe (SPACECRAFT_ID = 'GP').         Spacecraft power is provided by two radioisotope         thermoelectric generators. Propulsion is accomplished via a         bipropellant system of twelve 10- newton thrusters and one         400 newton engine. The command and data subsystem consists         of multiple microprocesors and a high-speed data bus.          The Galileo atmospheric probe will be deployed from the         orbiter 150 days prior to Jupiter encounter. The probe         consists of a deceleration module and a descent module. It         weighs about 331 kilograms, half of which is the heat         shield. After entering the Jovian atmosphere and slowing its         descent, the descent module deploys a 2.5 meter parachute         and begins transmitting data from its instruments at a rate         of 128 bits per second. (Refer to Yeates, et al, 1985;         Johnson, et al, 1992.)        Platform Description       --------------------          Platform PROBE DESCENT MODULE            The atmospheric descent module contains seven scientific           instruments: the atmospheric structure instrument (ASI), the           neutral mass spectrometer (NMS), the helium abundance           detector (HAD), the nephelometer (NEP), the net-flux           radiometer (NFR), the lightning and radio emissions detector           (LRD), and the energetic particles instrument (EPI). The           instruments are contained in hermetically sealed housings           designed to withstand a pressure of 20 bars. The instrument           data are transmitted to the orbiter over two simultaneously           operating channels in the L band. (Refer to Yeates, et al,           1985; Johnson, et al, 1992.)