/* Template: Instrument Host Rev: 1993-09-24*/ /* Hierarchy: INSTRUMENT_HOST */ /* INSTRUMENT_HOST_INFORMATION */ /* INSTRUMENT_HOST_REFERENCE_INFO */ PDS_VERSION_ID = PDS3 OBJECT = INSTRUMENT_HOST INSTRUMENT_HOST_ID = "GO" OBJECT = INSTRUMENT_HOST_INFORMATION INSTRUMENT_HOST_NAME = "GALILEO ORBITER" INSTRUMENT_HOST_TYPE = "SPACECRAFT" INSTRUMENT_HOST_DESC = " 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. Galileo is the first spacecraft to operate in a dual-spin mode. The orbiter uses a dual-spin attitude stabilization system consisting of a spun section (the rotor, which spins at approximately three rpm) and a despun section (the stator, which maintains a fixed orientation in space). This design accommodates the different requirements of the two types of instruments on board: the stator contains the remote sensing instruments and the rotor contains the fields and particles instruments as well as spacecraft engineering subsystems. There are eleven subsystems on the orbiter and nine scientific scientific instruments. The orbiter weighs 2,380 kilograms (which includes 1089 kilograms of propellant). It can transmit data to Earth at data rates ranging from 10 bps to a maximum rate of 134 kilobits per second at S-band and X-band frequencies. The rotor has one 4.8 meter high-gain antenna and two low-gain antennas. The stator contains a radio relay antenna operating at the L band for receiving data from the atmospheric probe. The rotor and stator are connected by the spin bearing assembly, which conducts power via slip rings and data signals via rotary transformers. Refer to [Johnson1992] Platform Descriptions ===================== Platform ROTOR The rotor is the spinning section of the orbiter which contains the high-gain communications antenna, the propulsion module, flight computers, and most support systems. The rotor contains two booms which were unfurled and extended automatically after launch. The science boom, which extends to a distance of three meters from the spacecraft centerline, is the mounting platform for the energetic particles detector (EPD), the dust detector (DDS), the heavy ion counter (HIC), and the plasma detector (PLS). The magnetometer boom extends outward eleven meters from the centerline and is attached to the science boom. It contains the plasma wave antenna (PWS) and two magnetometer sensors (MAG), one at the midpoint of the boom and the other at its outboard end. The extreme ultraviolet spectrometer (EUV) is mounted on the spacecraft bus. Refer [Johnson1992] Platform STATOR =============== The stator is the despun section of the orbiter. It is turned via an electric motor opposite to the rotation of the rotor, so that it maintains a stable orientation in space. Attached to the stator is a moveable scan platform which contains the remote sensing instruments: the photopolarimeter radiometer (PPR), the near-infrared mapping spectrometer (NIMS), the solid-state imaging camera (SSI), and the ultraviolet spectrometer (UVS). The probe and the probe relay antenna are also attached to the stator. Refer to [GLL1985]" END_OBJECT = INSTRUMENT_HOST_INFORMATION OBJECT = INSTRUMENT_HOST_REFERENCE_INFO REFERENCE_KEY_ID = "GLL1985" END_OBJECT = INSTRUMENT_HOST_REFERENCE_INFO OBJECT = INSTRUMENT_HOST_REFERENCE_INFO REFERENCE_KEY_ID = "JOHNSON1992" END_OBJECT = INSTRUMENT_HOST_REFERENCE_INFO OBJECT = INSTRUMENT_HOST_REFERENCE_INFO REFERENCE_KEY_ID = "SSR1992" END_OBJECT = INSTRUMENT_HOST_REFERENCE_INFO END_OBJECT = INSTRUMENT_HOST /* GALILEO PROBE */ OBJECT = INSTRUMENT_HOST INSTRUMENT_HOST_ID = "GP" OBJECT = INSTRUMENT_HOST_INFORMATION INSTRUMENT_HOST_NAME = "GALILEO PROBE" INSTRUMENT_HOST_TYPE = "SPACECRAFT" INSTRUMENT_HOST_DESC = " 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 [Johnson1992] 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 [Johnson1992]" END_OBJECT = INSTRUMENT_HOST_INFORMATION OBJECT = INSTRUMENT_HOST_REFERENCE_INFO REFERENCE_KEY_ID = "GLL1985" END_OBJECT = INSTRUMENT_HOST_REFERENCE_INFO OBJECT = INSTRUMENT_HOST_REFERENCE_INFO REFERENCE_KEY_ID = "JOHNSON1992" END_OBJECT = INSTRUMENT_HOST_REFERENCE_INFO OBJECT = INSTRUMENT_HOST_REFERENCE_INFO REFERENCE_KEY_ID = "SSR1992" END_OBJECT = INSTRUMENT_HOST_REFERENCE_INFO END_OBJECT = INSTRUMENT_HOST END