Your Partner in Environment Monitoring

Transcription

1 Your Partner in Environment Monitoring

2 Radiation Environment in Space The ionizing radiation in space represents one of the most severe environmental loads to space hardware and can cause a large number of problems; spurious errors or permanent damage of electronics, erroneous signals in detectors, electrostatic charging of spacecraft or health damage to astronauts are only some examples which illustrate the importance of continuous in-situ radiation monitoring. Additionally, radiation monitoring provides vital information for long term space weather forecasting, environmental surveillance and for the prediction of communication system performance on ground and in space. The accurate simulation and prediction of the radiation loads to be expected for space mission are therefore essential for mission planning and spacecraft design. Company Activities Contraves Space, Switzerlands largest space technology company, has extensive know-how in the design, manufacturing and testing of large lightweight structures for space applications. Its competence is demonstrated by more than 25 spacecraft structures and over 160 payload fairings built for European and US customers. Contraves Space has at its disposal a broad range of engineering capabilities for mechanical, optical, electronics and software design, development, production and testing of complex systems for space applications. Contraves Space incorporates the complete infrastructure needed for the space business and currently employs approx. 320 staff, around half of whom are highly qualified engineers. Located in Zurich/Switzerland the company generates annuals sales of CHF 113 million (US$ 82 Mil). Contraves Space is a division of the Swiss Unaxis Group and is fully owned by the Unaxis Holding AG. Contraves Space major products are: Payload Fairings for Launchers Spacecraft Structures High Precision Mechanisms Scientific Instruments Electro-Optical Systems

3 SREM Standard Radiation Environment Monitor Description The Standard Radiation Environment Monitor is developed and manufactures by Contraves Space in cooperation with the Paul Scherrer Institut (PSI) under a development contract of the European Space Agency (ESA). SREM performs a wide range of radiation monitoring functions in-orbit, and downloads the results via the host spacecraft telemetry to a user on ground. It is designed as a standard equipment compatible with all common spacecraft interfaces and mission constraints. The first SREM models have already been launched (see chapter in-orbit). Further models are already planned to be embarked on ESA satellites such as Rosetta, GSTB, Herschel, Planck and GOCE. Advanced Space Radiation Models The increasing use of advanced electronic component technology in space hardware and the planning of manned space missions with extended duration ask for a revision of the present radiation environment models in order to meet future prediction accuracy requirements. ESA and Paul Scherrer Institute gained large experience with a precursor of SREM, the REM, onboard of a STRV-1 and the Russian MIR station. Radiation measurements show pronounced variability of the dose oberserved in the GTO orbit of STRV-1. The prediction computed with today s static radiation models are used for comparison. In-Orbit Unit Satellite Launch PFM-001 STRV-1C November 15, 2000* PFM-002 Integral October 17, 2002* PFM-003 Proba October 22, 2001* PFM-004 Rosetta Delayed* PFM-005 GSTB (Galileo System Test Bed) Planned PFM-006 Herschel Planned PFM-007 Planck Planned PFM-008 GOCE (Gravity and steady state Ocean Circulation Explorer) Planned PFM-009 GAIA Planned PFM-010 ROSETTA flight spare * you will find actual in-flight data on our website < In-orbit measurements from Proba , 00:00: , 00:00: UTC 4.0 Latitude [º] log 10 (TCS counting rote [ 1/ sec ]) Longitude [º] 1.5

4 In-Orbit Performance The Standard Radiation Environment Monitor (SREM) is designed to perform a wide range of radiation monitoring functions such as: Direction sensitive particle spectroscopy for electrons (e ) and protons (p+). Detection and counting of cosmic ray events. Total radiation dose measurements. High memory capacity for storage of data. Counter de Discr. Level Particle [MeV] TC (1/2) Proton S1(2) 0.25 Proton S1(3) 0.6 Proton S1(4) 2 Proton S1(5) 30 Proton TC Proton S2(5) 9 Ions C Coin. Proton C2 0.6, Coin. Proton C3 0.6, Coin. Proton C , Coin. Proton TC Electron S3(2) 0.25 Electron S3(3) 0.75 Proton S3(4) 2 Proton PL1 Dead time PL2 Dead time PL3 Dead time Time-Count. 100 msec SREM time Key Figures Performance Features 1. Mass 2.64 kg 2. Dimension 96 mm x 122 mm x 217 mm 3. Sensors Three precision particle detectors (measurement error <1%) Internal total dose measurement Internal temperature measurement 4. Operation Microprocessor, memory and data storage capacity for autonomous operation Data downloading on request via host spacecraft telemetry Operational monitoring accessible from host spacecraft data handling system 5. Environment Compliant with all standard launcher vibration load spectra Temperature range 20 up to +55 C (operational) 55 up to +80 C (non-operational) Compliant with standard EMC/EMI requirements Qualified for space vacuum 6. Lifetime and Reliability >0.85 for 10 years in-orbit operation and 3 years ground storage Interfaces Host Spacecraft Accomodation 1. Mechanical Interface Mounting area 230 mm x 106 mm Four holes d = 4.3 mm 2. Thermal Interface Total contact area 2 x 14.5 mm x 122 mm Black paint (optional MLI cover) 3. Electrical Power Interface Floating spacecraft bus 20 V to 55 V DC Power consumption <2 Watt 4. Power Control Interface On/Off command lines Status interface switching Housing temperature monitoring 5. Data Handling Telecommand interface differential or single ended System Interface Telemetry interface differential or single ended 6. Remote Sensor Interface Sensor bias source interface Remote total dose sensor interface Remote temperature sensor interface Connectors: J1 Power connector (15 pin male) J2 Data handling (OBDH) (15 pin female) J3 Remote RADFET (31 pin female) D1, D2 and D3 Particle detectors Detectors D1 & D2 D3 J2 Data handling (OBDH) (15 pin female) J3 Remote RadFET (31pin female) J1 Power connector (15 pin male)

5 Design Modularity The Standard Radiation Environment Monitor houses the following functional blocks: Power supply with DC/DCconverter with output voltages for the digital and the analog circuits, as well as for the detectors. Three particle detectors with associated temperature sensors integrated in the detector housing. Analog front end with low noise signal amplifiers and signal conditioning electronics. Comparators with fourteen detection ranges. Interface for remote total dose and temperature measurement sensors. Signal processing electronics with host spacecraft interface for: 1. Data processing and storage of scientific data 2. Acquisition of housekeeping data and system health monitoring 3. Telemetry and telecommand interface with host spacecraft SREM Functional Block Diagram J43 Test Detector 1 Detector 2 Analog Front End Comparator Bank Processing and Interface J42 Test J2 TM / TC Detector 3 RadFet & Temperature Temperature and Total Dose DC/DC-Converter J42 Test Power on/off J1 Status Thermistor RadFet & J3 Temperature Calibration The SREM is fully calibrated at the Proton Irradiation Facility (PIF) of the Paul Scherrer Institut (PSI), which also operates the dedicated SREM electron calibration source. The proton calibration is performed with protons up to 600 MeV, using an energy spectrum representative for the conditions in space. The calibration with electrons covers the range up to 5 MeV. The numerical simulations of the detector response, performed with the GEANT code, are verified based upon the results of the calibration and provide therefore a reliable database for the system input signal response characteristics. SREM Calibration in Progress

6 Contact For additional information please, contact Contraves Space AG Marketing and Sales Department CH-8052 Zurich, Switzerland Phone Fax Contraves Space AG Schaffhauserstrasse 580 CH-8052 Zurich Phone Fax