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Platforms > Space-based Platforms > Earth Observation Satellites > TSINGHUA-1

Preferred term

TSINGHUA-1  

Definition

  • Tsinghua-1 is a microsatellite of Tsinghua University, developed and built in a joint venture between SSTL of Guildford, Surrey, UK, and Tsinghua University in Beijing, China. The TSRC (Tsinghua Space Research Center) was set up in Oct. 1998 with the goal to integrate all space research activities at Tsinghua University and to provide a means and facilities for S/C building. The joint-venture company in Beijing is referred to as T-SSSC (Tsinghua-Surrey Small Satellite Company). The cooperative program is to develop and build microsatellites (Tsinghua-1) and nanosatellites (THNS-1) and to provide integrated training in small satellite design. Tsinghua-1 (also referred to as "Hangtian" in Chinese) is a demonstrator microsatellite in the 50 kg class of size: 35 cm x 35 cm x 64 cm. The overall objective is to provide daily high-resolution imaging for disaster monitoring and mitigation on a worldwide scale. A further goal of Tsinghua-1 is to conduct communications research in LEO. The design uses the new MicroSat-70 platform modules or trays to carry the subsystems and payload. The power subsystem design includes the regulation, protection and distribution of a 35 W solar array and 7 Ah NiCd batteries. This subsystem essentially offers two buses: an unregulated 14 V bus and a regulated 5 V bus. The three payload modules include the GPS receiver (SGR-10 with 12 channels), transputer, and DSP/DTE (Digital Signal Processing/Data Transfer Experiment) unit. The three cameras and 3 reaction wheels are accommodated in the Earth Observation Compartment. Two GPS antennas are accommodated on the space facing side of the S/C. The spacecraft is three-axis stabilized using a combination of passive (gravity-gradient boom) and active (magnetorquers, reaction wheels) actuator elements. The platform is nadir pointing. Attitude is sensed by sun sensors and a magnetometer. The body-pointing platform has the capability to perform fast slew maneuvers within 15 about the roll axis (or 180 about the yaw axis). An off-nadir pointing configuration can be sustained for up to half an orbit. Onboard data handling is provided with a dual CAN (Controller Area Network) bus (ISO 11898 & ISO 11519-1) 20 Mbit/s, and INMOS serial point-to-point link 9.6 kbit/s asynchronous duplex UART (Universal Asynchronous Receiver/Transmitter). A launch of Tsinghua-1, along with SNAP-1 of SSTL as secondary payloads to Nadezhda-6, the prime Russian S&RSAT (Search & Rescue Satellite) of COSPAS, took place on June 28, 2000 on a Russian Cosmos-3M launcher from the Plesetsk Cosmodrome, Russia. Orbit: Sun-synchronous circular orbit, altitude = 700 km, inclination = 98, period of 100 minutes. Status of Tsinghua-1 mission: The spacecraft is operational as of 2004. Sensor complement: MEIS (Multispectral Earth Imaging System).MEIS is a demonstrator instrument intended for the upcoming DMC (Disaster Monitoring Constellation) mission. The objective is to acquire multispectral Earth surface imagery with a spatial resolution of 40 m (snapshot imagery). The MEIS camera assembly consists of three cameras (one for each spectral band) mounted at an angle of 15 from nadir so that the yaw angle can be selected to offer the required off-pointing angle of 15 from nadir. The image swath width is 80 km and each camera can collect four images contiguously along the flight path. The instrument performs autonomous onboard histogram analysis to ensure optimum image quality involving image processing, compression and onboard storage. The OBCs may also be used to carry out autonomous onboard cloud editing and high-compression thumb-nail image previews. SGR-10 (Space GPS Receiver-10). The objective is real-time positioning for tracking the satellite and providing orbital elements for the spacecraft mission and ground station. SGR is a customized COTS-developed receiver. The instrument is based on the second generation GPS chip set of MITEL Semiconductors. The SGR consists of the following elements: GPS antennas, LNAs, the RF section, the digital section and the TLM/TC node. RF section: The SGR has two separate RF front-ends in the RF section which are responsible for down-converting the GPS signals and digitizing the IF signals. The RF sections use the same local oscillator so that the measurements are referenced to the same fundamental TCXO clock. Digital section: This part consists of hardware correlator channels, memory, a 32 bit RISC microprocessor with supporting peripherals and the interface circuitry. There are 24 C/A code correlation channels available, although only 12 channels are available if only 2 antennas are used. TLM/TC node: A separate 8 bit microcontroller is used to provide telemetry and telecommands. The telemetry includes status monitoring of SGR, while telecommand include reset, power down parts of the receiver, some redundancy switching etc. The SGR-10 receives the L1 signal from the GPS constellation. The total SGR mass is 1.355 kg, including antenna/LNA. The accuracy of positioning, velocity and time synchronization (under Selective Availability on GPS) are: 150 m, 1 m/s, 3-D, 2 sigma approximately, and + 1 s, respectively. Information from http://www.eoPortal.org Group: Platform_Details Entry_ID: TSINGHUA-1 Group: Platform_Identification Platform_Category: Earth Observation Satellites Short_Name: TSINGHUA-1 End_Group Group: Platform_Associated_Instruments Short_Name: CAMERAS End_Group Group: Orbit Orbit_Altitude: 700 Orbit_Inclination: 98.14 Period: 98.68 Perigee: 687 Apogee: 713 Orbit_Type: LEO > Low Earth Orbit > Polar Sun-Synchronous End_Group Creation_Date: 2008-06-19 Online_Resource: http://directory.eoportal.org/get_announce.php?an_id=9264 Online_Resource: http://www.sstl.co.uk/ Group: Platform_Logistics Launch_Date: 2000-06-28 Launch_Site: Plesetsk Cosmodrome, Russia Primary_Sponsor: Tsinghua University (China) Primary_Sponsor: Surrey Satellite Technology Ltd. (SSTL) End_Group End_Group (en)

Broader concept

Change note

  • 2021-11-18 12:40:07.0 [tstevens] Move Concepts delete broader relation (null); add broader relation (TSINGHUA-1 [f9922bc7-cbad-4230-ad65-08c5998a8e0f,826923] - Space-based Platforms [b39a69b4-c3b9-4a94-b296-bbbbe5e4c847,835875]);
  • 2021-11-30 09:41:55.0 [tstevens] Move Concepts delete broader relation (null); add broader relation (TSINGHUA-1 [f9922bc7-cbad-4230-ad65-08c5998a8e0f,826923] - Earth Observation Satellites [3466eed1-2fbb-49bf-ab0b-dc08731d502b,826121]);

URI

https://gcmd.earthdata.nasa.gov/kms/concept/f9922bc7-cbad-4230-ad65-08c5998a8e0f

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