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Small Multimission Spacecraft (SMMS)

The MOU on the Cooperation in Small Multi-Mission Satellite (SMMS) project was jointly signed by China, Iran, Republic of Korea, Mongolia, Pakistan and Thailand on April 22 1998 in Bangkok, marking the initiation of this program. Bangladesh joined the program in 1999. between May of 1998 to May of 2001, five Project Committee meeting were held for the discussion and confirmation of responsibility distribution and working plans for the SMMS project for its launching in 2005.

The 5th Project Committee Meeting of Small Multi-Mission Satellite (SMMS) held in Beijing on May 11-13, 2001. 35 delegates from China, Thailand, Iran, Pakistan, and South Korea attended the meeting. In order to complete the work in the concept stage of SMMS and start the development of SMMS as soon as possible, it was agreed that all member countries will complete the work on the concept of subsystems and preliminary design review of the satellite system in late 2001.

The Sixth Asia-Pacific Conference on Multilateral Cooperation in Space Technology and Applications was held in Beijing 19-21 September 2001, with representatives from over 20 countries in attendedacnce. It announced during the conference that the Small Multimission Spacecraft(SMMS), a CAST968 bus based small satellite co-developed by China, Korea, Pakistan, Bangladesh, Iran, Mongolia and Thailand, would enter manuafacture pahse around end of 2001. Iranian engineers and scientists involved in the CCD camera development were in Beijing in mid-September 2001 to review progress on the spacecraft.

In June 2001 the China National Space Administration released an investigation form for possible international collaborations on the planned Environmental and Disaster Monitoring Satellite Constellation. China proposed to offer opportunities to international partners for providing one or more small satellites, piggy-back instruments or their components, cash investment, as well as applications of the constellation. The planned small satellite constellation would consist of four optical imagging satellites and four radar satellites.

China is establishing its disaster and environment monitoring capability mainly depending on the ordinary technologies, and meanwhile, China will also launch the small satellites to monitor the earth environment, and apply the satellite remote sensing technology to conduct all weather, around-the-clock and high time-resolution disaster and environment monitoring. The small satellite constellation for disaster and environment monitor are composed of 4 optical small satellites and 4 small satellites with synthetic aperture radar. During the period of the Tenth Five-Year Plan, China will launch 2 optical satellites and 1 radar satellite. The resolutions of CCD camera, the infrared camera and the synthetic aperture radar are 30m, 150m, and 20m, respectively. The average re-visit time is 32 hours.

China, Thailand and Iran are working on a joint Small Multimission Spacecraft (SMMS) devoted to civilian remote-sensing and communications experiments. The SMMS satellite will carry a low-resolution charge-coupled device (CCD) camera and an experimental telecommunications system. The SMMS will give Iran and Pakistan a semi-autonomous space-imaging capability. The 470-kg. (1,034-lb.) spacecraft is set for launch on a Chinese booster by 2004-05 into a 650-km. (400-mi.) Sun-synchronous polar orbit.

Pakistan also is involved with China in the regional remote-sensing initiative, but not necessarily in the SMMS hardware.

The SMMS spacecraft bus is envisioned as a standardized design that can be used in the future for other China or Asia-Pacific cooperative imaging or science missions. The CAST968 bus based small satellite co-developed by China, Korea, Pakistan. Three will be launched by 2005, with five more planned after that.

The CAST968A platform is a development development first small satellite public platform, this platform bases on comprehensively completes the Chinese Academy of Science to propose duty at the same time, but also must complete the new engineering research task which needs to develop for the following model. Has derived my courtyard each kind of model development experience in the design, the full use mature technology and the mature equipment, the utilization system integration, on the star product does not do the simple backup, stresses considered from software, uses the software redundant technology. Using the ground expert support program, repours into software, again constructs on the star the system, enhanced the satellite performance, avoids the entire star the simple point expiration.

Shan Liyu, which develops by this platform loading academy of science the effect experiment, the spatial grain the practice five satellites which and so on the payload equipment constitute to the radiation survey and the new engineering research instrument, authorized from 1996 to set up the item to start to 1998 August, the merely 24 month-long time, my courtyard has completed the project star and flies the planet development and the experiment, proved this platform the plan design was reasonable, the performance index met the user need and meets the system design technical specification requirements.

Main technical specification

Platform quality < 250kg
Permission loading payload quality <= 200 ~ 240kg
Platform size 1100-1200-500mm3
Solar cell area 3.4m2
Square matrix power 300 ~ 400W
Accumulator cell monomer capacity 17Ah (19)
A. is stable to the date direction detection three axle  Attitude control precision ±5°
Posture stability <0.05/s
B. is stable (safe mode) to date direction detection spinning Spinning speed 12±2rpm
Posture measuring accuracy < ±4°
C. is stable to the place direction detection three axle Posture measuring accuracy 0.5°
Posture stability <0.05°/S
International compatible unification observation and control system S wave band
With delivery mechanical connection for standard size -660mm
Design life 3 months ~ 2 years

CAST development satellite guiding ideology first satisfies the user request, and implements "the universalization" in the design, "the seriation", "the combination" and the public platform thought, in the existing small satellite platform foundation, for the adaption user new demand, carries on the compatible revision and the promotion, "rolls the type" to develop the small satellite technology. CAST according to the user to a sea satellite request, in the CAST968A platform foundation, the development has developed the CAST968B platform.

  1. In order to adapt the embarkation launch to request and to satisfy a sea satellite payload the working condition need, the increase , propulsion system, enable the satellite to have changes the axle ability and the track maintenance;
  2. The attitude control precision from 5 enhances to 0.4 ~ 0.5;
  3. Has enlarged a solar cell area, and enhanced the battery piece transfer efficiency, enhanced the platform output;
  4. Changes the stationary sun windsurfboard for the actuation type sun windsurfboard, can the automatic tracking, accurately to the solar direction detection;
  5. Increased the GPS positioning system, enhanced the satellite independently to decide the axle ability.

Main technical specification

Platform quality <260kg
Permission loading payload <= 240Kg
Platform size 1100-l200-500mm3
Solar cell area 5.5m2
Square matrix power 500 ~ 600W
Accumulator cell monomer capacity 23Ah (17)
Attitude control pattern
Posture measuring accuracy

Posture stability
Control direction precision
   Is stable to the place direction detection three axle
   Deals with, rolls <= 0.2°
   Drifts off course <= 0.3°
   Three axle <= 0.01°/s
   Deals with, rolls <= 0.4°
   Drifts off course <= 0.5°
International compatible unification observation and control system S wave band +GPS
With delivery mechanical connection for standard size -660mm
Design life 2 year ~ 3 years

According to domestic, outside the small satellite market demand analysis and at present started to prove the work each kind of small satellite to the platform demand, CAST968A and the CAST968B platform still cannot comprehensively satisfy the high performance satellite payload application the demand, like high spectrum imagery meter, high resolution camera, synthetic aperture radar and other microwave/optics remote sensing which must load to the place observation class satellite and so on, for this, CAST decided further promote in CAST968A and in the CAST968B platform foundation, causes it adaption user the demand, this platform can satisfy each kind of high resolution, the high performance, the multipurpose payload demand.

Main technical specification

The platform quality (contains advancement) <= 250 ~ 300kg
Permission loading payload quality <= 200 ~ 250kg
Platform size 1200-1250-500mm3
Square matrix power 500 ~ 1000W
Nickel hydrogen battery monomer capacity 30Ah
Attitude control pattern 
Posture measuring accuracy
  Posture stability  
  Control direction precision 
  The side pivot angle (rolls side to suspend)  
Is stable to the place direction detection three axle  
International compatible unification observation and control system  S wave band + GPS
With delivery mechanical connection for standard size -660mm
Design life 5 years

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