The China Aerospace Science and Technology Corporation (CASC) successfully launched the Terrestrial Ecosystem Carbon Inventory Satellite (TECIS) atop a Long March 4B rocket. The rocket took off from the Taiyuan Satellite Launch Center in China on August 4, 2022.
The Terrestrial Ecosystem Carbon Monitoring Satellite (TECIS) will contribute to fighting global warming by collecting information on forest biomass, atmospheric aerosol content, photosynthetic fluorescence. On board the satellite is four instruments: Multi-Beam LIDAR, Directional Multi-Spectral Camera, Directional Polarization Camera, and Chlorophyll Fluorescence Hyper-Spectral Monitor (SIFIS).
The Long March 4B took the satellite to a sun-synchronous orbit at a height of 506 km, where it will operate for an expected lifetime of 8 years.
The Long March 4B is a 3-stage, medium-lift, liquid-fueled rocket, which has been in service since 1999. It uses hypergolic fuels in all three stages. Long March 4B is an expendable launch vehicle, meaning that none of the stages are recovered.
The Long March 4B’s first stage is 27.91 m long, with a diameter of 3.35 m. It uses unsymmetrical dimethyl hydrazine (UDMH) for fuel and nitrogen tetroxide (N204) for an oxidizer. It has four engines designated YF-21C that use the Gas Generator combustion cycle. For more information on different types of engines, check out Everyday Astronaut’s video and article, “Is SpaceX’s Raptor engine the king of rocket engines?”
The YF-21 is a designation that refers to a cluster of four YF-20 engines mounted together. The stage as a whole has a thrust of around 2,960 kN (666,000 lbf). All the engines together have a combined specific impulse of 2,550 m/s (8,400 ft/s).
The second stage has a length of 10.9 m and a diameter of 3.35 m (same as the first stage). It also uses UDMH and N2O4 as fuel and oxidiser, respectively. The stage uses a single YF-24C engine. YF-24C is a designation that refers to a module of a YF-22C main engine and a set of YF-23C Vernier thrusters for attitude control. The YF-22 is the high altitude version of the underlying YF-20 engine used on the first stage. The thrust of the second stage is 742 kN (166,800 lbf). The specific impulse for the stage is 2,942 m/s (9,650 ft/s) for the main propulsion elements and 2,834 m/s (9,300 ft/s) for the Vernier thrusters.
The third stage is 4.79 m tall and has a diameter of 2.9 m. This stage again uses UDMH and N2O4 as for the two previous stages. The stage uses a pair of YF-40 engines. Each of these engines is a dual combustion chamber, in which each combustion chamber can gimbal for control authority. The YF-40 has a thrust of 103 kN (23,000 lbf) and a specific impulse of 303 seconds.
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