Shijian-18

Shijian-18 (Chinese: 实践十八号; transliteration: Practice-18) was a Chinese communications and technology demonstration satellite developed and launched by the China Academy of Space Technology on 2 July 2017. It was the median flight of the satellite bus, which is designed with 16-year lifespan. Shijian-18 carried 18 experiments on board involving communications and space telescopes. It was lost after a malfunction on the Long March 5 rocket carrying the satellite.

Design[]

Shijian-18 was the maiden flight of the DH-5 satellite bus, which is designed for a payload with a launch mass between 6,000 kg (13,000 lb) to 9,000 kg (20,000 lb). It would have been the heaviest geostationary satellite at the time of its launch,^[4] with a launch mass of 7,600 kg (16,800 lb)^[2]

The satellite incorporated a high-thrust ion propulsion system, a large trussed structure and a higher payload capacity.^[4] More specifically, it used the LIPS-300 xenon thruster for orbit keeping, developed by the Lanzhou Institute of Physics. It was planned for the LIPS-300 system to be fully certified in this mission so that it could be used for geostationary and deep-space operations.^[4] The satellite would operate at the Ka band with 70 Gb/s capacity, capable of providing broadband internet to whole mainland China.^[4]

Launch[]

Shijian-18 launched from the Wenchang Space Launch Site on 2 July 2017 at 11:23 UTC on board a Long March 5 rocket to a geostationary orbit. It was the rocket's second flight,^[3] the first being to launch .^[5]

The rocket encountered an anomaly shortly after launch, causing it to switch into a gentler trajectory. However, 45 minutes into the flight, it was declared a failure, with the loss of the payload.^[6][5] The cause of the failure was later determined to be a faulty oxidizer turbopump, which has now been redesigned twice.^[7] The rocket and payload crashed in the Pacific Ocean somewhere at the Philippine Sea.^[5]

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