# Shijian-18

> Chinese technology demonstration and communications satellite, lost due to a launch vehicle failure

**Wikidata**: [Q110010611](https://www.wikidata.org/wiki/Q110010611)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Shijian-18)  
**Source**: https://4ort.xyz/entity/shijian-18

## Summary  
Shijian-18 was a Chinese technology demonstration and communications satellite that was lost due to a launch vehicle failure on July 2, 2017. It was designed to test new technologies and provide telecommunications capabilities using the Dong Fang Hong 5 spacecraft bus. The mission launched atop the Long March 5 rocket from the Wenchang Satellite Launch Center but failed shortly after liftoff due to a turbopump issue.

## Key Facts  
- Launched on July 2, 2017, from Wenchang Satellite Launch Center  
- Operated by China Academy of Space Technology (CAST)  
- Designed as both a communications satellite and technology demonstration spacecraft  
- Part of the Shijian series; designated as Shijian-18  
- Built using the Dong Fang Hong 5 spacecraft bus  
- Launch vehicle: Long March 5  
- Lost during flight due to a turbopump failure in the rocket’s first stage  
- Country of origin: People's Republic of China  

## FAQs  
### Q: What happened to the Shijian-18 satellite?  
A: Shijian-18 was lost following a launch failure of its Long March 5 carrier rocket on July 2, 2017. The failure occurred early in flight due to a turbopump malfunction.

### Q: What was Shijian-18 designed for?  
A: Shijian-18 served dual purposes: demonstrating advanced space technologies and providing communication services via its payload.

### Q: Who built and operated Shijian-18?  
A: The satellite was manufactured and operated by the China Academy of Space Technology (CAST), one of China's leading aerospace organizations.

## Why It Matters  
Shijian-18 represented a key step in China’s efforts to advance its space-based communications infrastructure while simultaneously testing cutting-edge technologies essential for future missions. As part of the Shijian program—a platform for space experimentation—it contributed to national objectives in technological self-reliance and innovation within the space sector. Its loss underscored challenges in developing next-generation heavy-lift rockets like the Long March 5, which are critical for launching large satellites and supporting deep-space exploration initiatives. Despite its premature end, the mission highlighted both the ambitions and vulnerabilities inherent in advancing complex space systems.

## Notable For  
- One of the first major payloads launched aboard the Long March 5 rocket  
- Combined roles as a technology demonstrator and communications satellite  
- Utilized the high-capability Dong Fang Hong 5 satellite bus  
- Mission failure linked specifically to a turbopump component—an important technical lesson for future launches  

## Body  
### Overview  
Shijian-18 was developed under the Shijian program, a long-running initiative by China to conduct in-orbit verification of emerging space technologies. The satellite aimed to combine practical utility with experimental goals, serving as both a communications relay and a testbed for new subsystems.

### Technical Specifications  
- **Spacecraft Bus**: Dong Fang Hong 5 – a versatile and powerful platform used for large geostationary satellites  
- **Mission Type**: Dual-use – technology demonstration and communications  
- **Operator & Manufacturer**: China Academy of Space Technology (CAST)  
- **Series Affiliation**: Shijian program; numbered as the 18th mission  

### Launch Details  
- **Launch Date**: July 2, 2017  
- **Launch Site**: Wenchang Satellite Launch Center, Hainan Island  
- **Launch Vehicle**: Long March 5 (CZ-5) – China’s most capable heavy-lift launcher at the time  
- **Outcome**: Failure approximately six minutes into flight due to a faulty turbopump in the first-stage engine  
- **Impact**: Total loss of the satellite  

### Significance Within the Shijian Program  
The Shijian program has historically enabled China to refine technologies such as electric propulsion, attitude control systems, and advanced materials. Shijian-18 continued this tradition by incorporating next-generation components intended for broader deployment across future missions.

### Legacy and Impact of Failure  
Although Shijian-18 never reached orbit, its planned capabilities signaled China’s growing ambition in building more sophisticated and multi-role satellites. The associated launch failure also prompted investigations that led to improvements in the Long March 5 design, ultimately contributing to later successful flights.

## References

1. Jonathan's Space Report
2. [Source](https://www.nasaspaceflight.com/2017/07/long-march-5-lofts-shijian-18/)