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# Concepts and status of Chinese space gravitational wave detection projects

## Abstract

Gravitational wave (GW) detection in space probes the GW spectrum that is inaccessible from the Earth. In addition to the LISA project led by the European Space Agency, and the DECIGO detector proposed by the Japan Aerospace Exploration Agency, two Chinese space-based GW observatories—TianQin and Taiji—are planned to be launched in the 2030s. TianQin has a unique concept in its design with a geocentric orbit. Taiji’s design is similar to LISA, but is more ambitious with a longer arm distance. Both facilities are complementary to LISA, considering that TianQin is sensitive to higher frequencies and Taiji probes similar frequencies but with a higher sensitivity. In this Perspective we explain the concepts of both facilities and introduce the development milestones of the TianQin and Taiji projects in testing key technologies to pave the way for future space-based GW detections. Considering that LISA, TianQin and Taiji have similar scientific goals, are all scheduled to be launched around the 2030s and will operate concurrently, we discuss possible collaborations among them to improve GW source localization and characterization.

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## Data availability

The data that support the findings of this study are available from Y.G. upon reasonable request. The data for Fig. 2 can be generated from the code deposited in https://github.com/yggong/transfer_function.

## Code availability

The Python code can be obtained at https://github.com/yggong/transfer_function.

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## Acknowledgements

This research was supported by the National Key Research and Development Program of China under grant numbers 2020YFC2201504 and 2020YFC2201400, the National Natural Science Foundation of China under grant numbers 11875136 and 12075202 and the Major Program of the National Natural Science Foundation of China under grant number 11690021. B.W. acknowledges the support from Shanghai Education Commission. J.L. acknowledges support from the Guangdong Major Project of Basic and Applied Basic Research under grant number 2019B030302001.

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All authors contributed to the work presented in this paper. Y.G. analysed the data, contributed analysis tools and wrote the paper. J.L. conceived TianQin and reviewed the paper. B.W. contributed materials and wrote the paper.

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Correspondence to Yungui Gong or Bin Wang.

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Gong, Y., Luo, J. & Wang, B. Concepts and status of Chinese space gravitational wave detection projects. Nat Astron 5, 881–889 (2021). https://doi.org/10.1038/s41550-021-01480-3

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