Tianwen-2

Tianwen-2 is a planned Chinese asteroid sample return and comet exploration mission that is currently under development. Tianwen-2 was originally known as ZhengHe.

Overview
Tianwen-2 is scheduled to be launched on a Long March 3B rocket in May 2025. It will use solar electric propulsion to explore the co-orbital near-Earth asteroid 469219 Kamoʻoalewa and the main-belt comet 311P/PANSTARRS. The spacecraft will rendezvous with Kamoʻoalewa and conduct remote sensing observations in orbit, before landing on the asteroid to collect a sample of 100 g of regolith. A nano-orbiter and nano-lander will be deployed to conduct remote sensing and sampling observations, and explosives will be used to expose potential subsurface volatiles for detection.

The spacecraft will use both anchor-and-attach and touch-and-go methods to attempt collection of a sample from the asteroid. It would be the first time an anchor-and-attach method has been used on an asteroid, as both OSIRIS-REx and Hayabusa2 used touch-and-go.

Tianwen-2 will then return to Earth to drop off a return capsule containing the sample and conduct a gravity assist maneuver to propel the spacecraft toward 311P/PANSTARRS. A flyby of an unnamed asteroid may also be attempted en route to 311P/PANSTARRS. Remote sensing and in-situ measurements will be conducted at 311P/PANSTARRS for at least one year.

The original name of this mission referenced the 15th century Ming Dynasty explorer Zheng He.

History
In 2018, a deep space exploration roadmap covering the 2020–2030 timeframe was proposed by researchers at the Chinese Academy of Sciences, which included an asteroid exploration mission planned for launch around 2022 or 2024. In spring 2019, after a design study for the mission was carried out by the Chinese Academy of Space Technology (CAST), the CNSA began soliciting international proposals for scientific instruments to be carried on Tianwen-2.

Instruments
Tianwen-2 will incorporate several types of instruments, including wide/narrow angle multispectral and color cameras, a thermal emission spectrometer, a visible/near-infrared imaging spectrometer, a mass spectrometer, a magnetometer, and a charged/neutral particle and dust analyzer. International contributions to these payloads are being encouraged.

===Scientific payload ===
 * Visible Infrared Imaging Spectrometer
 * Thermal Radiation Spectrometer
 * Multispectral Camera
 * Medium Field Color Camera
 * Detection Radar
 * Magnetometer
 * Charged and Neutral Particle Analyzers
 * Ejecta Analyzer
 * Narrow Field of View Navigation Sensor
 * Laser Integrated Navigation Sensor