China National Space Administration’s (CNSA’s) Tianwen-2 is set to launch on a Long March 3B rocket in May 2025 as part of China’s deep-space ambitions. The craft follows the success of the prior craft in the Tianwen line, the Tianwen-1 at Mars. The Tianwen-2 mission will tap solar electric propulsion to explore two celestial bodies: the co-orbital near-Earth asteroid 469219 Kamoʻoalewa and the main-belt comet 311P/PANSTARRS. The 311 comet could hold clues about volatile compounds, such as water, in the solar system.
Tianwen-2 will carry instruments such as spectrometers for composition analysis and a drill for subsurface sampling. The craft aims to collect and return at least 100 grams of asteroid material.
Should Kamoʻoalewa prove to be lunar material, researchers could piece together the Moon’s early impact history. The asteroid might reveal how often debris pummeled the early solar system.
In addition, studying the comet-like outgassing of 311P—a rare main-belt comet—could hold clues on how volatile compounds behave in the inner solar system. That could shed light on how water reached terrestrial planets.
After launching in mid-2025, Tianwen-2 is expected to rendezvous with Kamoʻoalewa in 2026. It will employ both touch-and-go and anchor-and-attach sampling methods—using four robotic arms to drill beneath the asteroid’s surface—before returning samples to Earth around 2027–2028. After that, the spacecraft will continue on to 311P/PANSTARRS, arriving in the mid-2030s to conduct in-depth remote sensing and in-situ measurements. Small sub-satellites are also planned for deployment.
What sets Tianwen-2 apart from other asteroid sample return missions is its plan to use these two distinct sampling methods. Beyond a classic “touch-and-go” maneuver, the mission will deploy a pioneering “anchor-and-attach” system, involving four robotic arms designed to drill beneath the asteroid’s surface.
From an R&D perspective, the use of solar electric propulsion in the mission could pave the way for longer, more distant expeditions for future spacecraft. Tianwen-2 is also pioneering advanced drilling and anchoring techniques that build on—and extend beyond—previous small-body exploration efforts.
