Chinese scientists are proposing a bold and innovative mission to closely observe asteroid 99942 Apophis as it makes a historic near-Earth pass in 2029. The mission, dubbed the Apophis Recon Swarm (ARS), would dispatch a fleet of miniature spacecraft—cubesats—on multiple flybys to study the asteroid’s physical and internal characteristics, while also advancing global planetary defense capabilities.
Apophis, classified as an S-type asteroid, is composed of si silicate materials mixed with nickel and iron. Its shape, resembling a "peanut," adds to the mystery.
The initiative is led by researchers from some of China’s top institutions, including Beihang University, Tsinghua University, and Sun Yat-sen University. Their vision is to exploit the rare proximity of Apophis to Earth on April 13, 2029, when the 340-meter-wide asteroid will pass just 30,600 kilometers from the surface—closer than many geostationary satellites.
The ARS concept involves a rapid-response launch strategy using multiple cubesats, either deployed together or hitching rides as secondary payloads on other missions. These compact explorers would be equipped with advanced instruments for multi-spectral imaging, stereo surface mapping, microwave-based gravitational field measurement, and potentially other scientific payloads.
The primary scientific objectives include determining Apophis’s mass, surface morphology, spin state, and internal structure—data that could yield unprecedented insights into the composition and behavior of near-Earth objects (NEOs). The mission also aims to provide practical testing of planetary defense techniques and highlight the feasibility of deploying responsive, low-cost missions in future asteroid threats.
“Apophis presents a rare opportunity to test various concepts in planetary defense, such as the necessity, possibility, and technical challenges of implementing rapid-response reconnaissance missions,” the mission team stated in its proposal.
Apophis has fascinated scientists and the public alike since its discovery in 2004, when initial projections gave it a 2.7% chance of impacting Earth in 2029. While follow-up observations have since ruled out any collision risk for at least a century, its close flyby offers a unique chance to observe real-time tidal and gravitational effects on a celestial body.
China’s interest in Apophis builds on its growing planetary science ambitions. The country recently launched the Tianwen-2 mission for near-Earth asteroid sample return and previously made a successful flyby of asteroid Toutatis in 2012 using the extended mission of its Chang’e-2 lunar orbiter. China is also planning its first dedicated planetary defense test mission around 2027, which would target a different asteroid for kinetic impact deflection testing.
The ARS proposal was highlighted at the Second International Conference of Deep Space Sciences (ICDSS 2025) in Hefei, where Chinese and international scientists exchanged ideas via video links with the Apophis T-4 Years Workshop in Tokyo. According to Patrick Michel, a senior planetary scientist with France’s CNRS and chief scientist of ESA’s Hera mission, the Chinese delegation expressed strong interest in coordinating with international partners, although ARS has yet to secure formal funding.
“International collaboration could significantly enhance the science return,” said Michel. He emphasized that global efforts to study Apophis should be complementary and well-coordinated.
Global Missions Set Sights on 2029
China's ARS is one of several missions being proposed or planned worldwide to take advantage of Apophis’s flyby. The European Space Agency (ESA) is developing Ramses, a follow-on to its Hera mission, to observe Apophis’s changes caused by Earth’s gravity. ESA will make a final funding decision at its Ministerial Council later this year.
In the U.S., NASA’s OSIRIS-APEX spacecraft—formerly OSIRIS-REx—aims to rendezvous with Apophis shortly after the 2029 encounter. However, its fate is uncertain due to proposed budget cuts under a recent administration plan. The Janus smallsat mission, originally intended to fly by other targets, has also been recommended for repurposing toward Apophis.
Japan’s space agency JAXA is preparing the DESTINY+ mission, which, due to a launch delay, now has the opportunity to perform a flyby of Apophis en route to its primary target, asteroid Phaethon.
A Rare Celestial Event
Apophis’s dramatic 2029 flyby—occurring on Friday the 13th of April—will be visible to the naked eye across parts of Europe, Africa, and Asia. The asteroid is classified as an S-type (silicaceous) asteroid, likely composed of metal-rich rock. Its name is derived from Apophis, the Greek name for the Egyptian deity of chaos and darkness, fitting for an object once feared to pose a dire threat to Earth.
Add comment
Comments