HELSINKI — China could launch a mission involving multiple flybys of asteroid Apophis with a swarm of cubesats when the rocky body approaches Earth in 2029.
Scientists from a number of Chinese universities, including Beihang, Tsinghua and Sun Yat-sen University, are proposing a rapid response mission to make the most of a rare opportunity presented by asteroid 99942 Apophis to advance planetary science and planetary defense.
The Apophis Recon Swarm (ARS) proposal features a flexible mission design, consisting of multiple cubesats launched either together or as rideshares on other missions for multiple flybys of Apophis.
The mission would seek to measure the asteroid’s mass, surface morphology, spin state and internal structure. It proposes using cubesats with similar or diverse payloads, and use multi-spectral imaging, conduct stereo surface mapping, and employ microwave ranging for high-precision gravitational field assessment.
The series of flybys and subsequent data could provide critical constraints for the studies of Apophis interior structure and inform planetary defense strategies, according to the proposal.
China is working on its first planetary defense mission, expected to launch around 2027. It also launched a near Earth sample return mission, Tianwen-2, late May. It made a flyby of the asteroid Toutatis in 2012, using its Chang’e-2 orbiter for an extended mission.
“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,” authors of the ARS mission proposal stated.
The mission could also be collaborative, with the authors noting that contributions from international partners could enhance the science return.
Patrick Michel, a senior researcher at Centre National de la Recherche Scientifique (CNRS), who attended the Apophis T-4 Years Workshop held in Tokyo in April, told SpaceNews that the Chinese team was keen to discuss and coordinate its efforts with international partners.
China held its own special session on the upcoming flyby of Apophis during the second International Conference of Deep Space Sciences (ICDSS 2025) held in the city of Hefei. The two meetings overlapped, but Chinese researchers and international colleagues connected via video link to discuss potential collaboration. Michel stated that the Chinese proposal had yet to secure funding but welcomed international support.
ARS is one of a number of proposed missions globally to take advantage of Apophis’ close approach to Earth, with the event offering a unique chance to study a new celestial body and observe tidal effects of a close approach as it occurs.
The European Space Agency is working on its Ramses mission—based on the already-launched Hera spacecraft to follow up on NASA’s DART asteroid deflection test—with Michel as chief scientist. It will conduct a before-and-after survey of the asteroid’s shape, surface, orbit, rotation and orientation to determine how Earth’s gravity affected Apophis. A final decision on funding is due at a Ministerial meeting later this year.
The main spacecraft from the OSIRIS-REx asteroid sample return mission, renamed OSIRIS-APEX, is due to rendezvous with Apophis shortly after its close approach to Earth, though a May 30 Trump administration budget proposal would terminate this extended mission. The T-4 workshop meanwhile called on NASA in its recommendations for the agency to repurpose the twin Janus smallsats to visit Apophis.
The Japanese space agency JAXA will launch its delayed DESTINY+ mission, destined for another near Earth asteroid, Phaethon, in 2028. The slip in schedule allows the spacecraft to make a flyby of Apophis before it reaches Earth.
Apophis is around 340 meters in diameter and classified as an S-type asteroid, likely composed of rock and metal. It was discovered in 2004, with initial calculations giving a 2.7 percent chance of the asteroid impacting the Earth in 2029, sparking concern. This was later refined to zero risk, and is not considered a risk for at least 100 years.
Apophis is calculated to approach as close as 30,600 kilometers to Earth on Friday, April 13, 2029, passing inside geostationary orbit. The flyby will be visible to naked eye observers in Europe, Africa, and parts of Asia. The asteroid is named for the Egyptian god of chaos and darkness, Apep (Apophis in Greek).
