Apophis Recon Swarm (ARS): Rapid-response Multi-flyby mission to Apophis using a CubeSats Swarm

Asteroid (99942) Apophis will make a close encounter with Earth at a perigee distance ~38,000 km on April 13, 2029, offering a unique opportunity to advance planetary science, deflection technology, and public engagement. This rare event enables real-time observation of the tidal interaction between a hundred-meter-scale asteroid and a planet, especially the geophysical processes occurring on the Asteroid’s regolith layer, which promises rich scientific rewards to planetary science researchers. On the other hand, as a potentially hazardous asteroid, 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. Therefore, this encounter has been the focus of studies on asteroid missions for recent years. Here we present a concept that utilizes multiple flybys of Apophis with a swarm of CubeSats. This concept aims to determine the basic properties of Apophis, including its mass, surface topography, spin status, and internal structure during its close encounter. Multiple CubeSats will be launched either through dedicated missions or as secondary payloads on other launches, either all at once or in stages, to conduct a series of flybys simultaneously or sequentially. The CubeSats can take similar or different payloads to investigate the target in synergy. In addition to performing multi-spectral optical measurements, the CubeSats Swarm can also achieve stereoscopic imaging and morphological analysis of the asteroid surface, or pricisely measure the gravitional field through highly sensitive microwave ranging instruments, which will provide critical constraints for the studies of Apophis interior structure and its defense strategy. Once the science goals are defined and prioritized, one can define a threshold mission, a baseline mission, and an enhanced mission, each corresponding to specific science priority, risk profile, and cost profile. This framework will provide flexibility, versatility, expandability, and potential low cost to allow for rapid mission integration by accommodating the potentially fast-evolving mission concept development and implementations. It will also allow for contributions from various partners to expand the science and participation of a mission concept. On the other hand, the coordination and communication between various CubeSats and mission components could increase the complexity of both implementation and scientific operations of the mission. Our future research will identify the pros and cons of this mission framework in the context of the 2029 Apophis exploration.