ESA and JAXA set sights on Apophis: a once-in-a-generation chance to watch an asteroid change in real time
In April 2029, asteroid Apophis will skim past Earth at a distance of about 32,000 kilometers—closer than many satellites. To seize this rare opportunity, the European Space Agency and the Japan Aerospace Exploration Agency are planning Ramses, the Rapid Apophis Mission for Space Safety, to rendezvous with the asteroid, escort it through the flyby on April 13, and track how Earth’s gravity reshapes it.
Apophis is roughly 375 meters across—about the size of a cruise ship. At such a close pass, our planet’s gravity and tidal forces are expected to tweak the asteroid’s physical characteristics and potentially strip away parts of its outer layer, revealing material from beneath the surface. Ramses is designed to be on station before and after the flyby, giving scientists a before-and-after snapshot of any changes to Apophis’s surface, structure, and behavior. That kind of comparative dataset is incredibly rare and scientifically powerful.
This encounter is about more than curiosity. Understanding what asteroids are made of and how they respond to strong gravitational forces feeds directly into planetary defense. It helps refine models of asteroid interiors, stability, and surface cohesion—key inputs for any future deflection or mitigation strategies. ESA’s Hera mission is another step in this direction and is already underway, building the foundations for a robust planetary defense toolkit.
Ramses would complement NASA’s OSIRIS-APEX (Origins, Spectral Interpretation, Resource Identification and Security – Apophis Explorer), which is slated to arrive at Apophis about one month after the Earth flyby. Together, the missions could deliver a continuous arc of observations, from pre-encounter conditions through the immediate aftermath and into longer-term evolution.
There’s a clock on the plan. Ramses still needs formal approval from ESA’s Ministerial Council, with a decision expected in November 2025, and JAXA has submitted a corresponding funding request. If greenlit, the spacecraft must launch as early as April 2028 to reach Apophis by February 2029, ensuring it can document the asteroid before tidal forces take their toll and then follow it through the historic close pass.
Key points at a glance:
– Target: Asteroid Apophis, ~375 meters across
– Closest approach: About 32,000 km from Earth on April 13, 2029
– Mission concept: Ramses will rendezvous with Apophis, observe it before, during, and after the flyby, and study potential tidal effects that expose subsurface material
– Complementary mission: NASA’s OSIRIS-APEX arrives roughly one month after the flyby
– Planetary defense: Data will improve models of asteroid composition and behavior under stress, supporting future impact mitigation strategies
– Status and timing: Pending approvals in 2025; launch as early as April 2028 to reach Apophis by February 2029
If approved, Ramses would turn a dramatic celestial event into a natural laboratory, revealing how a near-Earth asteroid responds when it ventures deep into our planet’s gravitational field—and bringing us a step closer to safeguarding Earth from potential future threats.
