On 13 April 2029, the 375-metre-wide asteroid 99942 Apophis will pass within 32,000 kilometres of Earth – that’s closer than weather monitoring and communications satellites in geostationary orbit around our planet.
An asteroid of this size passes this close to Earth only once every few thousand years on average. While Apophis poses no danger to us, the flyby presents a unique opportunity for scientific observation and public engagement.
ESA’s proposed Rapid Apophis Mission for Space Safety (Ramses) would launch in 2028 and rendezvous with Apophis in February 2029, two months before it passes Earth.
Ramses would allow scientists to study the asteroid up close before, during, and after its interaction with our planet, delivering a treasure-trove of scientific and planetary defence data as never before.
As Apophis passes Earth, the side of the asteroid closest to our planet will be pulled more strongly than the side slightly further away, potentially causing disruptions to the surface, such as landslides, that could expose new material.
How Apophis changes, and what new material is revealed, will improve our understanding of what asteroids are made of, which is critical knowledge if humankind ever needs to put asteroid deflection to the test in a real scenario.