The European Space Agency (ESA) has announced a mission to monitor the passage, close to Earth, of the asteroid ‘99942 Apophis’ on 13 April 2029.
The idea is to pre-empt any future asteroid collisions.
Apophis, though not set to collide with Earth, will pass closer than geostationary communication satellites, less than 32,000 kilometres from our planet, says the ESA. The asteroid, whose diameter is 375 metres, presents a unique opportunity for research, as objects of this size only pass this close to Earth every 5,000 to 10,000 years.
ESA plans to send a spacecraft to the asteroid as part of the Rapid Apophis Mission for Space Safety (Ramses ) project, to study its entire passage past Earth. Earth’s gravitational pull is likely to affect Apophis, possibly altering the asteroid's orbit.
“By analysing the behaviour of Apophis during its passage, scientists will learn a lot about an asteroid’s response to external forces and its composition, internal structure, cohesion, mass, density, and porosity,” says the ESA. All these are crucial in working out how to alter the orbit of a hazardous asteroid on a collision course with Earth.
Additionally, data from the Ramses mission will provide deeper insights into the origins and development of the solar system, as “asteroids are also time capsules that formed over four billion years ago.”
Patrick Michel, Research Director at the Nice Observatory, commented that “we still have much to learn about asteroids, but so far, we’ve had to travel far into the solar system to study them and conduct our experiments to interact with the surface”.
He added that, for the first time, “nature is bringing us an asteroid and conducting the experiment itself. We just have to observe how Apophis is stretched and compressed by strong tidal forces which can trigger landslides and other disruptions, and where new materials can come back to the surface.”
Mission preparations have begun, with final approval expected at an ESA ministerial summit in November 2025. If approved, Ramses would be launched in April 2028 and arrive at Apophis in February 2029.
The passage of “99942 Apophis” will be visible to the naked eye (weather permitting) in certain regions of Europe.
The US space agency, NASA, is also sending spacecraft OSIRIS-REx to the asteroid. However, it will arrive a month after the asteroid has passed the Earth.
