In a bid to make sure we don’t go the same way as the dinosaurs, the European Space Agency (ESA) has today announced its beginning work on a bold new planetary defence mission, the Rapid Apophis Mission for Space Safety (Ramses).
This mission aims to rendezvous with the asteroid 99942 Apophis, an object roughly the size of a cruise liner, and accompany it during its close flyby of Earth in April 2029.
Apophis, measuring approximately 375 metres across, will pass within 32,000 kilometres of Earth’s surface on April 13, 2029. This rare event, visible to the naked eye across parts of Europe, Africa and Asia, will draw global attention. Such a close approach by an asteroid of this size occurs only once every 5,000 to 10,000 years.
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Astronomers have ruled out any chance of Apophis colliding with Earth in the next 100 years (phew). However, its 2029 flyby offers scientists a unique opportunity for scientific observation of a close-quarters flyby.
ESA’s Ramses spacecraft will arrive at Apophis two months before its closest approach to monitor the asteroid's physical changes due to Earth's gravitational forces.
Ramses will launch in April 2028 to ensure its arrival at Apophis by February 2029. The mission objective is to observe and study how Earth's gravity affects Apophis, potentially causing landslides and revealing new material from beneath the asteroid's surface.
Patrick Michel, Director of Research at CNRS at Observatoire de la Côte d'Azur, emphasised the importance of this mission, saying, "There is still so much we have yet to learn about asteroids but, until now, we have had to travel deep into the Solar System to study them and perform experiments ourselves to interact with their surface.”
“For the first time ever, nature is bringing one to us and conducting the experiment itself. All we need to do is watch as Apophis is stretched and squeezed by strong tidal forces.”
Using a suite of scientific instruments, Ramses will comprehensively survey Apophis, analysing its shape, surface, orbit, rotation and more.
This data will be poured over by scientists hoping to understand asteroid composition, structure and how to deflect potentially hazardous asteroids in the future.
Researchers expect Earth's tidal forces to alter the asteroid's rotational state and potentially trigger quakes and landslides. Ramses's presence for the flyby will, they hope, offer a detailed 'before and after' view of how Apophis is affected by its close encounter.
Ramses won’t be alone at Apophis, however – NASA has also redirected its OSIRIS-REx, now renamed OSIRIS-APEX, spacecraft towards the asteroid and is scheduled to arrive roughly one month after its flyby.
OSIRIS-REx was the first US mission to collect a sample from an asteroid. The mission returned to Earth on 24 September 2023, delivering a capsule containing material from another asteroid, Bennu.
After successfully releasing the sample capsule, the spacecraft was renamed OSIRIS-APEX before being sent on its new mission to explore Apophis.
“Ramses will demonstrate that humankind can deploy a reconnaissance mission to rendezvous with an incoming asteroid in just a few years,” said Richard Moissl, head of ESA's Planetary Defence Office.
“This type of mission is a cornerstone of humankind’s response to a hazardous asteroid.”
The decision to fully commit to the Ramses mission will be made at ESA’s Ministerial Council meeting in November 2025. If approved, Ramses will not only teach experts more about how to knock an asteroid off course if needed but also provide key scientific insights into the formation and evolution of the Solar System.
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