Ramses

Ramses, the Rapid Apophis Mission for Space Safety, is a European Space Agency planetary defense mission to the asteroid Apophis.^[1] It is a joint mission with the Japan Aerospace Exploration Agency (JAXA), led by ESA.^[1]

Why Apophis

Apophis, roughly 375 m across, will pass within 32,000 km of Earth's surface on 13 April 2029.^[1] Astronomers have ruled out any chance of a collision, but ESA estimates that an object this large comes this close only once every 5,000 to 10,000 years.^[1] Earth's tidal forces are expected to stretch and squeeze the asteroid, possibly triggering landslides and exposing material from beneath its surface.^[1]

The mission

To arrive in February 2029, two months before the flyby, Ramses must launch in April 2028.^[1] ESA committed to the mission in full at its Ministerial Council in November 2025 and signed the contract to build the spacecraft with OHB Italia on 10 February 2026.^[1][2] Like Hera, Ramses carries two small CubeSats; JAXA contributes the solar arrays and a thermal infrared imager.^[2] The two agencies signed their agreement in Berlin on 7 May 2026, with JAXA also providing the launch on its H3 rocket, which Ramses shares with JAXA's DESTINY+.^[3][4]

Ramses is to make a before-and-after survey of the asteroid's shape, surface, orbit, rotation and orientation, measuring properties such as its mass, density, porosity and interior structure.^[1] These are the properties that matter most when planning how to push a hazardous asteroid off course.^[1] The mission also shows that a reconnaissance spacecraft can be sent to an approaching asteroid within a few years, a first step in responding to a real threat.^[1]

NASA's OSIRIS-APEX is to arrive about a month after the flyby, giving two spacecraft at Apophis afterward.^[1] The asteroid itself is described on the Apophis page.