ESA and JAXA Sign RAMSES Cooperation Agreement to Send Spacecraft to Asteroid Apophis Ahead of 2029 Earth Flyby
Berlin signing on 7 May commits Japan to launch ESA's Ramses probe on an H3 rocket in 2028, in time to escort Apophis through its 32,000 km flyby of Earth.
Overview
The European Space Agency and the Japan Aerospace Exploration Agency have signed a formal cooperation agreement for the Ramses mission to near-Earth asteroid Apophis, locking in Japan’s role on a probe that must launch in 2028 to reach the asteroid before its close flyby of Earth in April 2029. The signing took place on 7 May at the Embassy of Italy in Berlin, where ESA Director General Josef Aschbacher and JAXA President Hiroshi Yamakawa concluded a Memorandum of Cooperation on planetary defence alongside the dedicated Ramses agreement.
What the Agreement Covers
Under the Ramses cooperation agreement, JAXA will provide the spacecraft’s lightweight solar arrays, an infrared imager, and the launch itself aboard the agency’s H3 rocket, according to ESA’s announcement. ESA oversees the Ramses mission’s spacecraft design, integration and operations. The wider Memorandum of Cooperation establishes a broader framework for joint work on planetary defence, formalising the priorities the two agencies set out in their November 2024 joint statement in Tsukuba, which named Ramses among four areas earmarked for expanded cooperation.
The Ramses spacecraft, short for Rapid Apophis Mission for Space Safety, has a tight schedule. The probe must launch in April 2028 to allow for arrival at Apophis in February 2029, two months before the close approach, ESA states on the dedicated Ramses mission page. At the asteroid, the spacecraft will conduct a thorough before-and-after survey of Apophis’s shape, surface, orbit, rotation and orientation.
Why Apophis, and Why Now
Apophis is roughly 375 metres across — about the size of a cruise liner — and will pass within 32,000 km of Earth’s surface on 13 April 2029, ESA notes in its mission documentation. That is one tenth the distance to the Moon and closer than satellites in geosynchronous orbit, ESA added in its 7 May announcement. The encounter offers a rare opportunity to watch an asteroid of that size be reshaped in real time by a planetary gravitational tide. Ramses is designed to accompany Apophis throughout the flyby, observing how Earth’s gravity alters its shape, surface, and motion, as Phys.org summarised. By comparing before-and-after measurements, scientists hope to gain insights into asteroid structure and composition that would inform any future deflection effort.
What JAXA Brings
Japan’s contribution covers both flight hardware and launch capacity. JAXA’s role had been under negotiation for months: in an earlier ESA update, Holger Krag, head of ESA’s Space Safety Programme, said “ESA welcomes JAXA’s increasing interest in participating in the Ramses mission. International collaboration lies at the heart of planetary defence.” Paolo Martino, Ramses mission manager at ESA, said working with JAXA colleagues had “been excellent” and that the two teams “truly feel like one globally integrated team.”
The 7 May agreement converts that interest into a binding commitment, with JAXA delivering solar arrays, an infrared imager, and the H3 launch, ESA confirmed at the Berlin signing. JAXA is also already a participant in ESA’s first planetary defence mission, Hera, which is currently en route to asteroid Didymos, according to ESA.
What We Don’t Know
ESA has not published the precise launch date within the April 2028 window, and the agency’s own materials describe the schedule as exceptionally tight. The full instrument complement of the main spacecraft and the role of any additional small spacecraft were not detailed in the public announcements accompanying the Berlin signing. The total cost of the mission and the breakdown of funding contributions across ESA member states and JAXA were also not addressed in the 7 May statements.
Context
The partnership builds on a track record of ESA-JAXA cooperation that already includes the EarthCARE Earth-observation satellite, the BepiColombo Mercury orbiter and Hera, ESA noted in its announcement. With the 7 May agreement, Ramses becomes the latest project under that umbrella, and the first dedicated planetary defence mission run jointly by Europe and Japan. As of the signing, no other spacecraft is scheduled to be in position alongside Apophis during the 2029 flyby.