![On 13 April 2029, the asteroid Apophis will pass less than 32,000 km from Earth. [ESA-Science Office]](/gc8/images/2026/06/23/56663-asteroid-apophis-trajectory-370_237.webp)
On 13 April 2029, the asteroid Apophis will pass less than 32,000 km from Earth. [ESA-Science Office] By Stephanie Dwilson |
The European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) are preparing to embark on a joint mission to rendezvous with and study an asteroid that is on course to pass close to Earth in April 2029.
The two agencies hope that through a close-up examination of how the Earth's gravity alters the asteroid’s motion and shape, they can learn how to defend our planet against future threats from space rocks.
The international collaboration is expected to mark a huge step forward in humanity's ability to rapidly respond to future space threats.
Discovered in 2004, the asteroid -- designated (99942) Apophis -- was named after the Egyptian god of chaos and destruction, after initial observations showed there was a small chance it could hit Earth, per the ESA.
![ESA and JAXA officials pose for a photo on May 7 at the Italian Embassy in Berlin, Germany, after signing agreements to deepen collaboration in planetary defense and on the Ramses mission to the asteroid Apophis. [Jorge Pérez de Lara/ESA Standard License]](/gc8/images/2026/06/23/56665-esa-jaxa-agreement-370_237.webp)
ESA and JAXA officials pose for a photo on May 7 at the Italian Embassy in Berlin, Germany, after signing agreements to deepen collaboration in planetary defense and on the Ramses mission to the asteroid Apophis. [Jorge Pérez de Lara/ESA Standard License]
Though an Earth impact has been ruled out since then -- for at least the next century -- Apophis will come within 32,000 km of our planet in 2029, in a rare cosmic event that happens only once every 5,000 to 10,000 years.
This will bring it even closer to Earth than satellites in geosynchronous orbit.
On April 13, 2029, the asteroid -- which measures roughly 375 meters across and is around the size of a large ocean liner -- will be visible to the naked eye in the night sky, even without the help of telescopes or other special equipment.
No doubt, there will be quite a few viewing parties on that date.
Planetary defense
Planetary defense is an international effort to protect Earth by detecting and characterizing near-Earth objects such as asteroids at an early stage and accurately determining their orbits to assess potential impact risks, per JAXA.
If a credible threat is identified, these efforts entail the development and implementation of measures to avoid or mitigate possible consequences.
Activities addressing asteroid impact hazards, commonly referred to as "space guard" have evolved into a global initiative.
The United Nations has established a planetary defense system that includes a network of observatories that monitor for potentially dangerous asteroids and a network of space agencies ready to respond, per a Global Dispatches report.
In 2024, the General Assembly declared 2029 the International Year of Asteroid Awareness and Planetary Defense, using the close approach of Apophis as an opportunity to raise global awareness about asteroids.
The initiative seeks to highlight the collaborative efforts of the Committee on the Peaceful Uses of Outer Space in mitigating potential hazards from near-Earth objects, while also providing an opportunity for a global educational campaign.
Rendezvous with Apophis
ESA and JAXA signed a historic agreement on May 7 to collaborate more deeply in planetary defense measures, including for a special mission called Ramses (Rapid Apophis Mission for Space Safety).
The Ramses spacecraft -- whose design is overseen by the ESA -- will launch in April 2028 aboard a Japanese H3 launch vehicle.
JAXA also will contribute to the mission by providing lightweight solar array wings (SAWs) and thermal infrared imager (TIRI).
The mission marks a strong example of the difference that international collaboration can make in keeping the public safe.
"Planetary defense is, by definition, a global responsibility," ESA director general Josef Aschbacher said in a statement.
"ESA and JAXA are moving decisively from shared intention to concrete implementation, translating commitment into missionlevel cooperation," he said.
"This partnership builds on trust, technical excellence and a shared determination to protect our planet."
Ramses will rendezvous with Apophis in February 2029 before it reaches its closest point to Earth, and then accompany Apophis as it passes by the planet.
The spacecraft will perform before and after surveys that record how the Earth’s gravity alters the asteroid’s motion and shape.
This data will give scientists a better understanding of how the Earth’s gravity can change an asteroid’s composition, interior structure, mass, density, porosity, and cohesion.
The results, in turn, will give scientists a better idea of how to defend against an asteroid that poses an actual threat to Earth.
After the flyby, NASA’s OSIRIS-APEX spacecraft (previously called OSIRIS-REx) will arrive at Apophis to perform its own study.
Previous collaboration
This is not the two countries’ first foray into planetary defense.
ESA and JAXA also have collaborated on the Hera planetary defense mission, which is part of a larger asteroid deflection mission in the Didymos binary asteroid system.
The mission is studying an asteroid called Dimorphos, which is technically a small 530-feet-diameter moonlet orbiting the Didymos system.
In 2022, NASA’s DART mission (Double Asteroid Redirection Test) tested the ability of a spacecraft to make a kinetic impact with Dimorphos and deflect it by purposely smashing into the moonlet asteroid.
The impact pushed Dimorphos into a smaller, faster orbit around Didymos, and also pushed both into a slightly different orbit around the Sun.
The Hera spacecraft will arrive later this year. It will perform a post-impact survey, while also demonstrating autonomous navigation around an asteroid.