Preparation Work Underway for ESA Ramses Mission
Preparation Work Underway for ESA Ramses Mission
Will Accompany an Asteroid During Near-Earth Flyby in 2029
ESA is preparing for an ambitious mission to launch a spacecraft that will accompany an asteroid when it makes a close approach to Earth in 2029.
“For the first time ever, nature is bringing one to us and conducting the experiment itself. All we need to do is watch.”
Patrick Michel, Observatoire de la Côte d'Azur
The Ramses (Rapid Apophis Mission for Space Safety) mission will gather data in an effort to determine what can be done to prevent a catastrophic asteroid collision with Earth. Ramses will rendezvous with the asteroid 99942 Apophis and accompany it through its safe but exceptionally close flyby of Earth in 2029. Researchers will study the asteroid as Earth’s gravity alters its physical characteristics, and their findings will improve our ability to defend Earth from any similar object found to be on a collision course in the future.
Roughly 410 yards across, about the size of a cruise liner, the asteroid Apophis will pass within 20,000 miles of Earth’s surface on April 13 April. For a short time, it will be visible to the naked eye in clear, dark skies for around two billion people across much of Europe and Africa and parts of Asia.
Apophis will miss Earth: astronomers have ruled out any chance that the asteroid will collide with our planet for at least the next 100 years. But the Apophis flyby in April 2029 is an extremely rare natural phenomenon.
By analyzing the sizes and orbits of all known asteroids, astronomers believe that an object this large comes this close to Earth only once every 5000 to 10,000 years. For comparison, a total solar eclipse takes place somewhere on Earth around once every 18 months, and Comet Halley returns to Earth’s skies every 76 years.
The 2029 Apophis flyby will draw the attention of the entire world and represents a unique opportunity for science, planetary defense and public engagement.
ESA’s Ramses spacecraft will rendezvous with Apophis before it passes Earth and accompany the asteroid during the flyby to observe how it is warped and changed by our planet’s gravity.
"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,” said Patrick Michel, Director of Research at CNRS at Observatoire de la Côte d'Azur in Nice. “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 that may trigger landslides and other disturbances and reveal new material from beneath the surface."
Ramses needs to launch in April 2028 to allow for an arrival at Apophis in February 2029, two months before the close approach. In order to meet this deadline, ESA requested permission to begin preparatory work on the mission as soon as possible using existing resources. This permission has been granted by the Space Safety program board. The decision whether to commit to the mission in full will take place at ESA’s Ministerial Council Meeting in November 2025.
Using a suite of scientific instruments, the spacecraft will conduct a thorough before-and-after survey of the asteroid’s shape, surface, orbit, rotation and orientation. By analyzing how Apophis changes during the flyby, scientists will learn a lot about the response of an asteroid to external forces as well as asteroid composition, interior structure, cohesion, mass, density, and porosity.
These are all very important properties for assessing how best to knock a hazardous asteroid off a collision course with Earth. As asteroids are also time capsules formed over four billion years ago, data from Ramses will also offer new scientific insights into the formation and evolution of the Solar System.
NASA, meanwhile, has redirected its OSIRIS-REx spacecraft towards Apophis. Due to the limits of orbital mechanics, the newly renamed OSIRIS-APEX will arrive at Apophis roughly one month after the asteroid’s Earth flyby.
Researchers anticipate Earth's tidal forces altering the asteroid’s rotational state and possibly triggering quakes and landslides. Having Ramses there in advance will provide a detailed 'before and after' view of how Apophis has been altered by its close encounter. Then, in the aftermath, having two highly capable spacecraft at Apophis after the flyby will enable additional scientific investigations and the measurement of longer-term effects.