In a cleanroom in Milan, a spacecraft that does not yet have its final shape has entered the phase where it stops being only schedule, engineering drawing, and nerves. On 23 September 2026, ESA announced that the Ramses planetary defence mission, developed with JAXA, had been powered up for the first time by prime contractor OHB Italia. The target is rare: reach asteroid Apophis before it passes close to Earth on Friday, 13 April 2029.
The news looks small if read as just another electrical test. It is not. According to ESA, the onboard computer and several integrated subsystems were powered inside the spacecraft body for the first time. That allows real commands between units that had previously been tested separately. For a mission that must leave in spring 2028 to meet Apophis on time, switching on the core module is less a formality than a first heartbeat.
Profile of a mission that cannot be late
Ramses stands for Rapid Apophis Mission for Space Safety, and the name says almost everything: speed, Apophis, and space safety. The asteroid, roughly 375 metres across, is expected to pass about 32,000 kilometres from Earth, closer than many geostationary satellites. No impact is predicted for this flyby, but the proximity turns Apophis into a natural laboratory for planetary defence.
Instead of waiting for a distant target, the mission tries to use a visitor coming to us. The idea is to observe how Earth gravity changes the rotation, surface, and possibly internal structure of a large enough asteroid to matter. Reporting by Heise captures the point: Ramses aims to study whether Apophis behaves like solid rock, a rubble pile, dust and ice, or something more complicated.
What came alive in Milan
The Ramses core module is being assembled inside a U-shaped structure. Critical units have already been installed: onboard computer, mass memory, power distribution, and remote terminal units that turn instrument outputs into digital data. Engineers can now test the set as a system, not merely as isolated pieces.
Paolo Martino, ESA project manager for Ramses, described the moment as a change of phase: before this there were calculations, simulations, and unit tests; now there is an actual spacecraft ready for integrated testing. The sentence matters because Ramses is in an unusual race. The Apophis flyby will not wait for manufacturing delays, calendar reviews, or comfortable margins. If the 2028 launch window slips, the 2029 scientific encounter is no longer the same event.
A collaboration with the clock running
Ramses architecture is split into two parts to save precious weeks. The core module is moving ahead in Italy; the propulsion module, with tanks, sensors, actuators, and related harnessing, is being prepared by ArianeGroup in Lampoldshausen, Germany. The two are due to be mated next spring at ESA ESTEC centre in the Netherlands, where vibration, thermal vacuum, and mission simulation tests begin.
JAXA enters the project with technical contributions and the launch plan on a Japanese H3 rocket. ESA also notes that Ramses will travel with two CubeSats, small observers that should add close-range perspectives to the asteroid study. The partnership is a reminder that planetary defence is not a national flag exercise: when the subject is understanding objects that cross Earth orbit, the political map matters less than having the right instruments in the right place.
Why Apophis matters now
The scientific value lies in before, during, and after. Observing Apophis before the approach creates a baseline; watching the flyby can show the response to Earth gravitational pull; comparing later data may reveal material shifts, rotation changes, or clues about internal cohesion. That is the kind of knowledge that turns planetary defence from disaster cinema into measurement-based engineering.
Ramses is also a test of institutional speed. ESA has technical heritage from the Hera mission, but here the luxury of a long timeline disappears. The spacecraft must be ready, tested, launched, and navigated to Apophis before a date that orbital mechanics has already written into the calendar. That is why the September switch-on matters: it is not the end of a showy stage, but the signal that the race has entered its physical phase.
ray28zz Sep 27, 2026 12:04 PM
the “Why Apophis matters now” section is the part that actually matters. In a cleanroom in Milan, a spacecraft that does not yet have its final shape has entered the phase where it stops being only…. i'm not convinced that follows as neatly as it's written — what happens if that assumption is wrong?...