🚀 This is not a toy, this is a tiny Martian spacecraft

A miniature space capsule, barely larger than a toy, has just been propelled to over 4,200 km/h (about 2,610 mph) from a cannon. This is the test conducted by the European Space Agency (ESA) to validate the safety of the Rosalind Franklin rover during the ExoMars mission in 2028.

To ensure that the landing module (EDLM) withstands the descent into the Martian atmosphere, engineers built twenty small capsules 7.5 cm (about 3 inches) in diameter. These scale models were launched from a compressed air cannon at a supersonic speed, nearly four times the speed of sound. Each shot simulated the aerodynamic forces encountered during entry into the atmosphere of Mars.


These capsules carried electronic circuits to record valuable data: acceleration, trajectory, stability. The results will help refine the design of the heat shield and parachute system, essential for braking the descent and protecting the rover from violent shocks.

These tests subjected the models to nearly 17,000 times Earth's gravity. Such a shock would have destroyed ordinary equipment, but the mini-capsules, designed with robust materials, emerged intact. The small robot figurine placed next to them in the image gives a toy-like appearance, but the stakes are very real: preserving the sensitive equipment that will search for traces of ancient life on Mars.

The Rosalind Franklin rover, equipped with a drill capable of digging up to two meters (about 6.6 feet) deep, is scheduled to launch in 2028. To achieve this, every step of the descent must be perfectly controlled. The data collected by these high-speed shots help teams validate the strength and trajectory calculations, a necessary step before the final launch.

These experiments, although spectacular, are only part of the countless tests awaiting the ExoMars mission. Behind the playful appearance of these small capsules lies meticulous engineering work.

The extreme conditions of Martian atmospheric entry

When a probe arrives at Mars, it must brake sharply in a very thin atmosphere, a hundred times less dense than Earth's. The initial speed, which exceeds 20,000 km/h (about 12,427 mph), drops to a few hundred km/h in less than eight minutes. This braking generates temperatures of over 1,500 °C (about 2,732 °F) on the heat shield, while accelerations reach 15 to 20 times Earth's gravity.

To reproduce these stresses on the ground, engineers use gas cannons or hypersonic wind tunnels. The small models launched at 4,200 km/h (about 2,610 mph) experience forces similar to a real entry, but over a very short duration. The onboard sensors measure vibrations, pressure, and heat, data that allows validation of the materials and shape of the capsule.

These tests also allow studying aerodynamic stability. An unbalanced capsule could tip over and disintegrate. The twenty successive shots help refine the center of gravity and the stabilizing fins.