The Challenge | Design by Nature

Design an autonomous free-flyer to inspect a spacecraft for damage from Micro-Meteoroid and Orbital Debris (MMOD).


A magnetic levitation-based system capable of scanning the entire surface of a module. The system is automated, can be reused and does not rely on propellant.


SpaceLev - Maglev technology in space applications
NASA SpaceApps Challenge Milano 20/10/18
Group: Space-Y
Federico Amadori, Francesco Bianchi, Rocco Biscione, Andrea Montaini, Dario Natalizia, Giovanni Silva

Small object impacting the surfaces at speeds of the magnitude of 5 km/s can create a crater with a depth that is between 2 and 5 times the diameter of the object. We need to be able to autonomously identify and inspect this damage without the risk and complications of a spacewalk. The solution had to repeatable easily during the whole mission without using finite resources like propellant. We thought of a probe moving on the surface of the spacecraft and inspecting the damage with a LIDAR system and an infrared camera.

But how can we move in the void of space in a precise and efficient way? Inspired by the technology in Maglev trains and the Hyperloop concepts we thought of magnetic levitation. A grid of electromagnets is positioned below the surface of the spacecraft and the probe moves thanks to a combination of EMS and LIM technologies. Two LIM motors, one perpendicular to the other, provide movement parallel to the exterior. The probe is kept at a fixed distance from the surface by constantly altering the strength of a magnetic field produced by electromagnets using a feedback loop. These electromagnets responsible for the levitation are positioned at the corners of the probe and interact with magnets on the surface.

The system triangulates the position of the probe using antennas placed on the extremities of the module that are always visible to the probe. This is corroborated with the sensing of the load on the electromagnets on the surface.

Knowing the position of the probe a calculator can create a track of alternating magnets used by the LIM for the propulsion. The electromagnets at the sides of the “propulsion track” are kept at a fixed polarity and provide the levitation (“levitation track”) as described above.

Once the inspection of the module is complete, the probe returns automatically to a docking station where is kept attached to the spacecraft with an electromagnet. The charging of the probe happens with induction.

Propulsion:: Control of Traction and Levitation of Linear Induction Motor Driven by Power Source With Frequency Component Synchronous With the Motor Speed (not the actual method used but useful for the understanding of the technology)
Space debris: Model and Risk analysis by Helner Klinkrad - Chapter 7



SpaceApps is a NASA incubator innovation program.