Self-eating rocket engine could slash satellite launch costs

The group, from Glasgow University and Oles Honchar Dnipro National University in Ukraine claim to have built, fired, and throttled up and down a so-called ‘autophage’ engine which they claim could be used to put small satellites in orbit more easily.

Today, most rockets use tanks to store their propellant as they climb, and the weight of the tanks is usually many times greater than the weight of the useful payload. This reduces the efficiency of the launch vehicle, and contributes to the problem of space debris.

However, a launch vehicle powered by an autophage engine would consume its own structure during ascent, so more cargo capacity could be freed-up and less debris would enter orbit.

Described in a paper published in the Journal of Spacecraft and Rockets, the engine consumes a propellant rod which has solid fuel on the outside and oxidiser on the inside. The solid fuel is a strong plastic, such as polyethylene, so the rod is effectively a pipe full of powdered oxidiser. By driving the rod into a hot engine, the fuel and oxidiser can be vaporised into gases that flow into the combustion chamber. This produces thrust, as well as the heat required to vaporise the next section of propellant.