Jet aircraft on Mars

There is a report of a jet engine being developed for use on Mars which would burn magnesium powder. The Wickman Spacecraft & Propulsion Co. tried different ways of fluidizing the magnesium powder. Using nitrogen gas to blow the magnesium powder seemed best but their turbine clogged up with carbon stripped from the carbon dioxide atmosphere by the burning magnesium. It seems likely that hydrogen gas would work better to fluidize the magnesium. Equations of the chemical reactions that might occur in such a jet engine are:

2Mg + 2H₂ + CO₂ ==> 2MgO + CH₄

and

2Mg + 2H₂ + 2CO₂ ==> 2MgO + 2CH₂O

The products of formaldehyde and methane would not cause carbon build-up, but putting magnesium oxide powder through a turbine seems incompatible with long engine life. The whole problem turbine wear and fouling could be obviated by using a ramjet engine such as was used on the CIM-10 Bomarc Surface-to-air missile which flew at Mach 2.6 at 60,000 feet (18 km). A ramjet would need a rocket stage to get it to the speed at which the ramjet can start. Then the aircraft would need to switch to rocket power again to land or land unpowered. Another problem would be the thinness of the Martian atmosphere. The highest altitude air-breathing jet engine on Earth was the SR-71 reconnaissance aircraft which flew at up to 26 kilometers altitude. The pressure of the Martian atmosphere at the surface is about equal to the pressure at 40 kilometers altitude on Earth, six times lower pressure than at the service ceiling of the SR-71.

So there is a possibility of an atmosphere-breathing ramjet-powered aircraft on Mars, but there are problems that might prevent it.