Spacecraft Powered From The Ground By Microwave Radiation

So, 63 years ago, started a piece in the TOMORROW’S THINKING section of Electronics Weekly’s edition of February 1st 1961

The story continues:

This is possibly due to the advances made in the generation of enormous output power by new tubes.

One of the studies they have undertaken, with the partial support of the USAF concerns a closed-cycle gas turbine engine using a microwave heat exchanger. The latter, receiving high-power radiation via horn antennas, heats up air, creating enough pressure to drive a turbine.

The turbine drives an air compressor and the pressure built up could be used as power jets to be exhausted to atmosphere via the tips of a rotor. The rotor would be driven round and in this way supply aerodynamic lift for a possible communications relay station, operating at a distance above the earth’s surface.

The air drive to the turbine is maintained by a compressor geared to the turbine; energy
being continuously fed into the closed-cycle system by the microwave radiation.

Another similar scheme uses a microwave-powered gas engine to give hot air lift for an airship.

Heating helium in a similar method might provide lifting power for balloons.

A plasma rocket machine is the subject of another study by Raytheon. Here the propellant is ionised and subsequently raised to the required exit temperature in an ionisation chamber, the source of power being beamed microwaves collected by an aerial. Specific impulse and thrust cut-off can be controlled quite easily from the ground in this way.

Microwave power can free a space vehicle near the carth’s surface from fuel limitations by using air as the medium for the tranfer of power from clectromagnetic to mechanical. Indeed, short-duration flight with relatively very large payloads is a possibility.

In the next  decade or two perhaps we may see spacecraft travelling above us  with no fuel tanks , driven by power beamed from the ground or from a stationary satellite.