Ages 8–12 · about 6 minutes

The Navy's Very Strange Patents

Why did the United States Navy patent a spaceship?

Do this first · Try this at home

Draw the motion and balance the energy

Start with your hands. The reading makes far more sense afterwards.

You need: Paper and a pencil

Tick each step as you do it

Draw four frames of a circle turning, then four frames of a dot moving back and forth. Label rotation and oscillation.
Draw two circles with arrows turning in opposite directions. Label this a design diagram, not a measured result.
Draw an energy box: 10 invented units enter; 6 leave as motion, 3 as heat, and 1 as waves. Assume stored energy ends unchanged. Check 10 = 6 + 3 + 1.

0 of 3 steps done

What should I notice?

Notice: These are invented numbers, not measurements from a patent. Keep the activity on paper; do not build, charge, spin, or power a device.

Now read on to find out why it happens.

The big idea

Follow the charge, the motion, and the energy. A predicted effect and a measured effect are different records.

electric charge: A property of matter involved in electric forces. Moving charge also contributes to magnetic fields.
oscillation: A repeated back-and-forth change. Rotation instead turns around an axis.
resonance: A strong response when a repeated drive is at or near a system's natural vibration frequency.
inertia: An object's resistance to a change in its velocity.

Salvatore Cezar Pais is named as inventor on three designs that list the United States, represented by the Secretary of the Navy, as assignee. The craft patent was published on December 4, 2018; the gravitational-wave generator patent on June 18, 2019. The superconducting-wire document published on February 21, 2019 is an application publication, a different edition type.

A workshop bench by a sea window with an old rolled drawing of a lens-shaped craft held flat by a mug and a magnifying glass. — An imagined workshop and craft drawing. This painting is not an original patent diagram, a flight photograph, or a measured result.

Charge in motion

Electric charge is involved in electric forces. Moving charge also contributes to magnetic fields. Rotation means turning around an axis; oscillation means a repeated back-and-forth change. The designs combine charged surfaces with these kinds of motion to produce electromagnetic fields.

The craft design places a cavity between an inner wall and an outer wall. Microwave sources supply electromagnetic waves inside it; the outer wall is charged and driven to vibrate. One version also rotates the cavity. Pais predicts that this arrangement changes the nearby vacuum and reduces inertia, the resistance to a change in velocity. That is the proposed effect, not a force measurement supplied by the drawing.

Resonance can make a vibration larger when a repeated drive is near the system's natural frequency. Timing matters, not just the size of each push. The drive supplies energy, and energy can leave through damping. A larger vibration alone does not show that new energy has appeared.

Three designs, different outputs

The gravitational-wave design uses a charged shell, microwave sources, and sound-driven, gas-filled cavities. Two cavities turn in opposite directions, which the design intends to provide stability. It predicts gravitational waves from the interaction of electromagnetic fields. Measuring a vibrating cavity would not, by itself, measure those gravitational waves.

The wire application proposes an insulating core with a coating, pulsed current, and vibration, including a piezoelectric version driven electrically. The predicted output is superconductivity at room temperature. Checking that claim would require electrical-resistance and magnetic-response measurements of that wire, not simply observing that it vibrates.

Where the energy goes

The generator drawing includes an electrical source and a motor. Their energy belongs in the account too. In an invented example, 10 energy units enter, while 6 leave as motion, 3 as heat, and 1 as waves. With stored energy unchanged at the end, 10 = 6 + 3 + 1 balances the account. These numbers are a paper example, not the performance of Pais's machine.

A laboratory comparison of the craft idea would need force and acceleration measurements, with vibration on and off, while accounting for ordinary electromagnetic pushes. A different result would need an explanation of what changed. The patent describes the arrangement and its predicted effect; those measurements would test the connection between them.

Sources: Pais, US10144532B2 (2018), US10322827B2 (2019), US20190058105A1 (2019); NOAA resonance glossary; NASA Glenn, First Law: Conservation of Energy.