The Lazward drive is a hybrid space engine for small-size vessels.

It can be best described as battery-powered microwave drive with optional quenching injection and chemical fuel enhancement. It is used in places where fusion drives are not readily available and fission engines would interfere too much with the geometry drive given the layout of the ship -- or for any other situation where fission is not desirable, for example due to fissile material availability.

The typical use case of a Lazward drive is a courier or light cargo ship expected to be primarily employed for interplanetary and low-end interstellar travels. It is mostly used for velocity matching prior to FTL translations but can also be employed for SSTO operations with chemical fuel boosting.

The core of a Lazward drive is its energy storage module, made of superconducting magnetic energy storage (SMES) units. Made of room temperature superconductors, these toroid-shaped coils are used to store large quantities of power produced by an external source. A typical Lazward unit may contain several hundred to thousands of them. The SMES units are stored in revolving cannisters that allow them to be rotated in and out of the engine section easily. The SMES are installed alongside the main tanks of metastable nitrogen used for chemical fuel enhancement. Finally, the propulsion module contains a foldable rectenna that can receive beamed power from a space station or another ship.

The Lazward drive has three propulsion modes -- a main one, and two optional modes.

-- The main mode of propulsion is a high-power microwave drive. Hydrogen propellant is pumped into the engine section and rapidly heated in a microwave plasma chamber, powered by the gradual discharge of an SMES unit. This mode allows the ship to match velocity with interplanetary targets, at moderate specific impulse and moderate thrust. The quantity of energy stored in individual SMES units make this drive vastly more powerful than regular stationkeeping ones, and comparable to low-end "nuclear lightbulb" rockets.

-- When in need of additional power, one or several SMES units can be diverted towards an auxiliary chamber where they are voluntarily ruptured. The superconductor disintegrates in an arc discharge and the generated gases are used to produce additional thrust. Quenching enhances the base thrust of the Lazward drive, giving it more punch for velocity matching, though it destroys SMES batteries while doing so.

-- Finally, when conducting surface-to-orbit operations or when in need of even more thrust for velocity matching, the Lazward engine uses an auxiliary high-thrust metastable nitrogen chemical rocket. Such propellants are sometimes called "nitromemes", for reasons better left to historians to elucidate.

If the ship runs out of SMES units, emergency beamed power can be used, but at a much lower efficiency. A solar moth unit is often paired with the Lazward module in case of emergency.

All consumables -- SMES batteries, hydrogen propellant, chemical propellant -- are relatively easy to source with a minimal industrial base. Specifically, they are commonly produced by high-tech systems with limited access to mass production of fissiles or industrial-grade fusion drives. These systems are the ideal location for the deployment of Lazward drive ships. Battery recharge is handled by local stations or gas giant habitats. It is possible to conduct fast recharge operations by simply swapping the SMES cannisters through hull openings.

The performance of Lazward drives is perfectly adequate for interplanetary velocity matches and the majority of interstellar ones, though faster destinations will require the help of a carrier ship. Lazward engines are civilian drives through and through. Their thrust is too low for effective combat manoeuvers and they are too complex to power a missile.

However, the lack of a nuclear drive and its accompanying shielding allows for a very compact engine section. Furthermore, heat rejection is low: while the design does need radiators (especially during quenching), the drive is fairly stealthy and only really visible from the rear. The Lazward engine doesn't require complex maintenance. SMES units are a well-understood technology while both microwave and nitromeme rockets are known quantities. Lazward schematics are under public domain licenses.

The main weak point of a Lazward are the SMES units. The energy storage coils are fail-deadly: if one of them is physically compromised, it can accidentally quench and propel high-velocity shrapnel through the ship. Cascading failures are not unheard of, due to the nature of the revolving cannisters. There are two main failsafes for SMES failure. The first one is to pre-emptively quench the failing SMES units, which melts them instead of creating shrapnel, scrapping the engine section but saving the crew. The second one is the emergency ejection of the entire cannister, using the same mechanism that allows for rapid charging.

The name "Lazward" is derived from the persian word for "blue". The origin of the nickname is unknown butiIt may come from the faint blue glow of the exhausts when quench-enhancing the drive.

Source: NASA public domain.