Crystal Engine

Written by skairunner

Crystal engines are the source of propulsion for practically all spacecraft currently in use, from the smallest station-hopping shuttle to the largest warship. The unique ability of crystals, particularly astrallite, to convert electrical energy directly into momentum, is widely considered the driving force for the current age.
Some spacecraft depend entirely on crystals for power, using generator crystals with crystal engines. Especially efficient spacecraft such as the Dragonfly Carrier, and smaller spacecraft, do not need generators, instead using batteries to store all the electricity they need for a journey.

Death of the Rocket Equation

The majority of early spaceflight was conducted with chemical rocket engines. These primitive rockets burned fuel and flung it through a nozzle to produce thrust. Although these engines were quite powerful they suffered from a critical flaw known as the tyranny of the rocket equation. To produce thrust they needed to throw combusted fuel off the ship. However each ton of fuel loaded on a rocket made the engine less effective at providing thrust, since it had to lift a heavier object. So as the desired range for a spacecraft increased the amount of fuel required became exponentially larger.
This meant that early spacecraft were cramped, fragile, and extremely expensive. Each gram of weight had to be shed wherever possible. It would take months or years to reach other planets, and only a tiny amount of payload would actually make it there, the rest having been burnt to provide the propulsion. Some technologies such as ion thrusters and solar sails can alleviate this issue. But both technologies generate small amounts of thrust and have their limitations. Ion thrusters require massive power expenditures, while solar sails can only provide thrust in some directions and none at all in the shadow.
Crystal engines do not suffer from the same problem. They can generate thrust in whatever direction desired, do not need propellant, and unlike ion engines generate a significant amount of thrust. Since this makes space travel much easier, the invention of crystal engines coupled with the discovery of astrallite farming is considered the transition marker from early to late spacefaring age for most societies.

Crystalline propulsion

All crystals generate momentum when they receive energy. The amount of momentum varies depending on the cut and characteristics of each individual crystal. This is why some crystal devices float, while many others do not generate enough lift to counter their own weight. Crystal engines take advantage of this property and amplify it to its maximum, sacrificing other properties such as energy storage or generation. Astrallite is the material of choice, and astrallite grown in higher orbits is preferable as it is more attuned to spaceflight.
Crystal engines use some of the largest crystals regularly cut and trained. Not only does the size of a crystals determine the maximum amount of energy they can handle before being damaged, larger crystals are more efficient at high loads. On the other hand, growing and cutting the size of crystal required for large spacecraft can get prohibitively expensive. Cheaper engines are build by using multiple smaller crystals to achieve the same effect. It is a balancing act, however, because managing the small differences from crystal to crystal gets harder as the crystal count increases.
Older spacecraft such as those of the Trident Empire often depend on a handful of massive crystals for propulsion. Newer spacecraft such as Dragonfly carriers tend to rely on cluster engines for economy. Cluster engines are composed of many smaller crystals acting together as if it were an engine created from a single large crystal. Advances in technology to manage heterogenous crystal characteristics as well as improvements in lapidary to produce more uniform crystals make these cheaper cluster-engines possible.

Planet By Planet

The source of electricity for crystal engines varies depending on the size and purpose of the spacecraft they are mounted on. Small spacecraft, such as station shuttles and intermoon ferries commonly have no power generation at all, instead using banks of crystal batteries to provide all the power needed for their short hops and recharging at their destination.
Couriercraft, interplanetary shuttles and leisurecraft often opt for crystal generators instead. Crystals can generate charge over time, and crystal generators are optimized to maximize this. Since crystal generators are often paired with batteries, these spacecraft can also take advantage of stations to recharge and provide even more performance.
Some spacecraft require a large amount of thrust or the capability to make very long burns. This includes most military spacecraft, fast cargocraft, and any vehicle expected to operate in the atmosphere. Then an onboard powerplant is required. Large spacecraft often opt for small nuclear fission-based powerplants to provide this energy, while atmospheric craft frequently use fuel cells or liquid fuels, which are easily the cheapest option.

Spanning the Stars

Some believe that the next challenge for humanity is travelling beyond the Sol System to other stars. There are many obstacles in the way, such as the hostile Oort Cloud environment, but of chief interest to engineers is the fact that astrallite engines weaken as the distance from the Sun increases, already less than half effectiveness at the Kuiper Belt and theorized to have no practical effect past the heliopause.
One possible solution is creating crystal engines from the volatile and dangerous oortite. An experiment involving a test fire of a very small oortite engine was proposed to and rejected by the Sentinels, so it was instead sent along with Fritz Fram's Kuiper Belt expedition. Unfortunately, the experiment was lost, and the subsequent deep space expedition carrying another version of this experiment never returned. As there is little interest in funding an expedition entirely for this single experiment, the potential of oortite engines is yet to be explored.

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See Also

Crystal Technology
Spacecraft Kallisti Aerospace ( Sunderer SF-1 · Sunbreaker SF-2 ) · Jupiter Stella ( Aerie O-1 · Cyklopes SSF-9 ) · Heretic GA-7 · Dragonfly Carrier · Airdocks Telepresence Interlace ( Super Wide Access Network ) · Remote Personality Cache/Display Other Bosonic Clock · Gateway Portals · Gravity Plates · Personal Computer Materials Astrallite · Aurorite · Oortite