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Spacecraft

Propulsion and Travel Times

Modern spacecraft use constant-thrust fusion drives. The standard operating profile is 1g acceleration to the midpoint of the journey, followed by turnover and 1g deceleration to arrival. This profile provides comfortable Earth-equivalent gravity throughout the voyage and is the basis for ship interior design (see Ship Design below).

Fleet vessels can sustain higher thrust (2g, 3g, or more) when military necessity demands it, significantly reducing travel times at the cost of crew stress and increased fuel consumption.

Route Distance (approx.) Travel Time (1g)
Earth ↔ Luna 384,000 km ~3.5 hours
Earth ↔ Mars (closest) 55 million km ~1.7 days
Earth ↔ Mars (average) 225 million km ~3.5 days
Earth ↔ Mars (farthest) 400 million km ~4.6 days
Earth ↔ Ceres 415 million km ~4.7 days
Luna ↔ Ceres 415 million km ~4.7 days
Ceres ↔ Jupiter 215 million km ~3.4 days
Earth ↔ Jupiter 630 million km ~5.8 days
Earth ↔ Saturn 1.3 billion km ~8.3 days
Earth ↔ Uranus 2.7 billion km ~12 days
Earth ↔ Neptune 4.4 billion km ~15 days
Earth ↔ Pluto 5.9 billion km ~17.5 days

Inner system travel (Earth, Luna, Mars, Ceres) is measured in hours to days. Outer system travel takes one to two weeks. System-wide journeys (Earth to Pluto) run two to three weeks.

This is what makes "stellar range" operations genuinely demanding — not because any single journey is impossibly long, but because vessels operate weeks from resupply, rescue, or reinforcement.

Operating Ranges

Fleet logistics uses four rough operating ranges:

  • Short range: Operations within the scale of a single planetary body's influence.
  • Medium range: Operations between two adjacent planetary orbits in the inner system (Mars and inward), anchored to areas with developed infrastructure.
  • Long range: Operations between multiple inner-system orbits, or adjacent outer system orbits, or operating in the inner system without anchoring to infrastructure.
  • Stellar range: System-wide operation.

Ship Classes

Fleet ships come in four standard classes:

  • Delta class: Short range fast weapons platforms, either single-pilot or unmanned. Never equipped with rotating sections. Crew: 0-2.
  • Lambda class: Short range freight carriers or medium range crewed vessels. Usually not large enough to carry or support more than 2 Delta class vessels. Never equipped with rotating sections. Crew: 2-6.
  • Beta class: The bulk of the Fleet. These ships come in medium and long range variants, usually large enough to carry 2-4 Lambda class and/or 8-32 Delta class craft depending on configuration. This is the fuzziest classification due to the variety of designs; Fleet is always attempting to "standardize" with predictable results. Crew: 12-40 depending on configuration and mission.
  • Alpha class: Large, long range craft designed for force projection — the "aircraft carriers" and "destroyers" of the UEF Fleet. The two main designs are configured accordingly: one as a platform for Delta/Lambda launch and support, the other as a large-scale weapons platform. Crew: 80-200+.

Fleet also fields a small number of non-standard ships designed for stellar-range operations. Stellar range ship design is a hot area of R&D.

Civilian and Corporate Vessels

Individually owned ships are almost always at the Delta or Lambda scale — few individuals can afford anything at Beta size or above. Larger organizations such as corporations and universities field craft at all scales.

Ship Design

Delta and Lambda scale ships are not large enough for rotating sections. They are designed for simulated gravity via thrust and zero-gee operations when not under acceleration.

The standard layout for Beta and Alpha class ships is a central spine with the drive at the rear and cargo and zero-gee operations modules along the spine. Ships designed for cetacean/human hybrid operation often include cetacean habitat sections along the spine. In addition to the central spine are one or more torus-shaped crew sections. These are designed so that interior compartments can rotate within the torus — aligning with acceleration under thrust, or aligning outward when the ship is not under acceleration and the torus is spun up to simulate gravity.

Areas of Innovation

Fusion engines and smaller ship designs have been refined over two centuries; short of completely new technology, there is little room for breakthrough innovation. The most fruitful areas for current innovation are:

  • Stellar-range ship design: Completely non-standardized. The challenges of system-wide operation have exposed the limitations of standard designs.
  • Cetacean-compatible ship design: Dolphins serve in Fleet, but not every ship is equipped to handle dolphin crew. Orca-compatible ship-side service is currently impractical — whether this can or should be addressed is an open question.