Landing Gear is designed to facilitate surface landings.
- It is an intrinsic item of Ship Equipment.
- Landing gear is either fixed or retractable.
- Retractable landing gear is housed within a compartment in the hull known as a well. On some designs, the well may be accessed from the interior of the vessel by a hatch or removable panel. The well is typically covered by an outer door when the undercarriage is retracted.
- Landing gear is generally considered to be intrinsic to the hull, incurring no additional cost and requiring no additional onboard volume.
Landing gear supports the weight of the hull.
- Due to their large size and mass and the high ground pressures that they generate vessels will generally land on a prepared landing surface such as a runway or a landing pad, or on solid bedrock. Landings on other surfaces are of course possible, but such operations are hazardous (the surface may slip or give way, or the vessel may sink). This risks damage to the vessel and possible local civic outrage.
A wide variety of landing gear is utilized but can generally be categorized into one of three types:
(1) Landing Skids
Landing skids are most commonly horizontal bars that transmit the weight of the ship to the surface on which it is resting. The surface should be level; the skids have no inherent leveling capability. The bars do not actually “skid” and the ship is immobile when landed.
- Fixed landing legs and landing wheels are a form of landing skid: a familiar example is the ubiquitous 800-Ton Broadsword class Mercenary Cruiser
- Some vessels may dispense with landing gear altogether, instead utilizing the ventral surfaces of the hull directly. Such designs generally have contoured surfaces with designated contact points. These contact points (pads) are usually proud of the main part of the hull and are specially hardened and reinforced.
- Early designs of space capsule generally rely on drogue parachutes and hardened ventral surfaces to achieve surface landings.
- In very cold environments, where there may be large bodies of ices and frozen volatiles, some vessels may utilize skis for takeoffs and landings.
(2) Landing Legs
The ship has landing legs ending in pads (or occasionally articulated mechanical feet or claws). The pads may rest on any reasonably stable, relatively level surface: the legs contain mechanical components that adjust to compensate for uneven terrain. The ship is immobile when landed. Landing legs are retractable.
(3) Landing Wheels
The ship has landing legs terminating in wheels. The undercarriage is retractable. The hull may land anywhere that Landing legs with pads can, but for the wheels to be able to roll, a relatively smooth flat surface (such as a landing strip or a metalled highway) is required. Most wheeled undercarriages are capable of rolling at very high speeds and contain shock absorbers and braking equipment. Some wheeled undercarriages may be powered.
- Some undercarriages utilize a tracked suspension rather than wheels. The ship must take off and land in the same manner as a vessel with landing legs, but while on the surface it is able to move in a similar manner to a vessel with a wheeled undercarriage.
The configuration of some hulls, despite their being fully streamlined and capable of atmospheric operations, may not be practical for surface landings. In such circumstances they may generally only land through the use of a cradle configured to the shape of their hull.
- Hull cradles are typically fixed mechanical assemblies within starport docking bays. They most commonly consist of powerful grappling arms and docking tubes that are able to safely support the hull. They can accommodate almost any shape of hull.
- A hull cradle may be specific to a particular design of hull. Vessels with a different hull shape cannot generally utilize the cradle.
- One or more vehicles mounting grappling arms may position themselves around the vessel, serving as a mobile cradle and acting to support the vessel while it is landed. Such vehicles may be robots and are frequently very large.
- Some hull cradles utilize gravitic technology such as repulsors.
- Floats are generally bulky, consisting of fixed buoyant pods or subhulls (either hollow or filled with a substance such as lightweight foam).
- Inflatable sacs constructed from tough airtight materials may be employed as flotation devices.
- Fixed floats are often hybrid devices, containing wheels to allow takeoffs and landings on landing strips.
- Many classes of starships and spacecraft are naturally buoyant and will float, though water pressure may cause ongoing damage to the hull, water displacement and movement may cause structural issues, and some of the vessel's design features may rapidly upset the buoyancy. Unless they are designed for maritime operations, prolonged exposure to an aquatic environment may present considerable risk to a vessel.
Some vessels have powerful onboard gravitic technology enabling them to float in place, forgoing the need for landing gear altogether.
The vast majority of sophont civilizations that have discovered aircraft have already discovered the wheel, but not all have.