Space Settlement Design Competition Glossary

Many of the words and terms used in Space Settlement Design Competitions materials are not part of familiar everyday usage. Here is a list of some of the various technical terms.

Air-breathing engine: a propulsion plant (motor) that acquires oxidizer from the air, rather than carrying it in tanks on the vehicle (as required by rocket engines).

Airlock: a chamber that enables people and things to move or be moved between volumes with different pressures; like a lock in a canal, the chamber starts at the pressure that the occupant is moving from, and changes to the pressure being moved to.

Attitude (of a vehicle): a vehicle's orientation relative to Earth, Sun, or other objects; typically used to describe a desired view, observation target, or heating environment (e.g., a "sun-facing" attitude assures that one side of the vehicle will always be hot, and the other side always cool)

Avionics: literally, "aviation electronics", mostly including commanding and monitoring of systems on aircraft and spacecraft

Cargo: the reason a vehicle flies; stuff that is carried by a vehicle from its starting point (ground or on-orbit) to the vehicle's destination; can include satellites, bulk materials, construction components, or people

Cargo container: a standard carrier in which cargo is carried for a mission; ideally, all spacecraft cargo is containerized, because complex installations and interfaces can be accomplished to the inside of the container, and the standardized exterior interfaces of the container can be quickly mated to the inside of a cargo vehicle (standardized containers have been used for decades on ships, conventional aircraft, railroad cars, and trucks)

Consumables: stuff that is used up during the course of a mission or over a period of time, and hence must be replaced; includes everything from rocket fuel to pet food to pencils

Contract: a legal agreement between a customer and a company (contractor), whereby the contractor agrees build something or provide a service within a defined cost and schedule, and the customer agrees to pay the cost when the product is delivered (contracts may have provisions for partial payments over the course of a long product delivery schedule)

Dirtside: of or referring to Earth, people living there, and things on it

Down area: in a rotating space structure, the interior surfaces through which the acceleration due to the rotation ("artificial gravity") appears to be vertical; conversely, surfaces inside a rotating space structure on which an individual could stand or things could be placed, as if they were on the ground

Downweight: amount of payload weight carried by a vehicle from orbit to the ground

Expendable Launch Vehicle (ELV): a launch vehicle which is used for only one launch; typically, it sheds some of its components, or stages, during the launch process, with only a small portion of the original "stack" being delivered all the way to orbit

Extravehicular Activity (EVA): an excursion by a person in a spacesuit outside of any vehicle or habitat

Fabrication: manufacture; the process of making, building, and/or assembling

Fiber optics: use of tiny, transparent strands to transmit light that represents electronic signals; can replace traditional copper wire with less weight and expense, and greater reliability, but is not capable of transmitting power

GEO: Geosynchronous Earth Orbit; objects in 22,300 mile orbits rotate around the Earth at the same rate that the Earth turns on its axis; when located above the Equator, these objects appear to be stationary in Earth's sky

Hypersonic flight: flight through an atmosphere at greater than five times the speed of sound (Mach 5) for that atmosphere

Lagrangian points, or L1, L2, L3, L4, L5: see libration points

Launch vehicle: a spacecraft that is capable of launching or flying through an atmosphere (e.g., Earth's) in order to get into space and achieve orbit

LEO: Low Earth Orbit; orbital locations above Earth's atmosphere and below the Van Allen radiation belts

Libration points: in orbital mechanics, when one large body (e.g., the Moon) is in orbit around another large body (e.g., Earth), there are five points in orbits around the larger body where gravitational forces balance out to enable satellites to be placed where they could not stay if the smaller of the large bodies were not present (also called Lagrangian points, for Joseph Lagrange, the mathematician who developed the theory that predicts their existence)

Low-g: acceleration environment with less than the acceleration due to gravity on Earth's surface

Mass driver: a device that electromagnetically accelerates small objects to very high velocities; can be utilized for efficiently launching material from airless surfaces

Micro-gravity (micro-g): an accurate description of "weightlessness", the condition experienced in space when forces balance out and objects seem to "float"; true "zero-g" is theoretically not possible, because there are always some tiny forces operating on all objects

Nanotechnology: devices with dimensions between one-millionth and one-billionth of a meter

On-orbit: in space, in an orbit; usually refers to an orbit around Earth

Orbit: the path assumed by an object in space, due to balancing or "cancelling out" of accelerations due to gravity and rotation; usually the elliptical path of a small body (e.g., satellite) around a very large body (e.g., planet, moon, or star)

Outweight: amount of payload weight carried by a vehicle from Earth's vicinity outbound to another location in the solar system

Overhead: the part of a budget that does not show up as part of the cost of work directly on a project, but is charged to the customer as part of the hourly charge for direct work (i.e., a contractor is paid for each hour an engineer works on tasks directly related to the project; the customer is billed a cost for the engineer's hours that is greater than the salary paid to the engineer; the difference pays for computers, upkeep of the facility, janitors, utilities, secretaries, and other costs required to support the engineer's work)

Payload: literally, "paying load"; cargo carried by a vehicle, for which a fee is being paid in exchange for moving the cargo to its destination

Payload capability: weight of payload(s) that a launch vehicle is capable of carrying to orbit

Payload integration: the process of safely stowing a payload (usually a satellite or complex device) on a launch vehicle and providing services (often including electrical power, avionics, and thermal control) that enable the payload to survive the flight and accomplish its purpose; includes design of payload services, analysis of payload's ability to survive environments it will experience, and installation in the vehicle

Profit: the difference between the price charged by a contractor for providing a product, and the actual cost the contractor incurs to make the product

Proposal: a document prepared by a company or other entity, with the intention of convincing a customer that the company should be selected as the contractor that will provide a certain product; it describes the company's recommendation for how it could provide the product, and explains why the customer should have confidence that the company has a superior design and can be relied upon to produce it according to the customer's requirements and within the described cost and schedule

Rectenna: receiving antenna, for electrical power produced by and transmitted from Solar Power Satellites

Request for Proposal (RFP): a document prepared by a customer, which describes features of a product they want a contractor to produce

Requirements: features that a customer requests to be included in the design of a desired product

Returnweight: amount of payload weight carried by a vehicle to Earth's vicinity inbound from another location in the solar system

Reusable Launch Vehicle (RLV): technically, any launch vehicle that returns from its missions intact, and is designed to be maintained after flight and fly repeated missions

Satellite: any object in orbit around another object; usually refers to human-made devices in orbit around large natural bodies (i.e., planets, moons, stars)

Shirtsleeve: an environment inside a vehicle or habitat that enables humans to operate without protective clothing

Single Stage to Orbit (SSTO): the capability of a launch vehicle to accomplish a mission from the ground to orbit without staging, or shedding of components during the launch process; such vehicles contain all of the fuels and oxidizer they require in tanks inside their structures, and return to the ground with the tanks intact (the amount of oxidizer required can be reduced through use of air-breathing engines)

Solar panel: a device that converts sunlight into electrical power

Solar Power Satellite: a satellite, usually very large, consisting mostly of large arrays of solar panels producing electrical power that can be converted (usually to microwave energy) and transmitted to users in other locations

Solar sail: a surface, usually very large and lightweight, that makes use of pressure due to solar wind for propulsion

Spacer: of or referring to people who live in space

Spacesuit: a garment that provides pressure, breathing air, fluids and nutrients, waste removal, and protection against the space environment, and that enables a human to move and operate in the space environment

SPS: see "Solar Power Satellite"

SSTO: see "Single Stage to Orbit"

Station-keeping: use of small rockets, solar sails, or other propulsion to prevent satellites from drifting out of their desired orbital locations

Terminator: intersection between day and night on the surface of a planet or moon, which appears on the surface as sunrise or sunset

Upweight: amount of payload weight carried by a launch vehicle to orbit

Van Allen radiation belts: bands of radiation trapped in Earth's magnetic field, which both absorb ambient deep-space radiation and provide protection for Earth's surface, and are a hazard for satellites and humans operating within them

Zero-g: see "micro-gravity"