Space Compliance Glossary

Technologies and missions designed to capture and remove existing debris objects from orbit.

The point in an orbit where the spacecraft is farthest from Earth.

The orbital element giving the angle, within the orbital plane, from the ascending node to the point of closest approach (perigee).

A US-led set of non-binding principles (2020) for cooperative and peaceful exploration and use of the Moon, Mars, and beyond, signed by a growing number of states.

The force that slows spacecraft in low orbits, causing gradual altitude decay.

The sum of all points where an unauthorized user could attempt to enter or extract data from a space system.

The subsystem that senses and controls a spacecraft's orientation, keeping instruments, antennas, and solar arrays correctly pointed.

The formal approval required from a National Competent Authority before conducting space activities within the EU.

A measure of how strongly atmospheric drag affects a spacecraft, combining its mass, cross-sectional area, and drag coefficient.

The probability of a human casualty resulting from uncontrolled spacecraft re-entry.

The French national space agency responsible for space policy and technical evaluation under the LOS.

An entity providing space situational awareness services including conjunction assessment and collision avoidance support.

The estimated likelihood that two space objects will collide during a predicted close approach, the key metric for deciding whether to manoeuvre.

The US statute (codified in Title 51) authorising the FAA to license commercial launch and reentry, including financial-responsibility and indemnification provisions.

The period after LEOP when spacecraft and payload are fully tested before operational handover.

The UN committee responsible for international space law development and governance of outer space activities.

National teams responsible for receiving and coordinating cybersecurity incident reports under NIS2.

The process of evaluating potential close approaches between space objects to determine collision risk and inform avoidance decisions.

A standardized message format providing detailed information about a predicted close approach between two space objects.

An operator that manages multiple coordinated satellites working together as a system to provide continuous or global coverage.

International forum developing standards for space data and information systems.

The geographical area or time period during which a satellite can provide service.

Mutual agreement between parties to not seek damages from each other for space-related losses.

A standardized small satellite format using 10cm cubic units (1U = 10×10×10 cm), enabling cost-effective space access.

An EU regulation setting cybersecurity requirements for products with digital elements across their lifecycle, including secure development and vulnerability handling.

A systematic evaluation of a space system's security posture against cyber threats, required under NIS2 and EU Space Act.

The protection of the night sky and radio-quiet environment from the effects of large satellite constellations on astronomy.

The process of stabilizing a tumbling spacecraft to regain attitude control.

The release of controlled technology to foreign nationals, treated as an export under US law.

A cybersecurity strategy using multiple layers of security controls throughout a system.

The change in velocity required for orbital maneuvers, a key metric for spacecraft propulsion budgets.

A documented strategy for removing a spacecraft from orbit at the end of its operational life, either through controlled re-entry or natural decay.

Spacecraft design approach ensuring complete or near-complete destruction during atmospheric re-entry to minimize ground casualty risk.

The change in observed signal frequency caused by the relative motion between a satellite and a ground station, which must be tracked and compensated.

A deployable device that increases a spacecraft's cross-sectional area to accelerate orbital decay.

Technology or items that have both civilian and military applications, subject to export controls.

The gathering of information about Earth's surface and atmosphere from space.

The orbital element describing the shape of an orbit, from a perfect circle (zero) to increasingly elongated ellipses (approaching one).

A class of spacecraft propulsion that accelerates propellant using electrical energy, achieving high efficiency at low thrust.

The process of encoding data so only authorized parties can access it, critical for space communications.

The final phase of a space mission when operational activities cease and disposal procedures are implemented.

A table or function giving a spacecraft's predicted position and velocity over time, used for tracking, communications scheduling, and collision avoidance.

The precise reference time at which a set of orbital elements is valid; orbit predictions are propagated forward or backward from this instant.

Under NIS2, a large organization or critical infrastructure operator subject to enhanced cybersecurity obligations and supervision.

The EU agency providing cybersecurity expertise and supporting NIS2 implementation across member states.

The European Union agency responsible for managing EU space programmes and coordinating space policy implementation.

Regulation (EU) 2021/821, the European Union framework controlling the export, brokering, and transit of dual-use items, including space-related technologies.

A proposed European Union regulation (COM(2025) 335) that would establish a unified framework for space activities across all EU member states; published by the European Commission in 2025 and not yet adopted.

The centralized European database of registered space objects, fulfilling UN Registration Convention obligations.

The system of technical standards for European space projects.

The intergovernmental organization responsible for European space research, development, and exploration activities.

The US regime (15 CFR 730–774) controlling dual-use and certain commercial items on the Commerce Control List, administered by the Department of Commerce's Bureau of Industry and Security (BIS).

US agency responsible for commercial space launch and re-entry licensing.

US agency regulating satellite communications, including spectrum licensing and debris mitigation rules.

An in-orbit breakup of a spacecraft or rocket body creating multiple debris objects.

The named radio-frequency ranges (such as L, S, C, X, Ku, and Ka band) used for different satellite services, each with distinct propagation and capacity trade-offs.

The process of obtaining and protecting radio frequency assignments for space communications through national and international regulatory bodies.

The European Union's global navigation satellite system providing precise positioning services independent of GPS.

A circular orbit at approximately 35,786 km altitude where satellites appear stationary relative to Earth's surface.

A highly elliptical orbit used to move a spacecraft from low altitude up to the geostationary belt, where it then circularises.

Germany's national research center for aeronautics and space, supporting regulatory functions.

Satellite constellations providing positioning, navigation, and timing services globally.

A cyber-physical attack that broadcasts counterfeit satellite-navigation signals to deceive receivers into computing a false position or time.

A disposal orbit, typically a few hundred kilometres above the geostationary belt, where satellites are placed at end of life to clear the operational region.

The Earth-based infrastructure supporting spacecraft operations, including ground stations and control centers.

The path traced on Earth's surface by the point directly below a satellite.

An orbit with high eccentricity, providing extended dwell time over specific regions.

A fuel-efficient two-burn manoeuvre that moves a spacecraft between two circular orbits via an intermediate elliptical transfer orbit.

A payload carried on another operator's satellite, sharing the spacecraft platform.

The Inter-Agency Space Debris Coordination Committee guidelines representing international best practices for debris mitigation.

Under NIS2, a medium-sized organization in covered sectors subject to cybersecurity obligations with reactive supervision.

An entity providing services to other spacecraft in orbit, including refueling, repair, debris removal, or life extension.

The mandatory notification of cybersecurity incidents and space safety events to relevant authorities within specified timeframes.

Legal arrangements whereby one party agrees to compensate another for potential losses.

Mandatory third-party liability insurance coverage that space operators must maintain as a condition of authorization.

A direct communications link between satellites, allowing data to be relayed across a constellation without routing through the ground.

A standardised identifier (COSPAR ID) assigned to a launched space object, encoding its launch year, launch number, and the piece of that launch.

The United Nations specialized agency responsible for global coordination of radio spectrum and satellite orbital positions.

The international standard for space debris mitigation requirements.

The international standard for information security management systems.

The International Traffic in Arms Regulations (22 CFR 120–130), the US regime controlling the export of defense articles and services on the US Munitions List, administered by the State Department's DDTC.

The dominant gravitational perturbation caused by the Earth's equatorial bulge, which steadily rotates an orbit's plane and apsides.

The deliberate transmission of interfering signals to disrupt or deny a satellite uplink, downlink, or navigation signal.

Japan's national aerospace agency and IADC member contributing to international debris guidelines.

The legal authority of a state over space activities and objects based on registration or other criteria.

The six classical orbital elements that uniquely describe a satellite's orbit and its position within it at a given epoch.

A theoretical scenario where debris collisions create more debris in a cascading chain reaction.

One of five positions in a two-body system where gravitational and centrifugal forces balance, allowing a spacecraft to maintain a relatively stable position.

The critical initial phase after launch when spacecraft systems are activated and checked.

An entity responsible for the preparation and execution of space launch activities, including launch vehicle operations.

Contract between a satellite operator and launch provider for launch services.

An entity responsible for managing and operating a facility from which space launch vehicles are launched.

A state that launches or procures the launch of a space object, or from whose territory or facility a launch occurs.

The 1972 UN Convention on International Liability for Damage Caused by Space Objects, establishing state liability for space activities.

A simplified authorization pathway under the EU Space Act for small satellites and low-risk space activities.

Orbital regime from approximately 160 km to 2,000 km altitude, the most congested region of space and primary focus of debris mitigation efforts.

The process of designing orbital maneuvers for station-keeping, collision avoidance, or disposal.

Orbital regime between LEO and GEO, approximately 2,000 km to 35,786 km altitude, primarily used for navigation satellites.

A very large satellite constellation, often comprising hundreds or thousands of spacecraft, typically in low Earth orbit.

A voluntary multilateral export-control arrangement (established 1987) that restricts the proliferation of missiles and the technology to build them, including many space launch and propulsion systems.

The 1979 Agreement Governing the Activities of States on the Moon and Other Celestial Bodies, which declares the Moon and its resources the common heritage of mankind; ratified by relatively few states.

An access-control method requiring two or more independent proofs of identity, such as a password plus a hardware token or biometric.

The US space agency, whose standards and practices often influence international space regulation.

The designated governmental body in each EU member state responsible for space activity authorization and supervision.

US agency licensing commercial remote sensing (Earth observation) satellites.

The EU Directive 2022/2555 on measures for a high common level of cybersecurity across the Union, applicable to space infrastructure operators.

The gradual rotation of an orbit's ascending node around the Earth's axis, driven mainly by the J2 perturbation.

The routine operational phase when a spacecraft performs its primary mission.

A sequential number assigned to each tracked space object as it is catalogued, used as the primary key in two-line element sets.

The angle between a spacecraft's orbital plane and Earth's equatorial plane.

The time a spacecraft or debris remains in orbit before naturally decaying into the atmosphere.

An assigned longitudinal position in the geostationary arc, coordinated internationally to prevent interference between satellites.

The UK statute requiring UK persons who operate a space object or procure its launch — anywhere in the world — to hold a licence from the UK Space Agency.

The 1967 Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, the foundational international space law.

The process of removing all stored energy from a spacecraft at end of life to prevent accidental explosions that could create debris.

The mission-specific equipment carried by a spacecraft to perform its primary function.

Authorised, simulated cyber-attacks against a system to identify exploitable vulnerabilities before adversaries do.

The point in an orbit where the spacecraft is closest to Earth.

An antenna of many elements whose beams are steered electronically by adjusting signal phase, without physically moving the antenna.

An entity that collects, processes, and distributes space object tracking data and orbital information.

The planned removal of a spacecraft from a protected orbital region at end of life — by controlled reentry, an accelerated deorbit, or a disposal (graveyard) orbit.

Spacecraft operations conducted in close range to another space object.

The framework of keys, certificates, and authorities that enables trusted encryption, authentication, and digital signatures.

The design and manufacturing techniques that make spacecraft electronics resilient to the damaging effects of the space radiation environment.

The return of a space object to Earth through the atmosphere.

A spinning flywheel used to control a spacecraft's orientation by exchanging angular momentum, without expending propellant.

The 1975 UN Convention on Registration of Objects Launched into Outer Space, requiring states to register space objects with the UN.

The 1968 Agreement on the Rescue of Astronauts and the Return of Objects Launched into Outer Space, obliging states to assist personnel in distress and return recovered space objects.

Launch arrangement where multiple satellites share a single launch vehicle to reduce costs.

The orbital element specifying where an orbit's ascending node lies relative to a fixed reference direction, orienting the orbital plane in space.

A minimal functionality state a spacecraft enters automatically when anomalies are detected.

Communication services provided via satellite, including broadcast, mobile, and fixed services.

An approach that builds security into a system from the earliest stages of architecture and development rather than adding it afterwards.

The orbital element that defines the size of an orbit; half the longest diameter of the elliptical path, directly related to the orbital period.

The standard propagation model used with TLE data to predict satellite positions.

A change of state in electronics caused by a single energetic particle strike — typically a recoverable bit flip rather than permanent damage.

The small but persistent force exerted on a spacecraft by sunlight, a significant orbital perturbation for high-altitude and large-area satellites.

Technical and operational measures to minimize the creation of orbital debris and ensure sustainable use of outer space.

The UK statute regulating spaceflight activities carried out from the United Kingdom — launch, return, spaceports, and range control — administered by the Civil Aviation Authority.

A maintained database of tracked resident space objects and their orbital data, the backbone of space situational awareness.

The comprehensive knowledge of the space environment including tracking of space objects, space weather monitoring, and near-Earth object surveillance.

The planning, coordination, and control of space activities to ensure safety and sustainability.

Conditions in space affecting spacecraft and ground systems, including solar activity effects.

An entity responsible for the command and control of a spacecraft during its mission, from launch through end-of-life.

The international law principle that states bear responsibility for all national space activities.

Orbital maneuvers performed to maintain a spacecraft in its assigned position.

A near-polar orbit where the satellite passes over any given point on Earth's surface at the same local solar time.

The ongoing regulatory oversight of authorized space activities by National Competent Authorities to ensure continued compliance.

The protection of space systems through security requirements and assessment of suppliers, vendors, and service providers.

The sharing of controlled technical data or defense services, regulated under ITAR/EAR.

Uplink commands sent from ground stations to control a spacecraft.

Downlink data from a spacecraft providing status information about its systems and payload.

A space operator based outside the EU that conducts space activities affecting EU interests or using EU infrastructure.

Insurance coverage for damage caused to parties other than the insured operator.

Curated, evidence-based knowledge about adversaries, their techniques, and indicators of compromise, used to inform defensive decisions.

A satellite payload component that receives an uplink signal, shifts its frequency, amplifies it, and retransmits it on the downlink.

The orbital element giving a satellite's angular position along its orbit, measured from perigee, at a specific moment.

A standardized data format for describing the orbital elements of Earth-orbiting objects, enabling position prediction.

The list of defense articles and services controlled under ITAR; Category XV covers spacecraft and related items.

Zones of energetic charged particles trapped by Earth's magnetic field, affecting spacecraft design.

The ongoing process of identifying, assessing, prioritising, and remediating security weaknesses across systems and software.

A multilateral export-control regime (established 1996) promoting transparency in transfers of conventional arms and dual-use goods and technologies, the basis for many national control lists.

A community-led initiative coordinated by ESA (2023) setting ambitious targets to stop the generation of new space debris by 2030.

A security model that assumes no implicit trust based on network location and continuously verifies every access request.