SpaceRef

SpaceRef


Glossary - NASA Crew Exploration Vehicle, SOL NNT05AA01J, Attachment J-6

Status Report From: NASA Office of Exploration Systems
Posted: Monday, January 24, 2005

Abort - Early mission termination due to failure(s) that preclude mission continuation. Return to Earth of the crew is accomplished inside the spacecraft designed for Earth return and landing (see Abort to Earth, Abort to Orbit).

Abort to Earth - Early mission termination, with direct return to the Earth's surface as the immediate objective.

Abort to Orbit - An early mission termination that has an immediate objective of placing the flight system (CEV) in Earth orbit, prior to return to the Earth's surface.

Acceptance Tests - Tests conducted to verify that hardware delivered to higher-level assembly prior to delivery to the flight test and prior to delivery to the operational inventory or for operational spares conforms to program requirements. Acceptance testing also includes final "sell-off" of the fully assembled CEV.

Annunciate - To provide a visual, tactile or audible indication.

Ascent - The time from liftoff from the Earth's surface, to spacecraft insertion into Earth orbit.

Ascent Abort - Early mission termination due to failure(s) that preclude mission continuation. Return to Earth of the crew is accomplished inside the spacecraft designed for Earth return and landing.

Attitude and Pointing Constraints - Constraints, restrictions or requirements on the vehicles orientation in space. These may include things such as requirements to orient a sensor at a specific target (such as a specific star), or a constraint limiting the amount of time a vehicle axis can be oriented toward a particular target (such as the sun, or deep space). They also include constraints or restrictions on maneuver rates and attitude deadbands.

Automated control - Automatic, as opposed to human operation or control of a process, equipment or a system; or the techniques and equipment used to achieve this. Automation is the control or execution of actions with no human interaction. Automated control does not exclude the capability for manual intervention / commanding, but manual intervention / commanding is explicitly not required to accomplish the function.

Autonomous operations - Defined as a flight vehicle operating independent of external commands or control (i.e., commands from mission control on Earth). Autonomous operations can be fully automated or require some degree of manual commanding/intervention by the onboard crew. Autonomous operations that do not require onboard crew involvement are, by definition, automated; therefore, the term "autonomous operations" used in the requirements assumes onboard crew involvement in the operations.

Berthing - A method of mating two or more Exploration elements in space. During a berthing operation, the two elements are mechanically connected prior to the structural capture and final mating (i.e., one element grapples the other with a robotic arm). One element controls the trajectory and attitude of the other element for the contact and capture. Final mating is generally performed by the berthing mechanism.

Catastrophic Hazard - A condition that may cause death or permanently disabling injury, major system or facility destruction on the ground, or major systems or vehicle destruction during the mission.

CEV Acquisition Strategy Phase 1 - This is the formulation phase for the CEV. This phase begins in 2005 with contract award to multiple contractors and continues through PDR for each design.

CEV Acquisition Strategy Phase 2 - This is the implementation phase for the CEV. This phase begins in 2008 with down select to one contractor and continues through 2014, with the first human launch of the CEV. This vehicle is a spiral 2-capable vehicle that also satisfies all spiral 1 capabilities.

CEV Acquisition Strategy Post-Phase 2 - This is both the initial operations phase and the spiral 3 upgrade phase for the CEV. The initial operations phase begins in the negotiation of firm options into the 2008 contract for additional CEV flight and also includes the sustaining engineering of the production vehicles. The spiral 3 upgrade phase has the contractor upgrade their CEV design to incorporate all spiral 3 capabilities. This phase will not occur if the contractor incorporated all spiral 3 requirements in their original design.

CEV System - Includes the spacecraft and all CEV-unique ground systems needed to support standalone and integrated operations.

CEV System Flight Tests - Operating flight tests during the development phase used to qualify that the integrated flight vehicle system (including the launch vehicle) and ground support equipment, as procured and verified by the acceptance test procedures, conform to the Constellation program requirements.

CEV System Level Requirements (CEV) - Requirements that will be developed by Constellation SE&I in conjunction with the CEV prime contractors. Includes performance/functional requirements for the CEV system and External Interface Requirements (EIRD) to other Constellation systems.

Commercial-Off-The-Shelf (COTS) - Commercially available products that can be purchased and integrated with little or no customization, thus facilitating customer infrastructure expansion and reducing costs.

Component - An elementary device or piece of equipment that is a basic part of a subsystem.

(Constellation) Ground Support System - This system provides all Constellation common ground-based capabilities (e.g., mission control, launch-site processing) needed to execute Exploration missions. It does not include ground based In-space Support Systems. Facilities and capabilities that are unique to a single Exploration system, such as the CTS, will be included as part of the system it supports.

Constellation System of Systems - The system of systems that includes all capabilities and systems that are critical to enabling safe and successful human and robotic missions across the solar system.

Consumables - Resources that are consumed in the course of conducting a given mission. Includes propellant, power, habitability items (e.g., gaseous oxygen), and crew consumables. Limited quantity items (such as propellants, power and life support fluids/gases) that are used during the course of the flight. Consumables are budgeted and managed to support all mission needs.

Consumables Product Development - The effort to produce planned usage profiles for all consumables that can constrain a mission by nature of their limited quantity (such as propellants, metabolic oxygen, and power generation). Used for preflight planning and real-time flight operations.

Contingency EVA Capability - An EVA capability provided to deal with critical failures or circumstances, which are not adequately protected by redundancy or other means.

Control Board - The board, panel or forum chartered to have authority over a particular subject or item (ex. Flight Rules Control Board, Crew Procedures Control Board, etc)

Crew Activity Scheduling Constraints - Constraints, restrictions or requirements on the scheduling of the flight crew. Includes such information such as required amounts of sleep, amount crew sleep can be shifted, amount of time for crew meals and exercise, etc.

Crew Exploration Vehicle (CEV) - The CEV provides crew habitation and Earth re-entry capability for all Exploration Spirals. In Spirals 2 and 3, the CEV has been functionally defined as the vehicle in which the exploration crew will be transported to the lunar vicinity and subsequently returned to the Earth surface. The CEV will also have the capability to perform automated and/or autonomous operations (loiter), from LSAM separation from the CEV for descent to the lunar surface, until the end of the lunar surface mission.

Crew Exploration Vehicle Launch Segment (CEVLS) - The CEVLS consists of a Crew Exploration Vehicle (CEV), a Crew Launch Vehicle (CLV), and all the dedicated ground support infrastructure necessary to launch the CEV to Earth orbit.

Crew Launch Vehicle (CLV) - The CLV is an element of the CTS. The CLV will be human-rated, and will deliver the CEV into a mission-specific Earth Ascent Target Orbit.

Crew Member - Human onboard the spacecraft or space system during a mission.

Crew Operations - The activities performed by the flight crew while in the vehicle or during a mission. A subset of the Integrated Flight Operations Execution that begins with crew ingress into the CEV prior to launch and concludes with the crew egress from the CEV post landing

Crew Transportation System (CTS) - The CTS encompasses the flight elements needed to deliver a human crew from Earth to a mission destination, and return the crew safely to Earth. In Spiral 1, the CTS includes the CEV and CLV. For Spirals 2 and 3, the CTS includes the CEV, CLV, plus other elements to be defined at a later date such as EDS and the LSAM. The CTS must interact with the Ground Support System (GSS) during all Spirals; current architectures require delivery of the EDS and LSAM through use of the CDS to rendezvous orbits.

Critical Hazard - A condition that may cause a severe injury or occupational illness, loss of mission, or major property damage to facilities, systems, or flight hardware.

Demo Flight - The 2008 demonstration flight performed as part of the flight test program.

Depot Operations - The operations performed offline to receive and accept new flight hardware components, recertify previously flown hardware components for reuse, and to perform maintenance and repairs within the Line Replaceable Units (LRU's).

Destination Surface to Destination Vicinity Phase - Starts with the initiation of the ascent (T0) from the destination surface. Representative mission activities include: ascent, abort, and orbit insertion or libration capture. Phase ends after successful destination vicinity insertion/capture.

Destination Vicinity Operations Phase A - Starts at the successful insertion/capture at the destination vicinity. Representative mission activities include: loiter and phasing, vehicle and system checkout, crew-cargo transfers, undocking and separation. Phase ends at the successful separation of surface lander system for descent burn.

Destination Vicinity Operations Phase B - Starts after the successful destination orbit insertion or libration point capture, following ascent from destination surface. Representative mission activities include: phasing, vehicle-system checkout, crew-cargo transfer, undocking and separation maneuver, element disposal and/or safing. Phase ends at the completion of the Trans-Earth Injection burn.

Destination Vicinity to Earth Phase - Begins with completion of Trans-Earth Injection burn and includes mid-course corrections, cruise to Earth vicinity, element separation and element disposal. Ends with arrival at Earth entry interface or successful Earth orbit injection.

Destination Vicinity to Surface Phase - Starts at the initiation of the descent burn from destination vicinity (destination deorbit burn or libration departure burn to destination). Representative mission activities include: descent to destination surface, descent aborts, landing, propulsion system shutdown and safing. For libration architectures, additional activities include orbit capture, phasing, and de-orbit maneuvers. Phase ends when the vehicle has completed all landing activities on the destination surface, including propulsion system shutdown and safing.

Development Tests - Any test that provides data needed to reduce risk, to design hardware or software, to define manufacturing processes, to define qualification or acceptance test procedures, or to investigate anomalies discovered during test or operations. Verification credit cannot be taken during development testing.

Docking - A method of mating two or more Exploration elements in space. In a docking operation, the structural mechanisms are brought into contact and captured through independent control of the two vehicles' flight path and attitude. Final mating is generally accomplished by the docking mechanism.

Earth Ascent Target Orbit - The planned CEV orbit, upon completion of ascent (separation from Crew Launch Vehicle).

Earth Departure Stage (EDS) - EDS will be used to provide the propulsive force needed to transfer the various flight elements to destination phasing orbits (including the CEV and LSAM). EDS will be launched on a Cargo Launch Vehicle, and are considered part of the CDS, except when mated to and operating with a crew-occupied flight element.

Earth Orbit Operations Phase A - Starts with completion of Earth orbit insertion. Representative activities include: phasing, rendezvous, docking and loiter. Ends with completion of a burn to leave Earth orbit (i.e., Trans-Lunar Injection burn or de-orbit burn).

Earth Orbit to Destination Vicinity Phase - Starts after completion of vehicle injection burn (i.e., Trans-Lunar Injection) and includes mid-course corrections, element separation/disposal, and cruise to destination vicinity. Ends with successful insertion/capture at destination vicinity.

Earth Re-entry Phase - Begins with completion of Earth orbit injection. Ends with de-orbit burn completion. Encompasses activities necessary to successfully execute direct-to-Earth aborts during ascent.

Earth Reference Orbit - The orbit designated for assembly of Exploration System elements prior to departure for exploration destinations, defined by the following parameters: Inclination: 28.5-29.0 degrees; Launch Azimuth: 90+/- 5 degrees; Altitude: 307 km - 407 km.

Earth to Orbit Phase - Starts with liftoff. Representative activities include liftoff through ascent to orbit, ascent crew escape/abort and re-entry/descent during aborts, disposal of elements. Ends with insertion to a stable, 24 hour Earth orbit or return to Earth.

Electromagnetic Interference (EMI) - What occurs when electromagnetic fields from one device interfere with the operation of some other device.

Entry footprint - Region on Earth's surface defined by the boundaries of the CEV Earth entry corridor.

Escape - Early mission termination that requires emergency egress of the Crew from the failing spacecraft, possibly using an escape system (e.g., extraction, ejection, escape pod).

Evaluation Factors - Criteria (cost and non-cost) by which a contractor's proposal will be evaluated to make a contract award.

Exploration Spiral 1 (Crew Transportation System Earth Orbit Mission) - Encompasses the capabilities necessary to insert humans into Earth orbit and return them safely to Earth, employing a post-Space Shuttle flight system. A programmatic constraint has been imposed on Spiral 1: "NASA shall conduct the initial test flight for the Crew Exploration Vehicle before the end of the decade in order to provide an operational capability to support human exploration missions no later than 2014". The flight elements of the Exploration Spiral 1 Crew Transportation System are the Crew Exploration Vehicle and Crew Launch Vehicle. Robotic Precursor Missions that are scheduled to launch prior to the Earth orbit demonstration of the Spiral 1 CTS are considered Exploration Spiral 1 missions.

Exploration Spiral 2 (Extended-Duration Lunar Campaign) - Encompasses the capabilities necessary to execute extended-duration human lunar exploration. Extended duration lunar missions will be 4-14 days in duration on the lunar surface, and do not require pre-deployed surface systems (e.g., Habitation Module or Surface Power). A programmatic constraint has been imposed on Spiral 2: "NASA shall conduct the first extended human expedition to the lunar surface as early as 2015, but no later than the year 2020, in preparation for human exploration of Mars and other destinations". Robotic Precursor Missions scheduled to launch after the Spiral 1 CTS flight demonstration, and prior to the first Spiral 3 Lunar mission are considered Exploration Spiral 2 missions.

Exploration Spiral 3 (Long-Duration Lunar Campaign) - Encompasses the capabilities necessary to execute a long-duration human lunar exploration campaign. This campaign requires development of extensive surface systems (e.g., habitation and surface power system), and long-duration lunar-vicinity parking capability of the crew transportation system. Long-duration lunar missions will extend from 14-98 days. Robotic Precursor Missions that are scheduled to launch after the last Spiral 2 extended- duration lunar mission, and prior to the initial Exploration Spiral 4 mission are considered Exploration Spiral 3 missions.

Exploration Spiral 4 (Crew Transportation System Mars Flyby) - Encompasses the capabilities to conduct a Mars flyby mission using elements of the Human-Mars Crew Transportation System. Upon completion of successful Mars flyby(s), Exploration Spiral 5 will commence. Robotic Precursor Missions scheduled to launch prior to the first Human-Martian surface mission are considered Spiral 4 missions.

Exploration Spiral 5 (Human Mars Surface Campaign) - Spiral 5 encompasses the capabilities necessary to execute human Mars exploration missions. Robotic Precursor Missions scheduled to launch after the final Mars flyby mission, and prior to the start of Exploration Spiral 6 (TBD content) are considered Spiral 5 missions.

Export Control - U.S. export control laws and regulations, including the International Traffic in Arms Regulations (ITAR), and the Export Administration Regulations (EAR) (see FFS 1825)

Export Licenses - Licenses or other approvals from the Department of State of the Department of Commerce related to export of hardware, technical data, or software, or provides technical assistance to a foreign destination or "foreign person" (see NFS 1852.225-70)

Extended-Duration (Lunar Mission) - Human missions to the lunar surface ranging from 4 days (96 hours) through 14 days. This capability is an objective of Exploration Spiral 2. Extended-duration lunar missions do not require pre-deployed Surface Systems (e.g., habitation modules or surface power system).

Extensibility - Capable of being extended.

Facilities - Includes vehicle processing facilities, integration facilities, launch pads, mission control centers, launch control centers, control rooms, training, test, checkout, and assembly facilities with associated data processing and communication systems.

Facility Loading - The level that a facility is expected to be used. For example, if nominal usage is defined as 40 hours of simulation support per week and 50 hours are required during key periods, facility loading would be 110%.

Facility Systems - Systems necessary to support the operations of the facility. Examples are facility electrical power, water, pneumatics, cranes, etc. It does not include ground support equipment.

Fault Tolerance - The ability of a system to cope with internal problems and still continue to operate with minimal impact.

FDIR - Fault Detection, Isolation, and Recovery. The means to detect off-nominal conditions, isolate the problem to a specific subsystem/component, and recover of vehicle systems and capabilities. FDIR may be accomplished by the onboard crew, onboard software algorithms, ground commanding, or a combination of the preceding methods.

FDIR Algorithm - An onboard software algorithm for the purpose of performing Fault Detection, Isolation, and/or Recovery of vehicle systems and capabilities.

Fit Checks - An engineering test, where hardware that is to be installed on a future mission, is brought together on the ground and structural interfaces are verified by physically mating the hardware.

Flight Controller - A mission operations team member that supports the CEV vehicle and flight crew anytime from pre-launch through vehicle recovery. A flight controller has a specified discipline of responsibility and a console from which he/she supports the flight operations.

Flight Design & Analysis - The activities performed to design the vehicle flight trajectory, mass properties profile, consumables profiles, and other parameters to execute all phases of the mission without violating any hardware, software, or operational constraints.

Flight Element - Major flight component of the Constellation System of Systems.

Flight Operations - the activities performed to use the spacecraft and support the crew to accomplish the mission objectives. These operations include flight design and analysis, flight planning, and crew and mission operations. The scope of flight operations begins with the early, pre-flight analyses and flight planning, flight product and procedure development and flight execution by the crew and mission operations.

Flight Planning - The process of developing a detailed mission flight plan that satisfies all mission requirements. The requirements are integrated into a single plan for ground and crew execution which includes flight design requirements, vehicle operational constraints (thermal conditioning, communications, attitude maneuvers, antenna pointing etc), crew scheduling constraints and payload requirements.

Flight Operations Products - Documents and analyses used for flight preparation and execution.

Flight Rules - A collection of outline preplanned decisions to minimize the amount of real-time rationalization required for nominal and off-nominal situations affecting the mission or vehicle during a flight.

Flight Tests - Any test that involves flight. For CEV, flight tests consist of the 2008 and 2011 flight demonstrations and the 2014 integrated flight.

Functional Tests - Operating tests that confirm that a particular hardware or software item functions in a way that will permit it to meet allocated requirements.

Ground Operations - The activities performed to prepare the flight hardware using ground systems for launch and post landing operations. Includes planning, ground processing, launch, and post landing operations.

Ground Operations Phase - Begins with the start of mission planning. Representative activities include: mission planning, training, receipt of government hardware/software, acceptance, test, checkout, repair, inspection, assembly, integration, servicing and countdown activities. Also includes ground contingency, emergency, abort and turnaround operations. Phase ends with vehicle liftoff.

Ground Planning - The preparation activities for ground processing and launch operations.

Ground Processing - The activities performed to prepare the personnel, ground systems and flight vehicles during preflight operations.

Ground Support Equipment (or Support Equipment) - Hardware and software designed to interface, transport, service, checkout, or handle flight hardware. It is used during assembly and test of flight hardware and to control the configuration of the flight hardware.

Ground Support System - This system provides all common ground-based capabilities (e.g., mission control, launch-site processing) needed to execute Exploration missions. Facilities and capabilities that are unique to a single Exploration System, such as the CTS, will be included as part of the system it supports.

Ground Systems - The facilities and facilities systems, ground support equipment hardware and software, and training systems which are required to support integrated test and operational flights. The ground systems include those needed for ground operations, flight operations, and training.

Ground System Operations - The operation of facilities, facility systems, ground support equipment, and associated software when the flight hardware is not present. These operations typically include validation of ground systems, preventative maintenance, and post-launch refurbishment operations. Also, includes the operation of training systems, whether for system maintenance and validation, or for use to certify/train Flight and Ground Operations personnel. For operations of Ground Systems when flight hardware is involved, see Ground Operations.

Ground Tests - Any test performed on system elements or the complete system that does not involve flight. Ground testing includes development, functional, integration, qualification, acceptance, pre-flight, and flight-worthiness tests.

Guidance and Control - The process of directing the movements of a space vehicle, including selection of a flight path and making changes in attitude and speed.

Hardware-in-the-loop (HWIL) Tests - Tests conducted with hardware under test, where a simulation forms part of the test support equipment.

Incentive - A fee offered to a contractor in accordance with the terms and conditions of the contract for superior performance.

Inclination - The angle between the plane of an orbit and the Earth's equator for all geocentric orbits.

In-Space Support System (IS3) - This system will encompass capabilities provided by infrastructure elements (e.g., a communication satellite) that are placed in orbital, or lunar/planetary locations. These capabilities are exclusive of those provided by elements of the DSS.

Independent Technical Authority (ITA) - A warrant issued by the NASA Chief Engineer, which identifies the holder as compliance officer over an identified set of engineering and technical standards.

Initial Lunar Phasing Orbit - Used in Spiral 2 and 3 to define the orbit where the CEV will assume delta V requirements for docking in lunar orbit. Defined by the following parameters: Altitude: 100 km x 500 km +/- TBD km (TBR); Maximum inclination error with respect to the Lunar Reference Orbit; 0.5 degrees.

Integrated Collaborative Environment (ICE) - The primary means of sharing, reporting, collecting, recording and accessing program information between NASA, CEV Contractor, major/critical subcontractors and authorized U.S. Government personnel connected with the CEV program. ICE provides real-time collaborative access to a single source of management information, product information and technical data. ICE is the principal mechanism for integrating a "program" digital information management environment.

Integrated Flight Operations Execution - Activities associated with the plans, processes, and schedules required for the integrated test and operational flight execution. This encompasses real-time support for all phases and aspects of mission and crew operations beginning with pre-launch activities through post-landing egress of the flight crew.

Integrated Master Schedule (IMS) - The IMS is an integrated, master schedule containing the networked, detailed tasks necessary to support the events, accomplishments, and criteria of the IMP. The execution IMS shall contain all of the contract IMP events, accomplishments, and criteria from contract award to completion of the contract. The IMS shall be a logical network-based schedule that correlates to the program WBS, and is vertically and horizontally traceable to the cost/schedule reporting instrument used to address variances (such as Cost Performance Report (CPR) and 533 Cost Reporting (533M/533Q).

Integrated Operations - The activities that involve the spacecraft and other flight elements or the resources of multiple organizations.

Integrated Product and Process Development (IPPD) - a management technique that simultaneously integrates all essential product development activities through the use of multi-disciplinary teams to optimize design, manufacturing and supportability processes. It is a systematic approach to the integrated, concurrent design of products and related processes, including manufacturing and support. IPPD is intended to cause designers and developers to consider all relevant life-cycle elements during the initial and early phases of technology or product development.

Integrated Product Team (IPT) - Use of multi-functional teams to make team related decisions based on timely input from the entire team.

Integrated Test Flights - flights where the spacecraft is integrated to another element(s) (e.g. CEV launch vehicle) with operational control performed by the combined government/contractor team. This covers the proposed flights from 2011 to the beginning of operational flights.

Integration Tests - Tests conducted to verify functional performance has been achieved after hardware and/or software items are assembled and interfaces activated.

Item Tests - Tests at the component or item level (i.e., the lowest element of the system that is serialized or otherwise tracked).

Launch Availability - The likelihood that a given launch will be achieved without a scrub once the mission timeline (first element launch for a multiple launch mission) or the launch countdown call to stations (for a mission scenario involving a single launch) has commenced. Launch availability is composed of four elements: system availability, launch probability, launch site weather constraints and abort weather constraints. Launch Availability can be expressed as: P(LA) = P(SA) x P(LP) x P(LW) x P(AW)

Where:

  • P(LA) = Launch Availability (overall probability of achieving a launch)
  • P(SA) = System Availability (probability of hardware being acceptable for launch)
  • P(LP) = Launch Probability (probability that the vehicle limits are not violated by upper level winds or other natural environment phenomena)
  • P(LW) = Launch Weather (probability that other launch site weather constraints are not violated)
  • P(AW) = Abort Weather (probability that abort weather constraints are not violated)

Launch Azimuth - The initial heading of a powered vehicle at launch.

Launch Operations - The final activities to prepare the ground systems and the integrated vehicle for launch, and the launch of the integrated stack.

Launch Opportunity - The period of time during which the relative position of the launch site and orbital plane permit the CEVLS to insert the CEV into the Earth Ascent Target Orbit, prior to transfer to the Earth Reference Orbit (see definition). Phasing of Launch Opportunities for the CEVLS are TBD at this time.

Level 0 Requirements (Constellation) - Requirements decomposed from the President's vision.

Long-Duration (Lunar Mission) - Human missions to the lunar surface that require pre-deployed Surface Systems. This capability is a requirement in Exploration Spiral 3, and encompasses surface stays from 42 days (threshold) up to 98 days (objective) (TBR).

Low Earth Orbit (LEO) - A stable orbit around the Earth with a minimum orbital altitude of 170 km.

Lunar Surface Access Module (LSAM) - Provides crew transport to the lunar surface from the Lunar Reference Orbit and return from the surface to the Lunar Ascent Orbit.

Mass Properties - The distribution of mass within the vehicle, which can change throughout the mission due to consumables usage and the transfer of hardware. The vehicle mass properties are tracked and managed to avoid adverse impacts to the vehicle's control characteristics.

Mating - The act of mechanically connecting together two major elements of a system. Mating can be performed in space, through docking or berthing, or on the ground through docking, berthing, or other interfaces.

Mission Capable - Refers to the status of an Exploration flight element or mated elements, which have sufficient consumables to fully execute its intended mission from its current location in space. Element(s) which are no longer in a mission-capable status must terminate the mission, and in the case of the CEV, return to Earth.

Mission Control Centers - The central command and control facility for Mission Operations.

Mission Operations - The activities performed to plan, direct, manage, and execute the flight by the mission control management, flight controllers, and support organizations. A subset of the Integrated Flight Operations Execution that begins at liftoff and ends with crew egress after landing.

Mission Opportunity - Refers to the Earth departure window to conduct a mission to another planetary destination such as the Moon or Mars. Typically constrained by orbital mechanics and the design of the Exploration System. If assembly of elements in Earth orbit is required, then "Mission Opportunity" refers to the departure window from Earth orbit based on the capability of the Exploration System.

Mission Phase Definitions - Used as the basis for functional flow and decomposition of reference Spiral 3 human exploration mission. The Mission Phases identified were Ground Operations, Earth to Orbit, Earth Orbit Operations, Earth Orbit to Destination Vicinity, Destination Vicinity Operations (A), Destination Vicinity to Surface, Surface Operations, Destination Surface to Destination Vicinity, Destination Vicinity Operations (B), Destination Vicinity to Earth, Earth Re-entry, and Recovery (see associated definitions).

Mockups - A training system or other facility with a physical similarity to flight or ground systems hardware for the purpose of training, engineering evaluations, or other studies.

Module - A self-contained unit of a spacecraft that performs a specific task or class of tasks in support of the major function of the craft. For example, a spacecraft may be broken up into an escape module, a living module, a propulsion module, etc.

NASA Operations Integrator (NOI) - The government/contractor organization providing overall Constellation program operations planning, coordination, integration and execution.

Nominal Operational Scenarios - Cases that describe situations that are within the planned capabilities of the vehicle (example, CEV docking with the lander across a range of lunar altitudes.)

Non-operating Environment Tests - Tests in environments (shock, vibration, acoustic, and temperature) while the hardware is not in an operating mode (i.e., without power, mechanical, or propulsion systems in operation).

Non Operational Environment - The environment (ground transportation, etc.) in which the vehicle will be exposed to when it is not intended to be operational.

Objective - Used in requirements language to define the desired capability above the threshold that should be evaluated for feasibility and affordability. Capabilities above the objective are not expected to be pursued or analyzed.

Off-Nominal Operations Scenarios - Cases that describe situations that are outside the planned operations (example, inability to dock lander to CEV, resulting in a need to perform an EVA to re-enter the CEV).

Open System Architecture - A system with common interfaces that facilitate products from multiple vendors to operate on.

Operating Conditions & Environment Tests - Tests of the flight and support assemblies in each operating mode and in the maximum (worst case) predicted operating and environmental conditions.

Operational Environment - The environment (thermal, pressure, radiation, etc.) in which the vehicle is intended to be operated.

Operational Flights - The activity phase occurring after the design, development, test, transition and deployment of the Exploration System to Space Operations Mission Directorate for the purposes of space exploration and pursuing the Vision.

Operational Interfaces - Formal organizational and personnel interactions required to implement contract responsibilities and the necessary interfaces to fully integrate and coordinate activities internal and external to the CEV program.

Operations - The processes, plans, system requirements, procedures, and work to be performed associated with the preparation, launch and flight execution, and recovery of the CEV. The scope of Operations concern the activities with equipment once it has been delivered to the government and are in support of the integrated test flights prior to the transition. This is applicable to all types of operations.

Part Task Trainers - Facilities and equipment that are highly specialized and serve to train a specific subset of a larger system.

Past Performance - The initiative to gather (and use in future source selection) factual information about the performance of a contractor against the performance requirements in the contract.

Phase 1 - Demonstration of a flight test in 2008 that minimizes risk for the CEV to be delivered in 2014.

Phase 2 - Completion of the development, test, and deployment of a human-rated CEV system capable of meeting CEV Spiral 2 requirements as a threshold, with an objective of meeting CEV Spiral 3 requirements. This phase also includes the contract options that may utilize the Phase 2 vehicle.

Phase 3 - All post Phase 2 activities.

Post-Flight Trajectory Reconstruction - Post-flight generation of the actual trajectory that a vehicle flew, based on the best available source (C-band tracking, GPS, etc.).

Post Landing Operations - The activities required to plan, deploy, prepare the landing sites and landing aids for the flight vehicle, aid crew egress and transport, perform medical/emergency operations, safe flight hardware, and transport/retrieve appropriate parts of the flight system.

Preflight Operations - All the activities performed prior to liftoff of the vehicle. Includes ground processing, training, flight design, analysis, planning and launch operations.

Preliminary Design Review - A design review that shows the CEV preliminary designs that have been completed for all subsystems and the flight software. This review demonstrates that the contractor is prepared to enter into detailed design activities. The scope of PDR at a minimum will cover spirals 1 and 2, with a clear roadmap to achieve spiral 3 objectives. The objectives of the PDR include demonstration that all subsystem level 3 requirements are met by the preliminary subsystem design, the integrated design solution meets performance and functional requirements levied at the system level, system level performance analysis to ensure key design drivers can be met (eg weight, power, thermal, avionics throughput, etc), the design is verifiable, the external system interfaces can be met, and the technical, cost, and schedule risks can be accommodated within the program baseline.

Probabilistic Risk Assessment - A set of methodologies employed to determine quantitative probability a given end state or states (e.g., Loss of Mission, Loss of Crew) will occur. Probabilistic Risk Assessment results can be used to develop or validate Fault Trees and Failure Modes analysis. They also can be used as a tool for making design and logistics decisions.

Procedure - Set of detailed instructions used by the crew, ground operations and flight operations personnel to assess status, reconfigure, operate, trouble-shoot, safe, and maintain CEV systems under both nominal and off-nominal conditions. The procedures may also be executed by spacecraft executor software to fulfill specific tasks.

Process Integrity Metrics - A measurement of how well a process is meeting its intended goal.

Proximity Operations - Orbital flight operations conducted during any period when two or more vehicles are operating near enough to affect one another (e.g., prior to or post rendezvous and docking).

Real-Time Support - Level of support that has the personnel, tools, and locale necessary to provide immediate response.

Recovery Phase - Begins with completion of Earth surface landing and includes recovery forces operations, vehicle safing, vehicle configuration for recovery, crew egress, crew return to post-mission facilities. Ends with vehicle recovery to post-mission facilities.

Remotely Commanded Operations - The capability to operate a vehicle, system, or subsystem from an external location (i.e. mission control). Remotely commanded operations do not require the presence of an onboard crew.

Risk - The uncertainty of attaining a performance outcome or result and is the function of the probability and the consequence of failing to attain the performance outcome or result.

Risk Management (RM) - The processes for planning, assessing, handling, and monitoring risk.

Qualification Tests - Formal tests conducted to demonstrate that the design, manufacturing processes and acceptance test program produce system elements that conform to all CEV program requirements including the range of projected environments and operating conditions anticipated over the service life.

Safety-Critical Software - Software is safety-critical if it meets at least one of the following criteria:

  1. Resides in a safety-critical system (as determined by a hazard analysis AND at least one of the following:
  2. a. Causes or contributes to a hazard.
    b. Provides control or mitigation for hazards.
    c. Controls safety-critical functions.
    d. Processes safety-critical commands or data.
    e. Detects and reports, or takes corrective action, if system reaches hazardous state.
    f. Mitigates damage if a hazard occurs.
    g. Resides on the same system (processor) as safety-critical software.

  3. Processes data or analyzes trends that lead directly to safety decisions (e.g., determining when to turn power off to a wind tunnel to prevent system destruction.)
  4. Provides full or partial verification or validation of safety-critical systems, including hardware or software subsystems.

Segment - Used in the CTS requirements development process to express the identity of two or more elements mated together and operating jointly in a given set of mission phases. Segments defined this way facilitate functional decomposition of capabilities throughout the reference Exploration Spiral 3 mission. For example, the In-Space Transportation Segment is compromised of the CEV and an Earth Departure Stage, and comprises the CTS from the Earth Orbit Operations Mission Phase until CEV-EDS separation during the Destination Vicinity Operations Mission Phase. Other segments were defined as the CEV Launch Segment (CEV and CLV operating through separation in Earth orbit), the Destination Transportation Segment (CEV and LSAM operating in the lunar vicinity), and the Earth Return Segment (CEV only, upon separation from LSAM Ascent Stage).

Simulation Based Acquisition (SBA) - Process in which NASA and Industry are enabled by robust, collaborative use of simulation technology that is integrated across acquisition phases and systems. The goals of SBA are to substantially reduce the time, resources, and risk associated with the entire acquisition process, increase the quality, operability, and supportability of a system while reducing total ownership costs throughout the total life cycle, and enable Integrated Product and Process Development (IPPD) across the entire acquisition life cycle.

Simulator - A training system or facility that generates conditions approximating actual or operational conditions to a level commensurate with the function it is supporting (e.g. training, testing, engineering evaluation).

Software Requirements Review (SwRR) - A requirements review that decomposes the Level 3 subsystem requirements into lower level flight and ground software requirements, which are documented in a series of Software Requirements Specifications (SRSs). The scope of the SwRR will cover at a minimum spirals 1and 2. The objectives of the SwRR includes decomposition of the level 3 requirements into lower level flight and ground software requirements, updated operations concepts to further refine mission profiles and ground/crew operations from a software perspective and analyze the feasibility of the software items fulfilling their allocated operational requirements, further decomposition of the software architecture, presentation of the refined software cost & schedule, presentation of an integrated software technical, cost, & schedule risk assessment, presentation of the overall SW V&V Approach, and analysis showing that all software requirements are testable.

Spiral Development Process - A phased super-system development process that allows increasing capabilities to be achieved in support of long range objectives. While work can be accomplished concurrently against the objectives associated with multiple spirals, the completion of all objectives for a given spiral is considered necessary to enable achievement of the succeeding spiral. See associated definitions for Exploration Spirals.

Standalone Operations - The activities that involve a single flight element.

Strategy to Task to Technology Process (STTP) - Use of engineering analysis to validate architectural and mission design approaches, and identify technology investment needs.

Statement of Objectives (SOO) - A document that expresses both technical and management requirements in the form of performance objectives.

Statement of Work (SOW) - A document that expresses the tasks to be performed by the contractor.

Subsystem - A system that is part of some larger system. A spacecraft is first broken up into modules (if needed), then into subsystems, and finally into components.

Subsystem Level Requirements (CEV Prime Contractors) - Requirements that will be developed by the CEV prime contractors. Level 3 requirements decompose system level requirements into subsystems/assemblies requirements. Includes Internal Interface Requirements (IIRD) within the CEV system.

Sustaining Engineering - Long term design engineering responsibilities and support associated with Operational flights.

System Design Review (SDR) - A requirements review that decomposes the Level 2 System Requirements into subsystem requirements allocations within an overall vehicle architecture. The scope of the SDR will cover at a minimum spirals 1and 2. If the SDR does not cover spirals 1 through 3, the contractor shall provide a clear roadmap and risk assessment to mature the design through the remaining spirals. The objectives of the SDR include review of the proposed overall system architecture, decomposition of the level 2 requirements into subsystem requirements (level 3 requirements), updated operations concepts to further refine mission profiles and ground/crew operations, overall avionics and software architectures, facilities, and an integrated technical, cost, & schedule risk assessment. Particular attention will be made to key design driver allocations including mass, power, thermal, and software allocations. The contractor shall also demonstrate the IRD specifications are met. The contractor shall perform and document a preliminary Hazard Analysis.

System Engineering & Integration (SE&I) - The technical and management efforts for directing and controlling the integrated engineering effort for the System.

System Engineering, Integration & Test (SEI&T) - The design, development, integration, and test of large and complex systems, where a system is understood to be an assembly or combination of interrelated elements or parts working together toward a common objective.

System Engineering and Integration Team (SEIT) - An IPT that handles system engineering and integration activities.

System of Systems - A set or arrangement of interdependent systems that are related or connected to provide a given capability. The loss of any part of the system will degrade the performance or capabilities of the whole. The systems contained in the Exploration System of Systems (ESS) are: the Crew Transportation System, Cargo Delivery System, In-Space Support System, Destination Surface System, Robotic Precursor System, and Ground Support System. Requirements, constraints, and guidelines that apply to all human and robotic exploration systems are levied against the Exploration System of Systems, and may apply against any or all Exploration Spirals, as specified. The term "System of Systems" is sometimes expressed synonymously as "Super-system".

System of System Level Requirements (Constellation) - Establishes the Crew Transportation System (CTS) requirements for spirals 1 thru 3. Also requires incorporation of the Human Rated Requirements (NASA STD 8705).

System Requirements Review (SRR) - A requirements review that decomposes CTS Level 1 requirements into System Level 2 requirements. Specifically, the SRR will allocate and decompose Level 1 requirements between the Launch Vehicle and the CEV, as well as establish external interfaces between the CEV and other Constellation flight and ground systems, and provide initial Concept of Operations regarding the ground, flight and mission operations. The SRR will be a NASA led review, leading to baseline of System Requirements Document (SRD) & External Interface Requirements Documents (EIRDs) for the CEV.

Surface Operations - A Constellation operating mode that starts with landing on the destination surface and ends with ascent from the destination surface. Note: This may be a quiescent state for the CEV.

Technical Performance Parameters (TPP) - Technical Performance Parameters are identified by the CEV Program Manager for monitoring during the design and development, such as margins for Mass Properties, Power Allocation, Volume, CPU Utilization, Bandwidth/Throughtput.

Technology Readiness Level (TRL) -

  • TRL 1: Basic principles observed and reported
  • TRL 2: Technology concept and/or application formulated
  • TRL 3: Analytical and experimental critical function and/or characteristic proof-of-concept
  • TRL 4: Component and/or breadboard validation in laboratory environment
  • TRL 5: Component and/or breadboard validation in relevant environment
  • TRL 6: System/subsystem model or prototype demonstration in a relevant environment (ground or space)
  • TRL 7: System prototype demonstration in a space environment
  • TRL 8: Actual system completed and "flight qualified" through test and demonstration (ground or space)
  • TRL 9: Actual system "flight proven" through successful mission operations

Test-Qualified Software/ Hardware - Software/Hardware certified for its intended use in test.

Threshold - Used in requirements language to define the minimum capability necessary to satisfy the requirement.

Timeline - A sequential series of events that describe the CEV operation. A timeline can represent the vehicles mission at different levels of detail (ex. overview, summary and detailed timelines). The timeline includes information on trajectory events and scheduled crew activities as well as associated ground activities.

Training Systems - The hardware, software, and facilities required to educate, test, certify, qualify, standboard, maintain proficiency, and otherwise prepare the crew, ground and flight operations personnel for successful execution of Exploration missions.

Transition - The handover of the CEV's operation and hardware responsibilities from the combined developing contractor team and NASA Exploration Space Mission Directorate to the NASA Space Operations Mission Directorate's operations, engineering and management teams.

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