Flight controller

Flight controllers are personnel who aid space flight by working in such Mission Control Centers as NASA's Mission Control Center or ESA's European Space Operations Centre. Flight controllers work at computer consoles and use telemetry to monitor various technical aspects of a space mission in real time. Each controller is an expert in a specific area and constantly communicates with additional experts in the "back room". The Flight Director, who leads the flight controllers, monitors the activities of a team of flight controllers and has overall responsibility for success and safety.

This article primarily discusses NASA's flight controllers at the Johnson Space Center (JSC) in Houston. The various national and commercial flight control facilities have their own teams, which may be described on their own pages.

NASA's Flight Controllers

The room where the flight controllers work was called the Mission Operations Control Room (MOCR, pronounced "moh-ker"), and now is called the Flight Control Room (FCR, pronounced "ficker"). The controllers are experts in individual systems, and make recommendations to the Flight Director involving their areas of responsibility. Any controller may call for an abort if the circumstances require it. Before significant events, the Flight Director will "go around the room," polling each controller for a GO / NO-GO decision, a procedure also known as a launch status check. If all factors are good, each controller calls for a GO, but if there is a problem requiring a hold or an abort, the call is NO GO. Another form of this is STAY / NO STAY, when the spacecraft has completed a maneuver and has now "parked" in relation to another body, including spacecraft (or space stations), orbiting the Earth or the Moon, or the Lunar landings.

Controllers in MOCR/FCR are supported by the "backrooms," teams of flight controllers located in other parts of the building or even at remote facilities. The backroom was formally called the Staff Support Room (SSR), and is now called the Multi-Purpose Support Room (MPSR, pronounced "mipser"). Backroom flight controllers are responsible for the details of their assigned system and for making recommendations for actions needed for that system. "Frontroom" flight controllers are responsible for integrating the needs of their system into the larger needs of the vehicle and working with the rest of the flight control team to develop a cohesive plan of action, even if that plan is not necessarily in the best interests of the system they are responsible for. Within the chain of command of the MCC, information and recommendations flow from the backroom to the frontroom to FLIGHT and then, potentially, to the onboard crew. Generally, a MOCR/FCR flight control team is made up of the more seasoned flight controllers than the SSR/MPSR, though senior flight controllers cycle back to support in the backroom periodically. One example of the usefulness of this system occurred during the descent of the Eagle Lunar Module, when "1202" and "1201" program alarms came from the LM. GUIDO Steve Bales, not sure whether to call for an abort, trusted the experts in the Guidance backroom, especially Jack Garman, who told him that the problem was a computer overload, but could be ignored if it was intermittent. Bales called "GO!," Flight Director Kranz accepted the call and the mission continued to success. Without the support of the backroom, a controller might make a "bad call" based on faulty memory or information not readily available to the person on the console. The nature of quiescent operations aboard the International Space Station (ISS) today is such that the full team is not required for 24/7/365 support. FCR flight controllers accept responsibility for operations without MPSR support most of the time, and the MPSR is only staffed for high-intensity periods of activity, such as joint Shuttle/ISS missions.

The flight controllers in the FCR and MPSR are further supported by hardware and software designers, analysts and engineering specialists in other parts of the building or remote facilities. These extended support teams have more detailed analysis tools and access to development and test data that is not readily accessible to the flight control team. These support teams were referred to by the name of their room in Mission Control, the Mission Operations Integration Room (MOIR) and are now collectively referred to by the name of their current location, the Mission Evaluation Room (MER). While the flight controllers and their backrooms are responsible for real-time decision-making, The MOIR/MER provides the detailed data and history needed to solve longer-term issues.

Unmanned U.S. space missions also have flight controllers but are managed from separate organizations, either the Jet Propulsion Laboratory or the Johns Hopkins University Applied Physics Laboratory for deep-space missions or Goddard Space Flight Center for near-Earth missions.

Each flight controller has a unique call sign, which describes the position's responsibilities. The call sign and responsibility refer to the particular console, not just the person, since missions are managed around the clock and with each shift change a different person takes over the console.

Flight controller responsibilities have changed over time, and continue to evolve. New controllers are added, and tasks are reassigned to other controllers to keep up with changing technical systems. For example, the EECOM handled Command and Service Module communication systems through Apollo 10, which was afterward assigned to a new position called INCO.


Flight controllers are responsible for the success of the mission and for the lives of the astronauts under their watch. The Flight Controllers' Creed states that they must "always be aware that suddenly and unexpectedly we may find ourselves in a role where our performance has ultimate consequences". Well-known actions taken by flight controllers include:

Common flight control positions

There are some positions that have and will serve the same function in every vehicle's Flight Control team. The group of individuals serving in those positions may be different, but they will be called the same thing and serve the same function.[1]

Flight Director (FLIGHT)

Leads the flight control team. Flight has overall operational responsibility for missions and payload operations and for all decisions regarding safe, expedient flight. This person monitors the other flight controllers, remaining in constant verbal communication with them via intercom channels called "loops".

Mission Operations Directorate (MOD)

Is a representative of the senior management chain at JSC, and is there to help the flight director make those decisions that have no safety-of-flight consequences, but may have cost or public perception consequences. The MOD cannot overrule the Flight Director during a mission.

Capsule Communicator (CAPCOM)

Generally, only the Capsule Communicator communicates directly with the crew of a manned space flight. During much of the U.S. manned space program, NASA felt it important for all communication with the astronauts in space to pass through a single individual in the Mission Control Center. That role was designated the Capsule Communicator or CAPCOM and was filled by another astronaut, often one of the backup- or support-crew members. NASA believes that an astronaut is most able to understand the situation in the spacecraft and pass information in the clearest way.

For long-duration missions there is more than one CAPCOM, each assigned to a different shift team. After control of U.S. spaceflights moved to the Lyndon B. Johnson Space Center in the early 1960s, each CAPCOM used the radio call-sign Houston. When non-astronauts are communicating directly with the spacecraft, CAPCOM acts as the communications controller.

As of 2011, non-astronauts from the Space Flight Training branch also function as CAPCOM during ISS missions, while the role was filled solely by astronauts for the Apollo and shuttle missions.

Flight Surgeon (SURGEON)

Directs all medical activities during the mission. Monitors crew health via telemetry, provides crew consultation, and advises the flight director. A private communication channel can be established between astronauts and the flight surgeon, to provide doctor-patient confidentiality.

Public Affairs Officer (PAO)

Provides mission commentary to supplement and explain air-to-ground transmissions and flight control operations to the news media and the public. The individual filling this role is often referred to colloquially as The Voice of Mission Control.

Apollo flight control positions

The flight control positions used during the Apollo era were predominantly identical to the positions used for the Mercury and Gemini vehicles. This was because of the similarity of the vehicle design of the capsules used for the three programs.

Booster Systems Engineer (BOOSTER)

Monitored and evaluated performance of propulsion-related aspects of the launch vehicle during prelaunch and ascent. During the Apollo program there were three Booster positions, who worked only until Trans Lunar Injection (TLI); after that, their consoles were vacated. Booster had the power to send an abort command to the spacecraft. All Booster technicians were employed at the Marshall Space Flight Center and reported to JSC for the launches.

Control Officer (CONTROL)

Responsible for the Lunar Module guidance, navigation and control systems. Essentially the equivalent of the GNC for the Lunar Module.

Electrical, Environmental and Consumables Manager (EECOM)

Monitored cryogenic levels for fuel cells, and cabin cooling systems; electrical distribution systems; cabin pressure control systems; and vehicle lighting systems. EECOM originally stood for Electrical, Environmental and COMmunication systems. The Apollo EECOM was responsible for CSM communications through Apollo 10. Afterward the communication task was moved to a new console named INCO.

Perhaps the most famous NASA EECOMs are Seymour "Sy" Liebergot, the EECOM on duty at the time of the oxygen tank explosion on Apollo 13, and John Aaron, who designed the drastically-reduced power budget for its return.[2] Aaron also saved the Apollo 12 mission by realizing that the capsule's backup power filter would solve all of the seemingly-unrelated problems caused by a lightning strike.

Flight Activities Officer (FAO)

Planned and supported crew activities, checklists, procedures and schedules.

Flight Director (FLIGHT)

The flight directors held overall control of all of the individual positions in the MOCR. Some Apollo era directors were:

Flight Dynamics Officer (FDO or FIDO)

Responsible for the flight path of the space vehicle, both atmospheric and orbital. During lunar missions the FDO was also responsible for the lunar trajectory. The FDO monitored vehicle performance during the powered flight phase and assessed abort modes, calculated orbital maneuvers and resulting trajectories, and monitored vehicle flight profile and energy levels during re-entry.

Guidance Officer (GUIDANCE or GUIDO)

Monitored onboard navigational systems and onboard guidance computer software. Responsible for determining the position of the spacecraft in space. One well-known Guidance officer was Steve Bales, who gave the go call when the Apollo 11 guidance computer came close to overloading during the first lunar descent.

Guidance, Navigation, and Controls Systems Engineer (GNC)

Monitored all vehicle guidance, navigation and control systems. Also responsible for propulsion systems such as the Reaction and Control System (RCS) and the CSM main engine also the navigation has to be precise.

Integrated Communications Officer (INCO)

Responsible for all data, voice and video communications systems, including monitoring the configuration of in-flight communications and instrumentation systems. Duties also included monitoring the telemetry link between the vehicle and the ground, and overseeing the uplink command and control processes. The position was formed from the combination of LEM and CSM Communicator positions.

Network (NETWORK)

Supervised the network of ground stations that relayed telemetry and communications from the spacecraft.

Organization and Procedures Officer (O&P)

Supervised the application of mission rules and established techniques to the conduct of the flight.

Retrofire Officer (RETRO)

Drew up abort plans and was responsible for determination of retrofire times. During lunar missions the RETRO planned and monitored Trans Earth Injection (TEI) maneuvers, where the Apollo Service Module fired its engine to return to earth from the moon.

Telemetry, Electrical, EVA Mobility Unit Officer (TELMU)

Monitored the Lunar Module electrical and environmental systems, plus lunar astronaut spacesuits. Essentially the equivalent of the EECOM for the Lunar Module.

Shuttle and Space Station flight controllers

NASA currently has a group of flight controllers at the Johnson Space Center in Houston for the International Space Station (ISS). The Space Shuttle flight control team (as well as those for the earlier Gemini, Apollo, and Skylab programs) were also based there. Console manning for short-duration and extended operations differed in operational philosophy.

The Space Shuttle (and prior program) flight controllers worked relatively brief periods: The several minutes of ascent, the few days the vehicle was in orbit, and reentry. The duration of operations for Space Shuttle flight controllers was short and time-critical. A failure on the Shuttle could leave flight controllers little time for talking, putting pressure on them to respond quickly to potential failures. The Space Shuttle flight controllers generally had limited capability to send commands to the shuttle for system reconfigurations.

In contrast, the ISS flight controllers work 24 hours a day, 365 days a year. This allows the ISS flight controllers time to discuss off-nominal telemetry. The ISS flight controllers have the opportunity to interface with many groups and engineering experts. The mentality of an ISS flight controller is to preempt a failure. Telemetry is closely monitored for any signatures that may begin to indicate future catastrophic failures. Generally, ISS flight controllers take a prophylactic approach to space vehicle operations. There are command capabilities that ISS flight controllers use to preclude a potential failure.

Shuttle flight control positions

Many Apollo program mission control positions were carried forward to the space shuttle program. However, other positions were eliminated or redefined, and new positions were added.

Positions remaining generally the same:

Positions eliminated or modified:

Assembly and Checkout Officer (ACO)/Payloads

Responsible for all shuttle-based activities related to construction and operation of the Space Station, including logistics and transfer items stored in a Multi-Purpose Logistics Module (MPLM) or Spacehab. Also responsible for all shuttle payloads, from Spacehab to the Hubble Space Telescope to deployable satellites. On Shuttle missions that did not dock with the ISS, this position was known as PAYLOADS.

Booster Systems Engineer (BOOSTER)

Monitored and evaluated performance of propulsion-related aspects of the launch vehicle during prelaunch and ascent, including the main engines and solid rocket boosters.[3]

Data Processing System Engineer (DPS)

Responsible for data processing systems in a space flight. This included monitoring the onboard General Purpose Computers (GPCs), flight-critical, launch and payload data buses, the Multi-function Electronic Display System (MEDS), Solid-State Mass Memory (SSMM) units, flight critical and payload Multiplexer/De-multiplexer (MDM) units, Master Timing Unit (MTU), Backup Flight Control (BFC) units and system-level software.

The space shuttle general purpose computers were a critical subsystem, and the vehicle cannot fly without them.

Emergency, Environmental, and Consumables Management (EECOM)

EECOM's revamped shuttle responsibilities included the atmospheric pressure control and revitalization systems, the cooling systems (air, water, and freon), and the supply/waste water system.

MPSR positions

EECOM's critical function was to maintain the systems, such as atmosphere and thermal control, that keep the crew alive.

Electrical Generation and Integrated Lighting Systems Engineer (EGIL)

Monitored cryogenic levels for the fuel cells, electrical generation and distribution systems on the spacecraft, and vehicle lighting. This was a portion of the job formerly done by EECOM.

MPSR positions

Extravehicular Activity Officer (EVA)

Responsible for all spacesuit and spacewalking-related tasks, equipment and plans when the EVA took place from the shuttle.

Flight Activities Officer (FAO)

Planned and supported crew activities, checklists, procedures, schedules, attitude maneuvers and timelines.

MPSR positions

Flight Dynamics Officer (FDO or FIDO)

Responsible for the flight path of the space shuttle, both atmospheric and orbital. FDO monitored vehicle performance during the powered flight phase and assessed abort modes, calculated orbital maneuvers and resulting trajectories, and monitored vehicle flight profile and energy levels during re-entry.

MPSR positions

External links

Ground Controller (GC)

Directed maintenance and operation activities affecting Mission Control hardware, software and support facilities; coordinated space flight tracking and data network, and Tracking and Data Relay Satellite system with Goddard Space Flight Center.

Guidance, Navigation, and Controls Systems Engineer (GNC)

Monitored all shuttle guidance, navigation and control systems.

MPSR positions

Instrumentation and Communications Officer (INCO)

Responsible for all data, voice and video communications systems, including monitoring the configuration of in-flight communications and instrumentation systems. Duties also included monitoring the telemetry link between the vehicle and the ground, and overseeing the uplink command and control processes. The INCO was the only position that uplinked commands to the orbiter. This position was a direct evolution of the Integrated Communications Officer from the Apollo program.

MPSR positions

Mechanical, Maintenance, Arm, and Crew Systems (MMACS)

Responsible for space shuttle structural and mechanical systems, monitoring auxiliary power units and hydraulic systems, managing payload bay door, external tank umbilical door, vent door, radiator deploy/stow, Ku-band antenna deploy/stow, and payload retention latch operations, landing gear/deceleration systems (landing gear deploy, tires, brakes/antiskid, and drag chute deploy), and monitoring the orbiter docking system. MMACS also followed use of onboard crew hardware and in-flight equipment maintenance. This represented another portion of the job formerly done by EECOM, with additional responsibilities added by the specific requirements of space shuttle operations. The MMACS officer served as the point of contact for PDRS, Booster, and EVA during periods in a mission when these positions did not require constant staffing.

MPSR positions

Payload Deployment and Retrieval System (PDRS)

Responsible for space shuttle remote manipulator system, also known as the Remote Manipulator System (RMS) or "robot arm".

Propulsion Engineer (PROP)

Managed the reaction control thrusters and orbital maneuvering engines during all phases of flight, monitored fuel usage and propellant tank status, and calculated optimal sequences for thruster firings.

Rendezvous (RNDZ)

Responsible for activities such as trajectory operations related to the rendezvous and docking/capture with another spacecraft, including Mir, the ISS, and satellites such as the Hubble Space Telescope.

Trajectory Officer (TRAJ)

Assisted the FDO during time-critical operations, responsible for maintaining the various processors that helped determine the shuttle's current and potential trajectories. A FDO was certified as a TRAJ first. Shares the FCR with FDO.

Transoceanic Abort Landing Communicator (TALCOM)

One of the few members of Shuttle Mission Control not physically present in Houston. If an emergency had occurred, such as loss of one or more main engine during a Space Shuttle launch, requiring the shuttle to land at one of the contingency landing sites in Africa, Europe or the Middle East, TALCOM would have assumed the role of CAPCOM providing communications with astronauts aboard the crippled orbiter. Like CAPCOM, the TALCOM role was filled by an astronaut. Three astronauts were deployed to the alternate landing sites in Zaragoza Air Base and Moron Air Base in Spain, and Istres Air Base in France. These astronauts flew aboard weather reconnaissance aircraft to provide support at the selected landing site.[4]

ISS flight control positions to 2010

The International Space Station flight control positions used by NASA in Houston are different from those used by previous NASA programs. These differences exist primarily to stem the potential confusion that might otherwise follow from conflicting use of the same name in two different rooms during the same operations, such as when the space shuttle was conducting mated operations with the space station. There are also differences in the control positions because of differences in the operation of the two. The following is a list of those flight controllers located in Mission Control Center - Houston. There are several other control centers which house dozens of other flight controllers that support the vastly complex vehicle.

Positions formerly used but eliminated or modified:

Starting in 2001, the ISS flight control room has consolidated six of the below positions into just two, to reduce staffing during low-activity periods. This concept is known as Gemini. After Assembly complete, the Gemini concept was eliminated in the realignment of the core ISS flight control positions.

Attitude Determination and Control Officer (ADCO)

Works in partnership with Russian controllers to determine and manage the station’s orientation, controlled by the onboard Motion Control Systems. This position also plans and calculates future orientations and maneuvers for the station and is responsible for docking the ISS with other vehicles.

MPSR positions

Biomedical Engineer (BME)

The BME monitors health-related station systems and Crew Health Care Systems (CHeCS) equipment. The BME provides technical and operational support for CHeCS and all other medical operations activities. Along with the SURGEON, the BME serves as a Medical Operations Branch representative to the USOS Flight Control Team.

Communication and Tracking Officer (CATO)

Responsible for management and operations of the U.S. communication systems, including audio, video, telemetry and commanding systems.

Environmental Control and Life Support System (ECLSS)

Responsible for the assembly and operation of systems related to atmosphere control and supply, atmosphere revitalization, cabin air temperature and humidity control, circulation, fire detection and suppression, water collection and processing and crew hygiene equipment, among other areas.

Extravehicular Activity Officer (EVA)

Responsible for all spacesuit and spacewalking-related tasks, equipment and plans when the EVA takes place from the ISS.

Inventory and Stowage Officer (ISO)

Responsible for the daily tracking and inventory of all US cargo on the ISS. ISO is the integrator for all cargo that is delivered to and from the ISS for ATV, HTV, Dragon, and Cygnus vehicles.

Integration Systems Engineer (ISE)

A specialist position, the ISE is the systems liaison between ISS and visiting vehicles that are berthed to the US side of ISS. The ISE flight control is responsible for the safety of the ISS such that the visiting vehicle can safely approach, berth, and integrate with the ISS. This includes HTV, Dragon, Cygnus, and even special missions like the deployment of Bigelow Expandable Activity Module (BEAM). ISE works closely with VVO.

Onboard Data Interfaces and Networks (ODIN)

The Onboard Data Interfaces and Networks (ODIN) is responsible for the Command and Data Handling (C&DH) system, the Portable Computer System (PCS) computers, the Caution & Warning (C&W) system, overall responsibility for commanding, and interfaces with International Partner avionics systems. The C&DH system consists of the Multiplexer/DeMultiplexers (MDMs) which are the ISS computers. Core software in each MDM (not User Application Software), the MIL-STD-1553 data busses, Automated Payload Switches (APSs), fiber optic network, Payload Ethernet Hub Gateway (PEHG), and the Ethernet network. This does not include the Ops LAN, Station Support Computers (SSC), or file server.

MPSR positions

Operations Planner (OPSPLAN)

Leads the coordination, development and maintenance of the station's short-term plan, including crew and ground activities. The plan includes the production and uplink of the onboard station plan and the coordination and maintenance of the onboard inventory and stowage listings.

MPSR positions

Operations Support Officer (OSO)

Charged with those logistics support functions that address on-orbit maintenance, support data and documentation, logistics information systems, maintenance data collection and maintenance analysis. The OSO is also responsible for mechanical systems—such as those used to attach new modules or truss sections to the vehicle during assembly.

Plug-in Port Utilization Officer (PLUTO)

The name PLUTO is inherited from the flight controller's original role, which was to maintain and coordinate changes to the U.S. segment of the electrical Plug-in Plan (PiP). The PiP is the tracking of portable electronic equipment, making sure equipment connected is compatible and does not violate constraints, and will not overdraw the power source. Along with this, PLUTO is responsible for maintaining the OPSLAN (Operations Local Area Network) and the JSL (Joint Station LAN). PLUTO has remote desktop administration and monitoring capability to the network from the ground. The PLUTO is also responsible for certain Station Developmental Test Objectives, or SDTOs during the mission. This includes programming the Wireless Instrumentation System (WIS) and also remote desktop commanding for ROBONAUT activities.

MPSR Position

Power, Heating, Articulation, Lighting Control Officer (PHALCON)

Manages the power generation, storage, and power distribution capabilities.

Remote Interface Officer (RIO)

Formerly known as the Russian Interface Officer. Responsible for integrating operations between MCC-Houston (MCC-H) and the other International Partner (IP) Control Centers. RIO is a FCR-1 position in MCC-Houston and works closely in conjunction with the Houston Support Group (HSG) teams located at the IP Control Centers:

Robotics Operations Systems Officer (ROBO)

Responsible for the operations of the Canadian Mobile Servicing System, which includes a mobile base system, station robotic arm, station robotic hand or special purpose dexterous manipulator. (Call sign: ROBO) represents a joint Canadian Space Agency-NASA team of specialists to plan and execute robotic operations.

Thermal Operations and Resources (THOR)

Responsible for the assembly and operation of multiple station subsystems which collect, distribute, and reject waste heat from critical equipment and payloads.

Trajectory Operations Officer (TOPO)

Responsible for the station trajectory. The TOPO works in partnership with Russian controllers, ADCO, and the U.S. Space Command to maintain data regarding the station's orbital position. TOPO plans all station orbital maneuvers.

Visiting Vehicle Officer (VVO)

A specialist position, the VVO is the guidance and navigation liaison between the ISS and "visiting vehicles" such as Progress, Soyuz or Dragon.

ISS Flight Control positions 2010 - Present

After Assembly complete in 2010, the core ISS flight control positions where realigned, and the Gemini manning concept eliminated. The new core positions are:

Attitude Determination and Control Officer (ADCO)

Remains unchanged.

Communications RF Onboard Networks Utilization Specialist (CRONUS)

This is a combination of the previous ODIN and CATO positions.

Environmental and Thermal Operating Systems (ETHOS)

This consists of the ECLSS system responsibilities as well as the internal thermal control systems from THOR.

Station Power, ARticulation, Thermal, and ANalysis (SPARTAN)

This consists of the electrical power (old PHALCON) and external thermal control systems from THOR.

The other specialty positions remain the same.

MPSR position - SPOC

Operations Support Officer (OSO)

Supports internal On-Orbit Maintenance tasks for both the preventive maintenance schedule and contingency/unplanned maintenance due to failures. The OSO position is also responsible for mechanical systems such as the Common Berthing Mechanism (CBM) used to attach new modules or visiting vehicles.[5][6]

MPSR position - OSO Support

See also

Space Centers and Mission Control Centers

Current and former NASA human space flight programs

Former NASA Flight Controllers


  1. http://spaceflight.nasa.gov/shuttle/reference/mcc/index.html
  2. http://www.honeysucklecreek.net/msfn_missions/Apollo_13_mission/hl_apollo13.html
  3. Navias, Rob. "FLIGHT CONTROL OF STS-69". Johnson Space Center. Archived from the original on 18 March 2010. Retrieved 17 August 2013. Booster Systems Engineer (BOOSTER) Monitors main engine and solid rocket booster performance during ascent phase
  4. "Space Shuttle Transoceanic Abort Landing (TAL) Sites" (PDF). National Aeronautics and Space Administration. December 2006. Retrieved 2009-07-01.
  5. https://www.nasa.gov/sites/default/files/files/Dan_Perri_MOD_DX_OSO_In_Space_Inspection.pdf
  6. http://www.tested.com/science/543050-dissecting-technology-martian-solving-problems-space/


External links

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