ISS Thermal Control Systems Flight Controllers Curriculum
“Houston, we have a problem.” These infamous words rang out in Johnson Space Center’s Flight Control Room during the Apollo 13 mission. This phrase, spoken by astronaut Jim Lovell, exemplifies the crucial responsibilities of Flight Controllers: to monitor, maintain and correct any problems onboard spacecraft. This curriculum provides the necessary training for an individual to become a Student-Certified Flight Controller or engineer for the thermal control system onboard the International Space Station (ISS). There are three different Flight Controllers or engineers who are highly trained to monitor and maintain the complex thermal control systems onboard the ISS. The Flight Controller is Thermal Operations and Resources (THOR), and the engineers are Active Station Thermal Resources & Operations (ASTRO), and Payload Rack Officer (PRO). Despite the fact that they are all experts on the thermal control systems, and that they often collaborate together on problems, they do work in different Flight Control Rooms (FCRs) and NASA facilities.
Where Do THOR, ASTRO and PRO Flight Controllers Work?
There is separate groups of Flight Controllers and engineers in distinct Flight Control Rooms (FCRs) that are in different NASA facilities, which manage the shuttle, the ISS, and the payloads onboard a spacecraft (see Exhibit 1). While most of the shuttle and ISS Flight Controllers are housed at Johnson Space Center (JSC) in Houston, Texas, the engineers for scientific payloads are housed at Marshall Space Flight Center (MSFC) in Huntsville, Alabama. Both Thermal Flight Controllers THOR and ASTRO work at Johnson Space Center. THOR works in the ISS Mission Control Center’s (MCC) Flight Control Room (often called the “front” room), and ASTRO works in the Mission Evaluation Room (MER) (often called the “back” room). PRO works at Marshall Space Flight Center (MSFC) in the Payloads Operation and Integration Center (POIC).
Exhibit 1. Flight Controller Rooms at Johnson Space Center and Marshall Space Flight Center
What are the Responsibilities of Flight Controllers at MCC?
Since 1998, Flight Controllers have been on duty 24 hours a day, 365 days a year in the Flight Control Room for the ISS. Their task is to keep a constant watch on all the systems onboard the ISS, in order to insure the safety of the crew and station. The Flight Controllers are equipped with some of the most sophisticated communication systems and computer equipment, in order for them to deal with any potential problems onboard the ISS, as quickly and efficiently as possible.
Flight Controllers are responsible for a variety of tasks, ranging from monitoring the ISS trajectory to the onboard station temperatures. In fact, NASA’s ISS Flight Control Room at Mission Control Center is organized into twenty different consoles, each representing ongoing tasks needed to operate the ISS successfully in space. These consoles are managed by highly trained Flight Controllers, who specialize in the specific tasks indicated by their console’s name. The many systems onboard the ISS must work together to keep the station operational. It is important for Flight Controllers to know each other’s responsibilities. Exhibit 2 provides a list of the ISS Flight Controllers who manage the twenty consoles in MCC. Their NASA call signs and a very brief description of their position responsibilities are listed in the table. For more interactive information about the twenty Flight Controllers visit the web site http://www.spaceflight.nasa.gov/shuttle/reference/mcc/index.html.
Exhibit 2. ISS Mission Control Center (MCC)
Flight Controller
|
Call Signs
|
Responsibilities on ISS
|
Flight Director
|
Flight
|
Oversees team of Flight Controllers
|
Communication and Tracking
|
CATO
|
Manages on-orbit communications & telemetry
|
Onboard Data and Information Network
|
ODIN
|
Manages computer hardware & software
|
Environmental Control and Life Support Systems
|
ECLSS
|
Manages cabin air supply, humidity, and temperature, along with other systems that influence the station’s environment
|
Power, Heating, Articulation, Lighting, and Control
|
PHALON
|
Manages the electricity to operate the station and its payloads
|
Attitude Determination and Control
|
ADCO
|
Integrates guidance and navigation for the station using the Motion Control System and manages docking of spacecraft on ISS
|
Thermal Operations and Resources
|
THOR
|
Manages the thermal control system, which regulates the dissipation of waste heat generated by equipment and payloads onboard the ISS
|
Robotics Operations System
|
ROBO
|
Plans and executes robotic operations
|
Extravehicular Activity
|
EVA
|
Responsible for all spacesuits and space walk activities
|
Operation Support Officer
|
OSO
|
Manages all station maintenance activities that includes maintaining the mechanic systems for attachment of modules to the ISS
|
Operation Planner
|
Ops Plan
|
Plans the station’s short-term crew schedules
|
Assembly, Activation & Checkout Officer
|
ACO
|
Responsible for all new assembly for development of station and all checkout procedures
|
Cargo Integration Officer
|
CIO
|
Assists in managing inventory of cargo that includes materials and equipment
|
Trajectory Operations and Procedures Officer
|
TOPO
|
Manages station’s trajectory planning all orbital positions
|
Visiting Vehicle Officer
|
VVO
|
Monitors visiting vehicles’ activities, while docking and undocking at the station
|
Flight Surgeon (SURGEON)/ Biomedical Engineer
|
BME
|
Monitors and manages the health of the crew
|
Ground Control
|
GC
|
Maintains Mission Control Center’s computers and coordinates the telemetry between MCC and the station
|
Spacecraft Communicator
|
CAPCOM
|
The spokesperson for Mission Control Center to the crew on station
|
Public Affairs Officer
|
PAO
|
Responsible to communicate to news media and the public the activities on station
|
Payload Operations director at POIC
|
POD
|
POD oversees the team of Flight Controllers at MSFC, however he is directly responsible to MCC for the payloads onboard station
|
What are the Responsibilities of the Engineers at Mission Evaluation Room (MER)
The engineers in the Mission Evaluation Room are highly skilled and specialized engineers in a given system onboard the ISS. Their main duty is to back up the Flight Controllers in MCC with the details of their systems components, function, and configuration. If a MCC Flight Controller needs information to solve an anomaly, the MER engineer must be able to supply this information on a real time bases, because the safety of the ISS crew and station is dependent on their abilities.
After the Columbia accident, the Mission Evaluation Room (MER), which previously housed both the ISS and shuttle engineers was broken up into two separate rooms. In October 12, 2004, the new shuttle MER room was dedicated allowing the ISS engineers ample room in the old MER.
Who are THOR and ASTRO?
The Flight Controller for the Thermal Control System in MCC is THOR, which stands for Thermal Operations and Resources. THOR is the Flight Controller that is responsible for the operation of the Thermal Control System (TCS) onboard the ISS. The Thermal Control System’s purpose is to maintain an appropriate temperature inside the ISS for both the crew and equipment, by removing waste heat generated by payloads and equipment onboard station. It involves a system of heaters, pumps, pipes, loops, radiators, sensors, valves, computers, Orbital Replaceable Units (ORU), and a lot more that will be discussed later. THOR also is responsible for the Thermal Control System outside the ISS. The TCS outside the ISS maintains temperatures for equipment on the surface of the ISS along with the proper dissipation of heat from the radiators on the surface of the ISS.
The Thermal Control System console in the ISS Mission Evaluation Room (MER) is the Active Station Thermal Resources & Operations or ASTRO console. ASTRO’s counterpart in MCC is THOR. If an anomaly occurs involving the TCS on the ISS, the ASTRO engineer is ready to support THOR with detailed information on the operation of the Active Thermal Control System. There is also a Passive Thermal Control System (PTCS) engineer in MER to help THOR if there is an anomaly with the Passive Thermal Control System onboard the ISS. It is vital that ASTRO knows and understands all the systems on the ISS, not only the TCS, because problems do not occur in isolation. Therefore, ASTRO must be familiar with the other MER consoles, their call signs, and their responsibilities. Exhibit 3 lists MER consoles, call signs, and responsibilities. Exhibit 4 is a list of MCC consoles and their counter parts in MER.
Exhibit 3. ISS Mission Evaluation Room (MER)
Flight Controller
|
Call Signs
|
Responsibilities on ISS
|
MER Manager
|
MER Manager
|
Oversees team of Flight Controllers in MER
|
Command & Data Handling
|
C&DH
|
Manages computer hardware & software
|
Communication and Tracking
|
C&T
|
Manages on-orbit communications & telemetry
|
Configuration Management
|
CM
|
|
Crew Health Care System
|
CHeCS
|
Monitors and manages the health of the crew
|
Mission Evaluation Room Life Support Integration
|
MERLIN
|
Manages cabin air supply, humidity, and temperature, along with other systems that influence the station’s environment
|
Power Hardware, Operations, Electrical Networks, and Illuminating eXperts
|
PHOENIX
|
Manages the electricity to operate the station and its payloads
|
Extravehicular and Crew Systems
|
EV&CS
|
Responsible for spacesuits and all space walk activities
|
Extravehicular Activity
|
EVA
|
Responsible for all spacesuits and space walks activities
|
Extravehicular Robotics
|
EVR
|
Plans and executes robotic operations
|
Flight Crew Systems
|
FCS
|
Manages all station maintenance activities that includes maintaining the mechanic systems for attachment of modules to the ISS, assists in managing cargo inventory, and responsible for assembly and checkout procedures for station
|
Guidance, Navigation & Control
|
GN&C
|
Integrates guidance and navigation for the station using the Motion Control System and manages docking of spacecraft
|
Logistics & Maintenance
|
L&M
|
Manages all station maintenance activities that includes maintaining the mechanic systems for attachment of modules to the ISS, assists in managing cargo inventory, and responsible for assembly and checkout procedures for station
|
MPLM NASA Element Management Officer
|
MNEMO
|
|
Operations Local Area Network
|
Ops LAN
|
|
Propulsion
|
Prop
|
Monitors visiting vehicles’ activities, while docking and undocking at the station
|
Rendezvous, Proximity Ops, and Capture
|
RPOC
|
Monitors visiting vehicles’ activities, while docking and undocking at the station
|
Structures & Maintenance
|
S&M
|
Manages all station maintenance activities that includes maintaining the mechanic systems for attachment of modules to the ISS
|
Safety & Mission Assurance
|
S&MA
|
|
Passive Thermal Control System
|
PTCS
|
Manages the passive thermal control system, which helps to regulate the dissipation of waste heat generated by equipment and payloads
|
Active Station Thermal Resources & Operations
|
ASTRO
|
Manages the active thermal control system, which regulates the dissipation of waste heat generated by equipment and payloads
|
Vehicle Integrated Performance and Resources
|
VIPER
|
Responsible for assembly and checkout procedures for station and assists in managing inventory of cargo that includes materials and equipment
|
Exhibit 4. MCC consoles and their MER counter parts
MCC Console
|
MER Counter Part
|
Flight
|
MER Manager
|
CATO
|
C&T
|
ODIN
|
C&DH
|
ECLSS
|
MERLIN
|
PHALON
|
PHOENIX
|
ADCO
|
GN&C, PROP
|
THOR
|
PTCS, ASTRO
|
ROBO
|
EVR
|
EVA
|
EVA, EV&CS
|
OSO
|
S&M, L&M, FCS
|
Ops Plan
|
No MER counter part
|
ACO
|
VIPER, L&M, FCS
|
CIO
|
VIPER, L&M, FCS, OPSLAN
|
TOPO
|
GN&C
|
VVO
|
GN&C, PROP, RPOC
|
SURGEON (BME)
|
CHeCS
|
GC
|
No MER counter part
|
CAPCOM
|
No MER counter part
|
PAO
|
No MER counter part
|
What Are Payload Operations Integration Center’s (POIC) Responsibilities?
The Payload Operations and Integration Center is located at Marshall Space Flight Center (MSFC) in Huntsville, Alabama. POIC oversees the science experiments that are called payloads onboard the ISS. As the ISS has expanded to three scientific laboratories, so has its payload capacity. At present, there are three fully functional laboratories with the capacity to contain 150 experiments. The US Destiny Laboratory was launched on the Endeavour Shuttle in February 2001. The European-built Columbus Module was launched on the Atlantis Shuttle in February 2008, and the Japanese-built Kibo Experiment Module arrived at the ISS in June 2008 onboard Discovery. All three laboratories contain racks for experiments. The engineers in POIC monitor these experiments and coordinate communications between the scientists on earth and the crew onboard the ISS.
Who is PRO?
There are seven consoles in POIC all of which have to do with managing the racks of scientific experiments in the Destiny Laboratory. These racks make up the payload or shipment of scientific experiments onboard the ISS. They are called ExPRESS racks. The PRO console is manned by the Payload Rack Officer (PRO), who manages the waste heat removal for the ExPRESS racks. ExPRESS racks generate waste heat that must be monitored and managed to prevent overheating that could cause damage to the experiments, crew, and station. If there is a problem on an ExPRESS rack that is affecting the TCS, PRO will coordinate efforts to fix this problem by consulting with THOR at MCC, ASTRO at MER, and the scientists responsible for the experiment on earth.
Since all of the engineers at POIC deal with payloads, they must be knowledgeable about each others’ duties and responsibilities. Exhibit 5 is a list of the POIC engineers, their call signs, and responsibilities. For more information about the engineers at POIC visit the interactive web site at http://www.nasa.gov/mission_pages/station/science/payload_ops.html. For more information about the Destiny Laboratory, Columbus Module, and Kibo Experiment Module with videos of the laboratories visit the web site http://www.nasa.gov/externalflash/lab_racks/labs.html
Exhibit 5. Payload Operations and Integration Center
Flight Controller
|
Call Signs
|
Responsibilities on ISS
|
Payload Operations Director
|
POD
|
Oversees team of Flight Controllers at POIC
|
Operations Controller
|
OC
|
Manages crew work assignments for science experiments
|
Payload Rack Officer
|
PRO
|
Manages the waste heat removal for science experiments
|
Data Manager Coordinator
|
DMC
|
Manages data and videos transmission of science experiments to scientist on earth
|
Payloads Communication Manager
|
PAYCOM
|
Communicates with the crew on ISS
|
Lead Increment Scientist Representative
|
LIS Rep
|
Manages research status of payloads
|
Shuttle Operations Coordinator
|
SOC
|
Manages scientific experiments while they are on shuttle
|
The Thermal Control Systems Onboard the International Space Station
What is the Active Thermal Control System (ATCS)?
The ISS generates large amounts of waste heat during operations. This heat is a byproduct of the operation of equipment and scientific experiments onboard the ISS. Just like on earth, when electrical energy is used to run a machine, waste heat is given off according to the conservation of energy, which obeys the laws of thermodynamics. This waste heat must be rejected into space in order to maintain comfortable temperatures for the crew and prevent overheating of the equipment onboard the ISS. The Internal Active Thermal Control System (IATCS) uses large loops to circulate water within the ISS. These loops collect the waste heat generated by the equipment inside the ISS. The water in the loops collects the waste heat from equipment onboard the ISS. The water in the loops then transport the heat to the External Active Thermal Control System (EATCS), which consists of loops containing 100% anhydrous ammonia located on the exterior of the ISS. The external ammonia loops then reject the heat to outer space from radiators. The system is considered active because it uses mechanical systems to circulate the fluids within the loops. The process is made complicated because fluids and heat behave differently in microgravity environments.
The present ATCS is new to the ISS. It recently became fully functional. It replaced the Early Active Thermal Control System that has been operating until now. With the full ATCS in place the ISS expands its capacity to support 6 astronauts along with a larger number of scientific experiments.
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