Program Systems Engineering Overview

Key Functions

  • Mission Objectives
  • Concept of Operations Development
  • Mission Architecture and Design Development
  • Requirements Identification and Management
  • Verification & Validation
  • Risk Management
  • Resource Budgets and Error Allocation
  • Technical Authority
  • Image Navigation and Registration
  • Modeling & Simulation
  • Trade Studies

GOES-R Program Systems Engineering (PSE) serves as the integrator between the ground segment and the space segment, ensuring that all development activities (including spacecraft, instruments, launch services, ground systems, antennas and products) are sufficiently integrated to ensure mission success.

Key Functions

Mission Objectives:

Users’ requirements and program constraints, appropriate to the mission are captured in the GOES-R Series Level I Requirements Document (LIRD) . PSE is responsible for translating the Level I user requirements into Level II mission requirements. Level II mission requirements include the top-level system requirements for the end-to-end GOES-R Series system. The Level II mission requirements that form the validation basis for the overall mission requirements are documented in the GOES-R Series Mission Requirements Document (MRD) .

All requirements are tracked to ensure they satisfy user needs and mission objectives and facilitate verification. PSE assesses the impacts of changes to requirements to ensure they do not affect the system’s ability to achieve overall mission objectives. The LIRD and the MRD document the full set of the technical performance requirements for the GOES-R Series. The delivery of key performance parameters from the on-board primary instrument observations to end users reflects the primary mission.

CONOPS Development:

The Concept of Operations (CONOPS) provides a general framework of how the GOES-R Series operates. The CONOPS was developed by the GOES-R program and coordinated with NOAA and NASA operational groups. PSE will maintain and update the CONOPS throughout the lifetime of the program.

Simplified System Architecture
GOES-R basic functional architecture

Mission Architecture and Design Development:

Program Systems Engineering oversees flight and ground system architecture design and development efforts to ensure that there is consistency across the program with mission requirements. GOES-R Series basic functional architecture is shown in the illustration to the right.

Requirements Identification and Management:

Requirements Management is described in detail in the GOES-R Series Systems Engineering Management Plan (SEMP). Requirements for the GOES-R Series Program have been separated into two distinct groups: programmatic and technical. Requirements are organized in a hierarchy with different requirement levels corresponding to levels of detail. This ensures that mission functional and performance requirements and program/project control requirements are managed comprehensively. GOES-R Series requirements are broken into levels:

Level I Level II Level III
Mission requirements are provided by NOAA users and stakeholders such as the National Weather Service, data centers, etc., to NOAA NESDIS and are documented in the GOES-R series Level I Requirements Document (LIRD) Program Control (Level II) requirements are provided by NOAA to the GOES-R Program and are documented in the GOES-R series Management Control Plan (MCP). Project Control (Level III) requirements are the GOES-R Flight Project and GOES-R Ground Segment Project respective project plans.
  System (Level IIA) requirements are provided by GPO to Flight and Ground Segment Projects and are documented in the Mission Requirements Document (MRD) and System Interface Requirements Documents (IRDs). Segment/Elements (Level IIIA) requirements define the subsystems that meet the system (Level IIA) technical requirements and the interactions between those subsystems.

Program Systems Engineering is responsible for requirements management and maintenance at a system level (Levels 1 and 2/2a) and the projects’ respective systems engineering leads are responsible at project (Level III, IV etc.) and below.

Verification and Validation:

Verification and validation (V&V) is an integral part of GOES-R Series Program Systems Engineering. PSE developed a GOES-R Series Program V&V Plan, which documents the test and evaluation approach and structure for system level V&V. The program V&V Plan outlines overall V&V planning, execution, and management. This plan is consistent with the GOES-R Series Program Systems Engineering Management Plan (SEMP) and supports the achievement of GOES-R Series system acceptance and handover to NOAA. PSE provides management and technical oversight of the overall GOES-R series V&V activities. This is done primarily through its role as chair of the GOES-R Integration, Verification, and Validation Working Group (GIVVWG), which includes membership from the flight and ground segment projects. PSE maintains insight into each project’s development and V&V activities to ensure system verification and validation is complete.

Risk Management:

Risk management is a continuous process developed to identify, track, and mitigate any potential risks to the GOES-R Series Program, ensuring mission success. The risk management process of the program will operate throughout the GOES-R Series mission lifecycle. Risk management encompasses risks posed to the entire program, including (but not limited to) technical and operational risks, program management risks, organizational risks, and external risks, such as legal or environmental.

The GOES-R Series Program risk management process utilizes rating scales for several risk attributes. The impact of a risk event can be to cost, schedule and/or technical performance simultaneously. For any risk, it is the impact with the most severe rating that is used to determine the risk exposure. A 5-level method is used for evaluating attributes. Risk attributes of likelihood, consequence, and timeframe are initially estimated and entered at the same time the risk is identified and documented.

Risk Assessment

Step Action
1 Evaluate to determine if there is a valid risk related to issue, concern, or problem identified. A risk is deemed valid if it truly represents a credible condition with some level of uncertainty having an impact on the program.
2 Risk attributes (impact, probability, timeframe, and expected value) are assigned using qualitative assessment.
3 Risk attributes are entered into the risk database.
4 Risk attributes are reviewed and corrected periodically by the risk management coordinator and the Risk Management Board (RMB).
5 Candidate or proposed risks are validated, assigned a risk ID, and prioritized in their respective areas by the GOES-R Series System Program Director, Project Manager, and the RMB.
6 Top significant risks are further evaluated using quantitative analysis, as needed.

Details of the process are documented in the GOES-R Series Risk Management Plan.

For more information see the GOES-R Series Program Risk Ranking Document.

Resource Budgets and Error Allocation:

Program Systems Engineering identified system-level metrics to monitor and track. Each Project Systems Engineering Lead is responsible for identifying and managing the mission resources allocated for their respective segment. Additionally, the Project Systems Engineering Lead defines acceptable resource margins and establishes a margin management philosophy based on various stages of the mission lifecycle. As the system architecture matures, the precision of the resource estimates will improve, as will the method of estimating the resource requirements. Resource margins shall be met in accordance with the Goddard Standard 1000 document.

Technical Authority:

The technical authority (TA) process for the GOES-R Series Program is defined in the Management Control Plan, Section 4.3. The technical authority process allows the designated TA to elevate a technical disagreements having significant impact on the GOES-R series Program or projects to the appropriate level of technical oversight.

Image Navigation and Registration:

The flight project has overall responsibility for the performance of Image Navigation and Registration (INR). The ground segment project is responsible for implementing flight-defined INR ground processing functions, including algorithms, operations, and sustainment. Program Systems Engineering provides oversight and coordination of the combined flight and ground segment efforts. The Mission Operations Support Team (MOST) developed plans for overall validation of INR.

Modeling and Simulation:

Program Systems Engineering leads the development, coordination, implementation, and execution of integrated models and simulations that span across program elements from space-borne instrument sensing to the creation of meteorological end products. The integrated models are commonly referred to as photons/particles-to-products (P2P) models. The P2P models and simulations are used to develop data as a basis for making program level managerial and/or technical decisions in the areas of system requirement deviation/waiver disposition, cost/benefit analyses, and predicted system performance monitoring.

Trade Studies:

Trade studies aid the program in making complex decisions with multiple options by evaluating each option against a set of engineering, performance, cost, schedule, support, and risk criteria. Trade studies can be performed at all levels of the GOES-R mission depending on need. PSE is responsible for coordinating trade studies across the different program segments.