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NASA Space Systems Cost Models

For time/processes - see Simulations


The term "model" is used here in the sense of an abstraction, an elaborate thought experiment, where mathematical formulas come together to create a predictive framework for the analysis and understanding of future systems. A model is different than a simulation, with models generally focusing on "what", for example a type of engine or technology, and "how" it is acquired.


Objectives in modeling space systems life cycle costs:

  • Completeness

    • "What"

      • Launch systems vs. in-space, spacecraft costs

    • "When"

      • Development vs. operations costs

    • "Where"

      • Direct vs. indirect costs

    • "Who"

      • Industry (price to the government, procurement costs to the government, for contractor, partner, support contractors, etc.) vs. government costs (NASA civil servants, personnel costs, or other costs for government program / project management, acquisition management, etc.)

  • Understanding Causality

    • What causes a cost (not the same as what comprises a cost)

    • "What" vs. "How" as cost factors - Technical (what, design, technology, characteristics) and non-technical cost contributions (how, acquisition approach, cost-plus or commercial, other transaction authority, process, practices, etc.)

  • Identifying Significance

    • Space systems characteristics and approaches that are drivers for significantly improving affordability and reliability

    • "Why" - Benefits

The current Life Cycle Cost (LCC) model

Older (inactive/archival) cost models:

  • LLEGO (2006-2010): This model emphasized reusable space transportation vehicle design (what) as well as processes (how), together for the first time. With an improved understanding of direct vs. indirect costs, what comprised costs versus what caused costs, LLEGO was  used in support of many NASA studies. One of these was the independent cost analysis of parts of the NASA Constellation program.

  • SFAC (2005): This model, unlike previous efforts, delved into non-recurring facilities and ground support equipment costs. The exercise was especially useful in understanding historical cost data.

  • SAGE (2004): This model was a bottoms-up model (unlike top-down models to date). The exercise was especially useful in understanding  levels of detail appropriate in different decision making phases.

  • AATe (2002-2003): This model added more details to inputs, with an emphasis on supporting decision making when architecting potential space transportation systems. The model was used in many NASA studies addressing the direction for what might follow the Space Shuttle.

  • AAT (1998-2002): This model was a prototype for calculation methods that would be used in future operations cost models for space transportation systems.

  • Vision Spaceport Partnership (1998-2000): This model significantly advanced operations cost modeling methods. A comprehensive set of technical characteristics (inputs), beyond just propulsion, were related to a recurring launch site operations effort and cost (outputs). Also, some programmatic, non-technical characteristics were explored.

  • Launch Operability Index (LOI) tool (1992): This model first used MS Excel to provide a graphic user interface and a calculation method to generate an operability index for propulsion sub-systems. The index was a relative measure of the operability of a propulsion system.

Papers & Presentations:

External Links:

"Zapata’s paper was written in 2009 and the space launch industry has changed considerably since then.  However, his model is definitely still valid for use in analyzing the current state of affairs."


Website Contact: Edgar Zapata, NASA Kennedy Space Center