Robert E. Bitten

Using Historical NASA Cost and Schedule Growth to Set Future Program and Project Reserve Guidelines

By looking at historical schedule and cost growth, the past can be used to established reserve guidelines for future missions. This paper looks at recent NASA cost and schedule growth history, categorizes the reasons for growth, isolates growth due to external programmatic reasons versus internal technical reasons, assesses relationships for causality and provides guidance for the proper cost and schedule reserves to be carried at both the Program and Project levels. Mission cost and schedule growth history from both planetary and Earth-orbiting programs, such as Mars Exploration, Discovery, Medium and Small Explorer, Earth System Science Pathfinder, New Millennium and others, are investigated. The reserve guidelines developed are compared to industry standard guidelines and rules of thumb to determine if these standard practices continue to be valid.

Optimism in early conceptual designs and its effect on cost and schedule growth: An update

This paper updates a previous effort investigating how the evolution of initial concept designs are related to the cost and schedule growth of missions.12 The paper shows examples of the design evolution, and associated cost and schedule growth, for twenty historical NASA missions. Issues behind the cost and schedule growth of missions are varied, but in part may be attributed to systems that have changed substantially from those examined at initial concept through to launch. Historical resource growth is investigated for a variety of missions and mission types to provide guidelines and lessons learned to be used during the initial conceptual design stage for future missions. The data developed for the paper should help both project managers and cost and schedule estimators to develop more robust estimates earlier in the design process.

Explanation of change (EoC) study: Approach and findings

This study investigated thirty historical NASA science missions to explain the cost change experienced. The study included investigation of historical milestone and monthly status report documentation followed by interviews with key project personnel. Based on the information collected, the reasons for cost change were binned, at the highest level, into four separate categories: NASA External, Project External, Internal Planning, and Internal Execution. The results identified that roughly a third of the change is outside of the projects control, a third is due to assumptions made in project planning, and a third is due to the inherent difficulty of building highly complex, one-of-a-kind, cutting edge, Earth and space science missions. The different causes for growth are discussed.

Phase E Cost Analysis for NASA Science Missions

Phase E is the long awaited payoff for the development of NASA science missions as it encompasses both the mission operations to collect the science data required for success as well as the data analysis to turn the data into a final useable product. Phase E growth, however, can be problematic as increased Phase E cost can take funding away from the development of new science missions. There are two kinds of Phase E cost growth: 1) cost growth due to underestimation of Phase E cost and 2) cost growth due to extension of mission life for additional science. A recent study examined 20 NASA science missions and showed that Phase E lifecycle cost (LCC) growth, as planned from Phase B start to launch, on average exceeded 30%. The research for this paper has extended that study with expanded data collection and analysis and also addressed the actual Phase E cost as compared to LCC estimates. This additional research has found within the 20 missions LCC growth to be on average 49% to the end of mission life. The 20 mission data set also was examined for trends during the operational phase based on mission characteristics such as: Directed versus Competed acquisition, Earth orbiting versus Planetary, and number of instruments. Competed missions, Planetary missions, and missions with more than 5 instruments demonstrated the highest cost growth in Phase E. Data from an additional 26 missions was also collected to perform an expanded analysis of actual operations cost for trends based on science theme, mission class and cost per instrument. Larger missions were found to have a greater annual Phase E cost as well as greater cost per instrument. Heliophysics missions were found to have lower annual mission and per instrument cost than any other science theme. Astrophysics missions were found to have the highest per instrument cost of all science themes. Planetary missions were found to have lower cost per instrument than Astrophysics and Earth Science missions but higher annual costs due to a larger number of instruments. A rule of thumb was also derived that showed flagship mission annual operating costs are generally two to three times higher than non-flagship missions. Finally, a rough order of magnitude cost estimating relationship was derived using the 46 mission data set to provide some ability to estimate the annual Phase E cost given mission class, science theme and the number of instruments on a mission.

The need for an instrument first, spacecraft second mission development approach

NASA science instruments have had a history of developmental delays. These development delays can lead to cost growth for the overall mission, as shown in recent studies of NASA missions and a larger historical data set. There are examples of historical missions, such as QuikSCAT and QuikTOMS, that have had shorter development times and less than historical average cost and schedule growth, which had instruments that were largely developed prior to the start of mission development. This implies that a similar approach, labeled instrument first, spacecraft second (IFSS), could provide reduced cost and schedule growth in future missions. This paper discusses the supporting data for such an approach.

Quantitative approach to independent schedule estimates of NASA Science Missions

This paper examines a multi-level quantitative schedule analysis and estimating approach similar to one that is used when evaluating proposal costs, and cost risks. The Aerospace Corporation has developed a process for performing independent schedule estimates (ISE), which utilizes an analogy-based schedule assessment methodology, permitting greater insight into mission development times. The authors have used this tool in many proposal evaluations and independent assessments when estimating planetary and earth-orbiting mission schedules. Specific examples of how this tool has been used to evaluate overall development time and interim development milestone plans will be presented. Additionally, data will be shown for a past application of this tool in evaluating the schedule risk of a mission, and how the data compares to schedule reserves guidelines. This paper illustrates the progression in schedule estimating, and the importance of equal treatment as a programmatic discipline on par with cost estimating.

Instrument schedule delays: Potential impact on mission development cost for recent NASA projects

NASA space-borne instruments, while trying to pursue world class science, have had a history of developmental delays. These development delays can lead to cost growth for the overall mission, as shown in recent studies of NASA missions and a larger historical data set. An analysis was conducted to assess if a new mission development process, labeled instrument first, spacecraft second (IFSS), could provide reduced cost and schedule growth in future missions by minimizing the impact of instrument development issues on mission development. A cost and schedule analysis was conducted for representative Tier 2 and Tier 3 Earth Science Decadal Survey missions to quantify the benefits. The results indicate that the savings resulting from such an approach is on the order of

Instrument first, spacecraft second (IFSS): A new paradigm in space mission development

2.5B, making more funding available for future missions, while providing a less volatile and more manageable mission portfolio.

Affordability assessments to support strategic planning and decisions at NASA

An analysis was conducted to determine potential benefits of initiating instrument development prior to full mission development for NASA Earth Science missions. A cost and schedule analysis was conducted for representative Tier 2 and Tier 3 Earth Science Decadal Survey missions to quantify the benefits. The results indicate that the savings resulting from such an approach is on the order of

An independent cost and schedule estimate process for NASA science projects

2B, making more funding available for future missions, while providing a less volatile and more manageable mission portfolio.