Historical mass, power, schedule, and cost growth for NASA science instruments
In the early stages of NASA instrument development, science instruments are typically the most nascent part of any NASA mission development. As the building of spacecraft become less challenging for a mature industry, NASA's continual need to push the cutting edge of science requires the revolutionary and evolutionary development of instruments to meet science requirements. Instruments then face substantial issues that can result in significant increases in mass, power, cost, and schedule. Although previous studies have identified such issues, there are few industry standard reserve/contingency design and programmatic guidelines for instruments. This paper compares historical mass, power, cost, and schedule growth to industry reserve guidelines while offering potential recommendations to minimize instrument mass, power, cost, and schedule growth for future missions.
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.
Preparation courses for a medical admissions test: effectiveness contrasts with opinion
Objectives  The Undergraduate Medicine and Health Sciences Admissions Test (UMAT) is used to rank applicants for admission to many medical schools. This study aimed to determine the effects of preparation courses on UMAT performance and on students’ perceptions of their performance.