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.
Historical mass, power, schedule, and cost growth for NASA spacecraft
Although spacecraft developers have been moving towards standardized product lines as the aerospace industry has matured, NASA's continual need to push the cutting edge of science to accomplish unique, challenging missions can still lead to spacecraft resource growth over time. This paper assesses historical mass, power, cost, and schedule growth for multiple NASA spacecraft from the last twenty years and compares to industry reserve guidelines to understand where the guidelines may fall short. Growth is assessed from project start to launch, from the time of the preliminary design review (PDR) to launch and from the time of the critical design review (CDR) to launch. Data is also assessed not just at the spacecraft bus level, but also at the subsystem level wherever possible, to help obtain further insight into possible drivers of growth. Potential recommendations to minimize spacecraft mass, power, cost, and schedule growth for future missions are also discussed.
SeaWinds: the QuikSCAT wind scatterometer
The QuikSCAT wind scatterometer, named SeaWinds, is a scanning, pencil-beam, microwave radar that was designed to measure global ocean surface winds from space. Originally planned for flight aboard the National Space Development Agency of Japan (NASDA) Advanced Earth Observing Satellite II (ADEOS-II) spacecraft, SeaWinds was expected to continue the series of Ku-band scatterometer data initiated by the NASA Scatterometer (NSCAT). Unfortunately, the failure of NSCAT's host spacecraft, ADEOS-I, prematurely ended NSCAT's mission and created a data gap. The QuikSCAT mission was rapidly developed to fill in the data gap between NSCAT on ADEOS-I and SeaWinds on ADEOS-II. A scatterometer nearly identical to SeaWinds was quickly assembled and launched on June 19, 1999 aboard the QuikSCAT spacecraft. In this paper, we describe the QuikSCAT mission, outline the key design features of the SeaWinds scatterometer, and mention some of the current and emerging science applications.