Space shuttle solid rocket booster recovery subsystem

The studies, the development, and the testing program that led to the design and delivery of all flight hardware are described. Special emphasis was placed on the recovery parachutes. The parachutes were designed to deploy in a severe environment and safely lower to Earth an 85 ton rocket motor casing

Bad news from a forecasting model of the U.S. economy

This paper describes and analyzes the 1990-92 economic forecasts of a Bayesian vector autoregression model developed by researchers at the Minneapolis Fed. The model's 1990 forecast was pretty bad - too optimistic about both inflation and economic growth, especially growth in consumption and housing. An analysis of the model's errors, however, turns up no reason to think the model is unsound. Based on data available on November 30, 1990, the model predicts weak economic conditions for the next two years: a likely recession in 1991 and moderate inflation and weak overall growth in 1991-92. The paper includes a technical appendix that describes how to statistically compare the accuracy of two sets of forecasts.Forecasting

Revisionist history: how data revisions distort economic policy research

This article describes how and why official U.S. estimates of the growth in real economic output and inflation are revised over time, demonstrates how big those revisions tend to be, and evaluates whether the revisions matter for researchers trying to understand the economy’s performance and the contemporaneous reactions of policymakers. The conclusion may seem obvious, but it is a point ignored by most researchers: To have a good chance of understanding how policymakers make their decisions, researchers must use not the final data available, but the data available initially, when the policy decisions are actually made.Economic policy

The U.S. economy in 1990 and 1991: continued expansion likely

This paper reports an optimistic forecast of U.S. output and inflation trends in 1990_91. Generated by a Bayesian vector autoregression (BVAR) model of the U.S. economy using data available on November 30, 1989, the forecast is more optimistic than a consensus forecast. The key to the model's greater optimism for real growth is its outlook for strong consumer spending. The model's optimism is defended by examining historical precedents as well as comparing the track records of the model and consensus forecasts. The model's measures of forecast uncertainty, however, suggest that its predictions should be taken cautiously. An appendix explains how the model can be used to generate conditional forecasts.Economic conditions - United States ; Forecasting ; Business forecasting

A bleak outlook for the U.S. economy

Economic activity in the United States has been growing more slowly than average for the past three years, and it is not likely to speed up soon. The slow growth has been due primarily to pessimism among consumers about their long-run personal income. That pessimism—and its extension to the U.S. economy as a whole—is confirmed by data on real estate prices and labor force participation and by the 1992–93 forecast of a Bayesian vector autoregression model.Business forecasting

Why no crunch from the crash?

Stock - Prices ; Stock market

Learning to be unpredictable : an experimental study.

This study tests experimentally whether the ability of subjects to play a noncooperative game's mixed-strategy equilibrium (to make their play unpredictable) is affected by how much information subjects have about the structure of the game. Subjects played the mixed-strategy equilibrium when they had all the information about other players' payoffs and actions, but not otherwise. Previous research has shown that players of a game can play a mixed-strategy equilibrium if they observe the actions of all players and use sophisticated Bayesian learning to infer the likely payoffs to other players. The result of this study suggests that the subjects in our experiments did not use sophisticated Bayesian learning. The result also suggests that economists should be careful about assuming in their models that people can easily infer everyone else's payoffs.Game theory

Structural and mechanical design challenges of space shuttle solid rocket boosters separation and recovery subsystems

The design of the space shuttle solid rocket booster (SRB) subsystems for reuse posed some unique and challenging design considerations. The separation of the SRBs from the cluster (orbiter and external tank) at 150,000 ft when the orbiter engines are running at full thrust meant the two SRBs had to have positive separation forces pushing them away. At the same instant, the large attachments that had reacted launch loads of 7.5 million pounds thrust had to be servered. These design considerations dictated the design requirements for the pyrotechnics and separation rocket motors. The recovery and reuse of the two SRBs meant they had to be safely lowered to the ocean, remain afloat, and be owed back to shore. In general, both the pyrotechnic and recovery subsystems have met or exceeded design requirements. In twelve vehicles, there has only been one instance where the pyrotechnic system has failed to function properly

Are economic forecasts rational?

This paper discusses at an undergraduate level how forecast rationality can be tested. It explains that forecasters should correctly use any relevant information they knew in making their predictions. It shows that forecast rationality can be tested by determining whether the forecasters' prediction errors are predictable. After addressing what data and methods can be used for testing rationality, the paper presents tests of the price-forecast rationality of individual professional forecasters. Unlike results of previous studies, the test results show that those forecasters' price predictions appear to be rational.Forecasting ; Rational expectations (Economic theory)

The U.S. economy in 1989 and 1990: walking a fine line

Economic policy ; Forecasting