ucimlr: UCI Machine Learning Repository

#' Challenger USA Space Shuttle O-Rings
#'
#' Edited from (Draper, 1993): The motivation for collecting this database was
#' the explosion of the USA Space Shuttle Challenger on 28 January, 1986. An
#' investigation ensued into the reliability of the shuttle's propulsion system.
#' The explosion was eventually traced to the failure of one of the three field
#' joints on one of the two solid booster rockets.  Each of these six field
#' joints includes two O-rings, designated as primary and secondary, which
#' fail when phenomena called erosion and blowby both occur. The night before
#' the launch a decision had to be made regarding launch safety. The discussion
#' among engineers and managers leading to this decision included concern that
#' the probability of failure of the O-rings depended on the temperature t at
#' launch, which was forecase to be 31 degrees F. There are strong engineering
#' reasons based on the composition of O-rings to support the judgment that
#' failure probability may rise monotonically as temperature drops. One other
#' variable, the pressure s at which safety testing for field join leaks
#' was performed, was available, but its relevance to the failure process
#' was unclear. Draper's paper includes a menacing figure graphing the number
#' of field joints experiencing stress vs. liftoff temperature for the 23
#' shuttle flights previous to the Challenger disaster.  No previous liftoff
#' temperature was under 53 degrees F.  Although tremendous extrapolation
#' must be done from the given data to assess risk at 31 degrees F, it
#' is obvious even to the layman "to foresee the unacceptably high risk
#' created by launching at 31 degrees F."  For more information, see Draper
#' (1993) or the other previous analyses. The task is to predict the number of
#' O-rings that will experience thermal distress for a given flight when the
#' launch temperature is below freezing.

#'
#' @format A list containing 2 data frames with 23 observations on the following 5 variables.
#' \enumerate{
#'   \item o_rings_at_risk: Number of O-rings at risk on a given flight
#'   \item thermal_distress: Number experiencing thermal distress
#'   \item launch_temp: Launch temperature (degrees F)
#'   \item leak_check_pressure: Leak-check pressure (psi)
#'   \item temporal_order_of_flight: Temporal order of flight
#' }
#'
#' @details
#' Predict the number of O-rings that experience thermal distress on a flight
#' at 31 degrees F given data on the previous 23 shuttle flights.
#'
#' There are two databases: (both use the same set of 5 attributes)
#' \enumerate{
#'   \item Primary o-ring erosion and/or blowby
#'   \item Primary o-ring erosion only
#' }
#'
#' The two databases are identical except for the 2nd attribute of the 21st
#' instance (confirmed by David Draper on 8/5/93).
#'
#' @references
#' Draper,~D. (1993).  Assessment and propagation of model uncertainty.
#' In Proceedings of the Fourth International Workshop on Artificial
#' Intelligence and Statistics (pp. 497--509).  Ft. Lauderdale, FL:
#' Unpublished.
#' \itemize{
#' \item Discrete model uncertainty analysis
#'
#' \item Analysis suggests that obvious different extrapolations of the
#' data exist at 31 degrees Fahrenheit (i.e., freezing), which sharply
#' discredits the assumption of no temperature effect.
#' }
#'
#' Dalal,~S.~R., Fowlkes,~E.~B., & Hoadley, ~B. (1989). Risk analysis of
#' the space shuttle: pre-Challenger prediction of failure. Journal
#' of the American Statisticians Association,  84, 945--957.
#'
#' Lavine, ~M. (1991). Problems in extrapolation illustrated with space
#' shuttle O-ring data. Journal of the American Statisticians
#'   Association,  86, 919--922.
#'
#' Martz~H. ~F., & Zimmer,~W.~J. (1992). The risk of catastrophic failure
#' of the solid rocket boosters on the space shuttle. American
#' Statistics, 46, 42--47.
#'
#' \url{https://archive.ics.uci.edu/ml/machine-learning-databases/space-shuttle/}
#'
#' \url{https://archive.ics.uci.edu/ml/datasets/Challenger+USA+Space+Shuttle+O-Ring}
#'
#' @source
#' \itemize{
#'   \item David Draper (draper@math.ucla.edu) University of California, Los Angeles
#'   \item Donor: David Draper (draper@math.ucla.edu)
#'   \item Date: 5 August 1993
#' }
"challenger"