Simple Bayesian estimate of Falcon 9 total failure probability

falcon-failure-estimate.pl

#! /usr/bin/env perl
use strict;
use warnings;

my %observed;
my %failure;
my $total_observed = 0;
my $n = 10000;
for my $i (0..$n) {
  my $x = $i/$n;
  $failure{$x} = probability_of_failure($x);
  my $o = probability_of_observation($x);
  $observed{$x} = $o;
  $total_observed += $o;
}

my $total_failure = 0;
for my $x (keys %observed) {
  $total_failure += $failure{$x} * $observed{$x} / $total_observed;
}

print "Estimated failure rate: $total_failure\n";

sub probability_of_observation {
  my $x = shift;
  return $x**35 * (1-$x) * 36;
}

sub probability_of_failure {
  my $x = shift;
  return 1 - $x**9 - $x**8 * (1-$x) * 9 - $x**7 * (1-$x)**2 * 36;
}