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SpaceX NASA Launches to the ISS

Load this example in Data Janitor

SpaceX has its flight manifest directly on their website. The objective is to extract NASA launches to the International Space Station and determine the number of days between those launches.

First step is to copy the data from the SpaceX Manifest web page, and paste it into Data Janitor.

Second step is to write the JavaScript function to transform that data. It is necessary to sort rows by launch date in order to calculate days elapsed. I wrote a special function sortByDate for sorting. It uses Underscore.js's sortBy to do that. The comparator function uses Moment.js's unix function to convert to a timestamp. Notice that only NASA launches are processed.

function sortByDate(list, column, descending) {
  return _.sortBy(list, function(o) {
    return moment(o[column]).unix() * (descending ? -1 : 1);
  });
}
function process(input, columns) {
  input = sortByDate(input, 'LAUNCH DATE');
  var output = [];
  var lastDate;
  input.forEach(function(inRow, r) {
    if (inRow.CUSTOMER.indexOf('NASA RESUPPLY TO ISS') >= 0) {
      var date = moment(inRow['LAUNCH DATE']);
      outRow = {
        Launch: date.format('LL'),
        'Days since last launch': lastDate ? date.diff(lastDate, 'days') : '',
        Customer: inRow['CUSTOMER'],
        Site: inRow['LAUNCH SITE'],
        Vehicle: inRow['VEHICLE']
      };
      lastDate = date;
      output.push(outRow);
    }
  });
  return sortByDate(output, 'Launch', true);
}

And the output. Notice we are missing flight 7. This relates to flight CRS-7, where Falcon disintegrated 139 seconds into flight on June 28 2015. It took another year (360 days) before the next launch.