Weather Delays on Space Launch and Recovery Operations

A proliferation of new launch vehicles and non-federal funding for space ventures is setting the stage for a substantial increase in space launch rate. As launch rate increases weather delays become a more important factor in launch and recovery availability and spaceport selection, design, and management. Increasing attention is being paid to the complex trade space between launch and recovery site selection, launch vehicle design, launch and recovery weather commit criteria, spaceport weather observation and forecast capability, and mission risk.

To help inform these analyses and guide future investments this paper reviews the root cause of launch delays at Cape Canaveral AFS and the NASA Kennedy Space Center (CCAFS/KSC) between 1988 and 2013, a unique sample of 779 countdowns leading to 522 launches. Emphasis is on the weather conditions responsible for delays and specifically how the weather impacts have changed over time, between the different expendable and reusable launch systems, and as a function of launch window duration, season, and time of day.

As launch vehicle and spaceport reliability has improved at CCAFS/KSC, weather delay rates have remained largely unchanged but the cause of the weather delays has changed. As expected, there are substantial seasonal and time of day variations which could be given greater considered in mission planning. Likewise, window duration is also a factor in weather delay rate. Weather delays due to winds aloft have become less frequent due to more robust vehicles and trajectory shaping techniques while delays due to ground winds have increased due to lean pad designs. Delays due to natural or triggered lightning continue as the next leading cause of launch delays. Delays due to spaceport safety requirements for debris risk, visibility, blast overpressure, and toxic dispersion have decreased reflecting the rationalization of safety requirements.