1. Weather Delays on Space Launch Operations and Impact on Launch Site Capacity
Michael W. Maier
Space Traffic Management Conference
Embry Riddle Aeronautical University
Daytona Beach, Florida
5-6 November 2014

2. Spaceport Effectiveness Factors
“Can I get and keep federal certification and licenses?”
“Can I get and keep affordable insurance?”
Safety
“Can I launch when I want to and where I want to?”
“Will the conditions be acceptable for launch?”
Availability
Reliability
Cost
“Can I afford to operate here?”

3. Spaceport Effectiveness Factors
“Can I get and keep federal certification and licenses?”
“Can I get and keep affordable insurance?”
Safety
“Can I launch when I want to and where I want to?”
“Will the conditions be acceptable for launch?”
Availability
Reliability
Cape Canaveral / KSC1
38% of the workload is added due to launch delays
50% of the launch delays are due to weather
Cost
“Can I afford to operate here?”
11988 – 2014 excluding SLBM

4. Day-of-Launch Reliability Components
Launch Vehicle
Payload
Vehicle Ground Support Equipment
Acceptable Upper Winds
Acceptable Ground Winds
Limited Precipitation Along Flight Path
Acceptable Recovery Conditions
Acceptable Space Weather
No Natural or Triggered Lighting Threat
Acceptable Ceiling and Visibility
Acceptable Off-Spaceport Overpressure
Acceptable Off-Spaceport Dispersion
Acceptable Winds for Impact Limit Lines
Minimum Range Instrumentation
Air Space Clearance
Sea Space Clearance
Space Collision Avoidance
SpaceX

5. Data
Countdown outcomes for all CCAFS / KSC (“Cape”) launches from January 1988 to September 2014.
Excluding sea launches.
N = 680 countdowns (424 eventual launches).
Consider only the period from the start of the Range countdown to end of launch window.
If two or more red conditions occur, red condition at planned T-0 is used.
Start of Range Countdown
Planned T-0
Window Close
Nominally 6 hours
0-4 hours
Red Condition 2
Red Condition 3
Red Condition 1
Scrub Called Here
< Scrub Cause of Record

6. Component Reliability (1998 – 2014)
Launch Vehicle
Payload
Vehicle Ground Support Equipment
Acceptable Upper Winds
Acceptable Ground Winds
Limited Precipitation Along Flight Path
Acceptable Recovery Conditions
Acceptable Space Weather
No Natural or Triggered Lighting Threat
Acceptable Ceiling and Visibility
Acceptable Off-Spaceport Overpressure
Acceptable Off-Spaceport Dispersion
Acceptable Winds for Impact Limit Lines
Minimum Range Instrumentation
Air Space Clearance
Sea Space Clearance
Space Collision Avoidance
0.831
0.957
0.972
0.999
0.979
1.000
0.913
0.997
0.996
0.987
Reliability 1 – (Nf / Nc)

7. Reliability by Requirement Ownership
0.831
0.907
0.913
0.990
0.982
All Weather 0.810
Reliability 1 – (Nf / Nc)
Launch Vehicle, Payload, and Vehicle Ground Support Equipment
Customer Weather Constraints (Upper Winds, Ground Winds, Flight Through Precipitation, Recovery Area Conditions, Space Weather)
Joint Weather Constraints (Natural and Triggered Lightning)
Range Weather Constraints (Ceiling and Visibility, Off-Spaceport Overpressure, Off-Spaceport Dispersion, Winds for Impact Limit Lines)
Range Instrumentation, Air and Sea Clearance, Space Collision Avoidance
Safety
Mission Assurance

8. Reliability Changes Over Time
All
Number of Countdowns
296
238
146
680
Launch Vehicle, Payload, and Vehicle Ground Support Equipment
0.82
0.84
0.85
0.83
Customer Weather Constraints (Upper Winds, Ground Winds, Flight Through Precipitation, Recovery Area Conditions, Space Weather)
0.88
0.92
0.95
0.91
Joint Weather Constraints (Natural and Triggered Lightning)
0.90
Range Weather Constraints (Ceiling and Visibility, Off-Spaceport Overpressure, Off-Spaceport Dispersion, Winds for Impact Limit Lines)
0.99
0.98
Range Instrumentation, Air and Sea Clearance, Space Collision Avoidance

9. Summary
For the Cape, weather is the leading cause of launch delays (129 of 256 scrubs since 1988).
Delayed launches represent 38% of the launch workload.
Reducing weather delays increases launch-on-time performance and spaceport capacity.
Despite significant investments, no improvement in weather delay rate noted since 1988.
Opportunities:
Improve resistance to natural and triggered lightning (59 of 129 weather delays).
Improve in-flight wind load tolerance (29 of 129 weather delays)
Improve ground wind load tolerance (19 of 129 weather delays)
Improved utilization of forecasts to schedule around unacceptable weather