Nov 2

Nov 2 The Future of Launch Weather Operations

Members of the 45th Weather Squadron launching a Jimsphere (Courtesy of NASA)

“Commander William Adama: Good Morning Starbuck, what do you hear?
Lieutenant Kara “Starbuck” Thrace: Nothing but the rain.”

— Battlestar Galactica (miniseries, 2003 edition)

With SpaceX proving that reusable rockets are not only possible but also economically feasible, the Outer Space launch industry is undergoing a seismic shift. This tectonic change means that launch operations no longer ends with the rocket escaping Earth’s gravity: launch personnel might also need to ensure that certain rocket components successfully land back on Earth right after launch.

With reusability and other technological advancements lowering the cost of rockets, many new private launch operators are springing up. The rise of this multitude of launch-oriented companies is greatly impacting the duties of launch weather officers. These governmental personnel work with rocket companies to ensure successful launch operations by analyzing weather data and making go and no-go launch decisions based on safety criteria checklists. These checklists, more commonly known as “Launch Commit Criteria” or “Launch Weather Criteria,” are generally rocket-specific and developed in concert with technical data and lessons learned from past launches.

In this post, I will look at how evolutions in the launch industry are necessitating a transformation of Outer Space launch weather operations. I will start by examining the history behind Launch Commit Criteria/Launch Weather Criteria and the personnel responsible for such operations in the United States. Then, I will walkthrough a few examples of these rocket-specific criteria. With this background, I will then discuss how the current paradigm shift in the rocket industry is challenging the existing launch weather infrastructure. Finally, I will end with a policy recommendation: the creation of a joint launch weather committee made up of members of the Space Force and private launch operators which will aid in adapting our weather operations for success in this new launch era.

The Origins of the Launch Commit Criteria and the Weather Vanguards

John T. Madura, a NASA meteorologist, is credited with establishing the modern-day Launch Commit Criteria (“LCC’). These LCCs were developed after the Atlas/Centaur (AC)-67 mishap in March 1987 when the rocket broke up during its launch. The investigation board found that, because of misinterpreted and inadequate launch criteria for lightning, the vehicle triggered a cloud-to-ground lightning strike that resulted in the complete loss of the rocket and the accompanying Department of Defense payload.

After this incident, Madura established a working group comprised of experts on lightning science to formulate a new set of “go for launch” metrics, which became the first instance of today’s LCCs. Since then, these LCCs have evolved into a comprehensive checklist that not only consider lightning strike probabilities but also the impact of other weather conditions as well. Some of these criteria were developed as a direct result of fatal launch tragedies that NASA had experienced. For instance, the Challenge disaster led to certain non-waivable no-launch conditions related to temperature as well as wind speed.

With LCCs at the heart of all launch weather operations, Madura also developed an extensive training program for weather officers to accurately analyze launch conditions. Over time, these LCCs have become highly successful and widely implemented by NASA, the Air Force, the Space Force, and the Federal Aviation Administration in capturing the environmental constraints of a launch vehicle in ensuring its safe launch and landing operations.

Nowadays, in support of most domestic launch activities, there are two United States Space Force weather squadrons that are dedicated to enforcing these LCCs or Launch Weather Criteria (“LWCs”): the 30th Weather Squadron and the 45th Weather Squadron. These squadrons were only recently realigned to the newly created United States Space Force, so pretty much all of its officers and enlisted personnel were trained by and grew up with the United States Air Force.

Located at Vandenberg Air Force Base, the 30th Weather Squadron is a part of the 30th Space Wing of the United States Space Force. Originally formed around the conclusion of World War II, the 30th is responsible for weather surveillance for west coast launches. In 2020, it has supported and will assist with several more launches including the maiden flight of Firefly Alpha, United Launch Alliance’s Delta IV Heavy, and several SpaceX’s Falcon 9s.

Meanwhile the 45th Weather Squadron is located at Patrick Space Force Base in Florida and is responsible for east coast launches. Its mission is to “exploit the weather to assure safe access to air and space.” In 2020, it has assisted with and will support several launches by SpaceX (both Falcon 9 and Falcon Heavy) and United Launch Alliance (both Atlas V and Delta IV Heavy).

Instruments for Launch-related Weather Data

The launch weather team uses a myriad of instruments to gather the data needed for LWC analysis. For instance, some of the tools, networks, and systems used by the public weather officers at the Kennedy Space Center include:

Radar: Launch weather officers have access to Patrick Air Force base’s radar and NOAA National Weather Service’s Doppler radars. These devices can detect rain intensity, wind velocities, and cloud formations for a surrounding radius of 200 nautical miles.
Lightning Warning System: Around Kennedy Space Center is a network of 31 field mill sites that can measure lightning activity and surface electric fields. Their data assist weather officers in making lightning advisories.
Cloud-to-Ground Lightning Surveillance System (CGLSS): The CGLSS can pinpoint and map cloud-to-ground lightning strikes within 125 nautical miles of the Kennedy Space Center.
Lightning Detection and Ranging (LDAR-II): The LDAR-II can detect cloud-to-ground, cloud-to-cloud, and intracloud lightning strikes within 100 nautical miles of the space center. Weather officers use this data to ascertain when lightning conditions have ended.
National Lightning Detection Network: Weather officers can rely on lightning information from this network to analyze lightning strikes across the country.
Rawinsonde: A weather balloon that can report temperature, dew point and humidity, wind speed and direction at various altitude points. The Rawinsonde can reach up to a height of 110,000 feet.
Jimsphere balloon: A mylar balloon that provides wind speed and direction information on altitudes up to 60,000 feet.
Weather Reconnaissance Aircrafts: T-38 jets and Shuttle training aircrafts can provide updates on actual weather conditions as they fly through and/or near different areas of interest.
50 MHz and 915 MHz Doppler Radar Wind Profilers: A network of Doppler radars (one 50 MHz and five 915 MHz) provides data on wind speed and direction from altitudes of 300 feet up to 60,000 feet.
Satellite Images and Data: Several orbital weather satellites can take high-resolution images of the launching and landing areas and transmit their data directly to earth-based terminals that are accessible by the weather officers.
Towers: A network of towers around the launch pad and landing facilities can collect data and profiles on wind, temperature, and moisture.
Buoys: Buoys in the Atlantic Ocean nearby the Kennedy Space Center can relay data on temperature, wind speed and direction, barometric pressure, precipitation, sea water temperature, wave height and period.
Metrological Interactive Data Display System (MIDDS): The MIDDS gather all of the weather data from different sources and aggregated them on a single display terminal for ease of analysis by weather officers.

Rocket-Specific LWC Examples

Since the LWCs are rocket-specific, most launch vehicles have their own set of criteria for the weather officer to determine whether conditions are right for launch. To help put this in context, we will walk through the LWCs for three specific platforms: (1) The Space Shuttle, (2) SpaceX’s Falcon 9, and (3) United Launch Alliance’s Atlas V.

Space Shuttle

The retired Space Shuttle had two sets of LCCs: one set for launch and another set for landing.

For a Space Shuttle launch, formal weather briefings for the astronauts, the flight director, and the mission management team will take place launch-minus-2-days. On the day of launch, several weather checkpoints—dictated by the LCCs—need to be satisfied before it is all green for blastoff. During these checkpoints, weather metrics such as temperature, wind, precipitation, lightning potential, cloud formations, and visibility will be analyzed. For instance, if there is any precipitation at the launch pad or within the flight path of the Space Shuttle, then launch cannot occur. At launch-minus-13-minutes, all of the LCCs are checked for a final weather-related go/no-go decision.

However, even if all of the weather conditions are satisfied, the LCC builds in a “gut check” mechanism through the “Good Sense Rule.” Under this rule, even if none of the LCC metrics would hold-up the launch, the weather team can still inform the launch director of any hazardous condition that the team senses. Based on this concern, the launch director can unilaterally decide to abort/pause the launch at any time.

Because the Space Shuttle is reusable and can execute an emergency landing if necessary, several launch abort landing sites are also scoped out for every launch. As part of the LCCs, the weather conditions for these sites must also be analyzed. Some weather forecasting is involved in this process because one of the abort sites is an emergency Space Shuttle landing site for the day after launch.

At the end of a mission, before a Space Shuttle can commence its deorbit, certain LCC conditions must be satisfied as well. Because the deorbiting and landing process will take several hours, the Space Shuttle might be given the green light to return home even though the current weather observations at the landing site indicate no-go conditions. As long as the conditions are improving and trending toward LCCs being met at the time of landing, the Space Shuttle can proceed with return operations.

Falcon 9

There are two sets of LWCs for SpaceX’s Falcon 9: one for cargo Falcon 9 launches and the other for crewed Falcon 9 missions. In fact, SpaceX’s historic first crew dragon launch was delayed precisely because of a violation of these LWCs.

Cargo Falcon 9 LWCs

For cargo Falcon 9 launches, launch cannot occur with the following weather conditions:

Sustained wind exceeding 30 knots measured at the launch pad’s 162-foot level.
Upper-level wind shears that could lead to launch vehicle control problems.
Presence of an attached thunderstorm anvil cloud within 10 nautical miles of the flight path (this is also known as the “Anvil Rule”).
- The Space Shuttle LCCs can override this Anvil Rule if the conditions for launch under the Volume-Averaged Height-Integrated Radar Reflectivity (“VAHIRR”) are met.
Presence of a detached thunderstorm anvil cloud within 10 nautical miles of the flight path.
Presence of disturbed weather clouds that contain moderate or greater precipitation and extend into freezing temperatures within 5 nautical miles of the flight path.
- If specific time-associated distance criteria can be met, this no-launch condition could be overridden.
Presence within the flight path of a cloud layer thicker than 4,500 feet that extends into freezing temperatures.
- The Space Shuttle LCCs can override this no-launch condition if the cloud layer is a cirrus-like cloud that (i) never been associated with convective clouds, (ii) located within temperatures of 5 degrees Fahrenheit or colder, and (iii) contains no evidence of water droplets.
Presence of cumulus clouds with tops extending into freezing temperatures within 10 nautical miles of the flight path.
- Space Shuttle LCCs can permit a Falcon 9 launch through these clouds if (i) all clouds are no colder than 23 degrees Fahrenheit, (ii) all clouds are not producing precipitation, and (iii) all field mills within 5 nautical miles of the flight path read between -100 volts per meter and +500 volts per meter for the past 15 minutes.
Presence of cumulus clouds formed as a result of or directly attached to a smoke plume.
- Space Shuttle LCCs can permit launch 60 minutes after the cumulus cloud detaches from the smoke plume.

Meanwhile, the following conditions will cause a delay in cargo Falcon 9’s launch countdown:

Delay of at least 30 minutes after any observed lightning strikes within 10 nautical miles of the launch pad or flight path.
- The Space Shuttle LCCs can reduce the delay if, provided that there is a field mill within 5 nautical miles of the lightning flash, (1) that field mill and all field mills located within 5 nautical miles of the flight path have been reading less than 1,000 volt per meter for 15 minutes and (2) the source of lightning has moved more than 10 nautical miles away from the launch pad or flight path.
Delay of at least 15 minutes if any field mill instrument reading exceeds +/- 1,000 volts per meter within 5 nautical miles of the launch pad.
- The criteria can become +/- 1,500 volts per meter if there are no clouds within 10 nautical miles of the flight path except those that (1) are transparent, (2) have tops below the 41 degrees Fahrenheit temperature level that have not been previously associated with a thunderstorm, or (3) are associated with convective clouds having tops above the 14 degrees Fahrenheit temperature level during the last 3 hours.
Delay of at least 30 minutes from the last observed lightning from a thunderstorm whose edge is within 10 nautical miles of the flight path.
- Delay of 3 hours if a thunderstorm debris cloud is within 3 nautical miles of the flight path unless certain specific criteria have been met.

Crewed Falcon 9 LWCs

The no-go/delay launch conditions for a crewed Falcon 9 launch include the circumstances for cargo Falcon 9 launches with a few additions. The crewed Falcon 9 LWCs will also require scrubbing a launch if there is any actual or high probability of a violation of weather limits on the projected flight path of the contingent Dragon escape mechanism. The probability is calculated using weather metrics for wind, waves, lightning, and precipitation. Launch weather officers will track and analyze such potential violations for 50 plus locations along the trajectory.

Atlas V

United Launch Alliance’s Atlas V has a set of LWCs that is very similar to Falcon 9’s. While Atlas V has the same delay conditions as the Falcon 9’s delay conditions, its no-launch conditions include:

If wind speed at launch pad exceeds 33 knots.
If visibility is less than 4 nautical miles or weather ceiling is less than 6,000 feet.
Upper-level wind shears that could lead to launch vehicle control problems.
Presence of a cloud layer thicker than 4,500 feet that extends into freezing temperatures within 5 nautical miles of the flight path.
- Space Shuttle LCCs can permit an Atlas V launch here if the cloud layer is a cirrus-like cloud that (i) never been associated with convective clouds, (ii) located within temperatures of 5 degrees Fahrenheit or colder, and (iii) contains no evidence of water droplets.
Presence of cumulus clouds with tops extending into freezing temperatures within 10 nautical miles of the flight path.
- Space Shuttle LCCs can exempt this no-flight condition if (i) the clouds are no colder than 23 degrees Fahrenheit, (ii) the clouds are not producing precipitation, and (iii) all field mills within 5 nautical miles of the flight path read between -100 volts per meter and +500 volts per meter for the past 15 minutes.
The presence of an attached thunderstorm anvil cloud within, depending on the circumstances, 10, 5, or 3 nautical miles of the flight path.
- The Space Shuttle LCCs can override this Anvil Rule and permit Atlas V’s launch if the conditions in the VAHIRR are met.
Presence of a detached thunderstorm anvil cloud within 10 nautical miles of the flight path.
- If specific time-associated distance criteria are met, this no-launch condition can be overridden.
Presence of disturbed weather clouds that contain moderate or greater precipitation and extend into freezing temperatures within 5 nautical miles of the flight path.
- If specific time-associated distance criteria are met, this no-launch condition can be overridden.
Presence of cumulus clouds formed as a result of or directly attached to a smoke plume.
- Space Shuttle LCCs can permit an Atlas V launch 60 minutes after the cumulus cloud detaches from the smoke plume.

Emerging Issues for Weather Launch Operations

As we enter into a new era for Outer Space, several emerging issues could strain existing launch weather operations.

With Outer Space becoming the provenance of commercial entities, domestic launch cadence has been increasing at a significant rate. Accommodating this demand, launch weather officers are no longer assigned to launches for specific companies, but are becoming generalists helping out with launch weather operations of any operator as the need arises. But, with more launches being scheduled than ever before, public launch weather operations will be severely stressed in maintaining its operational cadence. Additional resources and personnel will be needed to ensure that this increasing deluge of launches can be safely conducted.

Because private launch operators might be looking at different weather algorithms and factors in assessing their risk appetite for launch, launch weather decisions are becoming more divisive. While public weather officers might recommend a go-for-launch decision based on their analysis of the LWCs, a private operator’s risk assessment team might come to a different conclusion. If the weather officers do not have access to the operator’s sources, they will be unable to verify and provide their own feedback and analysis. This could sometimes lead to coordination problems and give Space Force a bad reputation when private companies, being more risk-adverse, abort a launch when public launch weather officers had already recommended a go-for-launch decision.

Additionally, launch logistics are getting more complex than ever before. With reusable rockets becoming the standard-bearer in the field, the process is no longer just about launching a payload into Outer Space. Launch weather operations will sometimes need to plan for intrigued recovery operations as part of launch procedures; projections need to be calculated for both the flight path up as well as the glide path down. Weather patterns for secondary recovery zones as well as emergency splashdown areas—such as a Crew Dragon launch escape—must be taken into consideration. This means that the weather-related go/no-go decision can depend on cooperative weather at launch as well as all recovery sites.

Evolving Launch Weather Operations for the Future

As Outer Space launches become increasingly privatized, frequent, and sophisticated, Space Force’s launch weather operations will need to adapt. One way of transforming the organization is through the establishment of a joint weather committee made of representatives from the Space Force and active domestic launch operators. The cooperation resulting from such a committee can ensure that Space Force’s weather officers will become better equipped to handle launch operations in this new Outer Space era.

As the Outer Space launch market becomes commercialized, market forces are driving innovation in this sector. Private launch enterprises are constantly adapting their vehicles for better performance and lower costs. In this competition for customers, proprietary rocket technology can be the most valuable asset of these companies and are guarded with extreme zeal. This caution is causing a fragmentation in the Outer Space launch sector; operators are extremely hesitant in collaborating with one another lest their trade secrets be accidentally uncovered. In turn, because launch weather officers might be working with several launch providers, companies sometimes divulge only the bare minimum amount of information needed to these personnel. Under these circumstances, weather officers might not have a complete picture of a particular vehicle’s characteristics, leading to inaccurate weather decisions.

Hence, public launch weather operations need to find ways to encourage collaboration among the different launch providers. One way to foster cooperation is through the establishment of a launch weather steering committee made of representatives from the Space Force and all active domestic launch operators. All participating enterprises will be encouraged to disclose their vehicles’ performance and proprietary data to the committee for the limited purpose of coming up with common launch conditions. These criteria can be rolled up into standards that will guide go/no-go launch decisions, helping to streamline existing rocket-specific LWCs.

This committee can also help to facilitate and govern the exchange of weather data among its members. Having a comprehensive and centralized repository of weather information will make relevant data more readily accessible by all personnel involved with launch weather operations; launch officers will be able to make more precise and informed decisions. Because every launch will implicate public safety concerns, launch operators should have no qualms with their participation in this process and share relevant weather data—which will solely be used to prevent any adverse events from occurring. While the cost for such a weather database can be spread out proportionally among its members, Space Force—as the public entity—will be responsibility for a majority of the expenditure.

Having this collaborative steering committee will also provide an opportunity for weather officers to have a close working relationship with their counterparts at private entities. This should help to foster a sense of common purpose among these individuals. Through this team-oriented environment, everyone will be working together toward a goal of ensuring safe and successful launches. These partnerships will also help to facilitate the flow of relevant information, enabling both sides to more effectively and efficiently to do their jobs.

As the Outer Space launch market becomes more heated, operational reforms are already taking place. While the Launch Commit Criteria/Launch Weather Criteria have been instrumental in ensuring safe launches for the past thirty plus years, times are changing. As more commercial entities enter this market, launch weather operations need to adapt with the times. By creating and operating a collaborative committee made up of both public and private entities, Space Force’s launch weather operations will be better equipped to handle this new era of Outer Space launches.