Why are these annoying weather rules needed to launch and land rockets?

The people responsible for launching the rockets have this old joke: if the rocket is ready to launch, then the weather will force you to postpone it for a day.

However, why is NASA, the 45th space wing of the US Space Forces, its director of safety and all launch-related services so much concerned about the weather? Who cares if it rains 18 km from the launch pad, even if the rules say that it should be no closer than 18.5 km from it? Isn't that far enough?

The answers to these questions are in the history of missile launch, and sometimes we learned these lessons as a result of painful, if not fatal, incidents. It was then that we learned what happens when those responsible for launching do not listen to the weather and do not take into account the capabilities of the missiles.

To prepare a missile launch, satellite and crew (in the case of manned flights) for each mission, you have to spend hundreds and thousands of hours of training, testing and preparation. Flight equipment should work flawlessly from the start of the countdown to ignition.

And after all this hard work, there remains only one point that is not controlled by anyone - the weather.

The weather section in the list of criteria for launching is a detailed set of instructions describing the extreme weather conditions that the spaceship can withstand during takeoff and landing to ensure the successful completion of the mission.

During the flight, variables such as wind direction, humidity, temperature, cloud cover, precipitation, etc. are taken into account. Also, launch permit criteria must take into account the safety requirements that protect people on land, at sea and in the air, advanced by the 45th space wing - this also includes the weather requirements for the rocket itself, put forward by the company owning and managing its launch.

Among some weather criteria for starting there is the maximum proximity of rain to the launch pad, wind speed and direction, the maximum allowable wind shear , and others.


The ice formed on the launch pad after the temperature dropped below the freezing point a few hours before the launch of the Challenger STS-51L

These two criteria for launching a rocket taught the United States a fierce lesson about space flights on January 28, 1986, when the Challenger shuttle was launched at near-zero a temperature that is 20 ° C colder than the minimum allowable temperature to start the MTKK Space Shuttle side accelerator .

Due to low temperatures, the main and auxiliary sealing rings of the right solid-fuel accelerator at start-up failed. Instead of the failed rings, a temporary seal formed, which collapsed due to the strongest wind shears that the shuttles have ever encountered (and which all subsequent missions will encounter).

Violation of these two weather rules and led to the death of seven astronauts.

Today, the cancellation of missile launch due to strong wind in the upper atmosphere is actively discussed in social networks. However, the Challenger disaster reminds us that an attempt to send a rocket into flight in conditions to which it is not adapted can have the most serious consequences.

In addition to the rules relating directly to the rocket, there are also rules designed to protect the employees of the space center and the public gathered to observe the launch on land, in the air and at sea.

This includes obvious rules, such as the need to avoid lightning so that they cannot damage the electronics with their hit - because then it will be impossible to destroy the rocket when it deviates from the course.

But there are lesser-known rules related to thunderstorms, which can cause staff to delay the launch, even when there are no lightning bolts near the launch pad.


Lightning Caused by Apollo 12 Launch Beats at LC-39A Cable-Gas Station

This is another example of a rule that comes from real experience. During the Apollo 12 mission to the Saturn 5 rocket, which included Pete Conrad, Richard Gordon and Alan Bean, lightning struck twice in the first minute of the flight.

A lightning strike resulted in the failure of several mission critical systems, including the fuel cells of the command and service module and all navigation displays. The control center began to receive distorted telemetry and messages from the rocket and the team.

Fortunately, the Saturn-5 flight computer, isolated from the Apollo spacecraft, had no effect on lightning strikes, and it continued to function as if nothing had happened.

The mission was saved by one person from the flight control center, who recalled that more than a year ago, one team asked for help to figure out where the strange data they received came from. In the end, he tracked them to the source, “Signal Conditioning Equipment (SCE),” located in the command and service module.

In order for the equipment to resume operation, in the Apollo-12 capsule it was necessary to press the special SCE button. Neither the flight director nor the mission commander knew about this button, but Al Bin remembered it in connection with a completely different training simulation.

Having restored telemetry and transmission of information, the mission entered orbit, conducted a full check of all systems, and as a result successfully landed on the moon, and then returned home.

As a result, experts began to better understand how missiles can cause a lightning strike, even in conditions where natural lightning does not appear.


According to NASA's February 1970 assessment of this event, “an aircraft with a conductive surface and ionized exhaust can cause lightning, which distorts potential lines of the electric field, increasing the potential gradient at the top of the vehicle and under the exhaust stream.”

In simple language, this means that the rocket is a giant conductor flying in the atmosphere, so the amount of electric charge required to cause lightning decreases, even in cases where there are no usual conditions for the natural appearance of lightning.

A lightning can be caused by a rocket flying through cumulus clouds, where there is usually no lightning, or through any dense clouds in principle.

In such cases, the launch will be delayed due to the danger of lightning (technically, this rule applies to cumulus / dense clouds), even when no lightning is observed near the launch pad.

When launched without people, the weather is evaluated according to the conditions in the immediate vicinity of the launch pad. But when there are astronauts on board, additional criteria related to the weather are taken into account.


Launch of the Falcon-9 rocket in overcast, but meeting the launch criteria weather conditions from the SLC-40 site at Cape Canaveral.

This can cause irritation for people who have traveled hundreds and thousands of kilometers to the launch pad and who have learned about canceling the launch in a situation where the weather is perfect right next to the launch pad.

In the shuttle era, weather conditions were fairly easy to evaluate, as the shuttles had to land on runways, where support teams could conduct test flights and confirm that the weather met or mismatched all conditions.

The shuttle could only be launched if it could realize all three available scenarios of canceling the mission: returning to the launch site, canceling with landing overseas, and canceling after one turn around the globe with landing either at Kennedy Airport or at a military base in California .

These forecasts were made in conjunction with a weather bureau at the National Oceanic and Atmospheric Administration and a meteorological space mission group in Houston, Texas.

For the SpaceX DM-2 demo mission, these two groups will reunite for the first time in nine years to give weather forecasts for a manned mission to the SpaceX rocket launch team at the Kennedy Space Center, the Hawthorne Mission Control Team, California, and the NASA Mission Control Team in Houston Texas.

Quite a lot of weather restrictions will apply during the launch of the long-awaited manned mission on the Dragon ship on Wednesday, in which Bob Benken and Doug Hurley will participate.

The following conditions prohibit the launch of the Crew Dragon ship:

• The constant wind speed at 162 feet [50 m] above the launch pad exceeds 30 mph. [48 km / h]
• The presence of a wind shear in the upper atmosphere that can cause problems with the control of a launched rocket.
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Weather on the route is tracked at more than 50 points along the take-off route along the east coast of North America and the northern Atlantic. The probability of weather outside the acceptable range is calculated at each point based on indicators of wind, waves, lightning and precipitation.

As for the space shuttle, in order to launch the Falcon-9 rocket with the Crew Dragon ship, the weather in certain places of the four zones of a possible mission cancellation must meet certain criteria.

Benji Reid, service director of manned missions from SpaceX, on Friday, during a dedicated willingness flight press conference, pointed out that NASA and SpaceX will track the weather in 50 points, stretching from 39A launch complex, on the eastern coast of the US and Canada, and across the Atlantic to Ireland.

At some of these points, indicators such as wind speed and direction, wave height, and other parameters related to sea weather will be tracked.

A critical role in determining whether a manned mission can start on Wednesday will be played by data from the beacons of the National Oceanic and Atmospheric Administration, the processing of which will be handled by the space mission's meteorological group.

Yes, of course, the delay in launching due to weather conditions can disappoint many, and even embarrass if the weather conditions seem ideal to them. However, these rules exist for the safety of not only the rocket itself, but also personnel involved in its launch, cargo, observers, and, of course, astronauts.