discover the climate criteria set by NASA for mission launch

Last Monday (29), the launch of the Artemis 1 mission, the first unmanned flight of NASA’s new lunar and deep space exploration program, was halted due to technical problems (learn more here).

The Space Launch System (SLS) mega-rocket docked on the LC-39B launch pad at Kennedy Space Center before the Artemis 1 mission cancellation announcement on Monday, August 29. Image: NASA Television

However, even if no anomalies were detected, the event was likely to be canceled just the same, given the bad weather that was burning through the venue that morning – even if one of them reached the launch pad by lightning.

Two backup dates have been set for the long-awaited launch of the transport complex created by the mega-rocket. Space launch system (SLS) and the Orion capsule to the Moon. The first will be this Friday (2) and the other on Monday (5).

During a video conference on Tuesday (30), NASA mission chief Mike Sarafin announced that the agency had decided to launch in a two-hour window starting at 15:17 on Saturday (3). ). If necessary, it is reserved during the activation window, which begins at 7:00 PM on Monday.

This entire schedule depends, among other things, on weather conditions in Florida, particularly at Cape Canaveral, home of the mission’s launch site, NASA’s Kennedy Space Center.

Weather regulations have been established by the agency as criteria for a safe launch of the SLS. These criteria are very strict and are designed to avoid possible unwanted consequences.

Meteorological criteria enabling the launch of the Artemis 1 mission

All space launches depend on favorable weather conditions, but for the Artemis 1 mission, given the complexity of the mega-rocket and the specifics of the systems involved, NASA was more careful in defining the guidelines.

To begin with, four factors had to be considered before rolling the car onto the starting pad. It was not possible to do this during the procedure:

  1. the lightning forecast was greater than 10% within 40 km of the launch zone;
  2. the predicted probability of hail at the launch site was greater than 5%;
  3. maximum winds were greater than 40 knots in the launch zone;
  4. the temperature in the firing zone was below 4 ºC or above 35 ºC.

After this stage, come to the criteria for the start itself. Now there are six main factors to consider: temperature, wind, precipitation, lightning, clouds, and solar activity.

Temperature

Tank filling should not be started in the following cases:

  • At 40 meters and 80 meters, the 24-hour average temperature is below 5°C;
  • At 40 meters and 80 meters, the temperature rises above 35 ºC for 30 minutes in a row;
  • Temperatures on 40 meters and 80 meters fall below the specified temperature limit for 30 consecutive minutes.

Temperature limits vary between 3°C and 9°C depending on wind and relative humidity. Higher winds and relative humidity result in limiting cold temperatures.

The wind

The flight should not start in the following cases:

  • winds above 29 knots and 39 knots between 40 meters and 80 meters respectively;
  • higher wind conditions can cause launcher control problems.

Precipitation

We call all water particles that fall from the atmosphere and reach the Earth’s surface, either liquid or solid, or both. Rain, snow and hail are different forms of precipitation. And the car should not be started in any of these conditions.

Flash

Tank loading is not permitted to begin from the center stage (or intermediate cryogenic propulsion stage – ICPS) during refueling if the forecast for lightning within a 9 km radius around the launch zone exceeds 20%.

Discovers the climate criteria set by Artemis 1

No rockets are allowed to take off under lightning. Photo: Rachel Sanner / Pexels

It is also not allowed to start:

  • up to 18 km from the flight path within 30 minutes after a lightning strike, if the specified conditions regarding distance from clouds and surface electric fields are not met;
  • if the flight path is within 18 km of the thunderstorm boundary within 30 minutes of the last observed lightning strike;
  • if the flight route is within 18 km of a lightning cloud, the temperature, time since last lightning strike and distance criteria are not met and the maximum radar reflectivity criteria are met at less than 6 km;
  • if the flight route is within 18 km of an isolated thundercloud, the temperature, time between flashes and distance criteria are not met and the maximum radar reflectivity criteria are not met within 6 km.

Clouds

As for the clouds, it is not allowed to start:

  • if the temperature, surface electric field and radar criteria are not met, if the flight path is within 6 km of the thunderstorm debris cloud within 3 hours;
  • if the flight path is within 10 km of disturbed air clouds extending to freezing temperatures and containing moderate or greater precipitation;
  • through a cloud layer thicker than 1.3 km and extending to sub-freezing temperatures at distances of less than 10 km unless specific criteria for radar reflectivity and cloud height are met;
  • if the flight path is within 18 km of cumulus with certain distance and altitude criteria (there are additional warnings for clouds below -5°C);
  • through cumulus clouds formed after or directly connected to the smoke plume, no later than 60 minutes after the release of the smoke plume;
  • Within 15 minutes, if there is no special cloud warning within 18 km of the flight path, field crusher instrument readings equal to or greater than 1500 volts per meter 10 km from the launch site.

solar activity

Finally, launching during intense or extreme solar activity is not permitted, resulting in an increased density of solar particles that can damage electronic circuitry and make radio communication with the launcher difficult or impossible.

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