Atmospheric entry/Effects

**Atmospheric entry effects** are heating effects caused by rockets entering the atmosphere of celestial bodies. For example, a Capsule re-entering Earth's atmosphere from a 35 kilometer orbit at a ~10 degree initial angle should heat up to around 1,700–1,900 degrees Celsius. However, if the capsule re-enters Earth's atmosphere from the Moon at a 30–35 degree initial angle, it would probably heat up to about 4,000 degrees Celsius.

## Heating

On Earth, the heating effect starts at various velocities. The velocity is higher if the altitude is higher. The thresholds for the heating differ on every planet.

Once the effect starts, parts exposed to the airflow will heat up and form burn marks. Affected parts will have gauges displaying their temperature, in degrees Celsius. The higher the velocity and the lower the altitude is, the more the surface of the craft exposed to the airflow heats.

### Trail

When a rocket heats up due to aerodynamics, exposed surfaces glow yellow, and a sound similar to a distorted Hawk Engine or Titan Engine is audible. The sound is louder when the rocket is at higher velocity. It also creates an orange trail that becomes more opaque as the temperature increases, and vice versa. The trail possibly represents plasma, a gas produced in real life re-entry.

## Cooling

As the velocity decreases, the trail fades, the rocket cools down, and the sound becomes quieter. The surface's glow also becomes dimmer as the temperature decreases, and burn marks from the heating become visible. The burn marks are created on wherever was exposed to the heating, and the intensity depends on how hot the surface was exposed to and how long it was exposed. Therefore, a rocket experiencing low temperature at re-entry will have to be exposed to the heat for a while to have burn marks is as intense as a rocket experiencing a high temperature re-entry for a short time.

## Burn marks

   Burn marks will appear on a rocket when a rocket experiences heat. They are created on wherever was exposed to the heating, and the intensity depends on how hot the surface was exposed to and how long it was exposed. Therefore, a rocket experiencing low temperature at re-entry will have to be exposed to the heat for a while to have burn marks is as intense as a rocket experiencing a high temperature re-entry for a short time.

## Max Q

Entry effects are also present at Max Q. When you reach a certain altitude and/or velocity, your rocket will heat up a little, but not enough to destroy parts. However, if you try to get major heating effects by turning steeply in the atmosphere, your rocket will heat up sufficiently to destroy some or all of it.

## Trivia

* Small parts can be turned dark gray by making them re-enter the atmosphere while spinning. However, this is very hard to do without the No Heat Damage cheat, as you will most likely burn up the part.
* The actual temperature sustained is a lot higher than the max part temperature. This means that a rocket re-entering Earth's atmosphere from the Moon will sustain a temperature of around 10,000 degrees Celsius, while the max part temperature was only 4,000 degrees Celsius. This was fixed in a later update.
* Fairings do not have any maximum heat tolerance. It is unknown why. This was fixed in a later update.
* Entry effects are also present when you launch a rocket. This may be comparable to Max Q.