Atmospheric entry
Atmospheric entry is the process of a spacecraft or other object entering the atmosphere of a celestial body. It is most commonly used when referring to the re-entry of Kerbin.
Naming
The scientific correct term is atmospheric entry and applies to all bodies with an atmosphere. Re-entry is only used when a craft enters the atmosphere of the body it started from. As all craft started from Kerbin it is only correct for entering Kerbin's atmosphere. Colloquially the term re-entry or reentry is used for all atmospheric entries. Aerocaptures can be treated as atmospheric entries, although an atmospheric entry usually describes slowing down in the atmosphere to assist in the landing.
Appearance
The atmospheric entry can first be detected then the velocity starts dropping although the craft is falling and the periapsis is still ahead. As soon as the craft sinks far enough into the atmosphere that the drag is building up effects can be seen which look like flames. Those effects were added in version 0.19.0.
Dangers for the craft
WARNING: The following is no longer accurate as of 1.0, and is only true on versions 0.90 and below. Heat from atmospheric entry can and will destroy spacecraft components as of version 1.0.
Although those flames appear dangerous and atmospheric entry is often the most dangerous point of missions in the real world they are usually quite harmless in Kerbal Space Program. Those effects are merely cosmetic and in the stock game the drag induced by the atmosphere can only destroy extended solar panels – the exception being the OX-STAT Photovoltaic Panels, which cannot be extended or retracted; since they lie flat against the surface to which they're mounted, they generally won't be harmed by atmospheric entry. The rest of the craft won't break apart during entry unless it strikes the atmosphere at extremely high velocity (generally beyond that which can be achieved without cheating) or it has many flexible part joints and an un-aerodynamic shape (e.g., a space station).
If returning to Kerbin, then disintegrating solar panels might be fun to watch, but this phenomenon can be a danger to probes on other bodies. In extreme cases, it is possible for solar panels without the protective casing to be destroyed despite being retracted, though this only occurs on Eve's dense atmosphere.
With their protective spacesuits, Kerbals can survive entering the atmosphere. Of course, they will usually die upon impact, although a glitch exists in which they may not be harmed if they hit the ground helmet-first.
A spacecraft can be easily obliterated during atmospheric entry if physics warp is activated. It is advised not to activate physics warp with a parachuting ship until the chute opens. Parachutes that have opened can survive the 3x physics warp on Kerbin.
1.0 Update
As of 1.0, re-entry heat is very dangerous if not prepared for properly. When re-entering an atmosphere, the flames will slowly begin to destroy your craft, which is very devastating especially if you are hauling a load of Science. To counter this, the player must put some kind of heat sheild on the craft.
If the player chooses not to have this kind of re-entry heat, or edit how dangerous it is, he/she may change it when starting a new game, selecting Custom difficulty, and sliding it all the way to the left (to turn it off) or to slightly adjust it to the player's liking. Alternatively, you can change this in-game via the in-game menu.
See also
- Atmospheric entry on Wikipedia
