Difference between revisions of "Heat shield"

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[[File:HeatshieldComparison.jpg|thumb|A size comparison of the available heat shield parts]]
 
[[File:HeatshieldComparison.jpg|thumb|A size comparison of the available heat shield parts]]
  
A '''heat shield''' is a part which protects shielded parts from overheating. almost all heat shields, excluding the [[Heat Shield (10m)]] work as [[w:ablative heat shield|ablative heat shield]]s. This means each has a certain amount of ablative material, [[ablator]], which slowly breaks apart carrying heat away. All of the heat shields currently in the game have a maximum temperature of 3,400 Kelvin and an impact tolerance of 9 m/s.  As a rule of thumb, it is recommended to use them on capsules which are expected to return from 55 km or higher.
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A '''heat shield''' is a part which protects shielded parts from overheating. Almost all heat shields, excluding the [[Heat Shield (10m)]], work as [[w:ablative heat shield|ablative heat shield]]s. This means each has a certain amount of ablative material, [[ablator]], which slowly breaks apart carrying heat away; this is represented by the ablator resource being consumed, cooling the heat shield. All four ablative heat shields have a maximum temperature of 3,400 Kelvin and an impact tolerance of 9 m/s.  As a rule of thumb, it is recommended to use them on capsules which are expected to return from 55 km or higher.
  
In version 1.1 the [[Heat Shield (10m)]] was added. This is the game's first '''inflatable''' heat shield. The part begins as a 2.5m component that inflates into a 10m diameter heat shield with a maximum temperature of 3,500 Kelvin.
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Unlike the ablative heat shields, the [[Heat Shield (10m)]] is an ''inflatable'' heat shield. The part begins as a 2.5m component that inflates into a 10m diameter heat shield. As it uses no ablator, the Heat Shield (10m) has a higher maximum temperature of 3,500 Kelvin.
 
 
Note that these can not only be used for atmospheric reentry, but also to separate a heat-sensitive stack from a heat-generating stage like an engine cluster.
 
  
 
All four of the [[w:ablative heat shield|ablative heat shield]]s resemble the heat shield of the [[w:Orion_(spacecraft)|Orion MPCV]].
 
All four of the [[w:ablative heat shield|ablative heat shield]]s resemble the heat shield of the [[w:Orion_(spacecraft)|Orion MPCV]].
  
As of [[1.1]], all heat shields can be jettisoned.
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All heat shields can be jettisoned without the use of a [[decoupler]].
 
 
In [[1.2]] a smaller 0.625m heat shield was added.
 
  
 
== Function ==
 
== Function ==
Heat Shields create a "cylinder of coolness" behind them which protect other parts from heating. Actually any leading part will create a similar zone of coolness behind itself but Heat Shields are particularly effective in this role as they have high temperature tolerances.
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While in the atmosphere, all parts create a "cylinder of coolness" behind them which protect other parts from heating. Any part within the cylinder of coolness will not experience aerodynamic heating. Heat shields are particularly effective in this role, as they have high temperature tolerances.
  
Any part within the cylinder of coolness will not experience aerodynamic heating, despite this a small amount of heat will conduct through the heat shield to connected parts, this heat by conduction is not normally a problem but can destroy unusually heat-sensitive parts mounted onto or very close to the heat shield.
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A heat shield is only able to completely protect parts which fit within this cylinder of coolness. A 2.5m heat shield will protect all 1.25m parts. In addition, conical parts (such as command pods) of equal radius will typically be protected (for example, a 1.25m heat shield will protect a [[Command Pod Mk1]]). Parts of the same general radius are sometimes protected, but any protrusions that stick out into the hot air will not be protected. For example, the [[Mk1 Lander Can]] extends beyond the 1.25m stack size, and will not be protected on reentry. Another example is the [[SC-9001 Science Jr.]]; it is protected by a 1.25m heat shield when the doors are closed, but if the doors are open, they will extend beyond the heat shield and the Science Jr. will be destroyed by heating. Even if a cylindrical part does fit behind the heat shield, the prograde or retrograde hold must be precise to ensure the part stays precisely behind the heat shield.
  
A heat shield is only able to completely protect parts which have a smaller radius, a 2.5m heat shield will protect all 1.25m parts, in addition conical parts (such as command pods) of equal radius will typically be protected, a 1.25m heat shield *will* protect a Command Pod Mk1. Cylindrical parts of the same general radius are sometimes protected but most often not, it depends on the precise radius and the presence of protrusions that stick out into the hot air - probe cores for example tend to have pokey out bits that make them difficult to shield from heat, another example is the Science Jr: if the doors are open it will not fit behind a 1.25m heat shield and will be destroyed by heating, if the doors are closed it does fit (just barely). Even if a cylindrical part does fit behind the heat shield, the prograde or retrograde hold must be extremely precise to ensure the part stays precisely behind the heat shield.
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In addition, a small amount of heat will conduct through the heat shield to connected parts. This heat by conduction is not normally a problem, but can destroy unusually heat-sensitive parts (like most probe cores) mounted onto or very close to the heat shield.
  
 
== Parts ==
 
== Parts ==

Latest revision as of 01:30, 13 July 2021

A size comparison of the available heat shield parts

A heat shield is a part which protects shielded parts from overheating. Almost all heat shields, excluding the Heat Shield (10m), work as ablative heat shields. This means each has a certain amount of ablative material, ablator, which slowly breaks apart carrying heat away; this is represented by the ablator resource being consumed, cooling the heat shield. All four ablative heat shields have a maximum temperature of 3,400 Kelvin and an impact tolerance of 9 m/s. As a rule of thumb, it is recommended to use them on capsules which are expected to return from 55 km or higher.

Unlike the ablative heat shields, the Heat Shield (10m) is an inflatable heat shield. The part begins as a 2.5m component that inflates into a 10m diameter heat shield. As it uses no ablator, the Heat Shield (10m) has a higher maximum temperature of 3,500 Kelvin.

All four of the ablative heat shields resemble the heat shield of the Orion MPCV.

All heat shields can be jettisoned without the use of a decoupler.

Function

While in the atmosphere, all parts create a "cylinder of coolness" behind them which protect other parts from heating. Any part within the cylinder of coolness will not experience aerodynamic heating. Heat shields are particularly effective in this role, as they have high temperature tolerances.

A heat shield is only able to completely protect parts which fit within this cylinder of coolness. A 2.5m heat shield will protect all 1.25m parts. In addition, conical parts (such as command pods) of equal radius will typically be protected (for example, a 1.25m heat shield will protect a Command Pod Mk1). Parts of the same general radius are sometimes protected, but any protrusions that stick out into the hot air will not be protected. For example, the Mk1 Lander Can extends beyond the 1.25m stack size, and will not be protected on reentry. Another example is the SC-9001 Science Jr.; it is protected by a 1.25m heat shield when the doors are closed, but if the doors are open, they will extend beyond the heat shield and the Science Jr. will be destroyed by heating. Even if a cylindrical part does fit behind the heat shield, the prograde or retrograde hold must be precise to ensure the part stays precisely behind the heat shield.

In addition, a small amount of heat will conduct through the heat shield to connected parts. This heat by conduction is not normally a problem, but can destroy unusually heat-sensitive parts (like most probe cores) mounted onto or very close to the heat shield.

Parts

Image Part Radial size Cost
(Funds)
Mass
(t)
Max. Temp.
(K)
Tolerance
(m/s)
Tolerance
(g)
Ablator
HeatShieldSmall.png
Heat Shield (0.625m) Tiny 150
(125)
0.075
(0.025)
3 300 9 50 50
HeatShieldSmall.png
Heat Shield (1.25m) Small 300
(200)
0.3
(0.1)
3 300 9 50 200
HeatShieldLarge.png
Heat Shield (2.5m) Large 600
(200)
1.3
(0.5)
3 300 9 50 800
HeatShieldHuge.png
Heat Shield (3.75m) Extra large 1100
(200)
2.8
(1.0)
3 300 9 50 1 800
Heat Shield (10m).png
Heat Shield (10m) Large / 10m 2 400 1.5 3 500
(3 250)
9 50