Difference between revisions of "Aerobraking"

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'''Aerobraking''' (sometimes '''aerocapture''') is a technique to lose velocity after reaching a celestial body.
 
'''Aerobraking''' (sometimes '''aerocapture''') is a technique to lose velocity after reaching a celestial body.
  
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Usually when the craft enters the sphere of influence of a celestial body, the relative speed to it will be much too high to enter an orbit, unless burning retrograde and expending a lot of fuel. In order to save the fuel, the craft can either perform a [[Tutorial: Gravity Assist|gravity assist]] or perform an aerobraking maneuver.
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Usually when a craft enters the sphere of influence of a celestial body, the relative speed to it will be much too high to enter an orbit, leaving the player with no option but to burn retrograde and expend a lot of fuel. In order to save fuel, the craft can either perform a [[Tutorial: Gravity Assist|gravity assist]] or perform an aerobraking maneuver.
  
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To perform an aerobrake, the trajectory of a craft has to be altered to pass through the atmosphere of a celestial body. The atmospheric drag will slow the craft down enough to reach an eccentric orbit around it. After the apoapsis is lowered to the wanted altitude, it is necessary to raise the periapsis outside the atmosphere to prevent additional aerobraking maneuvers.
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To perform an aerobraking maneuver, the trajectory of a craft has to be altered to pass through the atmosphere of a celestial body. The atmospheric drag will slow the craft down enough to reach an eccentric orbit around it. After the apoapsis is lowered to the desired altitude, it is necessary to raise the periapsis outside the atmosphere to prevent additional aerobraking maneuvers.
  
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Aerobraking is a dangerous maneuver. When the craft dips too deep into the atmosphere, it will lose too much speed and risk crashing. When it doesn't dip deep enough, it might not lose enough speed to enter an orbit. Usually it is better to be careful, because even when the orbit turns out to keep it just barely in the SoI of the planet, the orbit allows it to perform additional aerobreaks to slow it down more. In the current version ({{Check version|0.20.2}}) flying through an atmosphere at high velocity will cause dangerously-looking red flames around your craft, but this is completely harmless (except for extended solar arrays). It was already announced that later versions will implement reentry heat which can cause damage to a vessel. This factor could make aerobraking even more dangerous.
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Aerobraking is a dangerous maneuver. If the craft dips too deep into the atmosphere, it will lose too much speed and risk crashing. When it doesn't dip deep enough, it might not lose enough speed to enter an orbit. Usually it is better to be careful, because even if the orbit's apoapsis is just barely in the SoI of the planet, the periapsis will remain in the atmosphere and allow additional aerobraking maneuvers to further lower the apoapsis. In the current version ({{Check version|0.20.2}}) flying through an atmosphere at high velocity will cause dangerous-looking red flames around your craft, but this is completely harmless (except to extended solar arrays, which excessive drag will break). However, Squad has announced that later versions will implement reentry heat which can cause damage to a vessel. This factor could make aerobraking even more dangerous.
  
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For the ideal height for an aerobrake maneuver, consult the article about the planet. The following planets and moons have an [[atmosphere]] which allows aerobraking:
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For the ideal height for an aerobraking maneuver, consult the article about the planet. The following planets and moons have an [[atmosphere]] which allows aerobraking:
  
 
* [[Eve]]
 
* [[Eve]]
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* [[Laythe]]
 
* [[Laythe]]
  
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The difference between aerobraking and an aerocapture in real world science is, that the aerocapture captures the orbiter in an orbit on the first fly by while aerobraking isn't so aggressive.
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In real world science, an aerocapture is a capture maneuver intended to result in an orbit around the target body, while aerobraking is merely performed to lower the apoapsis of an existing orbit. However, the terms are generally used interchangeably in Kerbal Space Program.
  
 
== See also ==
 
== See also ==

Revision as of 18:58, 5 August 2013

Aerobraking (sometimes aerocapture) is a technique to lose velocity after reaching a celestial body.

Usually when a craft enters the sphere of influence of a celestial body, the relative speed to it will be much too high to enter an orbit, leaving the player with no option but to burn retrograde and expend a lot of fuel. In order to save fuel, the craft can either perform a gravity assist or perform an aerobraking maneuver.

To perform an aerobraking maneuver, the trajectory of a craft has to be altered to pass through the atmosphere of a celestial body. The atmospheric drag will slow the craft down enough to reach an eccentric orbit around it. After the apoapsis is lowered to the desired altitude, it is necessary to raise the periapsis outside the atmosphere to prevent additional aerobraking maneuvers.

Aerobraking is a dangerous maneuver. If the craft dips too deep into the atmosphere, it will lose too much speed and risk crashing. When it doesn't dip deep enough, it might not lose enough speed to enter an orbit. Usually it is better to be careful, because even if the orbit's apoapsis is just barely in the SoI of the planet, the periapsis will remain in the atmosphere and allow additional aerobraking maneuvers to further lower the apoapsis. In the current version (0.20.2[outdated]) flying through an atmosphere at high velocity will cause dangerous-looking red flames around your craft, but this is completely harmless (except to extended solar arrays, which excessive drag will break). However, Squad has announced that later versions will implement reentry heat which can cause damage to a vessel. This factor could make aerobraking even more dangerous.

For the ideal height for an aerobraking maneuver, consult the article about the planet. The following planets and moons have an atmosphere which allows aerobraking:

In real world science, an aerocapture is a capture maneuver intended to result in an orbit around the target body, while aerobraking is merely performed to lower the apoapsis of an existing orbit. However, the terms are generally used interchangeably in Kerbal Space Program.

See also

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