Maneuver node
A maneuver node is a planed velocity change along an orbit. Multiple maneuver nodes can be added which effect the following maneuver nodes. After adding a node it shows the velocity change needed to reach the next new orbit. It doesn't show a combination of all maneuver nodes, so after using a maneuver node it needs to be deleted manually and the system can showing the next prepared maneuver node.
Contents
Directions
Because movements in space or air are three dimensional there are three basic axes to burn. For each axis there are two opposite directions. So any movement could be described with a combination of up to three separate directions.
Prograde and retrograde
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These vectors are directly changing the speed of the craft. Burning prograde will burning to the craft's velocity vector and raising the altitude of the orbit on the other side. They are colored green like the pro- and retrograde vectors on the navball. This is the most efficient way to change the orbital shape, so whenever possible these vectors should be used.
Normal and anti-normal
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The normal vectors are orthogonal to the orbital plane. Any burning normal or anti-normal will change the orbital inclination. On the navball it is between the pro- and retrograde marker on the equatorline.
In most cases these vectors are needed to match the orbital inclination to another celestial body or craft. When the orbit crosses the other object's orbit burning normal or anti-normal is most efficient. To match the orbital inclination a normal burn is needed at the ascending node. At the descending node an anti-normal burn will move the inclination closer to the target's inclination.
Radial in and radial out
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The radial in vector is pointing to the orbited body while the radial out points away from the orbited body. When burning radially the orbit will rotate around the craft.
Using
After adding a maneuver node there are three values shown next to the nav ball:
- Velocity change needed in meters per second
- Time to maneuver node or time since the craft passed the maneuver node
- Estimated burn time
With maneuver nodes it is possible to reach a specific orbit, without checking the orbital map continually. Another usage is to add a maneuver node when performing an aerobraking maneuver. It will automatically updating the velocity change while in the atmosphere.
