Difference between revisions of "Navball"

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== Point of reference ==
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== Référentiel ==
As all movement in space is relative, the point of reference determines the object from which all distance measurements and velocity vectors are made. Clicking this area will toggle the point of reference between ''Surface'' and ''Orbit'', as indicated by the green text. If a target is selected, there is a third option, ''Target''. Changing the '''point of reference''' changes the location of the prograde and retrograde markers (described below).
 
  
To land on the surface of a planet or other celestial body, it is important to have the reference set to Surface to account for the rotation of the celestial body. For orbital maneuvers (i.e., not landing), the planet's rotation is unimportant, except in the case of a [[synchronous orbit]], in which case the point of reference should be set to Orbit, which is like Surface but without accounting for the planet's rotation.
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Dans l'espace, il n'existe aucun mouvement absolu. Chaque position ou mouvement (trajectoire) est défini dans un référentiel, c'est à dire par rapport à un point (ou un corps) de référence. En cliquant dans cette zone, vous pourrez changer de référentiel entre ''orbite'' (''orbit'') ou ''surface''. Si une cible est sélectionnée, vous pourrez choisir le mode ''cible'' (''target''). Changer le référentiel modifie la direction de votre pro-grade et rétrograde car vote vitesse (caractérisée par le ''vecteur vitesse'') n'est pas le même par rapport à l'orbite, la surface ou une quelconque cible.
  
=== Speed ===
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Pour atterrir sur une planète, il est important de sélectionner le référentiel ''surface'' pour tenir compte de la vitesse de rotation de la planète. Pour les manœuvres en orbite, la vitesse de rotation n'a aucune importance, choisissez donc le référentiel orbital (sauf si vous cherchez à faire une [[w:fr:Orbite synchrone|orbite synchrone]]). Notez que la plupart de ces changement se font automatiquement.
Your speed is measured relative to the '''point of reference''' and is given in meters per second (m/s). Speed is never negative. Even when you're moving toward a target (as in a docking maneuver), your closing speed will always be shown as a positive number.
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=== Vitesse ===
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Votre vitesse se mesure par rapport à ce ''corps de référence'' et est donnée en mètres par seconde (m/s). Elle n'est jamais négative, même si votre distance diminue, votre vitesse sera toujours indiquée comme positive.
  
 
== Ball instrument ==
 
== Ball instrument ==

Revision as of 10:11, 7 May 2014

La Navball est le principal instrument vous permettant de contrôler votre vaisseau. Comprendre son principe de fonctionnement est prmordial pour une mission réussie, que ce soit dans l'espace ou dans l'atmosphère. Quant la caméra n'est pas en mode chase (poursuite), la Navball est le seul moyen de connaître l'orientation du vaisseau et de prédire l'effet des manœuvres de rotation et translation. Cet instrument est similaire à un horizon artificiel tel qu'utilisé dans les avions.

1: Référentiel (point de référence)
2: Vitesse instantanée
3: Voyant RCS (actif)
4: Voyant SAS (actif)
5: Poussée moteurs
6: Force G ressentie
7: Delta-v requis pour la manœuvre
8: Données de la manœuvre
9: Navball affichant l'orientation du vaisseau et différents indicateurs d'attitude
10: Cap en degrés
11: Masquer la Navball

Référentiel

Dans l'espace, il n'existe aucun mouvement absolu. Chaque position ou mouvement (trajectoire) est défini dans un référentiel, c'est à dire par rapport à un point (ou un corps) de référence. En cliquant dans cette zone, vous pourrez changer de référentiel entre orbite (orbit) ou surface. Si une cible est sélectionnée, vous pourrez choisir le mode cible (target). Changer le référentiel modifie la direction de votre pro-grade et rétrograde car vote vitesse (caractérisée par le vecteur vitesse) n'est pas le même par rapport à l'orbite, la surface ou une quelconque cible.

Pour atterrir sur une planète, il est important de sélectionner le référentiel surface pour tenir compte de la vitesse de rotation de la planète. Pour les manœuvres en orbite, la vitesse de rotation n'a aucune importance, choisissez donc le référentiel orbital (sauf si vous cherchez à faire une orbite synchrone). Notez que la plupart de ces changement se font automatiquement.

Vitesse

Votre vitesse se mesure par rapport à ce corps de référence et est donnée en mètres par seconde (m/s). Elle n'est jamais négative, même si votre distance diminue, votre vitesse sera toujours indiquée comme positive.

Ball instrument

The most important part is the center ball, which shows the current orientation of the craft and multiple directions which maybe important for future movements.

While on the ground, the blue background hemisphere indicates the skyward direction (up; away from the center of gravity), while brown indicates groundwards (down, towards gravity). The thin white line separating the blue and brown hemispheres is the artificial horizon. These indicators are relative to the part from which the craft is controlled, not necessarily the nearest planet, target, or orbital plane. This can be changed by selecting Control from Here when right-clicking on docking ports or command modules that may be on the craft.

Level indicator

The level indicator is the gold V-shape in the center of the navball, which shows the direction the craft is facing (its orientation). The level indicator never moves; the navball rotates beneath it, providing a kind of cockpit window view without any window needed. For example, rotating the craft around its roll axis will turn the navball upside down.

Markers

On the navball are three different types of markers. All markers except the maneuver marker come in pairs, with an opposite marker on the opposite side of the virtual ball.

Prograde and retrograde

The green prograde marker indicates the direction of movement (which may not be the direction the craft is facing). Conversely, the green retrograde marker always faces in exactly the opposite direction; the direction the craft has come from. If the prograde marker is exactly aligned with the gold level indicator, the craft is facing "forwards" in the direction of travel. If the level indicator is over the retrograde marker, the craft is facing "backwards." As the craft orbits around a body, these markers will gradually move, because orbits are circular (or elliptical), while orbiting spacecraft typically hold still. Burning in the prograde direction will accelerate the craft, while burning retrograde will slow it down. Burning in any direction other than exactly prograde or retrograde will cause the prograde/retrograde markers to move toward/away from the direction the craft is pointing. These markers are relative to the point of reference.

Target prograde and target retrograde

If a target is selected, the purple icons will indicate the heading directly to the target. Because the target is typically moving, the target markers move as well. Usually the target marker and velocity marker don't follow exactly the same path and tend to drift away. This is important for docking, which requires frequent input to hold the craft on course. These markers are not relative to the point of reference.

Maneuver prograde

If a maneuver is planned on the map, the blue Maneuver marker points in the direction needed for the burn. This is the only marker without an opposite pair.

Symbols on the ball instrument

Information around

Maneuver Information

On maneuvers, there is a maneuver Δv indicator, a green bar and small info text right of the navball. The bar gives a visual indication of the total amount Δv required to accomplish the maneuver, and it will deplete as the burn is performed. The bar has no scale; it always starts out full, regardless of the amount of the burn. Below that is the estimated burn time: how long the burn will have to continue until the maneuver is completed. This is a simple estimate based on the current maximum thrust available. When engines get activated or deactivated this value will adjust automatically and may result in a longer burn time. The time estimate doesn't change if the engines are operated at less than 100% thrust; it simply counts down more slowly. Below the burn-time estimate is a countdown timer indicating the time left until the craft reaches the next maneuver node. Opinions vary on whether to:

  • Start the burn before the maneuver point, finishing at T-0
  • Start the burn halfway before, so that half of the maneuver's Δv is applied at T-0
  • Start the burn maneuver exactly at T-0

Throttle

Throttle indicates how much power all engines in the current stage are delivering (in percent). Beware of continuous full throttle, as engines can overheat and be destroyed. A single throttle controls all activated engines, so if the engines are not balanced the only way to adjust individual throttles is by setting/adjusting total thrust limits of the engines by using tweakables. The throttle controls percentage of maximum thrust, not absolute thrust, so smaller engines at full throttle will apply less force than large engines at partial throttle. Solid rocket boosters cannot be throttled.

Heading

The heading is the compass direction the craft is facing, in degrees ranging from 0° - being true north - to 359°, going clockwise (meaning 90° equals an eastern direction).

Pitch

Pitch is indicated in degrees, ranging from +90° (up) to -90° (down). To better indicate positive and negative pitch, the bottom half of the navball is painted brown and the top half in blue.

Roll Angle

Roll angle is indicated using the level indicator. If the level indicator is parallel to the dashed pitch lines, the vessel is orientated horizontally. Combining this with the knowledge that blue means skyward and brown ground-ward, it can even deduce if it is flying upside down by only looking at the navball.

G forces

The G force gauge provides a visual scale of the acceleration exerted due to gravity and/or craft acceleration, measured in g. One g is approximately 9.81 m/s2. Not to be confused with the SI-unit gram. G forces can be either positive (upwards on the scale) or negative (downwards). Note that experiencing sustained excessive g forces (the red zone on the scale) will kill any Kerbalnauts and may damage sensitive parts.

Show/Hide

Clicking the little arrow on the top of the navball (Hide) will toggles its display on-screen.

Basic controls

These are the most basic orientation controls of the craft, here is a short explanation on how their actions are represented on the navball with the default key bindings:

  • W moves the indicator down on the navball.
  • S moves it up.
  • A moves it left.
  • D moves it right.
  • Q rolls it counterclockwise.
  • E rolls it clockwise.