# Tag Info

Accepted

### Why is it most efficient to change orbit inclination while crossing the equator?

Why is it the most energy efficient to change orbit inclination while crossing the equator? Specifically, it's most efficient to do a plane change at one of the two "nodes" where the origin ...
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### Why is it most efficient to change orbit inclination while crossing the equator?

A great aid to intuition is to remember one principle about orbit changes: if the engine is off, the orbiter always returns to same point one orbit later. So for any orbit change, if you want to do ...
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### At which direction do you apply thrust to perform an inclination change maneuver?

To change an orbit's inclination, you need to apply thrust in the normal/anti-normal direction. The normal/anti-normal direction are some of the 6 main directions you can change your velocity. There ...
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### How to calculate Orbital Inclination knowing the launch azimuth and launch latitude?

It's just a matter of some spherical trig. $$\cos(inclination) = \cos(lat)*\sin(azimuth)$$ So in your example, the inclination would be equal to: $$\arccos(\cos(30.56)*\sin(123)) = 43.77\deg$$ ...
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### Satellite inclination, 3D scanning of earth's surface

Your comment on this answer has, I think, led me to understand what you are really asking about. What I am saying is that, presuming the inclination to be ZERO (Plane of orbit parallel to the ...
• 183k

### How to attain an equatorial orbital inclination from a non-equatorial launch site?

Changing the orbital inclination of an orbit is very energy intensive. But the people making that stuff happen have a few tricks up their sleeve to reduce the amount of energy (Δv to be precise) ...
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### Why is it most efficient to change orbit inclination while crossing the equator?

It's not just the most efficient way, it's the only way to achieve this particular target orbit. As the other answers have pointed out, an orbital inclination change must occur at the so-called ...
• 3,702
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### Change of inclination using low thrust

I found this kind of counterintuitive as well at first. This is the way I rationalized it to myself: consider a high-thrust maneuver to change inclination. Obviously if it's impulsive, you perform it ...
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### Why do geosynchronous satellites appear to oscillate in North-Southward direction? How to I trace out their path on the surface of the earth?

Let's first look at a typical orbit first for comparison. Note that the object being orbited could be anywhere. Note that it spends a time both above and below the equator. A few things about a ...
• 121k
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### Best time to perform an orbital inclination change — during ascent, or once in circular LEO?

If you're going to a higher inclination than your launch latitude (for example, going from Cape Canaveral at 28º to ISS at 51º), you'll want to do it as early as possible, while your horizontal ...
• 169k

### Satellite inclination, 3D scanning of earth's surface

Inclination changes are very expensive in terms of delta V/fuel. To do a 90 degree plane change you are thrusting against your current ~7 kilometer a second velocity to bring it to zero and also ...
• 22.6k

### Satellite inclination, 3D scanning of earth's surface

Although a little vexing, the GIF below and the answer it comes from shows that even fixed orbit will eventually pass over all places on a body that rotates underneath it that are at any latitude ...
• 149k
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### How exactly did Jupiter change Ulysses orbital plane from nearly ecliptic to polar?

In simple terms, gravity pulls an object directly towards another object. As an analogy, if you are running down the street and grab hold of a lamp post with your left hand you will swing around it to ...
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### Biggest orbital inclination change done in Earth's orbit

For low-earth orbit satellites, the IXPE satellite was launched from Canaveral to a 28.5 degree orbit. The 2nd stage of the falcon rocket then changed its inclination to a 0.2 degree, equatorial, ...
• 161
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### How will Chandrayaan-2 reach a polar orbit?

It will be a combination of things. Like TonyK mentioned in his comments, most of the change will occur during cis-lunar transfer. This is optimal because inter-planetary trajectories can be designed ...
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### How do long range space probes adjust trajectory?

New Horizons used its monopropellant attitude control thrusters for course correction. Because it couldn't make large course changes with the limited fuel available, the choice of targets was severely ...
• 169k
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### Oberth Effect for non-tangential acceleration

While delta-V - or change in velocity - remains the same, the effect on the trajectory depends in large part on the absolute velocity. While a small change of speed (a small modification of the ...
• 55k

### How to calculate Orbital Inclination knowing the launch azimuth and launch latitude?

To amplify on the correct answer of @M.A.H.: To apply this general spherical triangle (https://en.wikipedia.org/wiki/Solution_of_triangles) to the particular problem of orbital inclination: Point $C$...
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### Why do geosynchronous satellites appear to oscillate in North-Southward direction? How to I trace out their path on the surface of the earth?

I suggest building a 3D model to understand it. Start with a nice disk, such as a paper plate or the cardboard packaging of a frozen pizza. Mark the center and draw regularly spaced radial lines (“...
• 539

### Inclination and latitude of GEO satellite

First, 0.1° latitude is near zero. Second, latitude should be expressed in Earth-fixed frame, which uses the true equator, you might be using a Mean-Equator, Mean-Equinox frame (such as J2000), which ...
• 1,967

### Why is it most efficient to change orbit inclination while crossing the equator?

In the case of ANASIS-II, the situation is far more complicated than can be explained in ten seconds of livestream. Some general rules regarding plane changes: You can only make a plane change at ...
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### What is the optimal inclination change strategy?

I will give my current best shot at this problem, and others should feel free to strengthen the argument with additional mathematics. (Or poke holes!) You ask two questions, I will answer the first ...
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### Could any modern launch vehicle have put Ulysses in it's polar heliocentric without going to another planet first?

Barely, but it involving shenanigans even less practical than a Jupiter flyby. The lowest delta-v cost trajectory without any planetary flybys from Earth to a 1.35AU-5.4AU 79.11° orbit is the ...

### Change of inclination using low thrust

I would like to share a GMAT example that demonstrates the thrust node changes for the low thrust satellites. In this case my example relays on electric thrust with low Isp and N. Finite burn at the ...

### what is 'f' (true anomaly) for in the orbital inclination change equation

Let's see. What if we have a circular orbit ($e = 0$) with no argument of periapsis ($\omega = 0$), normalised to a unit mass, unit radius, so $a = 1$ and $n = 1$? The formula then simplifies to \...
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### Would lunar flyby be less costly in delta-v than direct change from ISS's to Hubble's orbit?

The trans lunar injection of the Apollo missions took a Δv of about 3000 - 3200 m/s. Let us assume all inclination change is for free (quite reasonable with careful planning and possibly multiple fly-...
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### At which direction do you apply thrust to perform an inclination change maneuver?

Comment with a drawing, illustrating points made by previous comments: Green is current orbit Red is the new, desired orbit Orange orbit has the same inclination as the desired orbit, but higher ...
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### Change of inclination using low thrust

This is a well-known phenomenon in helicopter dynamics and in control systems. In a second order control system (which roughly describes your low-thrust scheme), the phase angle change is 90° when the ...
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