39 votes
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 ...
user avatar
29 votes

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 ...
user avatar
  • 1,620
12 votes

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: $$ \arccos(\cos(30.56)*\sin(123)) = 43.77\deg $$ ...
user avatar
  • 1,246
10 votes
Accepted

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 ...
user avatar
9 votes

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) ...
user avatar
8 votes

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 ...
user avatar
8 votes

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 ...
user avatar
8 votes
Accepted

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 ...
user avatar
8 votes
Accepted

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 ...
user avatar
  • 633
7 votes
Accepted

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 ...
user avatar
  • 118k
7 votes

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 ...
user avatar
  • 148k
5 votes
Accepted

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 ...
user avatar
  • 18.7k
5 votes
Accepted

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 ...
user avatar
  • 458
5 votes
Accepted

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 ...
user avatar
5 votes
Accepted

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 ...
user avatar
  • 52.4k
5 votes

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 (“...
user avatar
  • 509
5 votes

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, ...
user avatar
  • 151
4 votes

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 $C$...
user avatar
  • 1,321
4 votes

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 ...
user avatar
4 votes

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 ...
user avatar
  • 11.5k
4 votes

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 ...
user avatar
  • 1,849
3 votes

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 ...
user avatar
  • 2,416
3 votes

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 ...
user avatar
3 votes

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 ...
user avatar
  • 31
3 votes
Accepted

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-...
user avatar
  • 12.7k
2 votes

Oberth Effect for non-tangential acceleration

I think I've answered my own question. As I mentioned, acceleration to alter inclination would be perpendicular to the orbital velocity, so any effect that is a function of that velocity should not ...
user avatar
  • 665
2 votes

Inclination change to Geostationary Orbit

There's two ways that are typically done. The first is to use a "Super Synchronous" orbit to reduce the delta-v overall. Essentially, the initial orbit is around twice geostationary orbit, which makes ...
user avatar
  • 118k
2 votes

What delta-v per orbit would a spacecraft need to hover next to Saturn's rings?

Here are some effective ring parameters. To simplify I'm just using the monopole term GM and not including the "extra gravity" near the planet from the oblateness which is okay since I'm rounding. (...
user avatar
  • 148k
2 votes

Does better satelite propulsion help selling secondary payloads?

If your propulsion system has a better specific impulse, then you can travel farther from your initial orbit. So as CubeSat/smallsat propulsion systems improve their efficiency, the range of orbits ...
user avatar
  • 711
1 vote
Accepted

Inclination Maneuver of GEO Satellite

I used JGM-2 and lunisolar perturbation. After maneuver, the satellite is starting to drift. Evidently, the inclination drift caused by lunisolar is not secular. The drift is secular if I just include ...
user avatar

Only top scored, non community-wiki answers of a minimum length are eligible