Does this manuever have a name?

[king of nowhere]

Lately I'm finding myself doing a lot of transfers according to a certain pattern.

First, I make an ejection burn from the parent body like on a Hohmann transfer, as shown in the image

However, this is NOT a Hohmann transfer, because I do not meet the target body at periapsis (or at apoapsis if I'm moving away from the central body, let's keep with the example from the pictures for simplicity)

I do not meet the target body immediately, because the transfer was not syncronized. Instead, when I am at periapsis, I make a retrograde burn (or prograde, but it would make for a more expensive intercept). This changes my orbital time enough that I will meet the target body at periapsis at a later orbit. It can be the next orbit, or a few orbits in the future; generally you can pay less if you're willing to wait more.

The picture shows it. Yellow manuever, at periapsis, is the change to get the right orbital time. In this case it's a big burn because the target is a small moon with negligible oberth effect, so I lose nothing by burning in open space - and I avoid cosine losses. but it's normally a small adjustment manuever. purple is not a manuever (0 m/s), but it's there to get the game to see the intercept several orbits into the future. And finally red is the capture burn.

I've done this extensively to reach all the moons of saturn. I've done it in going from ceres to vesta

I've done a slight modification in going to mercury. I've done it when leaving Venus.

 

This manuever is as expensive as a regular Hohmann transfer - give or take a small excess for the burn you make in interplanetary space, which is not as effective as burning near a planet. It takes longer, possibly multiple orbits. It has the advantage, though, that you can pick your planar nodes. When you have to make a transfer with high inclination, you can avoid a plane change if you make a hohmann transfer on the planar node; in that case you get to pay the plane change with the eject or capture burn, saving a lot of fuel by both oberth effect and combining two burn. But this hohmann transfer requires the right placement from you and the target body; you can't always count on the planets aligning for a hohmann transfer right when you're passing through the planar node. So you make this manuever instead, starting the hohmann manuever on the node, and then you syncronize to meet your target later.

You can also make this manuever when you are in an elliptic orbit, and you must burn at periapsis to leave cheaply, and you can't pick your direction. In this case, again, you leave when your ellipse is best aligned to save fuel, and you syncronize to meet your target later. Doing grand tours, I often find myself in an elliptic orbit, it's a lot cheaper to park the mothership like that than it is to circularize and then raise apoapsis again.

 

So I've done this manuever a lot, possibly more than any other. Yet I don't know a name for it, I don't even know if it has a name. I checked if I could find names of orbital transfers, but I only find the bi-elliptic transfer, which is something entirely different.

So, do anyone know if this manuever has an official name?

[Kekkie]

https://en.wikipedia.org/wiki/Orbit_phasing

This sounds like what you are doing - transferring to a more elliptical orbit so that you won't meet the target body, but adjusted so that when you come back around after an orbit or two, you can intercept. 

[jimmymcgoochie]

Phased orbit is a good description, more so than resonant orbit which is the other alternative I can think of.

[king of nowhere]

5 hours ago, Kekkie said:

https://en.wikipedia.org/wiki/Orbit_phasing

This sounds like what you are doing - transferring to a more elliptical orbit so that you won't meet the target body, but adjusted so that when you come back around after an orbit or two, you can intercept. 

It has a similarity, but it's not quite right, because orbital phasing entails changing your orbit, then going back to the original orbit.

It's actually a mix between orbital phasing and hohmann transfer. I'm surprised it doesn't have a name, ever since I started using rss - which has a lot more inclination than the stock system - I use this more than regular hohmann.

resonant orbit is not quite it; it's when you take a gravity assist from a planet and time your ejection orbit to return to the planet in a few more years

[Rocket Witch]

That reminds me of scenarios in Children of a Dead Earth where you engage from one gas giant moon to another. It's a realistic space combat simulator with a present-day tech level, so setting up a fleet in a strong orbit (often high and eccentric) that leaves its options open for short-notice transfers to multiple bodies is very desirable. That is the most relevant situation I can think of to compare with what you're doing, and explain why someone may manoeuvre in that way — convenience and a need to react to a situational changes.

By contrast, real scientific space missions are planned extensively in advance, and have not thusfar involved multiple plannet-hopping, so I don't think this kind of transit has had a chance to arise in reality yet. It's the kind of thing that will eventually get a name, but currently only a few people in very speculative and technical situations actually deal with it.

Edited July 17, 2022 by Rocket Witch

[mister_goo]

I often use this maneuver to do rendezvous. Intersect with the target obit first, and adjust the period at the intersection later to get an intercept. And I often arrange the intersection at the AN/DN to save some plane change dV.