SyncMFD Hohmann transfer?

[the.punk]

Hello,
I alsways intersept with sync mfd in many orbits and several burns.
Is it possible to do a hohmann transfer with sync mfd. I mean to do one burn at the right point. Wait half orbit and the to level the orbits and the targets. Like intersepting with mars. I have done such with IMFD; but that isn't good for this job.
Is that possible with sync mfd?

Thanks.

 

[eveningsky339]

I don't know; I've never tried it. I've used the Transfer MFD to reach space stations in geo-synchronous orbit before, though.

 

[Linguofreak]

I myself hate sync MFD. It's a bit more efficient than other methods, but I just tend to use TransX.

Sync MFD is meant to be used when your orbital parameters are pretty much the same as the target's, but you're at a different place in that orbit than the target is. It's also meant to help you deal with this over multiple orbits, since that's more fuel efficient. So up to this point you've been using it as it's meant to be used.

If you want to do things more quickly, or your orbit isn't pretty close to the target orbit to begin with, Sync MFD just won't work well (and in extreme conditions, probably won't help you at all), so you'll probably want to learn how to use TransX.

 

[Tommy]

It's very difficult to do this, essentially you have to guess when to burn prograde to put the AP in the right place. SyncMFD in Intercept 1 mode should show you arriving a few seconds after the ISS (if you are coming from a lower orbit), that way you'll be able to perform a prograde burn at your Ap to match orbits and be just behind the ISS. It's all about the timing of that first burn, and it's very difficult to get that just right. Often it's easier to to establish the transfer orbit an orbit or two before rendesvous, and make a small burn at your Ap on the second to last orbit to adjust the DTim to be just a few (2 - 5) seconds behind the ISS.

 

[the.punk]

I don't know; I've never tried it. I've used the Transfer MFD to reach space stations in geo-synchronous orbit before, though.

This was what I mean: Intersepting with a space station in higher orbit that mine.

I myself hate sync MFD. It's a bit more efficient than other methods, but I just tend to use TransX.

Sync MFD is meant to be used when your orbital parameters are pretty much the same as the target's, but you're at a different place in that orbit than the target is. It's also meant to help you deal with this over multiple orbits, since that's more fuel efficient. So up to this point you've been using it as it's meant to be used.

If you want to do things more quickly, or your orbit isn't pretty close to the target orbit to begin with, Sync MFD just won't work well (and in extreme conditions, probably won't help you at all), so you'll probably want to learn how to use TransX.

Thank you for the answer. I trie it with TransX. I'm no transX newbie, but I never used it for intersepting with ships.

 

[the.punk]

Tried it with TransX. Now I use TransX for intercepts for hohmann orbit and transfer with ships that are in a higher orbit that mine. (I:250km x 300; Target: 1000km). Sync mfd I use for ships with roughly the same altitude.
But I a question: I use "Ship periapsis" when I am ahead the target and "Ship apoapsis" when I'm behind the ISS.
But when must I use "Target periapsis" and "Tg apoapsis" as interception point?

 

[cinder1992]

I've found that IMFD can get you to stations in a +1000 Km orbit and it only takes one burn (unless your in orbit of jupiter, then things start to smell because of it's moons).

 

[the.punk]

I've found that IMFD can get you to stations in a +1000 Km orbit and it only takes one burn (unless your in orbit of jupiter, then things start to smell because of it's moons).

How did you do that?

 

[cinder1992]

pressed couse>target intercept

you gotta be carefull though. sometimes it rams you strait into the earth (or wherever you are)

 

[Tommy]

you gotta be carefull though. sometimes it rams you strait into the earth (or wherever you are)

Before pressing AB in Target Intercept, check Orbit Eject (set to course) to check your TEj. Orbit Eject will allow you to find a TEj that allows a burn that won't take you into the planet, and you can use the TEj from Orbit Eject in Target Intercept. In Fact, you should be able to use the AB in Orbit Eject instead of Target Intercept (even if you aren't actually ejecting), which is designed more for making MCC's than for doing the transfer burn. Target Intecept's AB doesn't account for your current position in your Orbit, meaning it will burn in whatever direction (Prograde, Retrograde, inward, outward, etc the course dictates. Using Orbit Eject allows you to tune your TEj so that your burn is in as close to a prograde direction as possible, which is safer and more efficient.

 

[Salamander]

But when must I use "Target periapsis" and "Tg apoapsis" as interception point?

i use those to intercept targets in elongated orbits from a nearly circular orbit that just touches the target orbit.

as example, target orbit periapsis is at 400km altitude, apoapsis at 1000km. first i raise vessel orbit to 400km, then circulize. now the ship apoapsis and periapsis roll around the orbit so much as to be unusable with sync mfd, but the orbit touches the target orbit at it's more stable periapsis.

likewise if the ship's orbit is originally higher than the target apoapsis, i adjust ship orbit to barely touch the target's apoapsis in a circualr orbit, and then take it from there.

the tricky part there is to get the timing right in just one orbit.

 

[the.punk]

i use those to intercept targets in elongated orbits from a nearly circular orbit that just touches the target orbit.

as example, target orbit periapsis is at 400km altitude, apoapsis at 1000km. first i raise vessel orbit to 400km, then circulize. now the ship apoapsis and periapsis roll around the orbit so much as to be unusable with sync mfd, but the orbit touches the target orbit at it's more stable periapsis.

likewise if the ship's orbit is originally higher than the target apoapsis, i adjust ship orbit to barely touch the target's apoapsis in a circualr orbit, and then take it from there.

the tricky part there is to get the timing right in just one orbit.

Yeah. Thank you.