Flight Question DG to ISS sync orbit help

sinncier

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I'm having trouble syncing orbit in the DG to ISS Checklist Mission 1.
How can i bring the DTmin time to 0.00 without gaining ALT. When i get the DTmin in SH Periapsis down to zero my ALT rises and when i do intercept the ISS i'm too far to make a dock because of the ALT difference, when i burn to drop or raise my ALT to match it with ISS at the apT, my DTmin raises. WTH, help.
 
I would suggest using intercept 1 or intercept 2 instead of SH Periapsis. Normally, you'll launch into a lower orbit than the ISS and catch up to it. Try for a circular orbit of 250k - 300k altitude and get your planes aligned. Then see where the ISS's periapsis is (the hollow dot on its orbit). If you have "non-sphereical gravity sources" turned on, it will move back and forth - just aim for the center. You will make a prograde burn when you get to the OPPOSITE side of the earth. Just "eyeball it" best you can. When you get to that point opposite the ISS's Periapsis, burn prograde to raise your ApA to just above the ISS's PeA. Now, set Sync Orbit MFD to intersect 1, and press the <LEN> button. Type in 9 then press enter on you keyboard. This will show more orbits. Now coast up until just before your Apoapsis. All of the sync burns will be made here, at our apoapsis. This should also be very close to the intersect point shown on SyncMFD. If the highlighted orbits are more than 5 orbits away, fast worward until they are about 5 orbits away. Egage prograde autopilot. Just a few seconds before ApoApssis, engage a bit of main engines, just a tap or two. Watch the DTmin in Sync to get close to zero - this will probably push the rendezvous down the list an orbit or two. You can use RCS thrusters in linear translation mode (6 and 9 keys) to fine tune it Once you are approaching your last orbit, fine tune the DTmin when you reach your Apoapsis. DTmin may change during an orbit, but it tends to return to it's original value when you get back to where you started from, so don't worry if it drifts - it just needs to be very close to zero when you are at the intersect point. Durning the last 1/8th of an orbit before the actual rendezvous, you can use prograde autopilot and linear RCS to tune the DTMin a bit. Once you are within 5k of the ISS, or you stop getting closer (whichever comes first) use Dock hud mode to null relative velocity, move in, and dock.
 
you gotta do your sync' burn at a point of intersection with the target's orbit

i always use intersection 1 or 2 mode... when i'm off track and feeling lazy, then i use tgt-periapsis....

if you use your OWN periapsis, there's no way you can ensure your altitude will be the same as that of the station once you get there - so always use a reference that's related to the target's orbit

that way, you'll make that point your periapsis as you accelerate, and when you meet with the station, you'll be in the same altitude :thumbup:
 
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