Impossible contract?

[VenatoS]

The missions gives very specific details on the Apoapsis and Periapsis but u can't get it perfectly to every meter its impossible.

I have made it pretty much as close as I can be but still the mission won't complete itself.

Please help.

[Richy teh space man]

Maybe it needs to be going in the other direction..?

[Elveswarrior]

you going the wrong way

[Jenteb07]

Or, go to tracking station and back

[VenatoS]

Yeah I think it might be the direction. but i have no idea how to switch it!?

[KerbMav]

Maybe it needs to be going in the other direction..?

Oh yes, this my first booboo in the first sat-contract I accepted ...

[VenatoS]

Yep the direction was the problem. I managed to fix it! Thank you very MUCH! <33

[J.Random]

If you look closely at the target orbit, you'll see dots following it. You should go in the same direction.

[colonel0sanders]

Yeah I think it might be the direction. but i have no idea how to switch it!?

The straight forward (and inefficient) way is to make a note of your orbital velocity, and then burn exactly twice that much pointing exactly retrograde

[Snark]

If you look closely at the target orbit, you'll see dots following it. You should go in the same direction.

Another handy indicator: check the ascending/descending nodes. If they say some number close to 180 rather than close to 0, you're backwards.

[arq]

I rarely look at the actual numbers for apo/peri. The tolerance is generous enough that one can get the contract just by lining them up in map view. I, too, have launched satellites the wrong direction and sat there puzzled for several minutes trying to figure out why I hadn't accomplished the contract yet.

[Wanderfound]

I rarely look at the actual numbers for apo/peri. The tolerance is generous enough that one can get the contract just by lining them up in map view. I, too, have launched satellites the wrong direction and sat there puzzled for several minutes trying to figure out why I hadn't accomplished the contract yet.

It's a rite of passage; the old Fine Print ​thread used to have this come up once every three or four posts.

[Grunnt]

Oh I hate going the wrong way on these contracts, happens to me all the time.

[Temeter]

Happened during my first satellite contract, too. Luckily enough i've got a tendency to overdesign light satellites, so I could just turn my orbit around.

[Caelib]

This problem comes up quite often, to which I have canned response:

[Uncle Mort]

Yep, we've all done it; and never have enough delta V to flip the orbit.

[Kuu Lightwing]

Yep, we've all done it; and never have enough delta V to flip the orbit.

Bi-elliptic transfer is your friend

It's actually could be your friend even if you just need to put it into orbit

[cephalo]

Bi-elliptic transfer is your friend

It's actually could be your friend even if you just need to put it into orbit

So I ran to wikipedia, and I can't see how this allows you to flip the orbit. Please explain.

[Kuu Lightwing]

You boost your apoapsis waaaay out, and then reverse orbit in apoapsis. That would cost you much, much less than just burning retrograde for 2x your orbital velocity.

For example, you need to reverse your 100km LKO. You spend about 900 m/s of dV to boost your apoapsis to Minmus orbit, then about 550 m/s of dV to reverse the orbit, and then another 900 m/s to circularize. That makes it ~2350 m/s maneuver, compared to like 4500 m/s you'll need to reverse it directly. And if you boost your apo a bit higher, you'll save even more, I think.

[cephalo]

You boost your apoapsis waaaay out, and then reverse orbit in apoapsis. That would cost you much, much less than just burning retrograde for 2x your orbital velocity.

For example, you need to reverse your 100km LKO. You spend about 900 m/s of dV to boost your apoapsis to Minmus orbit, then about 550 m/s of dV to reverse the orbit, and then another 900 m/s to circularize. That makes it ~2350 m/s maneuver, compared to like 4500 m/s you'll need to reverse it directly. And if you boost your apo a bit higher, you'll save even more, I think.

Niiice. Thanks for that.

[Archgeek]

Just watch out for the mun on the way out and back. It likes to interfere. Though you may be able to use it to cheapen the manuvre further.

[Caelib]

Inclination changes are also much cheaper in terms of delta-V the higher you are at the point of ascending/decending node/burn. I believe the ISS raises its orbit when it needs to do inclination changes.