Contract Won't Complete

[Popestar]

So, I picked up a contract in my career game to put a satellite into a specific orbit.  As you can see in the attached image, the contract details state:

• Ap of 16064820 meters
• Pe of 14825107 meters
• 180 degrees of inclination
• Minor variation is allowed

As you can also see in the image, I've got:

• Ap of 16067500 meters
• Pe of 14822600 meters
• 0.266 degrees of inclination

If you check the orbits, the pink line is where Probodyne wants this, and the blue line is where I'm at.  I have gotten as close as I can to the actual ring; any changing of Ap or Pe on my end results in the blue ring going either way inside or way outside the pink circle.  I also tried using the pink handles on maneuver nodes, and I've got the blue ring about as close to equatorial as I can get it.  And yet, no matter what I do, the contract is not completing.  I thought that perhaps it was due to the satellite still being attached to the engine with some structural stuff yet, but you can see that the requirement of 10 seconds of stability is checked green.

What am I doing wrong here?  Why won't this contract complete, and what do I have to do to get this done?  I'm asking this up front because, as you can see in the image, I've got a second contract for another satellite to do after this one, and whatever I'm doing wrong here I need to correct before I do the second one.

Help!

[Wobbly Av8r]

Yeah - this problem occurred recently - you'll have to *roughly* match up Ap and Pe... then it will complete. Revert is good thing...

[Popestar]

51 minutes ago, Wobbly Av8r said:

Yeah - this problem occurred recently - you'll have to *roughly* match up Ap and Pe... then it will complete. Revert is good thing...

There is no way to revert; the game has auto-saved multiple times since launch, which means that I have to load a saved game and start from the launchpad again.  Is there no way to get this to show completed, sans hacking the save game file?

[Wobbly Av8r]

Well, of course there is a way to adjust the orbit - create a maneuver at the point where the two orbits intersect and then perform a "radial in" or "radial out" burn, depending on which intersection you're at...

[Edit: if you're in the same position as above, a "radial in" burn [[ at the intersection just prior to the required orbit's AN, from what I can see ]] will reorient your current orbit towards the required one...]

 

[Edit second: I'm assuming the variation in inclination will not be significant, but if it IS beyond tolerance, you would want to adjust the inclination AT the AN BEFORE performing the radial in burn... but because the AN is BEYOND the first intersection I described above, you would do the intersection burn at the OTHER intersection (the one that is closer to the current DN) and in THAT case it would be "radial out" burn. Hope that isn't too confusing...]

Edited October 28, 2020 by Wobbly Av8r
clarification

[Popestar]

10 minutes ago, Wobbly Av8r said:

Well, of course there is a way to adjust the orbit - create a maneuver at the point where the two orbits intersect and then perform a "radial in" or "radial out" burn, depending on which intersection you're at...

[Edit: if you're in the same position as above, a "radial in" burn [[ at the intersection just prior to the required orbit's AN, from what I can see ]] will reorient your current orbit towards the required one...]

Radial in/out are which handles again?  I can't ever remember if that's the pink or blue ones...

[jimmymcgoochie]

You need to match the orbit shown on the map/tracking station. The contract parameters don’t list things like Longitude of Ascending Node or Argument of Periapsis, so don’t rely too heavily on those and always- ALWAYS- use the orbit on the map.

[Wobbly Av8r]

Radial IN

Radial OUT

Edited October 28, 2020 by Wobbly Av8r

[Wobbly Av8r]

If you don't have enough dV to make the Radial burn (it is fairly inefficient), the other solution (other than adjusting the inclination at the AN or DN) is to wait until you are abeam the required orbit's Ap or Pe and perform a prograde or retrograde burn, as appropriate - in other words, you would be stretching and contracting your current orbit AT the points that need to become the Ap or Pe...

If you have the time, this burn would be more efficient but would take the time to get through the various points of the orbit.

[ Edit: here is a link to the same kind of question ]

 

Edited October 28, 2020 by Wobbly Av8r

[HansAcker]

1 hour ago, Popestar said:

180 degrees of inclination
..
0.266 degrees of inclination

You're going the wrong way.

[Wobbly Av8r]

20 minutes ago, HansAcker said:

You're going the wrong way.

Huh. Well, now that you mention it... @Popestar are you sure you don't want to try and revert?!?

Good catch, @HansAcker!

Re: my recommendations to adjust orbit... "Nevermind!"

Edited October 28, 2020 by Wobbly Av8r

[Popestar]

19 minutes ago, HansAcker said:

You're going the wrong way.

Ugh.  So I have to pitch the other direction off the launch pad.  Sigh.

Well, that's on me for being in the mindset of always pitching East!

[HansAcker]

5 minutes ago, Wobbly Av8r said:

Good catch, @HansAcker!

I think that's a mistake probably every KSP player has done at least once :) I know I have.
"Equatorial orbit, no problem. Huh, why won't it complete? Uhh, why is the orbit line moving in the other direction?"

(And just recently, I landed a group of tourists on the wrong moon... I blame the pilot!)

[Popestar]

And I'm ready to give up.  I launch, pitching west this time, and my inclination isn't bad (I know I have to change that once I get into orbit, but not a big deal).  But my issues come when I start stretching that orbit out.  I go slowly, so that my Ap is never that far away from me Pe, going little by little, consuming as little fuel as possible.  And then when I get farther out there...I get all these stupid lines from every celestial body, and I can't figure out which one is mine and which one isn't.  And then, to make matters worse, no matter where I try to set the maneuver node, my inclination gets all wonky.  I'm currently sitting, without touching the radial buttons, at almost 90 degrees.  That's right - after pitching west to make sure I'd be close to 180 degrees, I am somehow pointing north/south.  What.  In.  The.  Holy.  Frak.

I'm ready to give up.  I cannot see what I am supposed to be doing thanks to all of the stupid orbit lines in every color you can think of.  No matter where on the orbit I put a maneuver node, the inclination gets wonky.  I cannot now seem to get to the right Ap or Pe; every time I get a maneuver close to either one of those the maneuver starts freaking out like I'm attempting an escape trajectory from either Kerbin or the Mun.

What am I doing wrong?

[Wobbly Av8r]

Just to make sure we're on the same page, a 180° inclination/inclined orbit is a heading of 270°.

Assuming that you were to keep your vessel oriented to prograde so that you're always heading in the direction of travel as you orbit Kerbin, an inclined orbit is a "great circle" that only initially maintains the heading (from the equator) that establishes the orbit, after which it oscillates in heading as it moves around the body. Take a look at the image below:

If you maintain a powered constant heading throughout the burn (black line = same angle/heading), you will eventually end up over the pole as illustrated by the black line on the right - because as you proceed further north, the lines of longitude converge and your flight path will "curly-cue" up to the pole and no matter which way you turn at the north pole you're flying south! A true inclined orbit actually changes/oscillates heading as it proceeds around the body, similar to the red-dashed line, which when looked at on a flattened map (left) looks like a sine wave.

Edited October 29, 2020 by Wobbly Av8r

[Spricigo]

7 hours ago, Popestar said:

  I go slowly, so that my Ap is never that far away from me Pe, going little by little, consuming as little fuel as possible.

Unfortunately that is not an efficient way to raise your orbit.

Just make a Hohmann transfer

   

 

Well, is also a shame no one noticed it at the time, but 1400m/s of deltaV was probably enough to flip the orbit, all you had to do was to burn retrograde.

Which bring us to an important fact for the issue at hand: for a orbit above the Mun is actually cheaper to revert the orbit at the apoapsis burn of the Hohmann transfer then to launch west.

 

 

[Superfluous J]

42 minutes ago, Spricigo said:

Which bring us to an important fact for the issue at hand: for a orbit above the Mun is actually cheaper to revert the orbit at the apoapsis burn of the Hohmann transfer then to launch west.

That's pretty interesting, actually. I wonder what other things would benefit from this idea. Asteroid encounters are one, if their Pe is near the equator it's probably better to do a "normal" launch, get your Ap way out as far as is practical, then do the orbit adjusting way out there.

[Fierce Wolf]

8 hours ago, Spricigo said:

Which bring us to an important fact for the issue at hand: for a orbit above the Mun is actually cheaper to revert the orbit at the apoapsis burn of the Hohmann transfer then to launch west.

IS IT?

Never tried it

[DerkyJerkyWreaksHavoc]

@Popestar your orbit might be aligned correctly with the periapsis and apoapsis but you might be orbiting backwards and your inclination appears to be wrong in your description. that's why the contract isn't complete. hope this answers your question.

Sincerely, DAFATRONALDO2007 IN SPACE

[Spricigo]

2 hours ago, Fierce Wolf said:

IS IT?

Never tried it

Just think about it: how much it costs a full reversal? Twice the initial velocity.

At the launchpad the craft have 175m/s (from Kerbin's rotation)

At LKO it will have around 2km/s

But at the apoapsis of a high elliptical orbit that may be just a few dozen m/s.

The possible issue is if you end up just a couple of degrees out, it may take a lot of time to reach the AN/DN.

11 hours ago, Superfluous J said:

That's pretty interesting, actually. I wonder what other things would benefit from this idea. Asteroid encounters are one, if their Pe is near the equator it's probably better to do a "normal" launch, get your Ap way out as far as is practical, then do the orbit adjusting way out there.

 

That's the way I do. "As far as is practical" in that case means it stays in Kerbin's SoI and allow for rendezvous with the asteroid at a convenient time. And "convenient time" means either soon after the  asteroid enter the SoI (if considerable saving can be done by lowering the Pe) of soon before the Pe (just in time for the capture burn)

 

 

 

 

 

[Superfluous J]

1 minute ago, Spricigo said:

And "convenient time" means either soon after the  asteroid enter the SoI (if considerable saving can be done by lowering the Pe) of soon before the Pe (just in time for the capture burn)

I always meet asteroids at Pe, then slow them down just enough to not go anywhere, and then either burn way out at Ap or get a Mun encounter (or both) to do the actual moving around. Either of the strategies (far out to tweak Pe right away or accept Pe for the first pass and fix it later) works, and I don't think - properly executed - either is much better than the other in general.

But if you're meeting at Pe and have the time, it seems launching directly East is  better in a lot of cases than (what I've always done and just assume was best), launching into the correct orbit from KSC by skewing your launch direction.

Granted, polar orbits don't cost as much extra as retrograde orbits, and skewed orbits in different directions cost different amounts, but I'm at least going to look into it next time.

[Spricigo]

@Superfluous J, rather than deltaV savings (as you said, is not a dramatic difference) what I feel like is advantageous in adjusting the orbit later is not being so much 'in a rush' to plan and execute the maneuvers for the rendezvous. It gives me plenty of time for corrections and refinement.

That's the kind of difference you may barely notice (if at all) because you already got so used to launch directly into the correct orbit that it become second nature.  

[Wobbly Av8r]

While I agree with the premise of performing the reversal at Ap, I think the dV cost is a little higher - at 83Mm orbit I still was movin' along at 114 m/s.

Even so, the total maneuver, tho, from wrong way orbit, through Ap up to 83Mm (135 m/s) , reversal burn (230 m/s) and then bringing the Ap back to requirements (135 m/s) in the correct orbit took ~500 m/s dV and 56 days to accomplish without respect to the additional timing that would be required to match the rough Ap and Pe of the required orbit. FWIW.

[Corona688]

On 10/28/2020 at 2:59 PM, Popestar said:

Ugh.  So I have to pitch the other direction off the launch pad.  Sigh.

Well, that's on me for being in the mindset of always pitching East!

Always be paranoid when a contract pays suspiciously well :)

[Spricigo]

3 hours ago, Wobbly Av8r said:

While I agree with the premise of performing the reversal at Ap, I think the dV cost is a little higher - at 83Mm orbit I still was movin' along at 114 m/s.

That was because your periapsis was a little higher too. Take a look of how "fast" you'd going if you had keep your periapsis at 80km:

Spoiler

In any case what I proposed was not to take the extra time and deltaV to raise the AP above the target orbit.

My idea was just to take advantage of the fact that at the time the craft reach the desired height, above the Mun, following a Hohmann trajectory from LKO , the orbital velocity will be lower than the 'orbital' velocity at the launchpad (Kerbin's rotation). And I say above the mun because at the Mun height it happens to be:

Spoiler

 

And we are not even taking in consideration gravity losses, aero losses, lower Isp and all those lovely perks of launching into orbit.