Map & Tracking Station Wrong trajectory prediction through SOI changes for many bodies (affects planetary return missions)

[Starhawk]

Overlapping bug reports merged yet again.

[Draradech]

While experimenting at different planets I first noticed (at moho) that it isn't just a flip prograde / retrograde. Moho showed radial out for what should be prograde. At Jool I noticed that the rotations are not multiples of 90 either (Jool has a mix of prograde and radial out for what should be prograde). I also noticed that the camera orientation changes when switching focus from the parent body back to the vessel and determined approximate angle differences for all bodies:

Moho	-85
Eve	-15
Gilly	-90
Kerbin	0
Mun	0
Minmus	-115
Duna	-135
Ike	0
Dres	-10
Jool	-50
Laythe	0
Vall	0
Tylo	0
Bop	-35
Pol	-15
Eelo	50

 

I edited the top post and changed the title.

[Scarecrow71]

Yeah, this needs to be one of the highest priority big fixes right now.

[Rubenio]

I've seen this behavior with simply trying to establish an orbit of Mun.  The SOIs are correct in the original display but the PE is not depicted on the Mun trajectory until AFTER the SOI.

[Scidleee]

Can confirm! Had to resort to infinite fuel just to get back from Duna. Felt dirty but had no choice.

[vianna77]

Well... I was post this bug but apparently it's happening to everyone.

Hopefully it will be fixed soon.

[Nnamleips]

I can confirm the bug. I had it on the way from Kerbin to Eeloo and back, and from Kerbin to Duna and back.

In both cases I had to make several corrective manoeuvres and the fuel I brought with me was too low although I had a reserve.

[pbau5]

I just hit this bug when leaving the Duna SOI for Kerbin intercept. I tried reloading, quitting, pasing through SOI at 1x speed. Nothing works. I've been working on weekly challenge 5 for weeks now, and every time I jump back in, I get another experience breaking bug like this. Here's to patch 2

[chargan]

7 hours ago, pbau5 said:

I just hit this bug when leaving the Duna SOI for Kerbin intercept. I tried reloading, quitting, pasing through SOI at 1x speed. Nothing works. I've been working on weekly challenge 5 for weeks now, and every time I jump back in, I get another experience breaking bug like this. Here's to patch 2

If you're in the correct launch window, just do a burn of around 650m/s on Duna's sunny side. Once you exit the SOI you can do the course corrections in Kerbol orbit to get a Kerbin intercept.

[pbau5]

Report back if patch 2 fixes this!

[LameLefty]

I have a "post-burn/pre-SOI transition" save I can load up and check but it will be a few hours until after work before I can check it.

[Scarecrow71]

Confirmed this is NOT fixed in patch 2.

 

[pbau5]

That's very sad. That was game breaking for me. Hours and hours of running my dV numbers and staging tweaks to pull off the perfect mission, and then BOOM orbit nuked.

[Dakota]

Going to post in here too:

We're aware of this issue and are looking into it. Do not currently have a timeline.

[axtpg2i]

This is a puzzling error. However, it seems to have little impact on me personally. When I need to perform interstellar transfers, I always accelerate to the speed just enough to escape from the planet first, and then perform orbital maneuvers to reach other planets. I understand that this approach is not very common in the real world, but it should basically eliminate the impact of this error.

[LameLefty]

9 hours ago, axtpg2i said:

This is a puzzling error. However, it seems to have little impact on me personally. When I need to perform interstellar transfers, I always accelerate to the speed just enough to escape from the planet first, and then perform orbital maneuvers to reach other planets. I understand that this approach is not very common in the real world, but it should basically eliminate the impact of this error.

This is more tenable from a planet with a reasonably sized SOI that you can escape from in short order (hours). Leaving from Jool SOI, it is much less so. This is because when you are leaving the SOI, it is so large that it takes DAYS to escape. By the time you’ve actually exited the SOI and plan your return burn, your phase angle is substantially different. This makes planning with any degree of optimization really difficult. As I’ve noted elsewhere several times, the net result is you still need to over-build your crafts to carry substantially more propellant and substantially less payload mass if you want to guarantee the ability to return. 

[Poppa Wheelie]

2 hours ago, LameLefty said:

By the time you’ve actually exited the SOI and plan your return burn, your phase angle is substantially different.

Since we'll have to use this "burn to leave the SOI and then make corrections" method for at least the near future (hopefully not for too much longer), and since it can sometimes take quite a while to actually exit the SOI, is it a reasonable approach to time the initial escape burn so that we are exiting the SOI right before the transfer window time?  If, for example, it will take 5 days to exit the SOI, then do the escape burn 5 days before the transfer window time.  I haven't tested this out yet, but it seems like this should minimize the dV requirement of the correction.

[Kim Hanson]

Version: 0.1.2.0
Windows 11 Pro
12th Gen Intel(R) Core(TM) i5-12600K   3.70 GHz
NVIDEA GeForce RTX 3070

no mods

Although returning from Minmus is fairly easy, the maneuver planner suggests it is impossible.   A retrograde burn will drop you back toward Kerbin and can easily be fine tuned on the fly, but the maneuver planner says you will go into a nearly circular orbit around Kerbin once you leave the Minmus SOI.  If you continue burning, the planner says you will enlarge the orbit around Kerbin and eventually exit the Kerbin SOI and go into orbit around Kerbol.  This of course is nonsense and no such thing will actually happen, this is just a bug in the maneuver planner for Minmus alone (are there others like this?).  This has been persistent since the initial release.

Edited April 19, 2023 by Kim Hanson

[Poppa Wheelie]

This same scenario has been reported for returning to Kerbin from Duna.  I don't know if there are other planets with the same issue.

[Scarecrow71]

To add to this, I noticed this bug today (patch 0.1.2.0) while returning from Minmus.

[Guest]

Bump. Also had this yesterday going from Duna to Kerbin.

[Anth]

@Kim HansonMerged your bug report with this one.

[RickJM694]

Reported Version: v0.1.3 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 10 | CPU: Intel I7-4790 @360GHz | GPU: MSI Gaming GeForce RTX 2060 6GB GDRR6 | RAM: 16GB

 

When orbiting Duna, and attempting to return to Kerbin, I encountered a bug where the maneuver nodes show the opposite effect of what they actually do. So a node that should show you decreasing your solar orbit to return to kerbin, shows you increasing it. once you execute the burn, it still shows this as your trajectory, but once you exit Duna's SOI, it corrects itself.  This bug is making it extremely difficult to get my brave kerbals home. I have attached videos of both a burn that should take you back to the inner planets in relation to Duna, and a burn that should take you to the outer planets in relation to Duna.  Both nodes show the opposite happening, and trajectories are incorrect until exiting Duna SOI, at which point they correct themselves.

 

severity is low, as it is still possible to do returns, but it is extremely annoying.

 

Included Attachments:

Desktop2023_06.28-00_08_34_05.mp4

Edited June 28, 2023 by Anth12

[Anth]

@RickJM694 Merged your bug report with this one.

[Dakota]

This bug was resolved in hotfix v0.1.3.2.