Why can't I de-orbit two ships at the same time?

[Klapaucius]

I had this weird thing happen.  I had a rocket that contained 3 Mk-1 command pods linked together (a money saving scheme for the Orbit Bootcamp challenge.)

 

Upon re-entering the atmosphere, I had two of the pods in close proximity.  I was able to switch between the two and see that both chutes had deployed. However, at a certain point it no longer allowed me to switch. So I monitored the progress in the orbital view. The other ship, despite a deployed chute hit the ground at an absurd speed.

 

I had a quicksave, so I tried again.  This time I was focused on the ship that had crashed last time. That one landed just fine, and the other now disappeared. You can see this in the video below (I had Mahler 9 playing in the background, in case you are wondering, and OBS picked it up.)

 

The third ship was still fairly high up by the time the other capsule landed. I was able to go back to orbit view, switch control to that ship and land safely.  So, two pods survived and one did not. Is there some issue with multiple ships in atmosphere?

 

Added to this, I have noticed that despite putting chutes on my spent stages, I never seem to recover any of them. They just vanish.  I thought we were supposed to be able to do that? In one case I saw the chute deploy yet there was nothing upon my return to the launch pad.

 

Thoughts on either of these issues?  I don't know whether this is a bug or a core part of the game, so I have posted it here.  You can see in the video below that the ship disappears from the radar at 

 

 

[AHHans]

23 minutes ago, Klapaucius said:

Upon re-entering the atmosphere, I had two of the pods in close proximity.  I was able to switch between the two and see that both chutes had deployed. However, at a certain point it no longer allowed me to switch. So I monitored the progress in the orbital view. The other ship, despite a deployed chute hit the ground at an absurd speed.

What happened was that the two pods got more than (AFAIK) 2.5 km apart from each other. At that distance from the currently controlled craft the other craft are unloaded, i.e. they are removed from the game engine, the physics for them is no longer calculated and they follow ballistic "orbits". If such an orbit gets too close to an planetoid (or too deep into the atmosphere) the KSP just assumes that it crashed and removes the craft from the game. (For Kerbin that is if it gets below 20 km altitude.) Because no physics is calculated for that not-loaded craft it doesn't matter if there are parachutes on it or not.

[Klapaucius]

17 minutes ago, AHHans said:

What happened was that the two pods got more than (AFAIK) 2.5 km apart from each other. At that distance from the currently controlled craft the other craft are unloaded, i.e. they are removed from the game engine, the physics for them is no longer calculated and they follow ballistic "orbits". If such an orbit gets too close to an planetoid (or too deep into the atmosphere) the KSP just assumes that it crashed and removes the craft from the game. (For Kerbin that is if it gets below 20 km altitude.) Because no physics is calculated for that not-loaded craft it doesn't matter if there are parachutes on it or not.

Thank you. That explains a lot.  I've gone back and got the individual ships more separated so that they hit the ground at very different times. That seems to solve the problem.

[DeadJohn]

1 hour ago, Klapaucius said:

...Added to this, I have noticed that despite putting chutes on my spent stages, I never seem to recover any of them. They just vanish...

There are severals mods that can help with this. You can use 1 of them or all 3 together. I prefer StageRecovery because it needs less micromanagement. FMRS can be fun, though, when you want to control SpaceX style booster landings.

 

 

[Klapaucius]

@DeadJohn  Thank you for the links.  This is really cool stuff I think I will be using.

[fourfa]

Also, if you just wait to separate the three pods until you’re through reentry and mostly falling vertically, all three will then stay within the 2.3km fine-physics bubble and function properly

[Reactordrone]

11 hours ago, Klapaucius said:

Thank you. That explains a lot.  I've gone back and got the individual ships more separated so that they hit the ground at very different times. That seems to solve the problem.

Just be careful about time warping when you have multiple ships on parachutes. physics warp is fine but if you land and time warp it will kill the chutes on anything that hasn't landed.

[HvP]

It seems that your question has already been answered but...

13 hours ago, Klapaucius said:

I had Mahler 9 playing in the background

I just wanted to compliment you on your musical tastes. Although, I'm particularly partial to his second.

[Klapaucius]

1 hour ago, HvP said:

It seems that your question has already been answered but...

I just wanted to compliment you on your musical tastes. Although, I'm particularly partial to his second.

So am I, actually. 2 and 8.

[linuxgurugamer]

You might find this enlightening:

 

[Klapaucius]

42 minutes ago, linuxgurugamer said:

You might find this enlightening:

 

I just watched it.

[Laie]

On 4/16/2020 at 4:41 PM, Klapaucius said:

Thank you. That explains a lot.  I've gone back and got the individual ships more separated so that they hit the ground at very different times. That seems to solve the problem.

That's the only safe approach in the stock game.

When trying to recover boosters, I've seen them disappear right in front of my eyes at relatively short distances, might have been as little as 200m.

[jimmymcgoochie]

On 4/17/2020 at 6:26 AM, linuxgurugamer said:

You might find this enlightening

How do you use physics warp (x2-x4) in space? Could be useful for some particularly slow running games where it drops as low as 1/5 speed...

[linuxgurugamer]

29 minutes ago, jimmymcgoochie said:

How do you use physics warp (x2-x4) in space? Could be useful for some particularly slow running games where it drops as low as 1/5 speed...

Hold Alt->

However, it won’t for slow running games. Look at the clock in the upper left, if it is yellow physwarp won’t help a lot, and if it is red, physwarp wont help at all