Several flights in atmosphere.. bad ending? [physics bubble]

[ilo]

Hi there! I'm working on the space station, providing (this time) with safety for the kerbals (Sorry for that!!!). I've included a few emergency capsules to return back to kerbin, I tried them and then.. well.. :'( POOR KERBALS!!!!

I tested one pod.. Decoupled, throttled retrograde.. atmosphere reentry was ok, parachute worked. Good. CHECK! Tried the same while focused on other vessel resulted in a dead kerbal. From my understanding the physics and parachute will only work if the vessel is the 'active' one, right? Otherwise it will just entry the atmosphere and crash into kerbin without hesitation.

If this is the case, what is the best approach to surpass this situation? On an emergency I'd like to send all pods back to kerbin, but I think it will not be safe to send all of them at the same time, right?

Edited February 23, 2015 by ilo

[Streetwind]

Only the active vessel is actually simulated.

All other vessels are considered "on rails" - the same thing that happens when you timewarp. Ships that are on rails do not interact with anything and do not execute any actions.

In addition, on-rails ships that get too close to a planet's surface get deleted outright. For Kerbin, that happens somewhere around 20km altitude. So your unfocused pod didn't even crash... it was simply removed before it got that far.

[Snarfster]

If the vessels stay within 2.5 km of each other they will be simulated.

I deployed by Laythe base that way. 4 modules with a parachute each all connected to a frame via decouplers.

At 5000 meters I popped all chutes and hit the decouplers, all 4 modules landed safely.

EDIT: If you do this too high up and they drift beyond 2.5 km, they will be lost.

[AlexinTokyo]

This is a function of how the game handles non-focused craft.

Any craft outside the 'physics bubble', a sphere of about 2.5 km radius centered on the currently controlled craft, is deleted completely if it goes below 23 km altitude on Kerbin (other heights on other atmospheric bodies). This represents it either burning up in the atmosphere or crashing, which is fine, but it doesn't take into account whether the craft could be controlled, or whether it has activated parachutes.

To work around it, you have two options - stagger the deorbit burns on your rescue craft so that craft 1 lands before craft 2 reaches 23 km, and so on down the track; alternatively, make sure that no more than 2.5 km separates all escape pods on the way down (this is the harder of the two).

Alternatively, if you don't mind mods, there are mods that expand the physics bubble (at the cost of performance) which would alleviate the issue.

[ilo]

Thank you!! problem "solved".. sort of!

Next steps:

- find those mods

- find more information about the "physics bubble"

[Snarfster]

You could make a stack of escape pods and de-orbit the stack. Then separate them at lower altitude. That way you ensure they land close together and are within physics range of each other.

[eddiew]

If you're not averse to a (lightweight) mod, Stage Recovery can solve this for you.

Whenever something that's not currently active drops below 20km altitude on Kerbin, it'll check to see if it has parachutes, or engines and a probe core, and figures out the typical landing velocity at sea level. If you can come down at less than 12m/s then it'll recover the vessel, crew, science, etc, at an appropriate % return for your distance from KSC