Parachute not deploying

[exxaminer]

Hi, I'm trying to land a craft that's been orbiting Mun for some time, but the parachute (set to 0,01/1000) won't fire, not even a drogue chute - I end up crashing into water at around 340 m/s with chute icon saying Not Safe until the last second. I am pretty sure if the drogue chute fired at 500 m/s, which I guess it should, I'd be fine. Is there anything I can do to either slow down even more or deploy chute by force at my own risk? 

[Streetwind]

Drogues should definitely deploy at some point if staged.

Maybe some screenshots of the craft, and the situations in which you expect a deployment but it doesn't happen?

[EveMaster]

3 hours ago, exxaminer said:

Is there anything I can do to either slow down even more or deploy chute by force at my own risk? 

I don't know why your parachute did not work. But you can try entering the atmosphere at a shallower angle to slow down more.

You could also try turning your craft 180 degrees before entering the atmosphere if it is also stable in that direction. With the pointy end first you will slow down less than with the flat end first.

[AHHans]

13 hours ago, exxaminer said:

Hi, I'm trying to land a craft that's been orbiting Mun for some time, but the parachute (set to 0,01/1000) won't fire, not even a drogue chute - I end up crashing into water at around 340 m/s with chute icon saying Not Safe until the last second. 

O.K. So I take it that you are not talking about landing on the Mun(,*), and that the chutes are in the "not safe" condition all the time during your descent through the atmosphere. The latter means that the craft is too fast for the parachutes to deploy. That doesn't depend only on the speed but also on the air pressure, so a speed at which it is safe to deploy the chutes at 10'000 m is not necessarily safe at 1'000 m.

My guess is that you either have too little drag in the way you go through the atmosphere - if you reenter pointy end first then don't be surprised if your craft imitates a lawn dart -  or that you are reentering too steep and thus don't spend enough time in the atmosphere to slow down. Try setting your PE to something between 20 km and 30 km, if that doesn't slow you down enough to land in the first pass, then you probably also don't have enough drag to survive the landing.

P.S. (*) Yes, we did have a question here why parachutes wouldn't deploy on the Mun...

[exxaminer]

Hey guys, thanks for suggestions. Yes, I am landing on Kerbin, I have too little fuel (delta v around 70m/s) to park in orbit so i try almost every angle for reentry ranging from 10km to 50km and the result is still the same - even with the higher orbits where you gradually decrease Ap in several orbits. Moreover, although I always enter retrograde, at some point in the atmosphere the craft wobbles back to prograde and due to aerodynamics, I am never able to turn it back and I am pretty sure that is part of the problem. I guess it has something to do with the shape (module + 2 crew cabins - see screenshot). Is there any chance to salvage this, or my crew is destined to death on impact?

Orbit: https://drive.google.com/file/d/1lFijV03BdKOVQPfS9L7JDTdE9ADSVgCg/view?usp=sharing

Vehicle shape and seconds before impact: https://drive.google.com/file/d/1xVbyPb0gDCgFao5bOjE_mv2apij6UVQn/view?usp=sharing

 

Edited June 25, 2020 by exxaminer

[AHHans]

5 minutes ago, exxaminer said:

I guess the aerodynamics of my ship does not help (module + 2 crew cabins).

Well, yes, without additional torque this just isn't controllable during reentry. I also tried this but only got it to work with an extra Mk1 reaction wheel. (And even that was pretty iffy.) My solution for an early game 5 Kerbal tourist transport was to replace the lower crew cabin with two Mk1 command capsules that are nose to nose. That gives the craft a curious waist but it works.

If you have enough fuel, you could try to keep the propulsion stage and use the engine gimbal to keep the whole craft straight. I.e. run the engine during the aerobraking at just enough thrust to keep everything straight. (Set SAS to "surface", "keep retrograde", then check the control inputs in the display at the lower left: if one of them seems like it is going to max out then increase thrust, continue until the parachute deploys then ditch the engine.) But a) that is not guaranteed to work, and b) with only 41 m/s vacuum dV left in orbit (and probably a terrier engine) I don't think you have enough fuel left...

So my guess is that it's time for a rescue mission: park that craft in orbit and rescue the Kerbals with another ship (or ships). If Jeb is carrying around a load of tourists, then you can also only rescue Jeb at first, and then rescue the tourists when you have the Klaw unlocked. (Yes, tourists cannot go on EVA but can crawl through a Klaw.)

Or you can be nasty and only save Jeb: have him exit the craft once the danger of overheating is over and then have him land with his personal parachute. (If that are non-tourists in the crew cabins then you can try to save more than just Jeb. But that is going to be hard! You'll need to keep everyone inside the 2.5 km physics distance bubble around the currently controlled craft or Kerbal.)

[exxaminer]

1 hour ago, AHHans said:

I also tried this but only got it to work with an extra Mk1 reaction wheel. (And even that was pretty iffy.) My solution for an early game 5 Kerbal tourist transport was to replace the lower crew cabin with two Mk1 command capsules that are nose to nose.

Oddly enough, this isn't the first time I flight this thing - I used the exact same config for suborbital and orbital tourist flights and always managed to land safely, so I assumed that coming from moon wouldn't make much difference that could not be compensated by choice of re-entry angle. But apparently not :-( I even tried the extra shallow angles starting with 60km Pe and having several more eccentric orbits - which is painstakingly slow but the effect was little to nothing. 

That's why I wondered if it is possible to deploy chute in Unsafe or Risky state - otherwise, why the indicator with that many states is even there, right?

But it seems that easiest way would be to restore game to pre-flight and try again (I spent mabye 5 hours trying to land this thing, I could have launched it 6 times from scratch) - but I just wanted to try to save a doomed mission Apollo 13 style. We are leaving no man behind - not even tourists :-)

[exxaminer]

1 hour ago, AHHans said:

If Jeb is carrying around a load of tourists, then you can also only rescue Jeb at first, and then rescue the tourists when you have the Klaw unlocked. (Yes, tourists cannot go on EVA but can crawl through a Klaw.)

Hmm, I will try this though... ;-)

[Curveball Anders]

17 minutes ago, exxaminer said:

 I assumed that coming from moon wouldn't make much difference that could not be compensated by choice of re-entry angle. But apparently not :-( I even tried the extra shallow angles starting with 60km Pe and having several more eccentric orbits - which is painstakingly slow but the effect was little to nothing.

There's quite a lot more kinetic energy stored in your vessel coming back from Mün than coming down from a low Kerbin orbit.

When I end up in that situation (it happens, a bit more often than I like to admit) I try to set a Kerbin Pe just inside the Atmosphere (with a quick save far out you can test how far in you can go without burning up).

Then burn what dV you have left at Pe and use the aerobraking to to bring you home.

Edited June 25, 2020 by Curveball Anders

[Streetwind]

1 hour ago, exxaminer said:

That's why I wondered if it is possible to deploy chute in Unsafe or Risky state - otherwise, why the indicator with that many states is even there, right?

IIRC, you can. You have to right-click the chute while in flight and tell it to deploy when unsafe. Then later, when you stage it, it will ignore the safety assessment, and deploy solely based on the pressure parameters.

However, I would only do this for drogues, and only if you have more than one drogue, and even then only if you have a window where the safety warning label is yellow. Because if you force a deploy while red, chances are near-guaranteed that all of them will tear off instantly. When yellow, you may luck out and have at least one survive long enough to meaningfully affect your speed.

Remember, though, that crew cabins are fragile. If you lose some of your chutes on the way down, you may end up with exploding tourists upon touchdown.

[EveMaster]

7 hours ago, exxaminer said:

Moreover, I always enter retrograde, but at some point in the atmosphere, the ship wobbnes and ends up prograde and due to air resistance I can never recover - pretty sure it's part of the problem.

You can try to quickly spin the ship along the axis of travel when you enter the atmosphere retrogradely. This way your ship is spin-stabilized and you might slow down fast enough without flipping over.

[Cant think of a username]

If you entered kerbin right from the mun without going into kerbin orbit first, you could be entering at a fast speed. I don't know how you got pass reentry without burning up since two crew cabins plus a mk 1 command pod always blow up. If you have fuel, try entering kerbin orbit first. Then slowly burn your engine (pointed retrograde) just so that your craft drops below 70 km. Then just wait as your craft reenters (you might need to wait for an orbit or two before it clears reentry. Then you should be slow enought to slow down. I tested your craft and if you dive straight into the kerbin from the mun with no burns, well I burned up during reentry so I have no idea how you survived that. I turned on the ignore max temp cheat and tried again. It was coming in really fast. You will need to slow down a lot. Try adding the radical parachutes on the pod and the the crew cabins as well

[king of nowhere]

i ued to deploy parachutes when risky (yellow) all the time before i unlocked better pieces, i never had any malfunction.

i tried to deploy them on red a few times in bad situations, they always ripped immediately. they didn't even slow down the craft slightly, which was all i was hoping for.