Keep hitting mountains on re-entry (suborbital mission)

[JoeSchmuckatelli]

It's been 5/6 years since I last played, and I've forgotten soooo much!  Running a new career campaign, with a simultaneous mission to go out of the atmosphere and test a Flea on a suborbital run (130,000).  None of my buildings have been upgraded at all.

I've completed the steps for the missions 3 times... except I stick the landing too hard; hitting the mountains somewhere to the east of the launch facility and blowing up at 1500m.  (At least that's what I think is happening, b/c its the dark side... can't see terrain, but with the chute deployed and everything looking good... I keep killing Jeb at 1500m).

So - what am I missing?  Max altitude is about 300,000m (although on my 3d attempt I kept it under 250,000 - going for a shallower profile), and from watching my reentry burns I don't think I'm coming in too hot.  Do I just need to turn 90 degrees and aim for the south pole (no mountains)?

 

Thanks for any replies!

[Superfluous J]

Go into settings and crank up your ambient light so you can see what's going on. Or launch 3 hours later so when you're landing, it's daytime.

It sounds to me like either:

• Your parachutes aren't actually deploying, possibly because you're going too fast. They have a safety feature.
• Your parachutes deployed but got ripped off, probably because you're going too fast. As you can turn off the safety feature (but shouldn't).

If I had to guess I'd say you're coming in head-on. Your rocket is shaped so as to have very little drag when going forward, so you're plummeting into the ground like an arrow, or a bullet. You need to make sure your vessel is back-heavy so it will come down backwards. The easiest way to do this is to put a decoupler right under your capsule and decouple everything but the pod and the parachute. The pod itself is weighted to come down flat-part first, and you will (well almost) always come down slow enough for the parachutes to trigger.

[JoeSchmuckatelli]

7 hours ago, Superfluous J said:

Go into settings and crank up your ambient light so you can see what's going on. Or launch 3 hours later so when you're landing, it's daytime.

It sounds to me like either:

• Your parachutes aren't actually deploying, possibly because you're going too fast. They have a safety feature.
• Your parachutes deployed but got ripped off, probably because you're going too fast. As you can turn off the safety feature (but shouldn't).

If I had to guess I'd say you're coming in head-on. Your rocket is shaped so as to have very little drag when going forward, so you're plummeting into the ground like an arrow, or a bullet. You need to make sure your vessel is back-heavy so it will come down backwards. The easiest way to do this is to put a decoupler right under your capsule and decouple everything but the pod and the parachute. The pod itself is weighted to come down flat-part first, and you will (well almost) always come down slow enough for the parachutes to trigger.

I worried about the same thing during the first two attempts - and took a much lower flight profile on the third run to get a longer burn / better flight path.  I'm pretty sure it's mountains. 

Reentry vehicle is the basic pod with heat shield, goo, thermometer and barometer.  Even with a nice long reentry burn (heat indicator on the shield went about 1/2 way down during the reentry) and a fully grey chute icon before deployment - the chute fully deployed, btw, and I was hanging nicely - when I was rudely exploded, again, at 1500m.

 

I'm now thinking that I set the chute deployment for too low of an altitude for the wider variety of Kerbin landing zones - something I never did way back when - but I picked up on the option during the tutorials. 

 

Love this game!  Been grinding on how to run the mission and save Jeb all night 

[Vanamonde]

Drag and aerodynamics have been adjusted several times and it sounds like your ship is too slick, and you're coming too close to straight down. A shallower return gives atmo more of a chance to slow you down. The trick is, the descent angle is set by the ascent angle, so try to turn more sharply on the way up. And yes, if you over-do that, you waste too much dV and end up failing to escape atmo at all. It's tricky. 

[Laie]

4 hours ago, JoeSchmuckatelli said:

I'm now thinking that I set the chute deployment for too low of an altitude for the wider variety of Kerbin landing zones - something I never did way back when - but I picked up on the option during the tutorials. 

The standard chute that goes on the 1-person pod takes a very long time to deploy. It you're tweaking tweakables, set it to at least 750m -- that's the minimum altitude you can get away with for splashdowns, on higher ground it may take more.

If you don't tweak, the default 1000m should be as safe as it gets.

+1to cranking up ambient lighting in the gameplay settings -- once you can see, the problem will probably be obvious.

If for whatever reason you want to stay in the dark, please take note the last airspeed displayed on the navball. If it's much faster than 10m/s, the chute hasn't fully deployed yet.

Edited May 1, 2020 by Laie

[SchwinnTropius]

There should be a slider to change the full deployment altitude, and the default is 1000m. Maybe increase this to 1500, like I do. Or try an additional chute?

[RoninFrog]

31 minutes ago, SchwinnTropius said:

There should be a slider to change the full deployment altitude, and the default is 1000m. Maybe increase this to 1500, like I do. Or try an additional chute?

1000m should work as it's measured from ground level not sea level.  I often put mine around 600m.

[SchwinnTropius]

19 hours ago, RoninFrog said:

1000m should work as it's measured from ground level not sea level.  I often put mine around 600m.

Im a paranoid pilot, and I've had too many bad lithobrakings after stuff happened on reentry. I'm hoping the OP may find this useful, at least until they diagnose why they reliably blow up at 1500m.

[JoeSchmuckatelli]

1 hour ago, SchwinnTropius said:

Im a paranoid pilot, and I've had too many bad lithobrakings after stuff happened on reentry. I'm hoping the OP may find this useful, at least until they diagnose why they reliably blow up at 1500m.

I did resolve the problem - went much higher on the 4th attempt, clearing the mountain and also used a different setting for the chute. 

 

Whatever the reason... I survived! 

[mikegarrison]

I'm confused here. There are mountains *west* of the launch site. You have to go quite a ways east before you get much of anything but sea.

If you launch straight up, the planet will rotate under you and you will come down to the west. But your biggest problem here is that you should not launch straight up. In the old days you could come straight down and survive, but with the later generations of KSP you need to make at least some effort to re-enter at a shallower angle. Sub-orbital flights are actually harder to survive re-entry than orbital flights are, in many cases.

Still, it's always been the case in KSP that landing in mountains is quite dangerous. The air is thinner so parchutes don't work as well, and the game is perfectly happy to land you on the side of a cliff, autocut your parachute, and then let you fall down the cliff to your fiery death.

[LoneKharnivore]

1 hour ago, mikegarrison said:

you should not launch straight up. In the old days you could come straight down and survive, but with the later generations of KSP you need to make at least some effort to re-enter at a shallower angle.

It's also not a good idea because the pad is extremely sensitive to impacts. I've landed a craft at around 5 m/s and had the thing just explode under me.

Edited May 2, 2020 by LoneKharnivore
Trimmed quote.

[mikegarrison]

55 minutes ago, LoneKharnivore said:

It's also not a good idea because the pad is extremely sensitive to impacts. I've landed a craft at around 5 m/s and had the thing just explode under me.

I turn that nonsense off. Indestructible buildings FTW.

[JoeSchmuckatelli]

9 hours ago, mikegarrison said:

I'm confused here. There are mountains *west* of the launch site. You have to go quite a ways east before you get much of anything but sea.

If you launch straight up, the planet will rotate under you and you will come down to the west. But your biggest problem here is that you should not launch straight up. In the old days you could come straight down and survive, but with the later generations of KSP you need to make at least some effort to re-enter at a shallower angle. Sub-orbital flights are actually harder to survive re-entry than orbital flights are, in many cases.

Still, it's always been the case in KSP that landing in mountains is quite dangerous. The air is thinner so parchutes don't work as well, and the game is perfectly happy to land you on the side of a cliff, autocut your parachute, and then let you fall down the cliff to your fiery death.

So - somehow I resolved the issue, without fully figuring out what had been happening.  My 'victory' run had me landing quite a bit further away from the previous attempts.

My flight path was, indeed, East.  I did, also, go quite a ways around the planet - to the next continent on those runs.  The ambient light was so dark, I never could figure out what was happening; other than being at 1500 feet, with a chute deployed (fully) and then exploding.  The chute wasn't cutting out.  I would be decelerating in the darkness, over land, and then... boom.  So I figured it was merely a tall rocky thing that was getting in the way of an otherwise beautiful flight.

[ExtremeSquared]

Really the only reason to launch in the dark is if you are using your first stage as part of a transfer stage to an outer planet, and even then, it's sort of a likely-unnecessary advanced technique. You may as well launch at sunrise.

[mikegarrison]

1 minute ago, ExtremeSquared said:

Really the only reason to launch in the dark is if you are using your first stage as part of a transfer stage to an outer planet, and even then, it's sort of a likely-unnecessary advanced technique. You may as well launch at sunrise.

If you want to launch directly to Minmus, you want to launch when KSP is near the AN or DN of Minmus. But yeah, I prefer to launch and recover in the sunlight if I can.

[ExtremeSquared]

I'm saying the practice of launching to a 70+ km circular parking orbit and then taking your time waiting for an appropriate transfer is easier and practical in most scenarios. Direct launch to transfer would be unnecessarily frustrating to people who haven't played a fair amount. And the benefit is just a smidge of oberth efficiency and less orbital debris, which realistically shouldn't be a concern until you become a more neurotic ksp player.

[paul23]

On 5/1/2020 at 4:20 PM, JoeSchmuckatelli said:

I worried about the same thing during the first two attempts - and took a much lower flight profile on the third run to get a longer burn / better flight path.  I'm pretty sure it's mountains. 

Reentry vehicle is the basic pod with heat shield, goo, thermometer and barometer.  Even with a nice long reentry burn (heat indicator on the shield went about 1/2 way down during the reentry) and a fully grey chute icon before deployment - the chute fully deployed, btw, and I was hanging nicely - when I was rudely exploded, again, at 1500m.

 

I'm now thinking that I set the chute deployment for too low of an altitude for the wider variety of Kerbin landing zones - something I never did way back when - but I picked up on the option during the tutorials. 

 

Love this game!  Been grinding on how to run the mission and save Jeb all night 

The altitude difference between mountains and flat area is really minimal in regards for landing: if you crash on mountains you'll crash on sea level too. Mountains just make you tumble over easier.

[Daniel Prates]

In more recent ksp versions, I adopted as a rule to have both drogues and a main chute. It is easier to have safer landings. Wasn't like that earlier.

[Klapaucius]

On 5/2/2020 at 6:34 AM, Laie said:

If you don't tweak, the default 1000m should be as safe as it gets.

I usually set it to the max 5000. It can make the descent painfully slow at times, but I have crashed several times because the chutes opened too late for a landing at higher altitudes. 

[LoneKharnivore]

3 hours ago, Klapaucius said:

I usually set it to the max 5000. It can make the descent painfully slow at times, but I have crashed several times because the chutes opened too late for a landing at higher altitudes. 

I set my drogues to 2.9atm/5000m and my mains to 6.8atm/3000m, this gives about 500m drop at semi-deployed for both chutes.