Is Val Doomed?

[Chequers]

Emergency!

While on what has become a routine mission to continue exploring Mun biomes, Val has had a bit of misfortune.

The mission proceeded nominally: Val clambered into the lander, detached from the CSM, and initiated the de-orbit burn to bring her down to the surface of the Mun at the designated landing zone, on Mun's south pole.

Then, catastrophe! A complete loss of input. Also known as, 'KSP Crashed'. 

I crossed my fingers and hoped there was an autosave somewhere nearby. And fortunately, as I reloaded and checked the Tracking Station, sure enough, the flight was still in progress.

Unfortunately, it's skipped a good part of the descent... and Val's lander is about 3,000m above the surface, without a landing burn initiated. I immediately hit pause: I know from previous calculations, this is not enough time to slow down. The lander will impact the surface of the Mun at over 100m/s, destroying the lander, and no doubt killing Val.

I don't have quicksaves or reverts enabled, so whatever I try, I only have one shot at trying to salvage this situation. Is there anything we can do to rescue Val? Here's what I have to work with:

The lander has two sections: the main lander, with science experiments. This has a terrier engine, which is currently engaged. On the surface, the Lander Can detaches from the base of the lander, for returning to the Command and Service Module in orbit. These radial boosters are not currently engaged... but I don't think they'll add enough thrust to slow down the craft; but perhaps they'll do enough to survive an impact?

Or is it worth having Val bail out and use her jetpack? I'm not sure she'd have enough stopping power either.

Thoughts?

Edited May 5, 2020 by Chequers

[Misguided Kerbal]

Why don't you try firing the radial boosters? It depends on how much of them you have and what type they are. As far as I know, 2 twitches + a terrier should be enough. Or, a why don't you try firing all the engines, and then when you're close to the surface, if it's not enough to slow down, then bail Val out. She'll bail out at a slower speed. Kerbals can usually survive impacts up to 30m/s, so if you try this option, you should be fine.

[RoninFrog]

TWR stats would be crucial.

Also, how fast are you descending?

Edited May 5, 2020 by RoninFrog

[bewing]

You want to get Val back to orbit to save her. So you don't need to land. So you don't need to cancel your horizontal velocity -- just your vertical velocity. If you would have had sufficient dV and fuel to land (assuming the burn started on time), then you definitely have enough fuel and dV to abort.

 

[Chequers]

2 hours ago, Misguided_Kerbal said:

Why don't you try firing the radial boosters? It depends on how much of them you have and what type they are. As far as I know, 2 twitches + a terrier should be enough. Or, a why don't you try firing all the engines, and then when you're close to the surface, if it's not enough to slow down, then bail Val out. She'll bail out at a slower speed. Kerbals can usually survive impacts up to 30m/s, so if you try this option, you should be fine.

There are four LV-1R's mounted around the Lander Can, mounted on Oscar-B's: it's perfect for hauling just the lander can back into Mun orbit - but it's not going to add much to the Spark stage (I think I may have mentioned it's a Terrier previously - it's actually a Spark). Certainly not enough to slow us down to anything reasonable I don't think.
 

1 hour ago, RoninFrog said:

TWR stats would be crucial.

Also, how fast are you descending?

My game is paused at around 3800m above the surface, and I'm travelling at ~500m/s at this point. TWR is rated at 4.5 for the Mun, with the single 48-7S 'Spark', and quad LV-1R 'Spider' boosters engaged.

 

1 hour ago, bewing said:

You want to get Val back to orbit to save her. So you don't need to land. So you don't need to cancel your horizontal velocity -- just your vertical velocity. If you would have had sufficient dV and fuel to land (assuming the burn started on time), then you definitely have enough fuel and dV to abort.

...I hadn't considered adding energy to re-orbit... I absolutely have enough fuel to land - I've hardly used any in the lander. What would be my most effective burn at this point? Perpendicular from the surface?

Edited May 5, 2020 by Chequers

[mystifeid]

Tried looking in ...\Kerbal Space Program\saves\[career name]\Backup ?

[bewing]

2 hours ago, Chequers said:

What would be my most effective burn at this point? Perpendicular from the surface?

You're definitely going to need quite a bit of Radial Out in order to keep from crashing into the ground -- to cancel out your downward velocity. Once your vertical velocity is positive (so you won't crash), then you will want to burn prograde to get back up to orbital velocity and get your Ap and Pe back above 8km or so.

 

[AHHans]

1 hour ago, Chequers said:

I absolutely have enough fuel to land - I've hardly used any in the lander. What would be my most effective burn at this point? Perpendicular from the surface?

Yes. Right now you don't want to land but to avoid a crash, so thrust straight up to reduce your vertical velocity. If your current velocity is mostly horizontal then you should be able to avoid a crash even without using the ascent engines. (But if you are currently going straight down at 500m/s then all you can do is watch the fireworks.) Once you arrested your vertical velocity then you can decide whether you proceed to land or abort back to orbit.

[Chequers]

Success! 

I pointed vertical and fired the engines, crossed my fingers and hoped... and (narrowly) managed to avoid hitting the surface. I got below 500m, and really didn't think I was going to make it at one point.

The poles are horrendously mountainous. It as actually a very eerie biome to land on... but I managed to push the apoapsis up high enough to avoid scraping any peaks. It actually didn't use much dV, and I was able to circularise at about 12,000m, and come around for a second landing attempt, managing to set down with less that 15m/s dV remaining in the descent stage.

Valentina was very thankful for the timely intervention of your advice! Thanks for saving another Kerbal - and (more importantly) the mission!

A very tense burn later, and Val is on the up!

Spoiler

Safely down!

Spoiler

 

Edited May 5, 2020 by Chequers

[jimmymcgoochie]

Nice save @Chequers and another useful lesson learnt- always save the game before attempting a landing! Also, radial out will make your rocket stop descending without affecting horizontal velocity, it’s a good idea to use that mode when landing too as it will avoid any wobbles if you’re descending slowly like with holding retrograde. Now, do you have enough fuel left to get back OFF the Mun again?

[Chequers]

11 minutes ago, jimmymcgoochie said:

Nice save @Chequers and another useful lesson learnt- always save the game before attempting a landing! Also, radial out will make your rocket stop descending without affecting horizontal velocity, it’s a good idea to use that mode when landing too as it will avoid any wobbles if you’re descending slowly like with holding retrograde. Now, do you have enough fuel left to get back OFF the Mun again?

I don't have saves or reverts enabled, friend! Hence the dilemma! If I couldn't save Val, she'd be lost forever.

It makes the learning curve very steep - but very rewarding.

I used very little fuel from the ascent stage during the abort burn - and so was able to proceed with the mission and comfortably rendezvous with the CSM in Munar orbit. Valentina is safely back on Kerbin, with plenty of stories to tell!

Edited May 5, 2020 by Chequers

[bewing]

Yay! And the lower you circularize, the less fuel it takes in either direction. So 12km was kinda high, especially if you then decided to try to land again.

 

[Chequers]

6 hours ago, bewing said:

Yay! And the lower you circularize, the less fuel it takes in either direction. So 12km was kinda high, especially if you then decided to try to land again.

 

Indeed; but I was so focused on the looming mountain coming within a few hundred metres of the lander, that I didn't notice how quickly I was pushing the apoapsis up. All was well though, a quick calculation once back in orbit meant I had sufficient dV to continue the mission, and still return to the CSM for return to Kerbin. I suppose that's the benefit of 'Apollo Style' missions; it divides the mission up into sections, so that as long as you can get your Kerbal back to the orbiter, you know you can get them home safely.

[Klapaucius]

This is what makes this forum so great!  All hands on deck to save one of our favourite Kerbals!

 

I'm now in the habit of quicksaving anytime I am about to make a new maneuver.  I've had a ton of "stack overflow" crashes in the last few months. I don't know why this is happening now, but I take precautions.

[Chequers]

21 minutes ago, Klapaucius said:

This is what makes this forum so great!  All hands on deck to save one of our favourite Kerbals!

 

I'm now in the habit of quicksaving anytime I am about to make a new maneuver.  I've had a ton of "stack overflow" crashes in the last few months. I don't know why this is happening now, but I take precautions.

So true! This forum has been invaluable as a new player: I'd hate to think how many missions would have gone awry if not for the great advice of you all.

I've not really had any issues with crashes until this one - and I think it was an update running in the background that caused the issue.

I can't quicksave, but @mystifeid suggested there's a backup folder which I might keep safe. 

Edited May 6, 2020 by Chequers

[Klapaucius]

6 minutes ago, Chequers said:

So true! This forum has been invaluable as a new player: I'd hate to think how many missions would have gone awry if not for the great advice of you all.

I've not really had any issues with crashes until this one - and I think it was an update running in the background that caused the issue.

I can't quicksave, but @mystifeid suggested there's a backup folder which I might keep safe. 

I would enable reverts and quicksaves. There is nothing to be gained by disabling them.  If you prefer to not use them for regular gameplay, that's totally understandable, but this game just crashes too often to take the risk. As an example, in the space station challenge I recently participated in, on a few occasions, when I switched to the large station from the approaching vessel, the entire station decided to shake itself apart. A quick revert, try again, and the Kraken went away. None of that was my fault, so it is not like i was reverting to correct my own mistake. (Though I confess I do that a lot in my own play).

This is not just me saying this. Matt Lowne has made that same point in some of his videos.

Edited May 6, 2020 by Klapaucius

[Chequers]

1 hour ago, Klapaucius said:

I would enable reverts and quicksaves. There is nothing to be gained by disabling them.  If you prefer to not use them for regular gameplay, that's totally understandable, but this game just crashes too often to take the risk. As an example, in the space station challenge I recently participated in, on a few occasions, when I switched to the large station from the approaching vessel, the entire station decided to shake itself apart. A quick revert, try again, and the Kraken went away. None of that was my fault, so it is not like i was reverting to correct my own mistake. (Though I confess I do that a lot in my own play).

This is not just me saying this. Matt Lowne has made that same point in some of his videos.

Perhaps I don't have the same self-discipline you do, friend! When I first started playing, I tried hard not to use them... but ultimately, even without using them, it took some of the tension away. I had to start my career again with them turned off to force my hand. I appreciate that's not some players idea of fun - and having to go through a huge testing phase of each section of the mission before committing to it might seem laborious. But it slows the pace down for me, turns simple missions into week long projects, and knowing that I completed a mission without quicksaves/reverts even being an option... it just gives me a sense of satisfaction that I've rarely felt in a 'game' before.

Of course, I've not had to deal with any major crashes yet, but I don't play with any mods, nor do I build anything outrageously complicated that could suffer from this mythical 'Kraken' I hear so much about. 

Perhaps in the future, I'll want to do more ambitious missions and some of the testing, and not being able to trial-and-error things easily, will become tedious.

My contracts are becoming decidedly inter-planetary now; I just  launched a probe to fulfil an 'orbit Eve' contract, and attempted to aerobrake to aid the capture burn; only to watch the probe become a firework even in the highest reaches of the atmosphere. The entire mission - and everything that went into it - was completely lost. I'll have to wait for the next transfer window to try again - and there's no promises that one will work either. For now, it's just exciting and tense - but perhaps eventually, it'll become frustrating and tedious, and maybe then I'll enable quicksaves.

[Klapaucius]

6 minutes ago, Chequers said:

Perhaps in the future, I'll want to do more ambitious missions and some of the testing, and not being able to trial-and-error things easily, will become tedious.

 

That was how I played Subnautica. Did not save anything for hours and then one too many times of losing EVERYTHING and I just decided I wanted to finish the game before the end of the millennium. Still, outside of KSP, the best thing I have ever played, hands down.

[mystifeid]

3 hours ago, Chequers said:

I can't quicksave, but @mystifeid suggested there's a backup folder which I might keep safe.

It keeps itself safe. The game keeps multiple rolling backups of the save game file - persistent.sfs - even if you have selected the no revert option, probably to provide some insulation from the effects of things like bsod's, game crashes, krakens and other bugs. Using them is not quite as easy or tempting as hitting F5/F9. I have a no revert career and so far I've killed four Kerbals. And they're still dead. But in the (distant) past I remember - for example - switching to perfectly good ships in interplanetary space only to find pieces of the ship drifting along. What would you do with your no revert game then?

[Dman979]

I'm sure that @Val appreciates your efforts! Remember, kiddos: Quicksaving is your friend.

[Space Nerd]

I don't think you even need to return to orbit to land again, just make sure you have a suborbital path that has an AP high enough to avoid the mountains, then come around to land at a different spot.