Rocket building guidelines/tips (1.0.5v1028, Career mode)

[KocLobster]

Let me start off by saying a couple things...god I love this game. After my first successful return mission from the Mun, it increased my love for KSP by a billion times. Let me also say that I have been through the forums, specifically the "The Complete Compendium of Tips and Advice!" thread by NASAHireMe.

I built a rocket that gets to the Mun, can land, and returns to Kerbin very well, although it just doesn't quite have enough delta V for my comfort (I'm not the most efficient and am not Scott Manley). I was introduced to KSP recently; I've never played a previous version before 1.0.5, by the way. So I tried building a more advanced rocket with bigger engines and more fuel tanks. I made a rocket with ~10k delta V, far more than I need for a simple Mun return trip, but it generally can't make it through the ascent. Tips on how to fix this specific rocket are great (I'll include a picture or two of it, as well as the successful rocket that could use just a little more delta V), but I'm looking for more tips and guidelines in general for building rockets, and how I can specifically start increasing the delta V of rockets so they can travel farther and do more, without turning the rocket into something that will be unstable when flying and can't even make it through Kerbin's atmosphere. I can't even begin how to fathom how I would get a mobile processing lab into orbit around the Mun.

Any help is greatly appreciated. This forum I've been watching for a while now, and everybody seems incredible smart and resourceful, I've never seen such a helpful online community. I look forward to your answers. Feel free to point out how bad of a rocket maker I am Oh by the way, please don't suggest using any non-stock parts (I need to fully understand all stock parts first before I move on to more advanced things) or parts that are very advanced in the R&D, or to just use autopilot. I want to learn how to do things correctly before I'd ever consider using MechJeb's autopilot, for example.

 

Without further ado, here is the failure rocket I talked about previously, if you wish to comment on it or whatever:

http://imgur.com/73kBZNL

Edit: I forgot I accidently deleted my successful rocket in my saved rockets folder in-game. But it was essentially the same as the other rocket, with the bottom stage being replaced with FL-T800 fuel tanks (10 total, 2 in the middle with 8 in four stacks of 2, symmetrically around the center), with the middle engine an LV-T45, and the other 4 engines LV-T30's with their gimbal's locked. (You've probably seen a similar setup many times). I hope this post wasn't too confusing, I tried my best to make it flow but I feel like I'm all over the damn place.
 

[Streetwind]

Well, you didn't say anything about what actually goes wrong during ascent, but I'm gonna hazard a guess here and say it wants to tumble head over heels.

Solutions:
- Stick close to the prograde marker at all times, steer gradually
- Remove the fins from the upper stage tanks. Rockets need to be built like arrows: heavy bits at the front, draggy bits at the back. Your rocket has draggy bits (those fins, and all the struts and equipment and greebling on your lander) at the front, and heavy bits (the lower stage) at the back. The lower stage's fins will help a bit, but in general, this rocket probably will want to fly backwards. Removing the upper stage fins will probably fix it almost instantly. Well, if that's your problem, anyway. You didn't specify.

Edited March 5, 2016 by Streetwind

[Foxster]

To make a more "powerful" rocket you will need to be thinking about TWR and Isp - if you aren't already. I wrote a guide that might get you started on that: 

As for it not making orbit: I think you have a lot of drag at the top and that's causing it to flip. As already suggested, find a way to get rid of the fins near the top. The other biggie is all those struts, they are very draggy. Try deleting all but the essential ones, you might find you need none. 

Edited March 5, 2016 by Foxster

[ForScience6686]

+1 to the fin advice.  I would also suggest you have to much engine on the lander.  I would loose the radial engines.  Otherwise not so bad, you would do better with the shorter radial decoupler, you'll have a wide enough stance with them to not worry to much about tipping.I would also guess you have too many struts which greatly increase your drag.  Ladders as well, you can Eva quite easily on the mun. Beyond that it's pretty much the same as what I would use.

Try and keep in mind that you should build the bear minimum.  Extra engines increase mass and hinder dv.  You should also get familiar with the rocket equation to ensure you have the dv needed and not too much more.

 

 

[Waxing_Kibbous]

Quote

I can't even begin how to fathom how I would get a mobile processing lab into orbit around the Mun.

A good "getting to the Mun" base rocket setup is the medium (or the next size down depending on load) 2.5m tank w/poodle, then an orange tank with a skipper supplemented with 2 other pieces if needed- either 2 of the big SRBs or 2 more orange tanks with skippers with fuel ducts feeding the center tank. If you get a good launch the poodle can even help in the landing. This is something I whipped up quick and is overkill (seems good enough to get to Duna and back...), may need a couple of kickbacks to add twr but probably not. Just an example of how a simple rocket can do a lot.

Edit: this really is overkill, you could get rid of S2 completely and get this into orbit around the Mun with a decent sloppy launch.

Edited March 6, 2016 by Waxing_Kibbous

[Snark]

+1 to earlier advice about losing the fins on the upper stage.  Before you stage away the boosters below, they're hurting you rather than helping.  After the boosters below are staged away, they could help... except you've got such a powerful lower stage that you ought to be completely out of the atmosphere by the time you stage away the last Big Orange.

From your staging UI, I see you're dropping the Big Oranges in pairs, so I assume you have them asparagused.  Just a sanity check:  You've verified that your asparagus setup is draining properly, and you don't have any lopsided mass distribution due to fuel-drain problems?

If those are Mainsails, your ascent stage is massively overpowered.  What's your launchpad TWR?  If it's much higher than 1.5, that's too much.  Seven Mainsails (if that's what they all are) could give that TWR for a craft that's over 650 tons on the pad, and somehow I don't think you've got 650 tons there.  Suggestion:  Keep the center engine as a Mainsail, and replace all the radial ones with Skippers.  You'll still have a perfectly respectable TWR, you'll save dV (due to more-efficient engines, and losing 18 tons of engine you don't need), and I expect you'll have fewer stability problems due to not going too fast when you're still too low in the atmosphere.

I notice that your lander has trilateral symmetry.  Be advised that trilateral can be a bit unstable, aerodynamically.  Is there some way you can refactor your lander so that it has 4-way symmetry instead of 3-way?  But save that for a last resort-- try ditching the top-stage fins and lowering the radial boosters to Skippers first, see if that helps you.

[KocLobster]

In order to make this large post smaller, I'm not going to use the quote feature, so..

@Streetwind
You're right, there is too much instability and this particular rocket likes to flip over during ascent unless I attempt to shoot it directly up. However, I have some ideas how to fix that, and there is a vast amount of help on these forums dedicated just to rockets flipping over during ascent, so I did not want the main focus of my thread to be about that (please don't take that to mean that I don't greatly appreciate yours, and everybody else's help).

I was under the impression that struts were one of those special physics-less parts that don't affect aerodynamics/drag/anything. If I remove all fins from the upper stage of my rocket, I won't have difficulty piloting it? Is this because it will only be piloted in space, where there is no atmosphere? Indeed, this rocket likes to flip over during ascent and then point to the ground, and will absolutely refuse to point anywhere but. Does the fact that I have a heavy lower part of the upper lander stage matter? It's just gonna get worse later, when I incorporate a MPL into my lander...

@Foxster: Appreciate the thread, I will take a look. I think part of my problem is the difficulty I have finding specific tutorials I am looking for on these forums. Maybe I just need to keep practicing with the search feature. Remove fins: check. Struts: check. I watched a video of someone making a rocket, and he insisted lots and lots of struts, especially between, for example, fuel tanks and engines, and other places, were absolutely vital. Maybe this was a much older version of KSP and that isn't necessary anymore? Maybe that potentially older version also didn't have the struts creating drag...I don't know.
Also, I think what might be a huge problem of mine Foxster is that I don't understand at all how TWR works, other than what it stands for. Same goes for lsp. All I know is that it roughly means how efficient an engine is. So I haven't really thought about those at all.

@ForScience6686: Normally I would just use a single LV-909, but when I added those extra 3 engines, it didn't affect my vacuum delta V negatively at all, and it greatly increased my thrust ability, so I figured it wasn't a problem. I thought it'd be better that way, it wouldn't take so long to perform burns...and in a vacuum it wouldn't matter? Also, I would almost always use the shorter radial decouplers, but I just couldn't fit the landing struts, fins, decouplers, ladder, struts, and fuel lines all on it without doing what I did. I guess that'll change now that I'll remove the fins and ladder since they aren't necessary.

@Waxing_Kibbous
I appreciate the description and picture, makes it a lot easier to make sure I understand your meaning. 7k delta V was exactly what I was shooting for, but when I realized I had 10k, I just went with it because I'm still new and know I don't do things the most efficient way. Since 1.0, I know ascent (and drag) has changed for example, and I may be doing things much more inefficient than most. In fact, I'm pretty sure I am, because I typically need a 1.5 minute burn to get into a under 100k periapsis with the Mun, whereas I think I remember Scott Manley typically only needing like a 35 second burn to do that? So I must be doing something wrong. Also, by kickbacks, you mean the massive SRB's, right? Last thing, in that picture, you have a total of two Poodle engines (top) and three Skippers (bottom), right?

 

@Snark
I've gathered now I really don't need the fins on that stage because you don't really need the fins in vacuum. Yes, they are asparaguse, but I don't know how I would check that they are setup and draining correctly. I know that every asparagus setup I've done works just fine, and the tanks empty in the order they should and everything. No, as new and uninformed as I am, I know that would be massively overkill. It is setup how you've suggested: a Mainsail in the center, with all the engines on the sides being Skippers. The bottom stage TWR is 1.78 (2.25 max). As I said earlier, I don't really understand what that means, just what the acronym stands for. I don't know why I chose tri-lateral symmetry instead of quad...I think I just saw it in a video.


If I didn't already say it, thanks everyone for your help and posts. It's seriously great how helpful and active this forum and community is. I'm going to incorporate pretty much everything everyone's said.

[Norcalplanner]

1 hour ago, Snark said:

I notice that your lander has trilateral symmetry.  Be advised that trilateral can be a bit unstable, aerodynamically.  Is there some way you can refactor your lander so that it has 4-way symmetry instead of 3-way?  But save that for a last resort-- try ditching the top-stage fins and lowering the radial boosters to Skippers first, see if that helps you.

This so much.  Better to use quad symmetry.  If you must use tri-symmetry, the radial stage you're controlling with the mouse needs to be placed on the east or west side of the rocket so that drag will be symmetrical N/S when you start the gravity turn.

And you have way too much engine for that rocket.  You should almost always have two or more orange tanks on top of a Mainsail.

Here's a simple Mun rocket that I threw together that doesn't use any asparagus staging and is pretty easy to fly:

There's also a lot of good advice in my tutorial thread: Rules of Thumb for Building Cheap and Cheerful Rockets.

[Waxing_Kibbous]

Quote

@Waxing_Kibbous
I appreciate the description and picture, makes it a lot easier to make sure I understand your meaning. 7k delta V was exactly what I was shooting for, but when I realized I had 10k, I just went with it because I'm still new and know I don't do things the most efficient way. Since 1.0, I know ascent (and drag) has changed for example, and I may be doing things much more inefficient than most. In fact, I'm pretty sure I am, because I typically need a 1.5 minute burn to get into a under 100k periapsis with the Mun, whereas I think I remember Scott Manley typically only needing like a 35 second burn to do that? So I must be doing something wrong. Also, by kickbacks, you mean the massive SRB's, right? Last thing, in that picture, you have a total of two Poodle engines (top) and three Skippers (bottom), right?

A good rule of thumb is to have 3500m/s dV to get to orbit, 850m/s to get to the Mun, and around 250? to circularize the Mun orbit (I forget the exact number). For landing and return 1600m/s is pretty safe and easy enough, my landers usually have about 2500m/s and I do an extra biome hop. These are good safe numbers to shoot for, and you may end up throwing fuel away, but that's cheaper than flying the mission again. Concerning the engines, I meant Thumpers, the smaller ones- the rocket pictured is way overbuilt already. There are 2 poodles, but the last one is basically for moving the science lab if you want to in the future. You could refine this a bit by replacing http://wiki.kerbalspaceprogram.com/wiki/Rockomax_X200-32_Fuel_Tank  with http://wiki.kerbalspaceprogram.com/wiki/Rockomax_X200-16_Fuel_Tank   , and you could easily remove either of the top stages if you wanted to keep it a bit simpler yet, play around with which 2.5m tank would suit your purposes best. Those are 3 Skippers- they are cheap and I find they give more dV than Mainsails, at least on this size rocket. If I have a small lander on top instead of what I pictured I have used skipper + orange tank + 2 kickbacks at the first stage.

 

The burn time I wouldn't worry much about, Scott M may have had a light craft with a higher TWR than yours- the thing that will stay the same is the dV

Edited March 6, 2016 by Waxing_Kibbous

[KocLobster]

@Waxing_Kibbous

Are you sure those d/v figures aren't for a more advanced player? I've been going off http://13375.de/KSPDeltaVMap/ using the realistic, and sometimes the casual settings. It's saying 4k d/V to orbit, 6k total to the moon (not additional from orbit), and another 1k back to Kerbin...for a grand total of 7k d/V for someone like me. The only reason I worried about the burn time is because one of the last rockets I built had loads of d/V, but I ended up not quite in orbit of Kerbin and in my final stage (read: single LV-909 engine), and while it would of been efficient, it still would of been like a 2 minute burn to complete a circular orbit burn just around Kerbin. So that's why I cared. I shouldn't have to though because I shouldn't be firing the LV-909 inside the atmosphere.

@Norcalplanner

Thanks for the pictures and the tutorial. The tutorial looks right up my alley and exactly what I'm trying to learn to do right now. With the kickbacks, is there anyway to recover those things like the in game description suggests?

Has the massive orange fuel tank + Mainsail overheating thing been fixed? Or is that intended and still exists?

Cheers everyone.

 

 

edit: had a chance to view your C&C thread in full, its awesome and just what I was looking for, thanks man.

Edited March 6, 2016 by KocLobster

[CSE]

7 hours ago, KocLobster said:

With the kickbacks, is there anyway to recover those things like the in game description suggests?

Try StageRecovery and attach two radial chutes per Kickback, with the parachutes in a stage after the stage that drops the Kickbacks. Almost all rockets will put enough distance between them that you don't have to worry about deploying the chutes, because the boosters pass out of physics range before they hit the ground.

[GoSlash27]

KocLobster,

The DV map you've referenced is actually already padded with enough reserve to make it comfortable for a newbie. You really don't need 10 km/sec for such a short trip. I would recommend doubling the estimate to land on the Munar surface, though. Bring at least 1 km/sec DV for the landing.

You can (and should) use vacuum engines while still in the atmosphere. The engine's efficiency improves as the air pressure drops, so you have 90% efficiency at 13km, 95% efficiency at 17km, and 99% efficiency at 26 km.

TWR (thrust to weight ratio) does matter for lifters, even upper stages. You want to keep it at least .7 for upper stages. If you don't do that, you may fail to achieve orbit regardless of how much DV you've packed.

The way I design lifters is simple and effective:

The upper stage to orbit is 1700 m/sec DV, uses a vacuum engine, has at least 0.7 t/w, and no aerodynamic control surfaces.

The lower stage is 1800 m/sec DV, uses an atmospheric engine, has at least 1.4 t/w, and carries any aerodynamic control surfaces I may need.

When designed this way, the first stage will get me to around 27 km altitude during a gravity turn, where the air is thin enough that vacuum engines are fully efficient and there's no risk of tumbling.

I recommend studying and understanding Foxster's tutorial on this. The Foxster is good, the Foxster is wise

Best,
-Slashy

 

[KocLobster]

@CSE

I swear I'm not trying to plug Scott Manley here, but I saw him suggest adding a parachute to a couple BACCs as it turned out. I highly doubt he had any mods or he would of said so. I tried it myself and they attempted to deploy chutes as soon as I ditched them, like 10km above the surface...Was it a staging problem? If I move the chutes to a stage after the decouplers that seperate them from my main stack, how do I deploy them when I can't even see them because they're so far away? That mod looks great, but I wonder if it's necessary? I always wondered how to do this, especially because the stock game has a stock rocket (kickbacks) that suggests rescuing SRBs and such. I shouldn't need a mod I would of thought...

 

@GoSlash27

Thanks for the guidelines and the reminder about his tutorial, in everyone's helpful posts, I forgot about that link, and that explains the underlying reasons why everyone is suggesting I do x and y. Been looking for that..

[CSE]

Plugging Scott's videos is fine by me.

In the Reusable Space Program, I think he had the parachutes in the same stage as the decouplers, with the boosters mounted far enough back that the rocket gets clear of them in the time it takes the chutes to semi-deploy. Then, with the rocket high and fast enough to be left to coast, switch focus back to the boosters while they're still above the clean-up altitude in time for the full deployment. The boosters would need to stay within physics range of each other, and I think perhaps the clean-up altitude was lower back in 2013 or whenever; it's now about 20km so you'd have to stay focussed on the boosters for longer.

Try Scott's Kerbal Space Program - Mods To Help Recover Stages for a more recent take.

I haven't used Flight Manager for Reusable Stages myself. With StageRecovery, as long as the parachutes are still present when the booster leaves physics range then the mod will take them into account when calculating the returned funds (or the returned parts if you also use Kerbal Construction Time). So I just put the chutes in one of the later stages of the rocket; the icons will disappear when the booster carrying them decouples.

[KocLobster]

@CSE

I was viewing one of his newer, 1.0+ career tutorials (~33 video playlist), and it was about going to orbit or something unrelated. There was just a small reference to saving the expensive SRBs and putting chutes on them. Essentially though, that mod will make it a lot simpler to recover stages? I don't understand what physics range really is, and don't exactly know what you mean. I was just under the impression you didn't need a mod to recover stages. But I think I'll try that mod, if it makes it a little easier. I'll also check out his video; a video dedicated just to how to recover stages would be nice, because I was just gleaming information from a video that wasn't specifically about this subject.

Do you mind giving me a general rundown of how to properly use StageRecovery to recover stages? I need chutes on my disposed engines/fueltanks/stages I want to recover obviously, I put the decouplers and the parachutes in the same stage so they deploy at the same time, and I have to switch my view to the debris for a period of time until my main ship that''s still accelerating is out of physics range of the debris? ...wat? lol. What altitudes on Kerbin is it safe to do this? How is it that the chutes don't just instantly deploy at this high ltitude that they'll likely be at, and end up burning up the chutes? That's the biggest thing I don't understand. If it's debris, you can't control it anymore..so how do you make sure the chutes don't deploy until they're at a safe velocity? I tried this twice a while back and they always immediately deployed, usually around 10-15km, and obviously they were going too fast and the chutes burned up. What am I missing (besides the helpful mod)?

Edited March 6, 2016 by KocLobster

[CSE]

In KSP, only the loaded vessels can perform any actions - one chosen "active" vessel and anything within a set distance of it (22.5 km I think; it was less in earlier versions) - including staging or deploying a chute. Non-active vessels just follow their last known trajectory, and if that's a sub-orbital trajectory then they'll crash into Kerbin or wherever and be removed from the game. They won't slow down even if their parachutes are open because drag is a physics engine calculation and the physics isn't run when the vessel is not loaded. To avoid this in pure stock, you'd have to switch to each vessel in turn to perform the deploy parachute action, and then switch again to land on the surface.

FMRS, if I understand it properly, puts the decoupled booster "vessel" into a parallel game save. You fly the core rocket to a stable orbit where it's safe, save, then load the booster save to go back in [game world] time and make the booster the active vessel. Once you've landed the booster, FMRS integrates the booster parts/funds (I don't know) back into the core rocket game save and cleans up the parallel world save. Something like that.

With StageRecovery, you just decouple the boosters as normal and let the game unload them when they get too far away from the rocket you're flying. When the game unloads the booster vessel, the StageRecovery mod checks whether the vessel has parachutes, and if so it estimates what the landing speed would be - it doesn't actually fly the booster down using KSP physics, just makes its own calculation, so the chutes don't have to be deployed by you. Landing slower (more/bigger chutes)and closer to Kerbin returns a bigger percentage of the booster's value. You just get a little message saying here are the funds recovered from vessel XYZ. So if the booster engine is in stage 5 and the decoupler in stage 4, then put the booster parachute in stage 3. Decouple nice and high (not worth a parachute for the smallest SRBs) so the rocket is 25km away by the time the booster would hit the ground. If the boosters are hitting each other, a couple of fins help them run straighter after separation.

1. Make the core rocket as normal.
2. Add decouplers as normal.
3. Add booster to decoupler as normal.
4. If booster separation would be after about 40s (use e.g. Kerbal Engineer), add a parachute to the booster.
5. Find the parachute icon in the staging and move it to the stage after the booster's decoupler. This is how you make them not deploy while you're flying the core rocket.
6. Launch, fly, and stage boosters away as normal: don't switch focus to boosters, stay with the core rocket.
7. Keep an eye on the messages button on the stock toolbar.

I find StageRecovery simple and clean to use. I get to design for re-usability, but my actual flying time is all spent flying the core rocket; recovered funds just turn up. I often run in a 6.4x or 10x rocket-based career where boosters are expensive and separation altitudes can be 20km+.

FMRS could probably land glider spaceplanes (as long as the pilot wasn't me) and other weird boosters that StageRecovery's simple estimator might not understand. And you might find you enjoy flying the boosters back down.

[KocLobster]

@CSE

Thanks for the tips, that helps me understand it a lot better. I think I got a good grasp on it. My only question is what to do if you empty your booster's tanks pretty quickly and/or somewhat closer to the ground, and as such there isn't enough time to get the main rocket 25km away? The booster will hit the ground before StageRecovery is able to save it, right? How can you work around this? I imagine this is only a problem with pretty small rockets.

[CSE]

If the quick-draining boosters are nice and cheap, you can just let them crash; that's typically what I do if the craft is just short of the TWR to leave the pad in a controlled fashion. Pitchover one degree to get clear of the launch facilities, and maybe leave off any nosecones or fins to keep the unrecovered cost down.

Assuming the quick-draining boosters are essential to your launch and are not cheap - and making it up as I go along, I'm afraid, because I don't remember finding myself in that situation - I think you'd need something like RealChutes to give you customizable parachutes. Set for a tiny deployment delay and the biggest and lightest parachute canopy available. I would guess that you'd either get out of physics range and the boosters will unload, or else the boosters slow down to a safe landing speed and touch down. I haven't tested this use though.

...

There are lots of design techniques to help dodge the question, too - drop tanks, because it's the engines that are expensive; fewer boosters and more fuel, if you have any leeway to run a lower TWR; asparagus boosters taller than the core first stage that they feed into; upward & outward sepatrons; probably many I haven't thought of.

[Plusck]

On 6/3/2016 at 9:43 PM, KocLobster said:

@CSE

I was viewing one of his newer, 1.0+ career tutorials (~33 video playlist), and it was about going to orbit or something unrelated. There was just a small reference to saving the expensive SRBs and putting chutes on them. Essentially though, that mod will make it a lot simpler to recover stages? I don't understand what physics range really is, and don't exactly know what you mean. I was just under the impression you didn't need a mod to recover stages. But I think I'll try that mod, if it makes it a little easier. I'll also check out his video; a video dedicated just to how to recover stages would be nice, because I was just gleaming information from a video that wasn't specifically about this subject.

Do you mind giving me a general rundown of how to properly use StageRecovery to recover stages? I need chutes on my disposed engines/fueltanks/stages I want to recover obviously, I put the decouplers and the parachutes in the same stage so they deploy at the same time, and I have to switch my view to the debris for a period of time until my main ship that''s still accelerating is out of physics range of the debris? ...wat? lol. What altitudes on Kerbin is it safe to do this? How is it that the chutes don't just instantly deploy at this high ltitude that they'll likely be at, and end up burning up the chutes? That's the biggest thing I don't understand. If it's debris, you can't control it anymore..so how do you make sure the chutes don't deploy until they're at a safe velocity? I tried this twice a while back and they always immediately deployed, usually around 10-15km, and obviously they were going too fast and the chutes burned up. What am I missing (besides the helpful mod)?

I'm a bit lost in the reordering of posts here, so maybe I'll be answering something that has already been answered.

I too saw that Scott Manley video, though "oh great gotta try that", and got burnt.

The answer is no, without mods you should forget about recovering stages. The time that it takes for a booster to drop to the ground on a parachute (bearing in mind that you really must have the parachute stage at the same time as the decoupler for the booster, or add yet another probe core to the booster and switch between it and your main vessel - not a good idea unless the ship is extremely stable) is just far too long. Your main vessel will in all likelihood be 25km away by the time the booster touches down, so it'll go "poof" and be wiped from the game before it hits the ground.

You could spend hours working out and trying different parachute settings so that the boosters drop almost to the ground before the chutes open, which might let you recover your very first stage in stock, but you should probably ask yourself if it is worthwhile...

I haven't tried the mod. I wholeheartedly agree with the principle of the thing - we absolutely should be encouraged to go the SpaceX way and recover all that precious hardware - but KSP stock isn't geared for it and I felt that it wasn't really worth it. There are a few engines that feel an utter waste to abandon - the Vector particularly - but when your build cost doubles when you finally add science instruments to it then you know where the game is pushing you to make savings on recovery. And it isn't first-stage boosters.

[Plusck]

Oh and as to the "what is physics range really?": when you are not in control of a ship, it is "on rails". The orbit is defined as a mathematical function, and your ship follows that line. If that line impacts terrain, the ship disappears. If it goes below a certain level in the atmosphere, it disappears.

When you are within the physics bubble (like when you approach another vessel in orbit and it comes within 2.3km) then the actual craft is loaded. It "exists" as an entity rather than just an orbit. In the atmosphere, this bubble is larger than 2.3km (otherwise things would be weird, like flaming discarded engines just disappearing on reentry): 22.5km apparently. The bigger the bubble, the more potential work your processor has to do and the more possiblity for lag, and also the more potential problems when a craft you really weren't involved with at all gets loaded into physics even if you had no reason to reconsider it at all (e.g. your monstrous LKO 300-part space station happens to fly overhead). We'll see if this changes with 1.1 (and which might make recovery of boosters a no-brainer in stock).

Edited March 8, 2016 by Plusck