Kerbal Space Program

[hobbsyoyo]

LOL I just realized on that picture of your tanker, the menu at the top right shows you have ~3/4 of your fuel left while the indicators on the lower left show <1/2 fuel left. WTH? lol effin space krakkin

One last thing (b/c that massive post I just wrote wasn't enough) -

I found out about this thing called 'stiching'. Basically, it's a way to strut your tanks to themselves to reinforce your stack. It's really helpful for core boosters that get wobbly when all of the side boosters and the struts attached to them fall off.

Basically, go to the joint between fuel tanks and put an 8-way symmetry stut on one side of the joint, then connect it to the other side of the joint. You won't really be able to see the struts (maybe just the end connections) but they're there and will hold the thing together. You can also use small cubic girders on either side of the joint to attach struts with but I don't see any advantage with that, it just adds more parts and complication.

Hope that helps you, it helped me a ton!

Edit: Just had some thoughts on the kind of mission architecture I'm going to need for my Laythe mission and I need to write it down before I forget.

I'm going to take either my low-orbit shuttle or my retrieval shuttle and turn it into the deep-space cycler for taking Kerbals back and forth between Kerbin and Laythe. I'm going to strip it down to the bare essentials and probably even take off the engines and fuel and just dump it in LKO with my booster. I'll place a clampotron sr to the back end and then launch a propulsion module that will probably be a large fuel tank and NERVAs to dock with it in Kerbin orbit and send it off toward Laythe where it will dock with my space station and tankers there to refuel. The only problem with this is that neither my low-orbit shuttle nor the retrieval shuttle have launch escape systems so if I want to launch it with a full crew to avoid a 2nd docking with yet another rocket, I'm going to have to put some sort of Launch Escape on it. Unfortunately, it's too big for my sepatron towers, so I'm probably going to have to radially-mount small SRB's to the side. I might even play around with using them to boost it towards laythe and then dumping them to save fuel in my propulsion unit.

The tanker design will be simple, just a big orange tank and some NERVA's. I'll probably put a 6-way clampotron on the front and a clampotron sr on the back to provide maximum flexibility.

For the lander, I'm think about using a modified version of my Duna Lander (medium sized fuel tank + 4 NERVA's). I'll probably add those side mounted thrusters to it to provide extra thrust and have them able to toggle on/off once I'm at a high altitude or speed to save fuel and just use the NERVA's from that point. Unfortunately, those side mounted engines are absolute fuel hogs so I'll probably have to add more fuel tanks, which may mean more thrusters...I'll just have to play around and design a lander that can SSTO from Kerbin as a way to verify the design. Question: Can you repack parachutes and reuse them after landing? If not, then that's going to be a design limitation because I'll only be able to bring enough chutes for like 3-5 landings before I have to send another lander to Laythe.

I have no idea what the Laythe research station is going to be like. Probably about the size of my fuel depot but with engines and room for more crew. I'll probably use all of the fuel it has sending it to Laythe so I'll have to immediately send out tankers. It's got to be able to dock with tankers, a deep-space cycler and at least one lander.

So I *think* the mission will go: Send out unmanned tankers to orbit Laythe. Then send an unmanned research station, dock with the tanker(s). Send out an unmanned lander, have it dock with the station and refuel it. Then I'll probably send and unmanned cycler out to the station to see how much fuel it has left when it gets to Laythe to see if the number of tankers I sent will be enough to refuel it and the landers. If not, I'll send out more tankers to dock with the station. At that point, I'll land the unmanned cycler on laythe, it will then serve as a landing point as well as a base of operations.

Once I've put enough tankers at the station, I'll send out a deep space cycler with 8-11 Kerbals. They'll dock at the station and some of them will transfer to the lander, land on laythe and return. Then they'll wait for a second cycler that will be sent unmanned. This way, when some Kerbals are sent back to Kerbin on a cycler, there is still another one at the station to bring back all of the Kerbals there in case of disaster.


*Finally* after the first batch of Kerbals land on Laythe and come all the way back to Kerbin, I'll send out another lander or two. This way, I can leave one lander down on the surface at the base so that I can permanently station Kerbins there and still get them back into orbit in case of an emergency.

Crap this is going to be hard and I may just skip the LKO science station to focus on Laythe and come back to it later.

Let me think how many launches it's going to need:

2 initial tanker launches
1 unmanned research station
1 unmanned lander
1 unamanned cycler which will land at Laythe
1 manned cycler (#2), which will dock with station, transfer Kerbals to lander then lander will land on Laythe and return.
1 more unmanned cycler (#3) will be sent to dock with the station; some Kerbals will return to Kerbin on the 2nd cycler

That will complete the mission objectives, but after that I'll probably send 2-5 more tankers and at least 2 or 3 more landers and more crew.

Crap, I forgot that each cycler will require 2 separate launchers (to dock the crew module with the propulsion unit) unless I develop a launcher that can haul it all. So I'm looking at least 9 separate launches just to complete the basic mission, I'll call it 10 to provide an extra tanker just in case. Then after that probably at least 5 more launches just to put a full crew compliment out there.

This station is going to get huge with all the stuff docked to it, I'm definitely going to have to use Clampotron Srs. I just hope I don't get bored with the mission before I finish it.

Hmm, I may add some parachutes and legs to my tankers so that when I they are empty, I can deorbit them and land them at my base to build up the infrastructure.

 

[warpus]

You can right click on an engine and disable it, then right click on others and activate them. This should work for you. Alternatively, you can group them to activate/deactivate them with a single button press in the action groups menu in the VAB. The mass of your mainsail is going to be pretty small compared to your whole lifter, so dumping it probably won't make a huge difference. Oh and one other thing, if you disable the mainsail and turn on the NERVAs, they are probably going to be in front of your center of mass for your stack. So your controls will be reversed, I think. You'll have to try it and see.

I've never thought about deactivating the mainsail of a core stage and using NERVAs to drain the core tanks. That would be a lot more efficient and I'll have to keep it in mind. Anytime I'm doing an interplanetary journey, if I have any fuel left in my core stage I always use that up completely before I ditch it. I only ever ditch a core with fuel if I'm doing an LKO mission where I don't need it and even then I always hate wasting it.

Yeah, I know that you can disable engines. I think I need to come up with a system that will allow me to ditch the mainsail eingine only once I'm in orbit. Then I have all that extra fuel for my interplanetary stage - and no heavy mainsail engine to drag around. Can you have a decopuler in between your engine and your fuel though? Maybe you need a smaller fuel tank attached to the engine and a decoupler in between the two fuel tanks? I guess I'll have to experiment.

I am pretty sure that the indicator....nevermind, I have no idea! I know how it works when you are asparagus staging and emptying tanks that you drop off, but when you are draining from a tank that you are keeping with you, I'm not sure. I think it just shows you total fuel in all the tanks connected to the engines and doesn't specify which tank exactly it's draining from so you have to manually check.

It doesn't seem to work correctly, because when I look at how much fuel I have left under resources, the progress bar there is always different. I might have 50% of fuel left, but the left-side progress bars will make it look like I have 10% left. Doesn't make sense.

Yeah, trying to make a landing on one of the tiny islands on Laythe is a big challenge in and of itself, especially since the maneuver nodes don't estimate the effects of air drag at all; it's a guessing game.

I reloaded 10 times - and the 10th time I was going down for a landing, but ended up on a very slopey hill, making me crash. Landing on the polar ice cap was cool, but much easier - one of these days I'll have to land on one of those islands.

If the LV-909's are the engines that I think they are, then they have a thrust of 50 vs the NERVA's 60, weigh about 25% as much as a NERVA and have much less Isp. On balance, I think they should be able to lift you off the ground, but you'll have to burn them for a while and burn off some fuel. Whether or not that will leave you with enough fuel to get to orbit and dock is anyone's guess. Good luck!

I tried it last night and the lander finally started moving once I had under 1,000 units of fuel left. But it started tilting to one side quite a bit and crashed right away.. I hav e no idea why, it seemed like it was unbalanced, but that didn't make sense to me. I gave up, but I might try again later today.

Anywhoo, what this means is that I'm always in danger of bumping into my asparagus boosters because I'm nearly always at some angle relative to the horizon.

Weird, I wonder why I almost never run into this problem. I can be facing at any angle, and dropping stages is almost never an issue. I would say 5% of the time something crashes into something else. Maybe I'm just lucky - that or my ascent process is significantly different from yours. Mind you you did say that you do your gravity differently, so that's probably ti then.

Oh random advice: one of the bugs on the orange tanks is that they overheat when used with mainsails so you can't burn at full thrust (which you usually need to burn at to lift a huge stack). A way to get around this is to attach a short tank that's as wide as the orange tanks to the bottom and attach the mainsail to that. This will keep it from overheating and since I found that out a couple of days ago I now use it for all my rockets.

Yeah, that's why I avoid the orange tanks. I wonder why they won't fix this bug. I also wonder why they won't fix the "Undo something in the VAB and stuff gets duplicated" bug.

Are those the ones that stick out really far? If so, those are the one's I use as well, though I usually have to stick 2-4 of them on top of each other to give the orange tanks enough space on an 8 booster asparagus design.

Yeah exactly.

Yeah it was nuts and that's what I mean about I can't just add a couple, I have to go full-blown rocket ********. That 250 SRB design launched a massive, 8 booster asparagus stage up to 10,000m by the way. It happened in about 15 frames as the fps slowed to a crawl. It worked but I never used it for anything because of the lag. I am also 150% sure I could never build anything like that again. It took a long time and a lot of patience and when it was done and I had no use for it, I was like lolwtf?

I think I'm very lucky that my gaming PC died and that I happened to have bought a far more powerful laptop just before that happened. I don't run into any slowdown issues, but mind you I don't create monstrosities like that Ok, there's slowdowns if you strap 128 boosters to your design, but it's not very significant.

Yeah I wish I had more time as well. Every time I play I end up wasting an entire day and I just don't have many days I can devote to a game like that.

KSP may very well the reason I don't end up producing offspring.

It's going to be enormous...but Laythe first, I still have time to beat you!

Let me know how the sr docking stuff works out. As for Laythe, I'm still sick, so I'm not doing any work when I get home. This means I'll have KSP time I have no idea how to build a better laythe lander yet though, so I'll have to do some research first. I think some people use jet engines or something?

(at 3:30am b/c the damn puppy woke me up).

Heh.. me too. My roommate's dog slammed into my bedroom door and woke me up. Stupid b@&%&!%!

Your Laythe mission sounds complicated. Do share your lander design tho

 

[Antilogic]

Wow, you guys are doing a lot.

I spent three hours relearning everything I've forgotten about docking just to have the wrong type of separators on my nuclear cluster. Cue the rage at finding out it was impossible to save the combined traveler so now I have to relaunch and hook up the propulsion module.

Also started working on a project nicknamed the Crotch Rocket III aka the ultra-Strangelove aka the Hobbs Express. No pictures yet.

 

[hobbsyoyo]

Yeah, I know that you can disable engines. I think I need to come up with a system that will allow me to ditch the mainsail eingine only once I'm in orbit. Then I have all that extra fuel for my interplanetary stage - and no heavy mainsail engine to drag around. Can you have a decopuler in between your engine and your fuel though? Maybe you need a smaller fuel tank attached to the engine and a decoupler in between the two fuel tanks? I guess I'll have to experiment.

You can put a decoupler between your fuel tank and your engine but then you'd need to run a fuel line to it (maybe using a small cubic strut and a fuel line directly to the engine).

I reloaded 10 times - and the 10th time I was going down for a landing, but ended up on a very slopey hill, making me crash. Landing on the polar ice cap was cool, but much easier - one of these days I'll have to land on one of those islands.

I landed on one of those islands near, but not at, the north pole. It was hilly as S&*% and my lander toppled over and broke up. The capsule stopped rolling just short of the water. I thought about reloading but I knew I didn't have enough fuel to get back into orbit and this was before docking so I just left it as realistically I could only have a marginally better outcome and even then they'd still be stranded.

I tried it last night and the lander finally started moving once I had under 1,000 units of fuel left. But it started tilting to one side quite a bit and crashed right away.. I hav e no idea why, it seemed like it was unbalanced, but that didn't make sense to me. I gave up, but I might try again later today.

Try burning some fuel and then manually checking to see if your tanks are draining unevenly due to a misplaced fuel line. Also check to see that an engine hasn't broken off during landing as they sometimes do.

Also, it may just be top heavy when it's tanks are nearly empty and there's nothing you can do about that really.

Yeah, that's why I avoid the orange tanks. I wonder why they won't fix this bug. I also wonder why they won't fix the "Undo something in the VAB and stuff gets duplicated" bug.

I wouldn't know, the undo button doesn't work for me so I never have this issue.

I think I'm very lucky that my gaming PC died and that I happened to have bought a far more powerful laptop just before that happened. I don't run into any slowdown issues, but mind you I don't create monstrosities like that Ok, there's slowdowns if you strap 128 boosters to your design, but it's not very significant.

I have 2 graphics cards and a hex-core processor. Unfortunately, the game doesn't use multi-core threading nor does it do much processing on the graphics cards so the extra horsepower I have is completely wasted.

That said, I really don't have huge lag issues, but since I often use such huge rockets the little I do have can be really frustrating over the course of a marathon gaming session.

KSP may very well the reason I don't end up producing offspring.

And yet you keep saying 'I'm kerbal'd out' or 'I need a break' but you keep coming back...lol

Let me know how the sr docking stuff works out. As for Laythe, I'm still sick, so I'm not doing any work when I get home. This means I'll have KSP time I have no idea how to build a better laythe lander yet though, so I'll have to do some research first. I think some people use jet engines or something?

Yeah you can use jet engines and I hadn't even thought of that. I will investigate and post some pics when I have time. Probably will be a few days.

Wow, you guys are doing a lot.

I spent three hours relearning everything I've forgotten about docking just to have the wrong type of separators on my nuclear cluster. Cue the rage at finding out it was impossible to save the combined traveler so now I have to relaunch and hook up the propulsion module.

Also started working on a project nicknamed the Crotch Rocket III aka the ultra-Strangelove aka the Hobbs Express. No pictures yet.

Were you inspired to make a crotch rocket by this:

Spoiler :

Oh man finding out that one crucial component of your rocket was installed wrong half way through the mission is such a PITA. I wish you could do an EVA and fix stuff.

 

[Antilogic]

Were you inspired to make a crotch rocket by this:

Spoiler :

Oh man finding out that one crucial component of your rocket was installed wrong half way through the mission is such a PITA. I wish you could do an EVA and fix stuff.

I think all my crotch rocket designs were ultimately inspired by Strangelove, but I need new names to give them. This design is intended to have the delta-V to take one kerbal (probably riding cowboy) on a grand tour of the solar system, dropping one tiny probe marker at every planet. Except for Kerbin, though, since it's obvious the mission originates from there and for symmetry's sake it's easier to have 6 probe markers than 7.

Don't know if I can pull off this design, will probably take some time. I've got the drive system largely figured out.

I'm also designing the "family van" that will allow 6 kerbals to ride cowboy in comfort around Kerbin, as well as a tiny go-kart-style craft for space.

 

[hobbsyoyo]

Lol that sounds like an awesome mission. I found out with my Explorer 5 program that just trying visit all the moons of Jool in one shot is a tall order, not to mention trying to go elsewhere. Do you plan on refueling mid-flight?

Also, what kind of seperator problems are you having? I once forgot to include fuel lines to my side-cluster of engines so I couldnt use the central fuel tank. However, when I docked the ship I was able to manually transfer fuel to the tanks. Maybe you can manually do it without docking? Idk

 

[Antilogic]

I am planning on building a rocket that has sufficient delta-V to visit all without refueling; it will have 3+2 nuclear engines (two can be dropped with the external fuel tanks to reduce the craft mass during flight). I'm currently planning the route, I think I have to go out first, then in, and time the burns just right to minimize fuel usage. There's not much up top, so hopefully it's possible.

I like to use a cluster of nuclear engines with the adapter like I showed for my Moho traveler previously. To use a mainsail on the main column I have to put separators below each engine in the quad and then another adapter. Now, because kerbal engineering is terrible, the separators fire and the engine casings tear all the engines off the craft. However, if I manually fire each separator in space, then quicksave/quickload, the engine casings magically disappear. However, if I use the yellow/black striped separators, or any separator that is 1m in diameter, it tears the other engines off. If I use the .5m white with red dot separators, they don't tear the engines off.

I want to test whether I can put the separator below the adapter and manually fire the engines to break off the lower adapter.

 

[warpus]

How much fuel are you going to need for that mission? Your burn times are going to be insane! I'm far too impatient for stuff like that, I use 6 nuclear engines no matter what. Then I just go alt > and it's not so bad, even when going to Jool.

Once you get your mission going, you should document it here. I wouldn't mind seeing that design

That will complete the mission objectives, but after that I'll probably send 2-5 more tankers and at least 2 or 3 more landers and more crew.

What's your strategy for sending 5 at a time? I've had slight timing issues when sending just 3, but all I did was: 1. get them into orbit 2. one by one give them jool intercepts and 3. individually jump from ship to ship, fixing the intercepts and making the periapsis as small as possible.

So then they all end up with different routes and different arrival times. And since they're tankers, minimizing fuel consumption to be able to aerobreak was my main concern, not timing. But then of course what happens is they all show up at random times, and with more ships sent, the higher the probability that you will have hairy situations when putting them all into good orbits. Or does it sort of usually just work out?

It just seems like you wouldn't want to wait for the next Jool window to send half of them or something - that's a long time to wait. So how do you optimize all that? I demand answers henceforth

 

[Antilogic]

How much fuel are you going to need for that mission? Your burn times are going to be insane! I'm far too impatient for stuff like that, I use 6 nuclear engines no matter what. Then I just go alt > and it's not so bad, even when going to Jool.

Once you get your mission going, you should document it here. I wouldn't mind seeing that design

It's still in the early planning stage; I need to calculate the delta-V for all the legs and that will determine the fuel requirement. I might switch it up and go for another engine scheme but the 3+2 scheme looks pretty convenient. Might do a 3+2+2.

This was something I cooked up last night after my larger traveler mission (with a hab module) ran into problems. It will take awhile.

 

[hobbsyoyo]

Well my plan is to have all of the basic architecture sent out unmanned at first before I ever send a kerbal out there. So if I am unable to send everything at once, it's not a big deal the rest can wait until the next window. I do not have experience sending multiple ships so it is definately going to be learning experience and it will have screw ups for sure.

I am not going to really on aerobreaking much. I might to it at Laythe if the opportunity arrives but doing it at Jool and then jumping to Laythe will probably waste more fuel than going for a straight Laythe injection pass. I might look into gravity breaking though, we'll have to see. I plan on building a big enough launcher that I can send a tanker on a direct tajectory from Kerbin without stopping in LKO. I will also make a launcher capable of doing most of the Jool injection burn without having to use the tanker's fuel. It will be a challenge but all of my interplanetary launches work like this so I think it can manage. Personally, if my launcher can't do a good chunk of the interplanetary burn I consider it a failure and tweak the design.

I am also not going to dock most of the tankers at first. I am just going to dump them in decent Laythe orbits and not dock them to the station until they are needed. This will save some lag as the station grows and gets cluttered and will save me the headache of docking everything at once. Then when they are empty I am going to land to land then at the Laythe base to build up infrastructure.

The one thing I am least confident about is the lander, that's going to take a lot of design work and testing. Oh and as far as leaving Kerbals down there for years between launch windows - I don't care really. By the time they get there the plan is to have a ready-made long-term base to house them semi-permanently or even permanently.

 

[hobbsyoyo]

Now that I can do large cluster engines, I think I can use boosters that are 5 orange tanks tall if they fit in the vab. I am also probably going to use all-girder construction instead of struts as I have heard a ton of good things about them and the struts just weren't cutting it for my last ultra mega rocket. I am not sure if I used stitching back then though.

Those 8 engines in the cluster are equivalent to a mainsail+ so if a mainsail can lift 3 orange tanks then a cluster can handle 5 at least.

 

[warpus]

I am not going to really on aerobreaking much. I might to it at Laythe if the opportunity arrives but doing it at Jool and then jumping to Laythe will probably waste more fuel than going for a straight Laythe injection pass.

Why haven't I ever thought of that?

And how do you do a gravity break or whatever? Won't it fling you around and send you flying?

So if I am unable to send everything at once, it's not a big deal the rest can wait until the next window.

I'm way too impatient to wait for launch windows to come around, if it was me doing your mission I'd probably put everything in orbit, send it all to Jool, and then lose 1/4 of all my ships or something. Then I'd wait for the next launch window and send replacements. That's the Polish way.

Now that I can do large cluster engines, I think I can use boosters that are 5 orange tanks tall if they fit in the vab. I am also probably going to use all-girder construction instead of struts as I have heard a ton of good things about them and the struts just weren't cutting it for my last ultra mega rocket. I am not sure if I used stitching back then though.

Those 8 engines in the cluster are equivalent to a mainsail+ so if a mainsail can lift 3 orange tanks then a cluster can handle 5 at least.

k so like.. when that ultra rocket is completed, I want to see it.

 

[hobbsyoyo]

Lol I was gonna call it the UM (ultra missile).

Gravity breaking is when you come in on a retrograd pass abd the planet's gravity slows you down. I think. When I figure it out I'll diagram it for you.

 

[hobbsyoyo]

I aced an orbital dynamics test today so I had some free time to work on Project: Beat Warpus At All The Things

I decided to work on the lander for my mission first because that requires probably the most R&D. I decided that since Laythe has .8g and .8atm, a reuasable lander basically has to be an SSTO. Unfortunately, I have no easy way to test my designs on Laythe so I am forced to test on Kerbin. I decided a good rule of thumb is that if I can SSTO off Kerbin, I could do it on Laythe with room to spare.

After a ton of tinkering with all-rocket designs, I couldnt find any combination of engines and fuel tanks that could SSTO from Kerbin. What drives me nuts is that I am fairly confident I could SSTO from Laythe with most of those designs but without a way to test it I am not going to do a ton of work to build a booster to send it to Laythe to have it fail.

So I tried Warpus idea of using jets and that seems to be the key to SSTO. I was able to put 8 turbojets on a lander with four rocket engines and get it to orbit and back. The jets got me to about 15km and 375m/s and then I had to switch to the rockets or risk a flame-out and tumble. The only problem was that this machine didn't have rcs or landing legs and when I added that, it couldn't reach orbit. Again, I am fairly certain it would work at Laythe but I can't be certain.

I tried a bunch of different combos and I even launched a 16 jet + mainsail monstrosity (100t SSTO) and it got to orbit. However, I had to add a ladder for my pilots (it had rcs and landing legs from the outset) and when I did that the game glitched out and not the turbojets won't throttle. It was extremely frustrating.

However, I looked up KSP turbojets and it turns out that they don't get near their max thrust until you hit 1000m/s (the thrust increases with velocity on turbojets in the game). So that got me thinking...instead of burning at a 45 degree AoA (which gave me altitude and speed) why not climb, turn horizontal and throttle up to high speed with a much more gentle climb - that way I am at half of orbital speed before I ever turn on my rockets? It should work...i think. And if it does my first design that couldn't get to orbit when I added rcs should be able to make it. The only problem is that keeping a steady AoA without wings is difficult. I will have to tinker more but I probably won't get a chance before the weekend at the earliest. I will post pics when I can.

 

[warpus]

Damn you hobbs, beating me with my ideas. Mind you, I read that on reddit somewhere, so it didn't really originate in my cranium

Building that lander seems like a pain. I was going to do that today but instead did non kerbal things. And tomorrow I sort of have to start looking for a hotel to book in Bangkok, cause.. I've put it off too long and I don't want to pay regular prices.

If I find something early, I'm going to start on my designs.. but it doesn't sound like it's going to be that easy..

Oh hey, 0.22 is almost out. Science is going to be in it.. and a tech tree.. and the ability to uhh whatdoyacallit.. build a launcher, save it, and then attach payloads to it without having to rebuild everything. I believe they are doing beta testing as we speak.

 

[warpus]

I finished putting together my Laythe rescue lander, codename Cech.

It's kind of crazy. I have no idea if it's going to work, but if I can get it to land, I think it will get into orbit. The part that made it more difficult is that you can't just use parachutes to land - you need enough thrust to slow down enough so that they don't rip right off your lander.. You've got to be going 100m/s or slower when they fully open, so I needed to have a bunch of slow-me-down rockets attached that I'll detach right before I land. I will also need them to correct my course during descent, and I'll probably use my interplanetary stage (that I'll dock with around Kerbin, not designed yet) for some of that too, not to mention the "ok, let's get down into the atmosphere" part.

This could all very well fail. I think it will be difficult to get it close enough to my lost guys, but maybe I can just burn retrograde with my interplanetary stage as much as I can and just sort of fall down instead of coming in at an angle. We'll see what the hell happens

 

[hobbsyoyo]

You might think of using jet engines to slow your descent. At re-entry velocity they will produce maximum thrust. Although it will be impossible to tell for sure if they can slow you down enough by the time you reach an altitude low enough to turn them on.

The tradeoff is that they will only sip fuel, but you would have to carry them all the way their without them providing any use in space and you can't be sure they will work as descent engines. You would probably also have to bring a lot with you to slow down enough. So idk

 

[warpus]

I went with those spike engines instead of jet engines. 8 of them. With "slow me down" engines attached all around, plus fuel tanks for those. With an orange tank sized core in the middle. Like I said, it's a crazy looking lander. My goal is to have full fuel when I land. Like I said, we'll see what the hell happens.

 

[hobbsyoyo]

I did an enormous amount of testing with aerospikes on my lander and they weren't powerful enough (thus requiring more engines and more fuel) and didn't have a good enough ISP. If either the thrust or the ISP was better they would have worked just fine. But for laythe they will probably be ok.

 

[Antilogic]

Random side note: I watched Gravity and didn't understand half the tension in the movie. After all, that was like a 10/10 landing in KSP.