I would take this rocket to...

[Kizarvexis]

Hi,

I know I am a bad pilot when it comes to landings. I wanted to post some screen shots of my spacecraft to make sure that it's not my spacecraft and my bad skills that make landings hard. In another thread, I_Killed_Jeb, asked if it was my rockets that might be the problem. I know I over-engineer them to bring lots of fuel to the party, so I don't think it is that. I figured, I would post some pics of my latest design to see what the expert pilots think.

I'm in career mode and have reached the 300 science level of parts. I have the Skipper LFE, but the 7 LV-T30's on the outside asparagus tanks work fine. I have 7 LV-T45's on the inner tank. The lander has 4 LV-909's and I swapped out two Science Jr's for more fuel (FL-T200's). I also put a FL-T400 under the capsule to supplement the outside FL-T400's. I haven't used this lander to try land on the Mun yet.

Usually, I get into orbit around the Mun and then burn retrograde to make the orbit path straight up and down. I then burn to slow down and land with very little drift as I am falling straight down. When I tried to burn retrograde and then zero out the drift as I landed, I ended up swanning all over the place before landing. So, what do you think? My guess is the experts would take this overpowered rocket all over the Kerbolar System without refueling.

VAB pic with Kerbal Engineer data (craft files below pic)

I tried to stick the pic in a spoiler tag, but it would not work.

Here are the files for both the Mercury IV and the upgraded Mercury V that is in the pic above to make them easier to find. It is vanilla with 2013-12-Engineer-Redux-v0.6.2.2 as the only mod.

Mercury-V => http://snk.to/f-chp52kj1 This one has a reaction wheel in the center stack and seems more stable than the Mercury IV.

Mercury-IV => http://snk.to/f-c7h90tcd Rolls sometimes for some reason I could never determine.

Edited January 17, 2014 by Kizarvexis
added craft files

[zeppelinmage]

I'm also a bit of a n00b, but 9000 m/s isn't all that much. My Mun rockets usually end up in the 8000-9000 range, so this one would get me to Minmus.

But I also design my rockets per stage... ie, a "lifter" stage, an "orbital/transfer" stage, then the "lander/return" stage. Just getting to orbit takes 4700-5000 m/s. Munar transfer is ~900, landing takes me almost 1000 (I do the same landing technique - bleed horizontal velocity to 0, then drop vertically), and returning back to Kerbin takes another 1000.

IMO, the final delta-V matters far less than your individual stages and what they're designed to accomplish.

[regex]

Is this the "in space" stage? If so, yeah, I could take this pretty much anywhere one-way, and return from almost anywhere except Moho, Dres, and Eeloo (Dres and Eeloo I could maybe do a return). The lander can get back up from anywhere except Eve, Tylo, and Laythe, with Moho being a bit iffy.

[mythbusters844]

This video might help for your landings.

[Kizarvexis]

This is a from the KSC rocket. I'll have to watch that video later. Thank you.

[Taki117]

9km/s dV will get you to Jool if you launch in the window. Instead of burning all your horizontal velocity in orbit try burning it closer to the surface (So that Gravity has less time to pull you down, resulting in a slower speed)

[Kizarvexis]

snip

This video might help for your landings.

Ok, so as I understand the video, you get into a low orbit and thrust retrograde varying your pitch while staying roughly the same height above the surface. When you get slow, then you use pitch and throttle to slow your descent speed and finish off the drift to land, correct?

If so, then I'll need to spend some time in sandbox mode the simulator practicing my control over the lander, before trying this in career mode.

[Kizarvexis]

9km/s dV will get you to Jool if you launch in the window. Instead of burning all your horizontal velocity in orbit try burning it closer to the surface (So that Gravity has less time to pull you down, resulting in a slower speed)

I usually do a few degree turn once I clear the launch clamps to angle away from the KSC for when I start dropping boosters. At around 20 km, I go over to 45 degrees or so until the AP is above 70km. Then I coast to near the AP to circularize. I usually have some of the second stage boosters left to start to circularize and end up with roughly 1/3 to 1/2 the fuel left in the center stack once I have a PE above 70km.

[Taki117]

I usually do a few degree turn once I clear the launch clamps to angle away from the KSC for when I start dropping boosters. At around 20 km, I go over to 45 degrees or so until the AP is above 70km. Then I coast to near the AP to circularize. I usually have some of the second stage boosters left to start to circularize and end up with roughly 1/3 to 1/2 the fuel left in the center stack once I have a PE above 70km.

I was talking about for your landing. It sounds to me like you're ascent profile is fine, it's just the landing you are having issues with, Less is more.

[federicoaa]

I believe you have too much thrust.

I usually design a 3-stage lifter to have TWR of 2, 1.5, and 1.

Your first stage has 2.43 and will reach terminal velocity so you will have to throttle down. Also, accelerating at almost 3g will make it harder to control

If you replace the engines with less powerful-more efficient ones you can reduce the TWR to less than 2 and get more dV

[Kizarvexis]

I'm also a bit of a n00b, but 9000 m/s isn't all that much. My Mun rockets usually end up in the 8000-9000 range, so this one would get me to Minmus.

The Mercury-IV, which had less lander fuel, made Minmus and back. I can land there, because the gravity is so low, but the Mun is another kettle of kish.

[Kizarvexis]

I believe you have too much thrust.

I usually design a 3-stage lifter to have TWR of 2, 1.5, and 1.

Your first stage has 2.43 and will reach terminal velocity so you will have to throttle down. Also, accelerating at almost 3g will make it harder to control

If you replace the engines with less powerful-more efficient ones you can reduce the TWR to less than 2 and get more dV

Only the Aerospike has a better ISP in Atmo and the 909, Poodle and Aerospike all have better in space. With the low thrust of the 909 and poodle, I went with the T30's and T45's. I don't have the Aerospike yet. Besides, 49 engines at liftoff is almost as good as MOAR BOOSTERS. I usually over-engineer rockets to bring extra fuel as I need it for landings.

[zeppelinmage]

Try fewer LV-T45s. I usually only connect 4 of them below my boosters (with ever-handy strut-clipping).

[zeppelinmage]

The Mercury-IV, which had less lander fuel, made Minmus and back. I can land there, because the gravity is so low, but the Mun is another kettle of kish.

Yeah, I haven't been to Minmus in a while; since squeezing all the science out of it. After I posted, I recalled needing LESS fuel for a Minmus mission than a Mun mission. Either way, 9400 m/s wouldn't get me very far. Maybe a one-way to another planet, but certainly not round-trip.

[Deathsoul097]

I had a lander rocket in career mode, pretty much where you are now, that was able to make it to the surface of duna and back. It was smaller than yours. This is hella over-engineered. I could probably make it to minmus, mun and then back to minmus, and return with this much D/V.

[technion]

The ultimate, definitive answer would be for you to post your craft file and let people actually try it.

[TheGeoninja]

KSP has a crazy learning curve that so far I have noticed two stages of and I am still trying to pass this second stage of interplanetary flight. My advice if you landings aren't going well is to do a powered burn above the surface of the mun or minmus and don't burn multiple times on the way down. This way you can land quicker and use less fuel. This also helps if you tip over on landings and if that doesn't work I would add some RCS on your lander. Practice makes perfect in this case and experimenting with different designs to find your play style is key.

[Superfluous J]

I doubt I could land that on both Mun and Minmus but I'm pretty sure I could low orbit both and maybe land on one of them in the same trip. Probably Minmus.

Though if you'd let me take a few of the rockets off the bottom to get the TWR lower, I could probably get that thing most anywhere.

[Kizarvexis]

I had to find a file sharing program and FileSnack seems to fit the bill. Here are the files for both the Mercury IV and the upgraded Mercury V that is in the pics in the first post. It is vanilla with 2013-12-Engineer-Redux-v0.6.2.2 as the only mod.

Mercury-V => http://snk.to/f-chp52kj1 This one has a reaction wheel in the center stack and seems more stable than the Mercury IV.

Mercury-IV => http://snk.to/f-c7h90tcd Rolls sometimes for some reason I could never determine.

[technion]

I'm not sure if it's the answer you were hoping for, but that rocket can definitely land on the Mun.

It can also make the return, although I broke off the lower part of the rocket when the chutes expanded.

Regarding the roll, this does tend to happen on certain types of rockets. I'm not sure there's a lot you can do at this point, but replacing those winglets with standard canard once you get them will help a lot. The bigger stability issue imo is the lander that wobbles. It makes it hard to target a manouever node accurately. I would add some struts for this. In terms of making the landing easier for you, is the goal here to do some sort of biome hopping? If this is your first Mun attempt, that's overshooting, and I don't believe this rocket has enough fuel to do it well anyway. There is therefore no point having more than two science kits. One for "in space near" and one for touchdown. You're also set to take them home, and packing a series of parachutes to make that happen. There are lights, stacks of RCS and far more batteries than you need.

I'm guessing you don't have the 48-7S engine yet, but I can see fuel lines and decouplers so I know you have those. Finally, those ladders aren't needed on the Mun. There's a probe core in there that would almost allow this to become an Apollo style mission, but the main rocket is out of fuel by the time it separates, and there's no docking port on the main rocket.

In short, that's a lot of weight that's making your landing more complicated than it needs to be. I've prepared a variation for you which is stripped back of those components.

You can see more how much fuel we get into Mun orbit with.

You'll find landing much easier (unless you land on a virtually 90 degree slope like my first attempt).

Look at the difference in dv with all the science parts blown.

It doesn't even need to use this stage, which has 1855dv.

Craft file: https://lolware.net/kerbal/Mercury IVb.craft

[Kizarvexis]

I'm not sure if it's the answer you were hoping for, but that rocket can definitely land on the Mun.

It can also make the return, although I broke off the lower part of the rocket when the chutes expanded.

I thought it could. I'm right in that it is my poor piloting that wastes all that fuel. Also, did the struts break? I thought I had strutted the parachutes to the lower half of the lander.

Regarding the roll, this does tend to happen on certain types of rockets. I'm not sure there's a lot you can do at this point, but replacing those winglets with standard canard once you get them will help a lot. The bigger stability issue imo is the lander that wobbles. It makes it hard to target a manouever node accurately. I would add some struts for this.

In the Mercury-V, there are more struts and a 3m reaction wheel in the center stack to make it more stable.

In terms of making the landing easier for you, is the goal here to do some sort of biome hopping? If this is your first Mun attempt, that's overshooting, and I don't believe this rocket has enough fuel to do it well anyway. There is therefore no point having more than two science kits. One for "in space near" and one for touchdown. You're also set to take them home, and packing a series of parachutes to make that happen. There are lights, stacks of RCS and far more batteries than you need.

Well, I was doubling up on science. I tried biome hopping on Minmus will modest success. I took this lander there and back multiple times. I just had bad luck on the Mun. I also would sometimes do science on Kerbin after returning from a single biome on Minmus and be able to do new science on Kerbin if I landed in a new biome there too. The Mercury-V only has two Science Jr's now, as I replaced the other two with fuel tanks. BTW, my Kerbalnauts are scared of the dark, so there is lots of redundancy on the power.

I'm guessing you don't have the 48-7S engine yet, but I can see fuel lines and decouplers so I know you have those. Finally, those ladders aren't needed on the Mun. There's a probe core in there that would almost allow this to become an Apollo style mission, but the main rocket is out of fuel by the time it separates, and there's no docking port on the main rocket.

In short, that's a lot of weight that's making your landing more complicated than it needs to be. I've prepared a variation for you which is stripped back of those components.

I have the 48-7s as I have everything through the 160 level and some of the 300 level. Like I said, I'm not a very good pilot, so without a ladder, the Kerbalnauts flail around for a while before finally grabbing the capsule. I had the idea of using the probe to put the debris back on the ground by leaving some fuel, but then I started taking it to Minmus and using it for the first part of the descent and crashing it there.

You'll find landing much easier (unless you land on a virtually 90 degree slope like my first attempt).

THAT is how I land. The video up thread has a neat way to doing a landing, so I'm going to hit the sandbox simulator to practice.

Look at the difference in dv with all the science parts blown.

Don't you want to return those for more science? I downloaded you craft file and will try it out in the sandbox simulator.

[Deathsoul097]

No. You don't return them. What you do is get a kerbal to EVA and collect the data, then ditch them and keep the data in the capsule. (If you want to do it the least efficient way possible. The best thing to do is to create a "science package" that can be reused. Simply, you use docking ports to collect and transport the science module down to the surface, then bring the module back up and keep it in orbit for further re-use, and cleanout by a mobile processing lab. You return the science by sending a dedicated crew shuttle or using your lander, gather it out of the module, and return the command pod to kerbin for recovery.)

Edited January 17, 2014 by Deathsoul097

[technion]

I have the 48-7s as I have everything through the 160 level and some of the 300 level. Like I said, I'm not a very good pilot, so without a ladder, the Kerbalnauts flail around for a while before finally grabbing the capsule.

Don't you want to return those for more science? I downloaded you craft file and will try it out in the sandbox simulator.

Great - I would swap those engines, or at least the two side ones. This will reduce weight a lot more. I've landed 48-7S's on Duna so I'm confident they'll manage the Mun.

As for the science, as another poster just said, your kerbal can EVA out and pick that science up. That kerbal will then place that science in a command module. All you then need to return is that module. This will allow for a much smaller rocket.

[Kizarvexis]

Ah, shiny. I knew you could reset the Science Jr's with a lab module and did that with my Skylab craft. I then landed the lab module to recover all the science. I didn't know you could do that with Kerbalnauts too. Thanks