Nao

Thanks RadHazard and Eric S for explanation on 48-7S. I would add that even the old 20kN thrust version of 48-7S was already making LV-909 obsolete. I did a small chart about it some time ago: - there is no flight configuration that make LV-909 better choice than either LV-N or 48-7S. Back to the topic, i don't hear anybody complaining about Skipper! Like RAPIER, it's not only inferior in relative performance to its counterparts (Mainsail and LV-T30), but also can be easily replaced by 3x LVT-30 for the same thrust (645 to original 650) for better Isp and less mass even with stack tri-adapter. It just happens that since it filled the large gap in thrust between LV-T30 and Mainsail, nobody had any complaints for it. And RAPIER fills the need of dual propulsion engine. Yes it's not as efficient as some alternatives, but it fills the gap and that is in my opinion the most important thing. Remember guys this is a Early Access game. RAPIER isn't supposed to be a "new shiny toy" to play with but a first engine for a noob to use on his first SSTO when the game is finally out.

Welp, i'll try to not get into big argument about it, but 48-7S is better than 90% of the stock engines, except partcount per thrust of course. Notably its almost always better than: Mainsail, LV-T30, RT-10, LV-909, and for ascents up to ~4500m/s aerospike engine. And this are the "best for the job engines" so i'm not even talking about others. This also makes any performance flight quite dull and taxing on partcount as its always either 48-7S or LV-N nothing else. It also is quite counter intuitive as IRL efficiency tends to increases with size, while in case of 48-7S is the other way. As for RAPIER vs jet-spike. It does give comparable performance, i didn't have much time to design new planes yet so i used stock aeris 4A and 2 rapiers have slightly better performance than 2x(jet+spike). And even 2x rapiers vs 2xjet + 1x aerospike, have quite similar performance. Using the aeris example 2jet-1spike i've got 1350m/s in 85x88km orbit (using the most efficient ascent profile) and 1340m/s at 85x88km orbit for 2x RAPIERs

In the above comparison RAPIERs have more than twice the power of the aerospike, and only 25% less thrust than turbojets. So I would say, that better comparison would be 2 turbojets + 2 aerospikes to two RAPIERs (where the latter would win). Of course we don't need as much rocket thrust for getting to orbit. But the problem is that RAPIERs are modeled after real life engines (SABRE have 50% more rocket thrust than jet) but KSP ascent profiles are quite different form real life ones. That said while it would be nice to have some small tweaks like getting more jet power and less rocket power on it. The RAPAIER as it is, is quite well balanced. It Has its niche, and more importantly helps KSP in maintaining the easy to learn hard to master trait, that is VERY important from game design standpoint. It's very much ok that people will fly their first SSTO on RAPIERS, and then as they learn discover that it's possible to be a little more efficient by using more complicated and harder to execute design. Also having every new thing be straight better then previous works only with DLC or microtransaction stuff. This is 0.23 patch, it's not the first nor the last engine added or tweaked. Let's be happy that they didn't make another 48-7S disaster.

You cant compare KSP engines to RL as the whole scale of simulation is skewed, and no engine in KSP is even close to the performance of RL counterparts. That is by game design and it works pretty well. Also for jets in KSP, Isp is counted including air, so actual liquid fuel Isp is 16 times more. So even at lowest Isp, the RAPIER has as much Isp as highly efficient real turbofan engine. I for one like the RAPIER, as it is not blatantly overpowered as some other new additions (48-7S). It has its use and comes very close to alternatives (turbojet+several 48-7S). Just a well designed engine fit for its purpose, just like Skipper.

Aside from that there is also a [bUG] there. For drogue the minimum pressure is actually 0.01 when tweaking (as with every other chute) while it should be 0.007 as for default.

+1 on the resource vents (preferably in right click menu), or maybe re introducing the "bug" as an option. It was quite handy for different uses, that tweakables does not cover.

In several hundred years KSP will become obsolete anyways. We'll be going to space on micorcline rockets powered by burning lignite bins. I'm sure it will be !!FUN!! edit: Oh boy, then i should be locked in a small room and kept under surveillance. I've spent probably as much time playing as crunching the numbers and the tip of my pencil

I've always wondered if SSTO principle allowed undocking part of the craft and then redocking it before return to Kerbin. All SSTO's i've seen are single shot planes that never loose or gain parts. But as i understand the idea of SSTO is to return with the whole craft excluding fuel (and other consumables) to kerbin surface. So docking should be valid strategy. Using docking for Eeloo and maybe even an Tylo SSTO could be possible, but i'd like to know other players thoughts on this mathod.

Your empty mass is 0.1.028 which is interpreted as 1.028... edit: wait ksp edits your part file and adds "0." ?? im not sure if i understand . Assuming empty mass of 1.018 everything adds up nicely...

@SRV Ron The mainsail does not overheat on orange tank anymore and we could use fuel tank as root part. (and fly without probe body, just steering the ship with engine gimbal) But still , from what i understand I can't just put the ship with a seat on launch pad and walk the closest kerbal to it.

I see everybody using pods, did i miss a rule about using command seats? Or is it just that the craft would need a pod anyways to have a kerbal that would ride the seat.

You are right. But that said, the least amount of dV spent does not mean the least amount of fuel spent.Having TWR lower than 2.1 required for terminal velocity ascent makes us use more dV to get to orbit, but that is offset by higher dV from lower engine mass netting us an increase in performance. At around ~1.8 TWR we get the lowest fuel spent per payload unit. And if we decrease TWR further, we get lowest craft mass at launchpad at around 1.6-1.7 constant TWR. So yes the whole thing "ascent at terminal velocity is the most efficient way" is a lie . Similarly to how people think asparagus staging is super important for ascent. But in KSP reality it only nets us like ~10% increase in performance.

Aside from following altitude / terminal velocity relation as Taki117 mentioned. You can just build the craft to fly at proper speed on 100% throttle. This is actually more efficient than following terminal velocity with varied thrust. Just make sure that each stage burnout TWR no bigger than 2.1-2.5 (the lower the next stage initial TWR, the higher your burnout TWR). That's for early, vertical ascent up to ~10km because above that terminal velocity increases really fast and during gravity turn you will need more than 2.5-3 TWR to have acceleration keep up with terminal speed increase. After that the cost of additional engines to keep terminal velocity will make the design severely inefficient, so keep TWR of around 1,5-2. If you want to play pure vanilla game, to save time on mass calculations, you can "launch" each stage on launchpad to see it's mass in map view.

1 Use only Ram intakes 2 You can attach two intakes to one octogonal strut and then place them radially on any surface (including wings, just need to rotate the cube)

This is quite interesting! Can you share some articles/links that deal with Hohmann efficiency? I kind of understand how that works, but can't think of actual mathematic formulas. Basic googling left me scratching my head still.

And let's not forget the 700m/s dV of EVA. That's enough to land on one of 6 moons (7 if we include Mun as it is a borderline case). Using rcs refill in pod, we could land on 5 different moons from low orbit with EVA alone in one mission.

Laythe, having atmosphere and big gravity well is probably the easiest of the Jool moons. I believe Eve has the *lowest* dV requirement out of any bodies in KSP to land on (if using Mun gravity assists, it could take even less than for Minmus orbit) Every Jool moon has lowered dV requirements due to Jool having atmosphere to aerobrake. Thus getting to Moho would be almost as hard as to Tylo, Also Eeloo is almost as hard to reach as Moho ... actually you could just use one of the dV charts floating around do do the rankings based on dV requirement.

I have nothing against cheats that fix the gameplay, especially when the player assumes he can do it from the start. But we already don't have much to design and test for in KSP compared to real world. Designing ladders is actually one of the more interesting problems in KSP, as it requires experience and filed testing to develop a system that works in an actual mission. It isn't really a bug when your kerbal falls at the end of the ladder. It is a lack in ladder length for current environment. And we can't really say "it worked before" since it have never actually worked *on Eve*. There is a reason for saying: "the advancement in aerospace technology is written in human blood". It's true in KSP too now more than ever with newer patches including astronaut complex with many applicants and some lost Kermans. But it all comes down to the way we want to experience the game. If its a light entertainment, once upon a time, there is nothing wrong with fixing stuff that we think should happen with cheats. But on the other side, when playing with a more serious approach, spending more time and effort we get much more fulfillment from successes and even failures. Cheating only detracts from that experience.

Edit: OK got that mess of a post and silly mistakes cleared out. It was done quick since i was short on time. Build from scratch, no testing, one launch. Everything went pretty much perfect (E: had to launch the second time due to lack of decoupler on the probe core ) 34434m/s 197parts The rocket itself is 131parts, and damn in this patch Mainsails don't like touching ground. On pad (with F3 and throttle up- showing that it's stable on pad) In space (had to burn +8minutes on Nerva and briefly return to atmosphere (Pe 60km) It uses 24 RT-10s, 12x Mainsails, 7x Skippers, and one LV-N With every engine except the NERVA in SSTO configuration.

Oh, if it is a tested design then i would definitely try getting him up by force. Try using A and D keys (alone or in combination with W and S) as they can give some different results, also shift jumping of the ladder could help maybe. Oh there is also one more way to mess around, time acceleration, since Eve has immense gravity the ship could bend under acceleration in the right way. Oh (2) if you have retractable landing gear you could try retracting one side only so that it helps in ladder tilt.

Hack gravity from debug menu? If you feel that's cheating (since technically it is) there is not much else to do. If your craft has some spare fuel (and a probe body) you could try launching with Bob on ladder, and then shutting off the engines and quickly getting to capsule on jetpacks. You could also send a crane rover with proper ladders

You could use "small gear bay" as a landing gear, it can survive hits above 15m/s and has no weight in flight. It feels cheaty but current landing gear is kind of wonky and really hard to use. Also throttling up a a little just before landing can help too. Oh and i would switch drogues to Mk16-XLs they provide around 4,5 times more drag due to weight and deployed drag differences (remember to strut them to the ship thou as they can get ripped off at 500m).

Well i guess I'll need to do some work it seems . Pretty sure it's possible to get 33,5-34km/s below 200parts (including struts) with ~1600t SSTO launcher. I didn't followed the thread closely thou, so I'm unsure if 33,7km/s is enough to beat your algorithm thou.

Hitting "f" in a split second that the rescue craft would not be possible. So I was thinking about another way to make the OP's rescue attempt on low dV budget. First thing that came to mind was a space cannon that could be used to bounce the free floating kerbal into rescue craft's orbit. In theory it could work for even big relative velocities as the flame had some lenght, that is if i've manage to hit him with the blast. So I've started testing. Launched a Kerbal into circular orbit first and then launched space cannon to rendezvous at medium speed of 333,3 m/s. Unfortunately as i approached the stranded kerbal this happened: (warning a somewhat disturbing image) That's Kelrey Kerman, a lot of them. All in a swarm that kept itself tight as my cannon flew by it. It seems like the kerbal have been infected with some kind of alien disease that mutated and reproduced him while I was busy launching the cannon into position. Experiment results: inconclusive. Next experiment: pending. Clearing of alien infestation takes top priority.

You guys are doing one thing wrong . There should be only one high twr stage. For example a rocket SSTO (based on 2/3 mainsail thrust and 1/3 aerospikes) with only ~1.3 TWR can have payload fraction of almost ~12%. I have a plans for craft with 33,7km/s dV and launch weight of around 1300-1400 tons using SSTO but i don't have time to actually do the first stage design and launch the whole thing. Good luck ! edit: and suddenly numerobis with an SSTO , this forums needs an "new posts since refresh" warning hehe.