Lt_Duckweed

I hope this isn't too much of a Necropost, but I just released my video of a single stage to Eve sea level (under 150m) and back to Kerbin: This is 1.11.2, Stock + Breaking ground. I have had the design mostly fleshed out for several months, but a couple weeks ago I finally just sat down and banged it out. It carries a full suite of science experiments (save for the science Jr.), a full suite of scanning equipment and solar powered isru, and a small selection of breaking ground deployable science experiments, along with a somewhat cramped (but much better than it could be) living space for its crew of 3. It uses a combination of vectors and nervs to ascent back to orbit, then uses ion engines to perform a series of pe kicks, combined with a small reserve of liquid fuel used to assist on the final ejection kick. Some technical details on the craft: 3050 m/s Vector vac dv 1650m/s Nerv vac dv if used after vectors (they actually burn them together, igniting at the same time, so realistically its a couple hundred meters a second less than this) Total ascent dv of about 4500 when used in a single stage, a very small amount of which is reserved to assist with the final ejection back home. Approximately 1800 m/s dv on Ion engines (a tad less but don't feel like looking up the exact number atm) 88.75 tons per Vector. 44.375 tons per Nerv Wing loading of 4.4 tons per wing area with 3 degrees incidence. Ignition is at 16.5km at electricity exhaustion, vector burnout is at about 2450m/s orbital speed with an angle between 15 and 20 degrees over the horizon ( I follow pure prograde until reaching the high atmo, once prograde drops to 15 degrees, I swap to SAS hold). 5.5 tons per large ducted fan blade, 1.26 tons per kNm of rotor torque.

Today, I flew an SSTO to near sea level (under 150m) on Eve, then all the way back home.

25-30 tons is a good starting number, and as you get more skilled at building sstos you can push that higher. To understand how to build sstos around these numbers, watch this video, it is the best ssto tutorial out there: If I'm making a "sporty" ssto where I don't care that much about squeezing out every last drop of performance I use about 35-38 tons per rapier. If I'm going for maximum possible performance I will take off from the KSC flats and use anywhere from 44-52 tons per rapier, depending on the exact mission parameters.

Sadly, there is no way to use the propeller blades underwater. They simply don't produce any thrust. However, you can use regular control surfaces as propeller blades!

I think that keeping in the spirit of the challenge would require using 1x timewarp at periapsis. In 1x time warp, the closest you can get without resorting to exploits is something like 150,000-200,000 km from the surface. With exploits you can get all the way to the atmosphere:

Closing in on 1600 hours myself. Been playing since Nov 2017

Basically, two payload bays that are perfectly aligned so they occupy the exact same space will shield each other from both aero and heat calculations

Damn those look sick! I love the thud/twitch/spider hypergol plumes! Oh, and the ion of course

On the whole, pointing prograde gets you a more efficient burn, as you have no cosine losses (take this to the limit, if you burn prograde for a full orbit, you have more orbital energy than before, if you burn pointing at the manuver node, cosine losses cancel out all of your gained orbital energy). The challenge becomes that its more difficult to keep the maneuver node precise when burning pure prograde.

Quick note on this, 3829 tons is the total launch mass, the rocket alone has a mass of 2818.28 tons.

With some goal post shifting flipping the decoupler around and counting it as payload can reduce part count by 1 lol :) I tried pretty hard to come up with a workable 25 part design but couldn't get anything to stick.

Here is my second entry: "1000 ton launcher low count" Partcount with payload: 31 Partcount without payload: 26 Payload: 1010.72 tons. Launch mass: 3829.0 tons. Mass without payload: 2,818.28 tons. Payload fraction: 26.40% Launch TWR: 1.50 SL Excess Delta-V in orbit: 80 m/s VAB On pad. 45 degrees at 5.8km. Staging at 16.7km and 960m/s. Engines off at 34.3km. Circularization burn? Never heard of it. Ok but actually. In orbit. Payload mass: 1010.72t

Here is my first entry: "1000 ton launcher low count ssto" Partcount with payload: 33Partcount without payload: 28Payload: 1010.41 tons.Launch mass: 4146.05 tons.Mass without payload: 3135.64 tons.Payload fraction: 24.37%Launch TWR: 1.57 SLExcess Delta-V in orbit: 18 m/s VAB On pad. 45 degrees at 4km. 20 degrees at 10 km. 10 degrees at 19km. Engines off at 24km. Small circularization burn. Circularizing. In orbit. Payload mass: 1010.41t

I've seen this before with realplume. In the save file you need to swap the order of the left and right shroud modules.

I was assuming runway takeoff and no nervs or aero loveery on the part of either the launcher or payload, using a "normal" easy to use plane. Its possible to exceed 63% by quite a bit when you really push the boundaries. I've done 65% with a detachable payload, and Brad has done 70% calculated on the laythe+tylo ssto (I've only managed 69% calculated on my 11k ssto).

Bingo Off the top of my head total takeoff mass was about 2400 tons. Payload fraction was like 53% or so

I built this a while back actually: 1258 tons payload if I remember correctly. In a few weeks when I'm back to my computer I may grab some more pictures and submit it as an entry.

Lowest mass would end up dominated by spaceplanes, as launching a 1000 ton payload would only require around 800 tons. And if you are going by mission cost rather than launch cost spaceplanes would win that too.

Theres been a lot of firsts, and obviously a lot of them were thrilling in the moment: first Mun landing, first Duna landing, first ssto, etc. But the one that is my favorite by far was my first successful Jool ssto: I was getting more and more tense/excited through the whole flight as it looked more and more like this would work, and when I saw the periapsis rise out of the atmosphere I was legitimately shaking and could hear my heart pounding in my ears from all the adrenaline.

The intakes will only be able to refill on Kerbin or Laythe, and as long as you are under 30km or so they will refill all the way back up to full.

And if anyone is curious, I specifically used this bad boy, 400 of them to be precise!

Today, I flew on Duna using stock jet engines

The reason being that restock very slightly changes the colliders and the drag cubes and thus is technically not stock physics. So this mod is for people like me (I run and film stock missions). I want good looking plumes, but need to stick with the stock parts & models.

For the purposes of landing, do water landings count or must it be on land?

Nerv does help though. On my Eve sstos, I use a ratio of 2 nervs for every 1 vector. I start up the nervs and vectors at the same time at 16.5km, the vectors then run out of fuel at a surface speed of about 2500m/s and the rest of the trip to orbit is done by the nervs. With these ratios I have been able to achieve 5% payload fraction to orbit. Ideal twr in terms of efficiency balance between engine dry mass and total fuel load seems to be ~78 tons per 1 vector and 2 nerv. So for a 176 ton ssto this translates out to 2 vectors, 4 nervs, and ~8.8 tons of payload. I found in my testing that taking away a pair of nervs and replacing with more fuel for the vectors had a negative impact on payload.