Eve 3000

[Laie]

As every career player knows, sometimes you're offered a contract that's simply preposterous. Here, I ask you to do one of them. For real.

Extract 3000 units of ore from Eve and deliver it to Gilly.

I'm aware that there's workarounds allowing you to satisfy such contracts without actually moving ore. This is not what I'm asking for. Truth be told, I'm demanding a little more than what these contracts usually specify:

• mission has to be manned. There must be an engineer on board for the mining operations, and anything that moves under it's own power must be controlled by an actual, living pilot (or for docking's sake, must be within 1km of a piloted vessel).
• landing site is supposed to be near sea level. Preferably right at the shores, but I'm aware that this may be hard to achieve. Let's set the cut-off point at 300m as measured by the altimeter.
• you're expected to fly plan for the whole mission, from liftoff on Kerbin until the recovery of the crew (EDIT: by which I mean, "recovery on Kerbin" -- sheesh, kids these days).
• cheapest vessel wins.

We're just looking at the rollout cost here, recovery doesn't matter (I expect it to be pretty negligible and refuse to even bother). No mining or refining until you've landed on another body. You may mine on Minmus or any other body if you like, but the fuel to get there has to be bought and paid for. Be reasonable with the command chairs.

No Part Mods: Making History is OK, except the silly Wolfhound which is explicitly forbidden. Eye candy and autopilots are ok, as is most everything else that doesn't change the game physics or cost structure. We're competing by cost here, and I'm unwilling to take a degree in comparative modology. So, no parts packs please.

Minor Mod Use is OK: I'm willing to overlook almost anything as long as it doesn't give you an undue advantage. The bulk of the vessel has to be stock, simply for reasons of comparability, but if there's a minor something, or a small act of whatever, that's probably OK. Yep, this isn't exactly a clear rule... but I found that most people have a good sense of what's fair and I'm sure we can make it work.

Damn the rules, I'll do it my way: Great! I'm open to "look what I did here" submissions. It may even end up as honorable mention on the front page.

Submission guidelines: Please have mercy with the poor sods who have limited bandwidth. I've been one of them... keep it to one or two pictures in this thread (putting them in spoilers won't help) and move the rest to an external gallery.

As for content, I want to see how your vessel works and how the mission was conducted. Show me everything you think is interesting, point out which mission steps you struggled with (and how you solved the problem), but don't swamp me with hundreds of pics of standard situations. I don't need to see every maneuver from Kerbin to Eve or from low Eve orbit to Gilly. Video submissions are welcome, but please keep it under ten minutes (and if you want to be nice, you provide a list of timestamps for easy skipping between mission steps).

If you want to take part in the competition, I need to be able and verify that you've been honest: I want to see the resource tab, or (preferaby) a deltaV chart including vessel mass (wet/dry), at least at key points of the mission. Preferably in every picture. Be prepared to provide your craft file upon request.

---

FAQ and Fine Print:

• will there be a badge?
  if you want to make one, go ahead.
• will it be OK if I...
  No. If you think it's so severe that you need to ask for permission, don't do it.
• but I just want to make sure...
  Oh that's easy: play stock. Anything else will put you at my mercy. I'll try to be reasonable, and if you try the same, we'll most likely agree. But if you want 100% certainty before you even start, just stick with stock.
• why no mining on Kerbin?
  Because I'm aware of only one way to determine vessel's dry cost, and that is to drain all tanks in VAB. If allowed, everybody has to do it in order to stay competitive. But IMO, tank-draining is busywork at best, a source of nasty mistakes at worst, and I don't think it would really affect the outcome: more expensive vessels will be more expensive under either metric, wet or dry. While I can imagine exceptions, I expect them to be rare-to-nonexistant in real life.
• not even refining?
  Sorry, no. I'm aware that you have a 3000u ore capacity on the pad and may find it hard to let it go unused. But I don't want to open the door to people tweaking their propellant-vs-ore ratios, which, again, would become mandatory if allowed.
• Command Chairs?
  The usual: only for relatively short durations (hours, not days) and in safe situations. No chairs-in-a-bay either: if you have to keep Bill out of the airflow to prevent him from going poof, you shouldn't be using a chair in the first place.
• some ballpark figures:
  I've flown this by going to Minmus for refueling, then on to Eve. It took me 2200m/s to get from Minmus surface to a low Eve orbit on Gilly's inclination. Propulsive landing on Eve required another 2200m/s, though that was pretty thin; with 2500m/s it's quite easy. Finally, 1500m/s from LEO to Gilly surface.
• Hyperedit: by all means, yes. It requires a lot of busywork but no particular skill to get from Kerbin to Minmus and from there to Eve. If you have 1500m/s left in LKO you may just jump to Minmus, and from there you may just flare off 2200m/s and teleport to Low Eve Orbit. If you want to do it on even less, you'll have to show your work.
  In the same vein, you don't have to land on the beach. Demonstrate a safe landing somewhere, then move your vessel to the launch site.

---

whodunnit?

jinnantonix - 973 kilofunds

ManEatingApe - 350 kilofunds, notable for utilizing a Rhino throughout the mission

jinnantonix - also 350 kilofunds. The rocket has seen a lot of fine-tuning, and it shows.

myself - once more 350k, using strap-on Poodles for interplanetary, and a Skipper low-power upper stage on Eve ascent.

ManEatingApe - 315k, using the same set of Poodles both for transfer and as an upper stage.

bayesian_acolyte - 300k using even moar Boar, Aerospikes for the upper, and saving on prarachutes (ouch!)

 

Edited March 29, 2019 by Laie

[Ultimate Steve]

Hmm... Might give this one a go if I can get another KSP thing and an essay done quickly enough.

[FinalFan]

I doubt I will do it, but I am interested enough in the concept to ask a clarifying question:  When you say "no mining or refining until you land on a body", does that mean it's prohibited to launch with the two ore tanks pre-filled and refine the contents into extra fuel? 

[Laie]

10 hours ago, FinalFan said:

does that mean it's prohibited to launch with the two ore tanks pre-filled

Exactly.

Specifically, I wanted to prevent smart-asses from mining on the pad -- which wouldn't be wrong in and of itself, actually. But it would require everyone to drain all their tanks for comparison purposes, which is a lot of hassle, for (I expect) little gain. In almost all cases, the more expensive vessel will be more expensive by either metric.

The "no refining until you've landed somewhere else" rule goes in the same direction, people are supposed to purchase actual propellant rather than ore. That said, filling up ore tanks you happen to carry anyway is a common technique and I could make a smarter rule for that. Updating OP.

Edit: on second thought, no. Look no further than Aeroboi's question below. Getting it right would demand half a page of rule and explanations... forbidding ore outright is much easier, rule-wise, and I don't think it will inflict undue hardship on the players.

Edited September 23, 2018 by Laie

[Aeroboi]

On 9/16/2018 at 9:13 PM, Laie said:

We're just looking at the rollout cost here, recovery doesn't matter (I expect it to be pretty negligible and refuse to even bother). No mining on Kerbin, no more than 3000 units of ore on the vessel at rollout. You may mine on Minmus or any other body if you like, but the fuel to get there has to be bought and paid for.

What does this mean? I need to bring 3000 units of ore with me from Kerbin? What do you mean with 3000 units of ore at rollout? I thought I had to mine it on Eve? So what does Minmus have to do with it? Or do you mean that I can refuel the eve ascent vehicle at Minmus or gilly?

If this part is cleared up I will give it a shot.

edit: can the pilot and engineer be in a command chair inside a service bay? I'm pretty sure the answer is no as it doesn't fit in with the strictness but this is information people have to know for sure, including me.

Edited September 23, 2018 by Aeroboi

[Laie]

1 hour ago, Aeroboi said:

What does this mean? I need to bring 3000 units of ore with me from Kerbin?

[...]

edit: can the pilot and engineer be in a command chair inside a service bay? I'm pretty sure the answer is no as it doesn't fit in with the strictness but this is information people have to know for sure, including me.

Rule update #2, outright forbidding ore again and added a FAQ entry for command chairs. You're right: if the situation demands protection from the elements, I want a proper cockpit. Even a lander can for all I care.

[Aeroboi]

W.I.P.

I have been working on a few lander lander designs over the weekend. I can still get the weight down a bit I guess on the current iteration. I thought to post the progress of it here first in hopes to motivate everyone to try and do the same.

@Laie On 'normal' difficulty or the career difficulty you play at, how much does that contract earn? One should be able to keep it below a million funds I reckon or there around. So maybe these contracts aren't as preposterous as one might think especially if you couple them with eva, flag and other surface or around Eve mission contracts.

My idea is to fuel feed all the stages of the lander to the bottom engines, attach a few drop tanks from launch at Kerbin to give it a little bit more Delta-V of the pad with the intention to use the entire lander as a ascent stage from Kerbin to Eve so I will need less rocket to get it to Eve and then mine and refuel the whole thing at the Evian surface. Then I use a return rocket left in Eve orbit to transfer the ore and kerbals to Gilly and then back to Kerbin.

I reckon that will be the most efficient way to do this.
I probably finish this project by at least next weekend, maybe sooner. Probably over the weekend as I intend to record it. I'll keep it posted

Here's a album showing the Eve sea level ascent https://imgur.com/a/Zc6s7nB
edit: I did forgot to pin the Ore containers until mid way thru the flight so they're visible from the 11th picture.

 

Edited September 25, 2018 by Aeroboi

[Laie]

39 minutes ago, Aeroboi said:

On 'normal' difficulty or the career difficulty you play at, how much does that contract earn?

Someone posted a screenshot over at reddit a while ago; I know nothing about the difficulty involved, but plus/minus strategy modifiers it would have been about 700k advance payment and 2 million reward. You can definitely make a hefty profit (especially if you don't even go down to sea leavel -- I'm demanding it for this challenge, but ofc the contract doesn't).

1 hour ago, Aeroboi said:

I did forgot to pin the Ore containers

Just show the resource panel :)

Your mission plan is sound; you definitely want to leave fuel in LEO for transfer to Gilly, that's cheaper than bringing it up from the surface. I'd also suggest a fuel stop on Minmus. I've found that if you can SSTO to Minmus, you can also proceed to a propulsive landing at Eve, requiring no heat shields at all.

There's a lot of expensive Vectors, though... pressure-wise, 10km at Eve is about sea level at Kerbin, so more ordinary engines will already work quite well by then. No need to go with Vectors all the way. Also have a look at the LFBs. They're not the best engine on Eve, but they still work and are dead cheap.

 

[Aeroboi]

24 minutes ago, Laie said:

Just show the resource panel

lol

24 minutes ago, Laie said:

I'd also suggest a fuel stop on Minmus. I've found that if you can SSTO to Minmus, you can also proceed to a propulsive landing at Eve, requiring no heat shields at all.

Good point, that made me consider going for Minmus first.

24 minutes ago, Laie said:

There's a lot of expensive Vectors, though... pressure-wise, 10km at Eve is about sea level at Kerbin, so more ordinary engines will already work quite well by then. No need to go with Vectors all the way. Also have a look at the LFBs. They're not the best engine on Eve, but they still work and are dead cheap.

I tend to use a lot of spaceplane ssto's to recover my launch costs. Of course this challenge demands lowest launch cost and have therefore overlooked the available options. I wish I thought about the LFB twin boar a lot sooner. it's about the same cost of a vector with twice the thrust + a lot of fuel only with slightly less ISP.
I'm probably going to remake a more efficient vessel using them.

Edited September 25, 2018 by Aeroboi

[Laie]

I've been doodling on this on and off since quite some time. This challenge was posted mostly because I wanted to see how other people approach the problem. I'm still curious, but for the time being, here's how I'm tackling it:

Mammoths are still expensive, but compared to vectors they're a bargain. Upper stage is a skipper. One of the outriggers remains in LEO, for the voyage to Gilly. The other is just extra fuel capacity, which I need:  In my experience so far, it takes 2.2km/s to get from Minmus surface to LEO (coplanar with Gilly), another 3km/s for a safe landing. This requires ever so slightly more fuel than my Eve lifter carries for it's own needs.

As I said, I've been tinkering for quite a while now. Eve lifters as such are not much of a challenge any more, but trying to optimize for cost drives me towards designs I usually wouldn't consider.

[foamyesque]

It's been a while since I was at Eve, but near the oceans I've never, ever seen any ore to mine in the first place.

[jinnantonix]

OK, here is my crazy rocket for this crazy challenge.  Making an Eve ascent vehicle for low cost was hard enough, then figuring out how to land it in one piece, and getting to Kerbin orbit added a lot of cost.  Just over $1M in funds for this puppy.  Still got one or two tests to go, but expect to have the mission completed in a few days.

Edited October 22, 2018 by jinnantonix

[Aeroboi]

I've done a lot of testing on this because this mission is so very intriguing.

I concluded that there is no best type of EAV (Eve Ascent Vessel). There is the option of creating a single stage rocket that can get to minmus from Kerbin to refuel there as suggested by Laie. However, these rockets are the low twr/high Dv type EAV's because only such types have the sufficient dry/mass ratio to come with the required Dv to do this.

I tried building many types but ultimately builded most of my favorite type of EAV's which are high TWR and streamlined rockets. These are the type I normally create and have a eve SLT of 1.8 and much more dead engine mass off of the launch pad compared to other designs like any of yours. These type of rockets can never get to Minmus in one go. The only theoretical way for them to do so is use a mission specific LV-N. But then you require 10k, 20k or even 30-40.000 extra funds. So making it all single stage isn't ultimately a deciding factor in making the mission more cheap.

It turns out that a rocket that does not have the required Dv to get to Minmus turns out to be just as expensive when it uses drop tanks.

Scenario 1:I made a very complex, high part count vessel that costed just over 400.000 Funds and could get to Minmus from Kerbin.
Scenario 2:I also made a less complex vessel with higher TWR and less Dv and could get to Minmus using drop tanks from the KSC also for just over 400.000 Funds.

Fact: If you care for the cheapest Eve vessel you don't care about playing inconveniences like endless aerobraking. Right? I needed some heatshielding as I didn't had all the Dv to do propulsive aerobraking only. I could be SSTO and have more fuel tanks and more Dv and not use a heatshield system at all. But is that cheaper then? A inflatable heatshield is only Funds 1.500,00 a piece. What's ultimately cheaper, more fuel/funds for more dv or more funds for braking system?

Furthermore, there are some points of criticism about the challenge as it stands.

The TS @Laie has a problem with the Wolfhound engine like many of us do as it is OP. I tried the Wolfhound anyway because I tried testing all aspects of this mission. I concluded that nothing is OP about the Wolfhound on a Eve rocket. The flight conditions where the Wolfhound becomes useful on Eve is at altitudes above 30Km.
And that is when it has just more ISP then i.e. a Skiff. That means that you would design your Eve vessel to have a functionally used Wolfhound at 40Km altitude.

From there on it is ~2.000 <> 3.000 Dv into LEO. A Wolfhound has a advantage from that point on in the flight plan and eventually gives more Dv but only a little. It's the last stage so the profit you'd be expecting is ultimately marginal. The Wolfhound itself is a lot heavier then any other engine and you still require a few of them to have enough thrust for the final push into orbit on the final stage.

The way I tested it the Skiff comes out on top because it has the lowest mass per unit of thrust while having excellent vac ISP of 330. Also, because the Atm ISP of the Skiff is 265 it can be used at lower altitudes of ~10Km on Eve. This way you can use Skiff engines as late stage vac engines that can already be fired at lower altitudes for which you would otherwise require other engines for.

The way I see it the Wolfhound is optional and used under specific circumstances can have a design specific performance perk. This perk is indistinguishable from any other engine combination or legal stock peripheral that would be considered allowed. So the Wolfhound should be a optional engine.

Allow reusability?

I also think that reusability can be a thing to drastically lower the cost. I envision a EVE two stage to orbit so that a larger more complex final stage can be salvaged one which you would have thrown away otherwise.
The argument that a single stage to Minmus vessel is cheaper is correct. But a SSTO bringing the EAV to LKO can be just as cheap. Cheaper perhaps since a lower Dv EAV is often less complicated and cheaper on its own so that a SSTO carrying still has less fuel/engine cost.
Bring the EAV to LKO with a SSTO will also consume less time. Landing on Minmus and refuelling is more time consuming I think then de-orbiting a mission specific cargo SSTO with which you launched your Eve rocket.

So far I created a rocket that costs just under 500.000 Funds and checks all the mission rules/objectives.
It's a rocket that uses drop tanks off of Kerbin to have enough Dv in LKO to reach Minmus or a near Kerbin asteroid.
It uses a combination of Aero and propulsive braking.

The module on the right near the bottom engines is jettisoned at Eve which is a tug for the ore to Gilly and refueler to get to Kerbin. It decouples around Minmus so the rocket can refuel and then recouples around Minmus before going to Eve.

 

[Laie]

5 hours ago, Aeroboi said:

I've done a lot of testing on this because this mission is so very intriguing.

I noticed from the occasional topic over at Gameplay Questions... the self-balancing stages were impressive. Are they still part of the project?

5 hours ago, Aeroboi said:

Fact: If you care for the cheapest Eve vessel you don't care about playing inconveniences like endless aerobraking. Right?

Not exactly looking forward to it, but if that's what it takes, that's how it is. I've been making doubtful compromises myself, so who am I to judge?

5 hours ago, Aeroboi said:

I also think that reusability can be a thing to drastically lower the cost. I envision a EVE two stage to orbit so that a larger more complex final stage can be salvaged one which you would have thrown away otherwise.

I'd expected that little more than a pod or perhaps a small spaceplane might return to Kerbin, and didn't want a sub-competition of how much you can eke out on the margins. Actual re-usability is another matter entirely, but honestly, I believe it when I see it.

Regarding the Wolfhound: It's banned as a matter of principle. Eve->Gilly requires a good space engine, as does getting to Eve in the fist place. My Minmus-Eve budget was tight, too, so I started adding a few drop tanks and/or more efficient engines, never mind the burn time. Belive me, there'd be a place for Wolfhounds in this challenge.

[jinnantonix]

@Aeroboi your Eve Ascent vehicle looks very compact.  I did a lot of testing, and could not reduce the size and cost the way you have.  I am not using Making History parts,  and used a combination of twin boar and vectors.  I don't know too much about Wolfhound, but it sounds like it may be giving your design an substantial edge.

Also, if you haven't tested the transport of the ore from Eve to Gilly, suggest you look into that.  It requires a considerable amount of fuel.  I used a multistage craft using 4 x LN-V engines and drop tanks.  Even with the tanks empty on Kerbin launch, the craft weight and cost that this adds to the launch  Minmus transit are not insignificant.

[Aeroboi]

4 hours ago, Laie said:

I noticed from the occasional topic over at Gameplay Questions... the self-balancing stages were impressive. Are they still part of the project?

No! The gains are ultimately to little for the effort required to make it. And the gains are only noticeable if you balance the spring on the engines very precisely which is very finicky and not worth any design. But it does work an I'm happy I made it. I still look for ways to perfect it.

4 hours ago, Laie said:

I'd expected that little more than a pod or perhaps a small spaceplane might return to Kerbin, and didn't want a sub-competition of how much you can eke out on the margins. Actual re-usability is another matter entirely, but honestly, I believe it when I see it.

I assume that the mentality for challenging people to do this is to find ways how to cash in on that particular contracts as much as possible. Or is it me assuming that such a mentality is for everyone? I think all options should be on the table to achieve that. Also remember that a pod, fuel tanks and engines are supposed to get into LEO regardless.
I think it is better then to have fuel tanks as a rendezvous then another return ship when you want to reduce cost. You already brought engines into Eve orbit so why would you want other engines and another pod to sit in?

I'm not going to post the mission as I still have to fly it but you'll see that I jettison my top assembly into smaller segments when reaching LEO to later dock into a small return vessel around gilly. The actual rendezvous vessel in LEO is pure fuel tanks and some verniers for maneuvering.

 

4 hours ago, Laie said:

Regarding the Wolfhound: It's banned as a matter of principle. Eve->Gilly requires a good space engine, as does getting to Eve in the fist place. My Minmus-Eve budget was tight, too, so I started adding a few drop tanks and/or more efficient engines, never mind the burn time. Belive me, there'd be a place for Wolfhounds in this challenge.

Ok, I expected this and of course it's OP. I ho hope you understand it doesn't deliver.

1 hour ago, jinnantonix said:

@Aeroboi your Eve Ascent vehicle looks very compact.  I did a lot of testing, and could not reduce the size and cost the way you have.  I am not using Making History parts,  and used a combination of twin boar and vectors.  I don't know too much about Wolfhound, but it sounds like it may be giving your design an substantial edge.

I tried to make it as aerodynamic as possible by creating a design that has 4 fuel tank stacks plus a center core. The less individual stacks the better the aerodynamics. Improving on reducing the amount of stacks can have the same aerodynamic benefit as changing a adapter for a nosecone at every attachment node. To make it compact was by using a lot of slanted tanks so the outer tanks move outward so they don't hit the center stack when decoupling. These slanted tanks are less aerodynamic, but a fifth or sixth stack is draggier anyway. These and other things decide the looks of it.

1 hour ago, jinnantonix said:

Also, if you haven't tested the transport of the ore from Eve to Gilly, suggest you look into that.  It requires a considerable amount of fuel.  I used a multistage craft using 4 x LN-V engines and drop tanks.  Even with the tanks empty on Kerbin launch, the craft weight and cost that this adds to the launch  Minmus transit are not insignificant.

The fuel tanks hanging on the underside is what is left in LEO as rendezvous to get the ore to gilly and the kerbalnauts back to Kerbin. The amount is considerable indeed and uses asparagus. I personally wouldn't use the LV-N for this at all. A LV-N costs 10.000 funds. 4 x LV-N = 40.000 Funds. It's much cheaper to use terriers or poodles with only a few extra fuel tanks.

Edited October 23, 2018 by Aeroboi

[jinnantonix]

@AeroboiI had considered using terriers for the for the return, and since you mention it, you are right they are way cheaper.  I will put some thought into that idea, thanks.

[Flying dutchman]

I will just try to do it. I will not be looking at the cost or anything other than just merely completing this challenge. Why? Because it sounds to me like this challenge is hard enough without trying to optimise for cost.

[Flying dutchman]

Gilly keeps jumping out of its orbit, very strange..

[Aeroboi]

3 hours ago, Flying dutchman said:

I will just try to do it. I will not be looking at the cost or anything other than just merely completing this challenge. Why? Because it sounds to me like this challenge is hard enough without trying to optimise for cost.

Doing it at all is hard. I wish I'd already seen more submissions or W.I.P. and I have a gut feeling we haven't seen more because people are held back by the launch cost optimization goal of this challenge. Getting it low cost from launch is just endlessly creating stages, reducing drag, trying out new engine combos and improve ascent profiles. It's not even fun to test that much, but the fun in explosions and eventually getting somewhere through effort is glorifying. If I hadn't had that attitude I wouldn't have made jack gooey.

IMO I think a best "cost" submission should be a category. I think low cost is a intriguing goal for me personally so I try to reduce it as much I can. While it's hard and perhaps not for you partial reusability is possible and ultimately full reusability also. It has been done a few times already. I hope there's a place for people that devise these type of missions.
I also hope this thread is going to be a showcase on many different design choices from which I can learn. Unfortunately it is not the most popular challenge yet, maybe it's because of Eve, I hope that changes.
 

1 hour ago, Flying dutchman said:

Gilly keeps jumping out of its orbit, very strange..

I had the same. I haven't tested enough to be 100% sure but it might be due to the Hyperedit mod. You use it? Anyway, it seems to be only graphical. You can still get a gilly encounter if you know it's actual location.

Edited October 23, 2018 by Aeroboi

[Flying dutchman]

I indeed use hyperedit:)

 

But is is not only visual. I set up a node for an encounter and the patched conics keep moving. Even when i have an encounter, as soon as i stop the burn the line shifts and i no longer have one.

 

The longer i wait before i timewarp the more it shifts

[Laie]

Ahhhh. That may be phantom forces -- a micro-acceleration of just a few mm/s. I'm getting that occasionally... and on highly eccentric orbits it can have a serious effect. Check your AP, is it stable?

[Flying dutchman]

2 hours ago, Laie said:

Ahhhh. That may be phantom forces -- a micro-acceleration of just a few mm/s. I'm getting that occasionally... and on highly eccentric orbits it can have a serious effect. Check your AP, is it stable?

Phantom forces?:)

 

I believe ap is stable, craft does not have rcs btw. Maybe it's down to one of the visual mods i have installed, i'll figure it out:)

[jinnantonix]

I thought I was close to doing this mission, but then discovered problems with my Eve ascent vehicle.  Big difference between launching from 500m and launching from 10m. From sea level I am still a 300dV short of getting to orbit.  I keep adding engines and fuel, and success is no closer.  I no longer care about the mission cost.  Just completing the mission will be an achievement.

Edited October 28, 2018 by jinnantonix

[Laie]

1 minute ago, jinnantonix said:

Big difference between launching from 500m and launching from 10m.

Yep, that's Eve for you. Being higher means better ISP, means more thrust, means better acceleration, mains gaining altitude more quickly for a faster increase of ISP and thrust... it's a bit like compound interest, and especially pronounced if you have a low TWR to begin with.