DAL59

SSTO Tylo No Refueling Or Docking

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This is arguably the hardest task in ksp.  Feel free to cooperate and discuss ideas, as doing this alone would make this even harder.  Nobody, as far as I know, has managed to send an SSTO to Tylo.  @Matt Lowne and Bradley Winstance have both done SSTOs, but the former used a detachable lander, and the latter refueled on Tylo.  No mods other than informational or visual mods, or Take Command.  

Note: I have no idea if this is possible.    

With no gravity assists and no aerobraking at Jool, 11040 delta vee is needed from LKO.  

With ion engines, this might be possible!  

Of course, you can't land on tylo with ion engines...

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59 minutes ago, DAL59 said:

This is arguably the hardest task in ksp.  Feel free to cooperate and discuss ideas, as doing this alone would make this even harder.  Nobody, as far as I know, has managed to send an SSTO to Tylo.  @Matt Lowne and Bradley Winstance have both done SSTOs, but the former used a detachable lander, and the latter refueled on Tylo.  No mods other than informational or visual mods, or Take Command.  

Note: I have no idea if this is possible.    

With no gravity assists and no aerobraking at Jool, 11040 delta vee is needed from LKO.  

With ion engines, this might be possible!  

Of course, you can't land on tylo with ion engines...

This is probably not possible, while still being reasonable.

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I'd wager it's possible to make a SSTO that can go to and land on Tylo. The question is: can you get back. I'm going to take a wild guess and say no

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12 minutes ago, JK_Kerbineer said:

This is probably not possible

That is the point.  Its the hardest challenge.

6 minutes ago, EpicSpaceTroll139 said:

I'd wager it's possible to make a SSTO that can go to and land on Tylo.

It is.

 

But it uses mining after landing, so it doesn't count.

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Just now, DAL59 said:

That is the point.  Its the hardest challenge.

 

13 minutes ago, JK_Kerbineer said:

This is probably not possible, while still being reasonable.

Sure you can make a computer breaking, "plane" that is really just a cockpit with a bunch of engines on it that will do the job. But where is the fun in that? :D

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That's fine.  But remember, there are diminishing returns the larger you make the craft.  

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So really you want a single stage to Tylo's surface and back, or a SSTTSAB, and not a single stage to Kerbin orbit, which can then stage as much as needed to do the rest of the mission, or a ship that can, without staging, reach orbit around Tylo from Tylo's surface..

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9 hours ago, 5thHorseman said:

So really you want a single stage to Tylo's surface and back, or a SSTTSAB, and not a single stage to Kerbin orbit, which can then stage as much as needed to do the rest of the mission, or a ship that can, without staging, reach orbit around Tylo from Tylo's surface..

The first one.  The entire ship has to go from the surface of kerbin to the surface of tylo, without refueling, and then go back to the surface of kerbin.  

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~11 could be possible if 5000 of it had a TWR of more than one at Tylo. The most I've gotten out of an SSTO was just over 1,000 at a decent TWR. Maybe if you could somehow get it small enough it could work. I'll give it a look when I get home. No promises.

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8 hours ago, JacobJHC said:

~11 could be possible if 5000 of it had a TWR of more than one at Tylo. The most I've gotten out of an SSTO was just over 1,000 at a decent TWR. Maybe if you could somehow get it small enough it could work. I'll give it a look when I get home. No promises.

This one's gonna gonna take some creativity to be sure! Best of luck, @JacobJHC.

An honest suggestion, if you need extra TWR for landing on Tylo, consider Hammers for the final descent / initial ascent. When taking into account their drymass includes their tanks, Hammers have the best TWR in the game (~52), barring sepratrons (~300) and the LES (~70). While sepratrons would be ideal, they're super draggy unless you rotate them into tanks. These would of course be just for the very bottom of the gravity turn, low engine dry mass would prevent you from needing to carry around much heavier, lower TWR engines (eg. Vector) for the rest of the trip.

Also, while ions are often ideal for very-high-deltaV missions, keep in mind you get free fuel tanks with Nukes. Those BigS Strakes carry a ton of fuel without sacrificing Lift/mass! Also, mk0 liquid fuel tanks have the game's lowest drymass, which can really help out.

I love these edge-of-possibility missions!

 

Edit: I just realized that since the mission calls for landing on Tylo, and probably staying there for a minute,  we'd need two firings of the Hammers. Unfortunately, that would mean bringing extra engines, which kinda defeats the purpose of using a high TWR engine to lower dry mass. The sepratrons would still be worth it for the final 6 seconds of landing/launching, but that's not much. Sorry for the off advice! Hopefully some tucked-in sepratrons will still take a bit of edge off the bottom of that gravity turn.

Edited by Cunjo Carl

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This would require a lot of dV, even with gravity assists

LKO -> Tylo:   1050m/s + another ~ 7-800m/s to get to low orbit.

Tylo landing: ~4600 m/s

Low Tylo orbit -> kerbin ~1000 m/s

So you would need to have ~7.5 km/s left in LKO.   probably doable with ions, but you need twr for the tylo landing.

I would say that this is not possible,  but still worth a try.

 

 

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12 hours ago, Nefrums said:

This would require a lot of dV, even with gravity assist.

I know, right? My best SSTO at the moment does ~4.5-5km/sec from LKO, which definitely comes up a few km/sec short. I think I could squeak a couple more out of it by upgrading its tech, scaling it and pulling out the Kerbal. It's the interplanetary pinball that has me concerned, and which I'm hoping @JacobJHC has a good scheme going.

Can I ask how you sussed the 1050m/s LKO to Tylo? Did that involve any gravity assists or was it just for the simple transfer?

Edit: J/K nevermind, 1050m/s will just get you out of Kerbin's SOI, so it must be with assists! Don't know how I didn't spot that.

Edited by Cunjo Carl

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1 minute ago, Cunjo Carl said:

Can I ask how you sussed the 1050m/s LKO to Tylo? Did that involve any gravity assists or was it just for the simple transfer?

The 1050 m/s wasn't enough for Tylo, the SSTO I had do this went to Thatmo from the Outer Planets Mod. From what I've experimented with in the SPH, it may just be possible, but I don't appear to have the cunningness to design the ship.

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Just now, Cunjo Carl said:

@JacobJHC I can take a stab at building the thing if you can pilot it? :cool:

Sure, although when it comes to KSP the designer is usually the better pilot, I will pilot it with pleasure but I want you to take a stab at flying it first. If you can build a plane with that amount of power, you will truly have built the greatest SSTO of all time.

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4 minutes ago, JacobJHC said:

Sure, although when it comes to KSP the designer is usually the better pilot, I will pilot it with pleasure but I want you to take a stab at flying it first. If you can build a plane with that amount of power, you will truly have built the greatest SSTO of all time.

Hah! I hope I haven't oversold this thing before I've built it. I'd definitely take care of flying it to LKO. It's the gravity assists that plague me, so If I can get it up there with enough deltaV to manage, I'll toss it your way like a hot potato. At the moment, I think this one is a tad on the far side of the edge of possibility, but here goes nothing.

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Couldn't you have engines with extremely high TWR that aren't solid-fuelled (eg. Vector engines) to get you to Kerbin and Tylo orbit from their surfaces, with a Nerv stage for all the operations from LKO to Tylo orbit and back, and toggle the engines when you need them? Of course to cut down on weight even more you could just use ion engines instead of Nervs, you'll just need to prepare for some REALLY long burns. By using ion engines almost all of the weight of the SSTO will be only for the Kerbin surface to orbit and Tylo surface to orbit.

Edited by [insert_name_here]

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Hit 7.8km/s from LKO, including some high TWR for the landing, but there's a lot more improvement to go before it's ready for an attempt.

@[insert_name_here], I'll probably be implementing something just along the lines of what you're suggesting. I was hoping to avoid ions for play-enjoyment reasons, but it looks like they'll probably be necessary. I'll hold out for just a little while longer because the downside of ions is, even though they have a lovely ISP, they have huge amounts of dry mass, which really hits hard on an SSTO. This is also the case for liquid engines and their fuel tanks, which is effectively the reason I was trying to avoid using exclusively liquid engines for the Tylo landing. The practical advantages of liquid seem to win out though! Too bad, because solid looked so nice on paper. Thanks for the ideas!

 

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version 0.1

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47 minutes ago, Cunjo Carl said:

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That's beautiful! :o It's like Star Trek or something, but only just after warp tech developed :rep::rep::rep::rep:

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7 hours ago, Dark Lion said:

That's beautiful! :o It's like Star Trek or something, but only just after warp tech developed :rep::rep::rep::rep:

Thanks! The trick is a glitch exploit developer-unintended-strategy which allows you to make long lines of wobbly parts rigid. Without it this craft would flop like a jelly fish! Simply put a grandparent autostrut on every other piece, and heaviest-part autostrut on one of the off-pieces near the end. Magic! There's other configurations that work too, and I've tried to figure out the mechanism, but it's surprisingly finicky.

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18 hours ago, Cunjo Carl said:

Can I ask how you sussed the 1050m/s LKO to Tylo? Did that involve any gravity assists or was it just for the simple transfer?

That is when taking PLADs K-E-K-K-J route

 

 

 

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15 hours ago, Cunjo Carl said:

Hit 7.8km/s from LKO, including some high TWR for the landing, but there's a lot more improvement to go before it's ready for an attempt.

@[insert_name_here], I'll probably be implementing something just along the lines of what you're suggesting. I was hoping to avoid ions for play-enjoyment reasons, but it looks like they'll probably be necessary. I'll hold out for just a little while longer because the downside of ions is, even though they have a lovely ISP, they have huge amounts of dry mass, which really hits hard on an SSTO. This is also the case for liquid engines and their fuel tanks, which is effectively the reason I was trying to avoid using exclusively liquid engines for the Tylo landing. The practical advantages of liquid seem to win out though! Too bad, because solid looked so nice on paper. Thanks for the ideas!

 

ezgif-5-5cd767a886.jpg

version 0.1

I've tried numerous times to create an Enterprise  and you go do it by accident when chasing a challenge !

I'm really skeptical this challenge can be done.    A vessel's mass divides into fuel, engine and payload.    Engine % can't be reduced too far because of the TWR requirement for Tylo,  so to get a higher fuel fraction you can go bigger in order to make the payload (probe core, KErbal in a command chair) a smaller % of the total.  But you're close to maxing that out on a 50 ton vessel, a 5000 ton monster won't do that much better.

 

I've made a liquid fuel only mk1 SSTO that was about 100 tons, whose payload was a mk1 cockpit.    Had 6k delta V in orbit and about 0.4 to 1 TWR on NERVs at that fuel state.      Some other guys in the same challenge built craft twice the weight, used oxidizer to make orbit and only had one NERV, got over 8000dV.   But TWR nonexistant.

I won't enter this challenge because I can't gravity assist my way out of a paper bag.   

If the full challenge proves impossible,  my vote for watering it down in a realistic way

1.  Allow refuelling on the surface of Tylo.        When you land,  you have to wait for a launch window to return anyway, why not drill that godforsaken lump of rock while you sit in time warp?    

2.  Allow    disposable booster engines/drop tanks and make the challenge one of who can get to the surface of tylo and back, with a kerbal, for the least money,  without docking,  using gravity assists, landing on bodies other than Tylo,  or recovering any launcher stages.    In other words, save money, but not in a way that lengthens the play tiime requirement of the mission (by making you plot assists, make extra landings, land a cargo SSTO from LKO etc),

That's how I normally do missions that are beyond the range of my SSTOs - combo of engine dumping and mining at the destination.

dwWE4bL.png

Heavy jet engines outlive their usefulness...

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40 minutes ago, AeroGav said:

1.  Allow refuelling on the surface of Tylo.        When you land,  you have to wait for a launch window to return anyway, why not drill that godforsaken lump of rock while you sit in time warp?    

2.  Allow    disposable booster engines/drop tanks and make the challenge one of who can get to the surface of tylo and back, with a kerbal, for the least money,  without docking,  using gravity assists, landing on bodies other than Tylo,  or recovering any launcher stages.    In other words, save money, but not in a way that lengthens the play tiime requirement of the mission (by making you plot assists, make extra landings, land a cargo SSTO from LKO etc),

No.  The point is to do something that has never been done before, and that is a no refueling no detachable lander Tylo SSTO.  It might be possible with ion drives.  

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1 hour ago, DAL59 said:

No.  The point is to do something that has never been done before, and that is a no refueling no detachable lander Tylo SSTO.  It might be possible with ion drives.  

I had something earlier that was just shy of being able to land. Will try again.

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I played around a bit in the VAB with Kerbal Engineer, with little success.  I could get maybe 3/4 of the way there on delta V.

So then I turned to excel, because while it only takes one success to prove something possible, only math can prove something impossible.  I'm not 100% sure on the assumptions I made, but I believe it is mathematically impossible to do a stock Tylo surface SSTO.  The spreadsheet works from bottom to top, using the rocket equation to find the wet mass after each step of the mission and finally telling you what mass you have to devote to your fuel tanks and what you have left over for stuff like wings, cockpit, and engines.

I assumed it takes 2000 m/s to go from Kerbin orbit to Tylo orbit, 4500 to land and ascend from Tylo, and 1000 to return home.  With perfect gravity assists and piloting, you might be able to reduce those numbers.  I also assumed the Kerbin ascent had a payload fraction of 35%, which was the highest I found in the recent payload fraction challenge.  Edit: should have assumed much higher, because that fraction was an inert payload, not counting engines, wings, and systems.  I got 66% in testing.

 

Negative percentage for the "budget" line mean it's impossible to get the required delta V with that engine combination.

https://drive.google.com/open?id=1ykMPBYGOo0YHkErJf0mClUfqGF-t1W5r

Edited by sdj64
wrong assumptions in the math

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