Tylo Landers

[KerikBalm]

Yea... certain things I feel are just "cheap" (not cheating, lets not argue there), so I don't do external command seat landers, nor do I make use of small ISRU units (I would even advocate heavier 2.5m ISRUs, and I am glad that they increased the mass from 0.15 tons to 1.5 tons for the drills).

To preserve "the challenge", I do missions to Moho/Eeloo/Tylo/ Eve where I prohibit myself from using ISRU or external command seats... and with the exception of Eve, I try to make everything re-usable/recoverable.

Anyway, to the OP's question... you can do SSTO tylo landers, and so far I've verified the following engines are adequate:

• KR-2L
• Aerospike
• Poodle

I'm pretty sure the following engines would also work well:

• Mammoth (I think somebody reported here that it does)
• Vector (its a bit worse than the mammoth, but if the mammoth works, this probably does)

Then if you're willing to "get creative" (no crew compartment, intakes as landing legs, clipping to avoid landing legs completely, etc), you could probably make other engines work as well

• LV-909 - Worse TWR an Isp than the Poodle, but I suppose it should work (especialy if you don't carry science stuff)
• Skipper - the TWR is decent (22.1 compared to 27.2 for a mammother), the Isp is better than a mammoth (320 vs 315)... it might work (the mammoth can lift 23% more fuel+ tank than the skipper, the skipper gets 1.5% better Isp... :/)
• Mainsail - same TWR and thus abiity to lift fuel+ tanks as the vector, 98.4% of the Isp of a vector... if the vector works, this soul work, by the transitive property... if the mammoth works, this sould probably work.

I wouldn't want to try any of the radial engines, or the small size engines... or the 1.25m engines other than the 909/aerospike/vector(doesn't really belong in the same class as other 1.25m engines). The LV-T45 has worse vacuum TWR than the poodle, and only 320 vs 350 Isp... soo.... also the aerospike is superior in every relevant metric(TWR, Isp) to the LV-T30, and every relevant metric (except vectoring) to the T45.

[Temstar]

9 minutes ago, KerikBalm said:

Yea... certain things I feel are just "cheap" (not cheating, lets not argue there), so I don't do external command seat landers,

Would it make you feel better about using command seats if I told you NASA in fact asked the Apollo contractors to look into building just such at thing in case the LM ascent engine failed to ignite?


I mean basically, it's a rocket powered witch's broom.

[KerikBalm]

Yea, I've heard about that before... but basically I'm not willing to play with TAC, but I'm also not willing to send my kerbals on interplanetary missions stuck in a pod the whole time, and then not even provide a pod/lander cabin at the end. While an EVA suit would be sufficient for a landing and liftoff, I like to pretend that after years of travel, my kerbals do a little bit more than just get out, spend 1 minute picking up a rock and planting a flag before heading back to orbit and going home. If they go all that way, they should have someting that plausibly would allow a longer stay on the surface. I suppose if we're talking about surface rendevous with an ISRU faciity, one could also stick some hitchiker modules around it an call it a surface hab... in which case my objection to the lawnchair landers is reduced.

Still, I haven't used them enough to know if one gets the engineer drill spee bonus. Their portrait doesn't show up in the lower right, does it? You certainly don't get an IVA view...

[Jouni]

On 2.1.2016 at 3:30 AM, parameciumkid said:

Sadly, despite the lack of atmosphere, I find LV-N engines are still no good. They simply don't have the TWR for an effective lander. It can theoretically be done, but it ends up being more economical to just use chemical rockets.

Before 1.0, the LV-N was the best engine for reusable Tylo landers, especially considering that you could use the same engines in the transfer stage and the lander. With 1 tonne of payload and 5 tonnes of propellant per engine, you got a lander with around 6500 m/s of delta-v, initial TWR 0.85, and landing TWR 1.35. The payload fraction was 11.3%.

1.0 increased the mass of the LV-N from 2.25 tonnes to 3 tonnes. The same design still works with the new heavier engines, but the payload is only 0.25 tonnes/engine.

[problemecium]

^ Yeah that. They still technically work, but I find Tylo landers generally cheaper, easier to build, and more compact if I stick with chemical engines.

...today I learned that "landers" is not in Firefox's dictionary o_O

[Temstar]

7 hours ago, KerikBalm said:

but I'm also not willing to send my kerbals on interplanetary missions stuck in a pod the whole time, and then not even provide a pod/lander cabin at the end. While an EVA suit would be sufficient for a landing and liftoff, I like to pretend that after years of travel, my kerbals do a little bit more than just get out, spend 1 minute picking up a rock and planting a flag before heading back to orbit and going home. If they go all that way, they should have someting that plausibly would allow a longer stay on the surface. I suppose if we're talking about surface rendevous with an ISRU faciity, one could also stick some hitchiker modules around it an call it a surface hab... in which case my objection to the lawnchair landers is reduced.

Even for Apollo flag-and-footprint style missions an open space ascent stage still makes sense. To RP the life support aspect you just put your capsule / hitchhiker on the descent stage so they have somewhere to live. Then when it's time to return to the orbiting spacecraft you take off in the ascent stage which is a super light open space craft.

For Tylo you will always have some kind of orbiting spacecraft, you wouldn't want to make your ascent stage be the craft that return you to Kerbin since that will make the ascent stage and therefore the descent stage huge.

[GoSlash27]

11 hours ago, KerikBalm said:

Yea... certain things I feel are just "cheap" (not cheating, lets not argue there), so I don't do external command seat landers, nor do I make use of small ISRU units (I would even advocate heavier 2.5m ISRUs, and I am glad that they increased the mass from 0.15 tons to 1.5 tons for the drills).

To preserve "the challenge", I do missions to Moho/Eeloo/Tylo/ Eve where I prohibit myself from using ISRU or external command seats... and with the exception of Eve, I try to make everything re-usable/recoverable.

Anyway, to the OP's question... you can do SSTO tylo landers, and so far I've verified the following engines are adequate:

• KR-2L
• Aerospike
• Poodle

I'm pretty sure the following engines would also work well:

• Mammoth (I think somebody reported here that it does)
• Vector (its a bit worse than the mammoth, but if the mammoth works, this probably does)

Then if you're willing to "get creative" (no crew compartment, intakes as landing legs, clipping to avoid landing legs completely, etc), you could probably make other engines work as well

• LV-909 - Worse TWR an Isp than the Poodle, but I suppose it should work (especialy if you don't carry science stuff)
• Skipper - the TWR is decent (22.1 compared to 27.2 for a mammother), the Isp is better than a mammoth (320 vs 315)... it might work (the mammoth can lift 23% more fuel+ tank than the skipper, the skipper gets 1.5% better Isp... :/)
• Mainsail - same TWR and thus abiity to lift fuel+ tanks as the vector, 98.4% of the Isp of a vector... if the vector works, this soul work, by the transitive property... if the mammoth works, this sould probably work.

I wouldn't want to try any of the radial engines, or the small size engines... or the 1.25m engines other than the 909/aerospike/vector(doesn't really belong in the same class as other 1.25m engines). The LV-T45 has worse vacuum TWR than the poodle, and only 320 vs 350 Isp... soo.... also the aerospike is superior in every relevant metric(TWR, Isp) to the LV-T30, and every relevant metric (except vectoring) to the T45.

For the mission profile of initial acceleration 1G (Tylo relative), 1t payload, and 5,675 m/sec DV here's the candidates:

Poodle makes the lightest and cheapest lander at 33.5t and $6,900. Other decent choices are 5 Nervs, 2 aerospikes or 7 terriers. The other options fall prey to the rocket equation, but are at least technically feasible: Skipper, Rhino, Mainsail, Vector, Twin- Boar, Mammoth, and Swivel (although the Swivel is an especially silly option). Anything beyond those won't work.

Best,

-Slashy

 

Edited January 5, 2016 by GoSlash27

[Fearless Son]

7 hours ago, KerikBalm said:

Yea, I've heard about that before... but basically I'm not willing to play with TAC, but I'm also not willing to send my kerbals on interplanetary missions stuck in a pod the whole time, and then not even provide a pod/lander cabin at the end. While an EVA suit would be sufficient for a landing and liftoff, I like to pretend that after years of travel, my kerbals do a little bit more than just get out, spend 1 minute picking up a rock and planting a flag before heading back to orbit and going home. If they go all that way, they should have someting that plausibly would allow a longer stay on the surface. I suppose if we're talking about surface rendevous with an ISRU faciity, one could also stick some hitchiker modules around it an call it a surface hab... in which case my objection to the lawnchair landers is reduced.

Yeah, while this does not exactly fit the OP's scenario, if we want to be self-challenging about it, I would think that any mission to Tylo where the Kerbals were expected to be on the surface for more than few hours would have sent an unkrewed one-way lander with a survival shelter and maybe scientific instrumentation on a launch ahead of the krewed lander, then have the krew touch down near it.  I can certainly see command seats being sufficient if what they want is a mass-efficient lander to get down from a transfer stage to the habitat and back again.  

If you are really feeling like external command seats are an aberration, you can stick them inside a big service bay and pretend the thing is a landing can stripped down of all non-essentials to shave a little mass off of it.  

[MaxL_1023]

Why do people hate ISRUs? It actually makes it harder to do most single body return missions (except for Duna/Eve/Laythe/Tylo) since the weight/cost of the ISRU + Drill + Extra electric generation makes it require a much larger rocket to actually get you off Kerbin, often in the 1000+ ton range.

A Lander can + 5 FTL-800 + 5 Terriers (asparagus or radially staged) will get you basically anywhere and back (except Tylo and maybe Laythe) with a Mainsail + Kickbacks then Skipper lifting it into orbit - you often don't need 3.75m parts at all. 

 

[AlphaMensae]

Timely topic as I'm currently desgining my own Tylo and Laythe single-stage landers, or rather a lander that ideally can do either world.  I'm in science mode and unlocked the whole stock tech tree without mods, but now making use of a few key mods, one of the main ones being Tweakscale so my designs aren't pure stock (I'm planning to use 7.5 and 10m versions of Porkjet's Nucelear Lightbulb for next-gen interplanetary ships, so you can see what I'm aiming for--no minimalism, it's go big or go home).

Anyway, my rough-draft lander uses a central Kerbodyne 3600 tank upsized to 5m, with 4 stock 3600's attached radially and 4 Rhinos downsized to 1.8m.  Payload is the Mk2 lander can, with a 2.5m service bay with a science jr and full load of instruments on the bottom (for ease of access and to protect the science package from Laythe entry heating, though I do pretty gentle atmo descents anyway), plus a 4K battery and 2 stock RTGs, and probably 4 mk16XL chutes; landing is on 4 LT-2 struts upsized by 125%.  There's also the 2.5m docking port, 8 RCS quads and the FL-R13 RCS fuel tank from FTP

KER stats show an intial Tylo TWR of 1.16 and a DV of 5642 m/s with a mass of 167.3 t.  This baby already can quite easily get into Kerbin orbit (with the engines upsized just a bit) with plenty of DV to spare, so I'm not worried about Laythe, but is it enough to land and take off from Tylo with enough DV left to rendevous with the mothership (or a tug--like the sound of that idea)?  I'm still tweaking the design.

[KerikBalm]

7 hours ago, MaxL_1023 said:

A Lander can + 5 FTL-800 + 5 Terriers (asparagus or radially staged) will get you basically anywhere and back (except Tylo and maybe Laythe) with a Mainsail + Kickbacks then Skipper lifting it into orbit - you often don't need 3.75m parts at all.

Laner can: 0.6 tons

+5 FL-T800 tanks = 23.1 tons

+5 terriers = 25.6 tons

A minimal ISRU craft witha  vacuum dV over 2000 m/s can be done or under 8 tons using the small ISRU.

Get to Minmus, get to anywhere... basically.

[Nefrums]

Spark also works well for small ~2t tylo landers.

 

[McFarnsworth]

Question: Anyone think it can be done with a Rapier/Nuke combo? Like you can find on most infinite range SSTO spaceplanes for example.

[GoSlash27]

 

27 minutes ago, McFarnsworth said:

Question: Anyone think it can be done with a Rapier/Nuke combo? Like you can find on most infinite range SSTO spaceplanes for example.

McFarnsworth,

 No, not going both ways. The Rapiers would be too inefficient to use, so they'd just be dead weight. You'd need 8 nukes just to lift a single Rapier, and that's not counting the actual payload.

Best,

-Slashy

[McFarnsworth]

3 hours ago, GoSlash27 said:

 

McFarnsworth,

 No, not going both ways. The Rapiers would be too inefficient to use, so they'd just be dead weight. You'd need 8 nukes just to lift a single Rapier, and that's not counting the actual payload.

Best,

-Slashy

I did say it was an infinite range plane, so that implies it has mining equipment. That also implies it can get to Minmus in a single stage, so I guess the dV available is sufficient. Taking off on the rapiers and circularizing with the nukes once the oxidizer runs out to get an orbit might work actually.

You're probably right when it comes to landing the thing though. Ideally you'd want to burn off the oxidizer first before switching to nuke power but that means you've got high TWR at the start of your descent and pretty much none near the landing so that's not an option. And if you do it the other way around you're wasting a lot of dV with your nukes carrying oxidizer around.

And even if you do somehow manage the above, it's assuming you have a fuel depot in Tylo orbit already, which sort of defeats the purpose of doing it with a self sufficient spaceplane in the first place

[Fearless Son]

Speaking of plane designs, I want to know if anyone has ever tried a horizontal landing on Tylo, touching down on a set of rolling landing gear.  Yeah, I know it would be difficult with an uneven surface, but the theory here being that it could hit with a shallow descent angle, then use the breaks on the gear to bleed off its angular momentum until it can come to a complete rest.  Or is Tylo so big that any attempt to do so would be moving so quickly tangential to the surface that its horizontal velocity would exceed the gear's impact threshold?  

[AbacusWizard]

51 minutes ago, Fearless Son said:

Speaking of plane designs, I want to know if anyone has ever tried a horizontal landing on Tylo, touching down on a set of rolling landing gear.  Yeah, I know it would be difficult with an uneven surface, but the theory here being that it could hit with a shallow descent angle, then use the breaks on the gear to bleed off its angular momentum until it can come to a complete rest.  Or is Tylo so big that any attempt to do so would be moving so quickly tangential to the surface that its horizontal velocity would exceed the gear's impact threshold?  

Lithobraking done right! I've tried it on Minmus (easy with the big flat regions and reasonably slow orbits) and it works quite well--not sure if it'd be as feasible elsewhere.

[GoSlash27]

6 hours ago, McFarnsworth said:

I did say it was an infinite range plane, so that implies it has mining equipment. That also implies it can get to Minmus in a single stage, so I guess the dV available is sufficient. Taking off on the rapiers and circularizing with the nukes once the oxidizer runs out to get an orbit might work actually.

You're probably right when it comes to landing the thing though. Ideally you'd want to burn off the oxidizer first before switching to nuke power but that means you've got high TWR at the start of your descent and pretty much none near the landing so that's not an option. And if you do it the other way around you're wasting a lot of dV with your nukes carrying oxidizer around.

And even if you do somehow manage the above, it's assuming you have a fuel depot in Tylo orbit already, which sort of defeats the purpose of doing it with a self sufficient spaceplane in the first place

McFarnsworth,

 If ISRU is included, then yeah. It's pretty easily doable.

Best,

-Slashy

[Sir Haxington]

It's pretty easy without ISRU (if you're a good pilot and can operate on razor thin margins). This simple three-seater can drop in from about 30km, land, and re-orbit to about 10km. There are actually two fuel tanks, the smallest 2.5 and the smallest 3.75. Three command chairs and some science equipment, a reaction wheel for a little more control and two aerospikes for thrust. Don't forget a ladder! This all assumes you have a way to refuel once you've got back into orbit and you're landing from that 30km orbit with a full tank.

[Jouni]

5 hours ago, Fearless Son said:

Speaking of plane designs, I want to know if anyone has ever tried a horizontal landing on Tylo, touching down on a set of rolling landing gear.  Yeah, I know it would be difficult with an uneven surface, but the theory here being that it could hit with a shallow descent angle, then use the breaks on the gear to bleed off its angular momentum until it can come to a complete rest.  Or is Tylo so big that any attempt to do so would be moving so quickly tangential to the surface that its horizontal velocity would exceed the gear's impact threshold?  

Somebody did it a couple of years ago, probably in version 0.23.5. I can't find it on the new forums, but the Imgur album is easy to find. Basically there is a huge flat area that can be used as a runway, and VTOL engines are necessary for both landing and takeoff.

[KerikBalm]

18 hours ago, McFarnsworth said:

I did say it was an infinite range plane, so that implies it has mining equipment.

I hate the term "ifinite range", especially considering this is KSP.

Anything that can get to solar escape velocity in KSP can go an infinite range from kerbin. Anything that goes to orbit can travel an infinite distance.

Somebody may have a spaceplane that can do ISRU, but that doesn't mean it will make it to Eeloo, or solar escape velocity, or that it can go to Moho even after a refuel at Gilly.

I'd prefer just "ISRU capable plane", rather than "infinite range plane" because infinite range doesn't really have much meaning in the context of a space plane.

More precisely, an ISRU capable plane with a dV of XXXX between refeulings. That tells me what I need to know (well that plus TWR).

But back to the subject, it should be possible to go to minmus, transfer to Ike, refeul transfer to Jool with some gravity assists, refuel at Val, transfer to Tylo, land on the surface using the rapiers at the end for high TWR, then refuel and get back to orbit. Maybe you can skip the ike refuel.

You'll need 860 m/s to get off of val... another 1,100 to get into low tylo orbit, and another 2,400 to land on tylo... call it 4,400 m/s, and the *last* few hundred m/s will need to be with a high TWR, and thus likely the 305 Isp rapiers... Keeping in mind that Val has a surface gravity 42% higher than Mun, and you may want to use some rapiers on liftoff.

Considering that all you need for a SSTO with ISRU capability to get to Minmus is ~2,000 m/s after airbreathing mode, it would be quite difficult to get one to Tylo.

In theory, you could get to tylo after refueling on Bop for less dV, but you'd have to wait a while for the right transfer window... but time is probably not of the essence if you're stopping at bodies along the way to even get to Jool (though a duna/ike stop is probably completely unneccessary for any design that will land on tylo. Pol works too, but the transfer time is 5x longer than from val... it would save you about 900 m/s over a val design though.

[McFarnsworth]

2 hours ago, KerikBalm said:

I hate the term "ifinite range", especially considering this is KSP.

Anything that can get to solar escape velocity in KSP can go an infinite range from kerbin. Anything that goes to orbit can travel an infinite distance.

Somebody may have a spaceplane that can do ISRU, but that doesn't mean it will make it to Eeloo, or solar escape velocity, or that it can go to Moho even after a refuel at Gilly.

I'd prefer just "ISRU capable plane", rather than "infinite range plane" because infinite range doesn't really have much meaning in the context of a space plane.

More precisely, an ISRU capable plane with a dV of XXXX between refeulings. That tells me what I need to know (well that plus TWR).

But back to the subject, it should be possible to go to minmus, transfer to Ike, refeul transfer to Jool with some gravity assists, refuel at Val, transfer to Tylo, land on the surface using the rapiers at the end for high TWR, then refuel and get back to orbit. Maybe you can skip the ike refuel.

You'll need 860 m/s to get off of val... another 1,100 to get into low tylo orbit, and another 2,400 to land on tylo... call it 4,400 m/s, and the *last* few hundred m/s will need to be with a high TWR, and thus likely the 305 Isp rapiers... Keeping in mind that Val has a surface gravity 42% higher than Mun, and you may want to use some rapiers on liftoff.

Considering that all you need for a SSTO with ISRU capability to get to Minmus is ~2,000 m/s after airbreathing mode, it would be quite difficult to get one to Tylo.

In theory, you could get to tylo after refueling on Bop for less dV, but you'd have to wait a while for the right transfer window... but time is probably not of the essence if you're stopping at bodies along the way to even get to Jool (though a duna/ike stop is probably completely unneccessary for any design that will land on tylo. Pol works too, but the transfer time is 5x longer than from val... it would save you about 900 m/s over a val design though.

Call it what you want to call it, as long as we both mean the same thing it's fine by me.

4400m/s seems quite reasonable actually, even less when refueling at Bop or Pol. I might even have a few designs that can already pull that off, or get really close to it anyway.

Time to do some tinkering I think.

[Geschosskopf]

17 hours ago, Sir Haxington said:

t's pretty easy without ISRU (if you're a good pilot and can operate on razor thin margins)........

..... AND you don't much care where exactly you come to a stop.  Any design that relies on minimal fuel and/or TWR requires requires a long, flat landing run that makes landing even in a given general region rather difficult and at a specific location within that region pretty much impossible.  This is not an issue if you're just doing a flags-and-footprints "yay I did it" mission. but OTOH, if that's all you're doing, why bother trying to make a reusable / 1-piece / SSTO Tylo lander?   If that's all you're doing, you can drop stages without losing mission capability and thus have an easier time designing the lander.

You only need a 1-piece Tylo lander if you're going to use it more than once.  Such as to rotate crew or shuttle supplies to a colony.  Which means you need to land pretty close to your surface base.  Which means you need a lot more fuel and/or TWR to do the precision landing than you do with a "land anywhere, just land somehow" mission.

Now, somewhere in between these extremes you have the mission to visit every biome.  But Tylo is the game's best rover country IMHO and driving between the biomes is a LOT easier than hopping a lander between them.  So here you land the crew in a multi-stage lander and the rover goes down for keeps.  Both need to come down within the same general region but if the rover has a probe core, it can drive to the lander if it's not too far away.  So you need very little precision for the lander and only medium precision for the rover (but it doesn't have to take off ever again), so you have (for Tylo) reasonable design flexibiliy.  Then circumnavigate Tylo, claim your Elcano patch, and fly the crew home in what is, after all, a 1-use flags-and-footprints lander.

[AlphaMensae]

5 hours ago, Geschosskopf said:

.....  But Tylo is the game's best rover country IMHO and driving between the biomes is a LOT easier than hopping a lander between them.  

Speaking of rovers, I'm also designing a series of super to megasized rovers that can function as a full reusable lander.  They all share the same basic format, and range in mass from 20t to over 400.  That big one is meant for Tylo and Laythe, and has 4800 m/s DV.  This is it on Tylo (decided to use HyperEdit so I can test it out):

The central tank is a stock Ketbodyne 3600 upsized to 7m using Tweakscale, the others are from Fuel Tanks Plus (the disc tanks also upsized).  Four slightly-changed Rhinos and one stock areospike are the engines.  The wheels are 315% normal size, and the lights and 4K battery also are upsized. It drives real nicely on Tylo, accelerates on flat ground to about 26 m/s.

Unfortunately, I ended up with only about 900 DV left from a starting altitude of 32,000 m, so more tweaking (heh) is needed.

[Terwin]

My Tylo/Lathe lander has ~3200m/s d-v on kerbin with a TWR close to 2 on Kerbin fully loaded with fuel.(it has ISRU and ore tanks, but I doubt I would be able to get more than a token amount of fuel refined in time to be useful during take-off, it is mostly intended for refueling the transit ship before I realized I could land the whole thing on Pol, Bop, and Val)

Seems like it should be adequate to get to orbit on Tylo, but as the nose is a docking port Sr, I am not sure about getting back to orbit on Lathe.