If I ever make it back from Eve

[farmerben]

 

I got this thing to work.  There is a tiny heat shield on the very top above the mini docking port, which is enough to handle ascent heating.  The lander cans at the bottom spare me the need to install ladders.  The whole thing is protected by inflatable heat shields on the way down.  At liftoff all the parachutes, science instruments, landing gear, etc decouple. 

I use asparagus staging.  First stage is 3 vectors and 2 aerospikes.  Second stage is 1 vector and 2 aerospikes.  Third stage is a single vector which needs the winglets to make the turn without flipping.   Final stage is a terrier.  It can reach an orbit with average altitude of around 200km.  

[Reinhart Mk.1]

18 hours ago, herbal space program said:

flipping that aft heat shield

yo HOOOOW do i do this? it never deploys...

[GRS]

Click it and click deploy...

[Reinhart Mk.1]

4 hours ago, Reinhart Mk.1 said:

flipping

no i mean i flipped it in the VAB and it can attach it just can't inflate

[GRS]

Maybe some "gravity" turn, keep the Aerodynamic part in the front, if Acceleration got so big to remain save.

[herbal space program]

6 hours ago, Reinhart Mk.1 said:

yo HOOOOW do i do this? it never deploys...

I mounted four of them  to the tops of empty T100 tanks, offset from the main stack using another T100 tank and a couple of small hardpoints, all offset to the max:

 

If you attach them at the other end, as I found out and assume you did, they don't work properly. If you just want to use one, you can likely figure out a way to mount it to the bottom using various struts, etc, but if you want to flip it pointy end-up  you should do it by rotating the part underneath it, so that it remains attached by the bottom.

Edited February 27, 2019 by herbal space program

[Laie]

Still wondering if I should put up a challenge. I've sent around a few PMs, but response has been lukewarm at best. Problem is that I can't decide what to focus on. The obvious options are:

• payload fraction from sea level
• payload fraction from X altitude
• cheapest from X altitude

Starting at altitude would probably be more useful, in the sense that the results are directly applicable to career gameplay. But I'm afraid that it lacks thunder -- that the only true Eve challenge is starting at sea level. Just running three challenges in parallel doesn't strike me as a brilliant idea, either.

Is anyone here even interested? If so, any preferences?

[herbal space program]

2 hours ago, Laie said:

Still wondering if I should put up a challenge. I've sent around a few PMs, but response has been lukewarm at best. Problem is that I can't decide what to focus on. The obvious options are:

• payload fraction from sea level
• payload fraction from X altitude
• cheapest from X altitude

Starting at altitude would probably be more useful, in the sense that the results are directly applicable to career gameplay. But I'm afraid that it lacks thunder -- that the only true Eve challenge is starting at sea level. Just running three challenges in parallel doesn't strike me as a brilliant idea, either.

Is anyone here even interested? If so, any preferences?

As I've been thinking about this, what interests me the most would be something along the lines of your previous Eve 3000 challenge, but with the mission being to take some significant payload from Kerbin to the shore of some sea on Eve and then return/recover it for the least total cost possible, i.e. allowing ISRU and counting recovery costs,  with the provisos that (as before) you can't mine before you land on another body, and also that you can't offset costs by returning more fuel to Kerbin than you left with. That IMO would basically isolate the question of how close to making a practical SSTO for Eve can you get. Based on my experience trying to make a big low-dV lifter above, I suspect you could get very close to doing this from a  high enough  launch altitude, so if i were to try to relaunch my own challenge, I would allow the use of rovers to take the payload down to the water and back, as I think the challenges inherent in those on Eve and the need to bring them back to orbit for cost recovery would be balancing for those. I do think it would be something if somebody could manage to take a 15t payload from Kerbin to the shoreline on Eve and back without staging anything off, and I'm not convinced it's impossible. If you decide to take a pass, I might just give that a shot. I think what I had before was too tedious.

[Foxster]

2 hours ago, Laie said:

Still wondering if I should put up a challenge. I've sent around a few PMs, but response has been lukewarm at best. Problem is that I can't decide what to focus on. The obvious options are:

• payload fraction from sea level
• payload fraction from X altitude
• cheapest from X altitude

Starting at altitude would probably be more useful, in the sense that the results are directly applicable to career gameplay. But I'm afraid that it lacks thunder -- that the only true Eve challenge is starting at sea level. Just running three challenges in parallel doesn't strike me as a brilliant idea, either.

Is anyone here even interested? If so, any preferences?

They are far from the obvious options to me, hence my lack of interest. 

None of those make any sense from a practical point of view. Why would you want to lift any kind of load from Eve other than a Kerbal and some science?

What is useful is to get a craft up from Eve with the lowest mass or dV because they are the craft that you can practically get to Eve and back. I mean, what's the point of some 300t to orbit craft if its near-impossible to get it to Eve?

 

[farmerben]

I'm not an expert on the thermal physics of KSP.  If somebody can point to a good thread/tutorial about this it would be appreciated.  

One thing I have discovered is that the big S wing strake can make a huge difference.  It seems to provide heat conduction and some shielding for the part it is attached to.  Provided the wing strake is not the very front part, it is unlikely to explode.  Perhaps most of the wing parts act similarly, though I don't notice much benefit from the elevons alone.  

I'm trying to land a plane on Eve.  Zero success so far.  

[herbal space program]

1 hour ago, Foxster said:

They are far from the obvious options to me, hence my lack of interest. 

None of those make any sense from a practical point of view. Why would you want to lift any kind of load from Eve other than a Kerbal and some science?

What is useful is to get a craft up from Eve with the lowest mass or dV because they are the craft that you can practically get to Eve and back. I mean, what's the point of some 300t to orbit craft if its near-impossible to get it to Eve?

 

Depends on what the objective is I guess, but if it's the most science/buck, then  sending one of each type of Kerbal,  as well as  a working rover with ISRU capability, multiple experiments, a science lab/storage units, and transmission capability, would allow you to collect surface data from multiple biomes in one mission and return it to Kerbin, and also to land at a much higher site than you ultimately collect your data from. If all of that can then be returned to Kerbin in one piece or at least staging off as little stuff as possible, you would be collecting a really large amount of science for very little money! As to a 300t ship being near-impossible to get to Eve, it's not really so hard, especially if you can land it under power and then refuel it by ISRU. Most craft that can make it off Eve will be able to SSTO on Kerbin.

[Reinhart Mk.1]

1 hour ago, farmerben said:

I'm trying to land a plane on Eve.  Zero success so far. 

it's literally taken me almost a solid month, finally down to a design that im confident will orbit... more or less. good luck man!

[Atkara]

4 hours ago, farmerben said:

I'm trying to land a plane on Eve.  Zero success so far.  

You'll have better results if it's mostly empty when you interface with Eve's atmosphere. You will also need to come in at a high angle (~70-80 degrees), as you want to bleed off a lot of speed, before hitting the lower atmosphere. Your initial target periapsis depends on the design.

The one thing you don't want to happen during the plasma phase is to flip -you really don't want to. If it does, play around with your remaining fuel, or re-design. Once out, the craft will propably be close to entering a stall. If you see it wobble left and right, it's time to let the nose drop.

If done right, it's far easier than trying to come down and land vertically. I was doing it in my 1.3.1 career save and I did again last week with a smaller plane I landed there, for testing purposes.

Edited February 28, 2019 by Atkara

[herbal space program]

14 minutes ago, Atkara said:

You'll have better results if it's mostly empty when you interface with Eve's atmosphere.

I'll heartily second that. The less mass you have behind you the easier it will be to slow down before you burn up. I have never actually landed a plane on Eve, but in other situations where I was coming in hot with a space plane, the ability to skate on the upper atmosphere, turning  velocity into lift, seems to have made heating much less of a problem for me on final re-entry than it has been with more brick-like re-entry vehicles. I may have to try to build one just to see...

Edited February 28, 2019 by herbal space program

[Atkara]

9 minutes ago, herbal space program said:

seems to have made heating much less of a problem for me on final re-entry than it has been with more brick-like re-entry vehicles. I may have to try to build one just to see...

It's not that it won't heat up. It will come close (even really close), but once you finalize your initial target periapsis and do it right, it won't explode. Another thing to keep in mind, is that if a plane can't re-enter Kerbin's atmosphere really well, it has no chance of surviving Eve. So you need to design carefully.

Edited February 28, 2019 by Atkara

[Reinhart Mk.1]

If anyone new wants to go to Eve, don't. There is nothing but anguish and suffering. Turn around.

[I_Killed_Jeb]

we do it not because it's easy, but because it is hard

[Reinhart Mk.1]

21 minutes ago, I_Killed_Jeb said:

we do it not because it's easy, but because it is hard

:')

[Atkara]

7 hours ago, Reinhart Mk.1 said:

If anyone new wants to go to Eve, don't. There is nothing but anguish and suffering. Turn around.

I generally don't like posting old screens, but you seem to be in need of motivation:

The rest of that expedition's mementos can be found here. You're smart, you'll understand what I was doing

PS: The extraction vehicle is a 3-seater (there's a 2-seat module inside that fairing). Better than the old Mk2 capsule, in terms of mass.

Edited February 28, 2019 by Atkara

[Frank_G]

Getting back from Eve... like in the olde days, when we needed 12 - 15km/s of deltaV...

Just get your stuff together and do it man...

https://imgur.com/a/ZZXfD

[Laie]

21 hours ago, herbal space program said:

but with the mission being to take some significant payload from Kerbin to the shore of some sea on Eve and then return/recover it for the least total cost possible

21 hours ago, Foxster said:

None of those make any sense from a practical point of view. Why would you want to lift any kind of load from Eve other than a Kerbal and some science?

Looks like we can't agree on any kind of terms, then.

Edited February 28, 2019 by Laie

[herbal space program]

2 hours ago, Laie said:

Looks like we can't agree on any kind of terms, then.

Well thanks for trying anyway. I think I'm going to spend some time seeing what I can build that pushes the frontier of what's possible on Eve, and then maybe make a new challenge out of that once I've set some kind of a respectable benchmark. If nothing else, this whole conversation has definitely served to teach me all about Eve, so to speak, so it's been thoroughly worthwhile at least for me.

[FleshJeb]

On 2/27/2019 at 12:34 PM, farmerben said:

I'm not an expert on the thermal physics of KSP.  If somebody can point to a good thread/tutorial about this it would be appreciated. 

As far as I know, a good one doesn't exist. This is a start:

• https://forum.kerbalspaceprogram.com/index.php?/topic/108298-physicscfg-what-do-the-numbers-mean/
• https://forum.kerbalspaceprogram.com/index.php?/topic/113772-part-heating-rate/

This explains the numbers when you show thermal info in the right-click menus: https://wiki.kerbalspaceprogram.com/wiki/Overheating
The relevant real-world physics principles are linked.

I don't have time to write a full guide, but I've been playing with thermal engineering. Lessons learned:

       0. Radiator parts are only practically useful for ISRU. Don't waste time putting them on aircraft/aerobraking spaceships.

1. Good aerodynamics is important. Drag means heat. Know your aero engineering. Fly Surface Prograde
2. Know your part .cfgs. See my comments in all caps below.
3. Max Temp is good, high Emissivity Constant is better.
4. If something gets too hot, attach something with a high emissivity constant to it. Preferably where it's least subject to drag.
5. Parts with low internal or external heat tolerance (Cockpits, materials bays, etc) should get an insulating part (Service Bays) between them and hot parts.
6. As above, put a radiating part behind them. Precoolers (0.95 emissivity) are fantastic behind Mk1 Inline Cockpits.
7. The basic Structural Wings are magic. A wing, oriented parallel to your velocity, with another wing surface/elevon attached behind it can survive almost anything.
8. Attach the wing that remains the coolest to the body of your craft. The frontmost wing segment will get the hottest. Build wings longitudinally and only attach them to one spot on the fuselage.
9. You're trying to move heat away from or through the body. This strongly influences part placement and build order.
10. By observation, the controlling factor in radiating heat appears to be the Static Ambient Temp shown in the AeroGUI window. You want to be where it's as low as possible. Radiation power is proportional to emissive_constant * (part_temp - ambient_temp) ^ 4
11. Again, that's the 4th power. Small improvements in thermal survivability can make a huge difference.
12. Per #10, know what the atmo curves for your planet look like. (see graphs the bottom). This is not as helpful for launching, but you have to survive the trip down to go back up.

PART CONFIGS:

Big-S Delta, typical of Big-S parts:

name = wingShuttleDelta
thermalMassModifier = 8.0 --HOW MUCH HEAT CAN WE ABSORB RELATIVE TO PART MASS
heatConductivity = 0.06 // half default --HOW FAST HEAT GETS TRANSFERRED TO OTHER PARTS ATTACHED TO THIS ONE
emissiveConstant = 0.95 --HOW GOOD IS IT AS A RADIATOR. 1.0 IS MATHEMATICALLY PERFECT. DEFAULT IS 0.60
maxTemp = 2400 --DUH

Standard delta wing (and most other wing parts) have identical stats, but note that the conductivity line is commented out. They transfer heat twice as fast as the Big-S parts.

name = deltaWing
// heatConductivity = 0.06 // half default

Intakes have an additional line. I haven't explored the ramifications yet: I assume they transfer a lot of heat to the part behind them:

name = shockConeIntake
heatConvectiveConstant = 0.75 // air goes into jet, not bashes on intake. --NOT SURE WHAT THIS MEANS

Compare to Fairings. I assume the skinInternal is what slows down heat transfer to the parts within, or to the internal temp.

name = fairingSize1
thermalMassModifier = 2.0
skinInternalConductionMult = 0.25 --NOT SURE YET
// heatConductivity = 0.06 // half default
emissiveConstant = 0.8
maxTemp = 2600 // = 3400

Precoolers are flipping magic:

thermalMassModifier = 1.5
skinMassPerArea = 2
emissiveConstant = 0.95
heatConductivity = 0.24 --TWICE DEFAULT
maxTemp = 2000 // = 2900

On the other side, we have insulators like the Service Bays:

name = ServiceBay_125
maxTemp = 2900
heatConductivity = 0.04 --VERY SLOW. THIS IS AN INSULATOR FOR PARTS BEHIND IT
thermalMassModifier = 5.0 
emissiveConstant = 0.95

ATMOSPHERES:

Eve: I'd do my aerobraking at 70km.
https://wiki.kerbalspaceprogram.com/wiki/Eve Graph by OhioBob.

Jool: Counterintuitively, aerobrake at 130km or below.
https://wiki.kerbalspaceprogram.com/wiki/Jool Graph by OhioBob

APPLIED THEORY:

I spam this pic a lot, but I'm disgustingly proud of it. Design features of note:

1. The Structural E wings in the back are attached to the NCS adapter and the small nose cone in the front. They're offset a long way.
2. There are two service bays in the front. Note that the front one is glowing; the rear and everything behind isn't.

What can you infer about the way these wings are built? (Ignoring those hot elevons--Some things are still goofy.)

@4x4cheesecake You're the reason I taught myself KSP thermal engineering. This is ALL your fault.

Edited February 28, 2019 by FleshJeb
Links to Wiki and credit to Bob. Some more lessons learned, and an additional pic.

[4x4cheesecake]

1 hour ago, FleshJeb said:

@4x4cheesecake You're the reason I taught myself KSP thermal engineering. This is ALL your fault.

Your're welcome

But look at all the sweet numbers and graphics you have created...it's beautiful!  

[FleshJeb]

6 minutes ago, 4x4cheesecake said:

Your're welcome

But look at all the sweet numbers and graphics you have created...it's beautiful!  

To be fair, @OhioBob did those graphs and added them to the wiki--I just slam things into the atmosphere until they work.