Extreme Sunbathing

[KAL 9000]

Get a probe as close to Kerbol as you can! (No Hyperedit, obviously, but non-ridiculous part mods are allowed. YES, NO ALT+F12 EITHER!!!) Your score will be calculated as 1000000*(600000/closest distance (in meters, not kilometers)). Screenshots will be helpful, but are not required if you are not a liar (required if you are ). Bonus points if your probe comes back to Kerbin, and/or if it's manned.

Top scorers: 

Foxster - 85 Mm, 7060

Edited April 2, 2016 by KAL 9000

[Spudrotuskutarsu]

Do i have to launch from Kerbin?

[Foxster]

Here's the good ship Muffy...

She is OK at 100.009Mm Pe. The temperature wasn't at max so a little lower should be good. I could also have put another heat shield on to make it heat-proof all round and the ion engines would still have worked but I kinda liked the more realistic look as it is. 

Oh, this is KSP1.1 obviously. 

Update...

I added some Thermal Control System panels to see if they helped at all and I was able to get a bit lower at about 85Mm...

Edited April 2, 2016 by Foxster

[KAL 9000]

15 hours ago, Spudrotuskutarsu said:

Do i have to launch from Kerbin?

Uh... Duh?

6 hours ago, Foxster said:

Here's the good ship Muffy...

She is OK at 100.009Mm Pe. The temperature wasn't at max so a little lower should be good. I could also have put another heat shield on to make it heat-proof all round and the ion engines would still have worked but I kinda liked the more realistic look as it is. 

Oh, this is KSP1.1 obviously. 

Update...

I added some Thermal Control System panels to see if they helped at all and I was able to get a bit lower at about 85Mm...

Ok, 85 Mm... That's a score of about 7060! Amazing job!

[Turf]

Do I have to use 1.1 or 1.05? Or make a separate scoreboard for 1.05 and 1.1?:

[KAL 9000]

Either one, you're fine.

[Turf]

I see my vessel overheats differently depending the exposure to Kerbol.... I'll have to design it as narrow as possible.

[maceemiller]

Imma have a go at this today

[tseitsei89]

It's not a probe so technically not allowed for this challenge but will post anyway.

It's manned and has been as close to kerbol as 69,96Mm (probably can go around 60Mm but I have never flown it that close...).

Plus it can also safely return the kerbal back to kerbin.

I originally made it as an entry to my own challenge (that didn't turn out to be popular at all):

 

[maceemiller]

Im at 87000k atm but still trying to get closer!

[Leeman]

Could it be that heat distribution / radiators work differently if you are in physic/time warp? *scratch* Was perfectly fine at a 150 000 000 meter periapsis.. tried to warp to AP to get closer and blew up on my way up *scratch*

[nli2work]

yeah heating calc is different when you timewarp. 

[nli2work]

you should run this again when I get my 100m sunshield finished

[tseitsei89]

6 hours ago, Leeman said:

Could it be that heat distribution / radiators work differently if you are in physic/time warp? *scratch* Was perfectly fine at a 150 000 000 meter periapsis.. tried to warp to AP to get closer and blew up on my way up *scratch*

Yep definitely. Heat works VERY MUCH differently when in time warp (even in physics warp at x2 x3 and x4 speeds). In my experience if you time warp x2-x100 speeds it actually lowers the temperature but if you time warp x1000 --> it overheats so much easier.

That's why it is important for this challenge that you spend some time in no time warp mode when you are at you kerbol Pe. This way we get comparable results with each other.

[cubinator]

I've found that when things get hot during reentry, spinning the ship very quickly can help keep overheating to a minimum. Spinning the ship rapidly should allow it to get much closer to the sun before it overheats.

[tseitsei89]

Just tested the limits of my earlier design. First of the 3 heatshields blew at around 55Mm and the whole ship exploded at 53.78Mm so that will be my final result with this design.

 

I have an idea for a new concept that I might build sometime if I have time/motivation

[tseitsei89]

Okay. Using hyperedit to set my new concept up for some testing I get to ~47Mm.

Now I just need to build a lifter/transfer stage for that to actually launch it there properly and maybe even upscale it a little bit to see if that gets me a few Mm closer...

[tseitsei89]

Ok this is probably the last version I'll do for this challenge. last "stable" pic at 34.95Mm and exploded at 34.77Mm.

The trick is to spin your ship very quickly so that none of the heatshields is exposed to the sunlight for a long period of time and has time to cool while on the shadow side...

Right before I exploded I was spinning almost one full revolution per second

I can't think of any groundbreaking new concepts anymore to get closer. You can probably get a little closer by optimizing amount of radiators, angle of the heatshields and how fast you spin but testing takes time and nerves since you can't timewarp at the last stages because it stops rotation and ship blows up. So I won't be optimizing this design.

 

I will post again if I come up with some totally new concept that achieves significant improvement.

And I wait eagerly to see if anyone can beat this

[Cunjo Carl]

Hi! New technology brings new frontiers! Which is a fancy way of saying I found an exploit with the new inflatable heat shield. In the video below, we bring Bob down to 599,040m above the surface of the sun, and just within the atmosphere. We get an EVA report of Bob 'Flying at the Sun"- it's pretty neat, and I think worth the watch. There's a lot of opening patter I put in because I was having fun, which you can skip past if desired to the explanation and mission at 4:20.

    My amazing wife has made a badge for anyone who manages to touch the sun (gets below 599,044m), which I'll take the liberty to post . I think it came out great! Please consider it an extension of the challenge, and good luck!

http://postimg.org/image/mpfksn2b5/

    Surprisingly, using the heat shield in this way isn't actually a bug, it's an exploit which takes advantage of a new mechanic introduced in KSP 1.1 . The new heat shield has an attribute called boundsMultiplier, which eliminates radiant heating to objects whose outer surface are within the set point (0.7) diameters of the shield. For example, if you put few short rockomax tanks on the heatshield, the inner two are protected (within .7 diameters) and the outer one will explode. Likewise, If you put 15 rockomax-size battery discs on the heat shield, the inner 10-ish are protected. This seems to work on any of the heat shield's connectors, and I believe the mechanic is intended to be a work around for ships blowing up due to radiant heat coming off the inside of the heat shield during reentry.  In real life it wouldn't (provided you coat the bag's interior with a high emissivity material), but in KSP it would be difficult to program the effect. Directions and distances are very different calculations when optimized for speed. As a note, I can't seem to get boundsMultiplier to work on other parts despite some creativity/persistance, and I suspect it has some logic tied intrinsically to the new heat shield part.

    So the funny thing is, bounds multiplier doesn't decrease the radiant energy experienced by the heat shield itself, just the things near it. So if you inflate the heat shield it'll still explode near the sun like normal. However, if you use your radiant-heating-immune parts to shade the heat shield, you're in business! Just make sure to keep the thing pointing at the sun, or it'll blow!

    I'm still waiting for the youtube upload, so.... more back story! I found this by serendipity while I was building a ship for this challenge. I figured the new heat shield in its undeployed state would be great, because it has a much smaller cross-sectional area but retains its high heat tolerance. It was working out quite well, especially with active heat dissipators on the shady side, I think I was in the mid 40Mm and dropping steadily. I started testing the mechanics of heatflow through struts, when I accidentally flipped my ship backwards and it.... was just fine. Better than fine, in fact- It became invincible! So I dug through the game files to find out why, wrote a silly story and had fun putting it all into a video. The struts on the ship in the video are just for looks by the way. Generally, the less things you have on board, the better. With a stripped down ship, it can get very slightly under 599,000m.

   If this sounds neat to you, the mechanics are ripe for exploring. I wonder if anyone can combine this with traditional heat shields to dip deeper into the atmosphere.

 

Much much later edit: It turns out I was wrong about the intention of the boundsmultiplier mechanic. It's instead a fudge factor introduced to calculate a part's bounds through the renderer. Learn something new every day!

Edited June 17, 2016 by Cunjo Carl
Ambiguous words called to me for fixing. Forgive me!

[cubinator]

@Cunjo Carl soo...In that 7m radius, no radiant heat is generated at all? If so, that means that a small craft with an inflatable heat shield (aka force field apparently) could enter deeper into the atmosphere and even land (?)!

[Cunjo Carl]

In a rush stream of conscious go!

2 hours ago, cubinator said:

@Cunjo Carl soo...In that 7m radius, no radiant heat is generated at all? If so, that means that a small craft with an inflatable heat shield (aka force field apparently) could enter deeper into the atmosphere and even land (?)!

   Yes! But also no.... Even though it would be protected from radiant heat, it'd still be affected by conductive/convective and adiabatic compression heating... the nasty reentry stuff. Wait, maybe it wouldn't have reentry heat. I just remembered Hydrogen cools down when compressed because of the Joule-Thompson effect. On the other hand, I guess it would still heat up because JT is due to intermolecular forces, so it probably wouldn't apply at the high temps of the sun. Jool, maybe, if squad happened to model the effect. Well, anyone game to try entering into Jool should check this out!

    Back to the matter at hand, the sun's still hot. The regular heat shields have ablators will help with the reentry heat, and the active coolers might help with the conductive/convective stuff. It would take some liberal clipping to make the ship shaped right, but it might be possible to dip quite deeply (~1km) into the upper atmosphere. After all, I've gone in 100m with a kerbal in a command seat, I have to imagine the drone cores can dig their way in handily. Sadly, I think the coveted "Everything is melting, including the electronicsssss........." from the materials bay in low atmosphere will be out of reach, but it's a fun goal!

   If you decide to give it a look, let us know what you find!

[cubinator]

@Cunjo Carl I was thinking about it, and yes, even though radiant heating isn't a problem the compression and even the ambient temperature will be a very big issue. I checked the graph on the wiki and at the top of the atmosphere temperatures reach 10000 K. I might see what I can do with a infinite fuel-equipped pod and Vector for a TWR great enough to surpass the crushing gravity of the sun. The atmospheric pressure is only .15 atm at surface, about twice that of Duna. Time to experiment! Unfortunately it wouldn't count for this challenge, as it will use cheats and not return to Kerbin.

Time to sundive! 

[cubinator]

I tried several designs today, but they all experienced radiant heating and exploded before getting to the atmosphere. Here are some pics, any hints @Cunjo Carl?

 

[Cunjo Carl]

 

6 hours ago, cubinator said:

I tried several designs today, but they all experienced radiant heating and exploded before getting to the atmosphere. Here are some pics, any hints @Cunjo Carl

 

I had my share of explosions too before figuring it out. Here's some things I found which might be helpful:

1. Even though the heat shield provides immunity to radiative heat, it is not itself immune. You need to keep it in shadow by putting some thin 10m thing on its big connection point. I prefer the big battery disc, but a thin rockomax tank should work fine. Oddly, it seems like the 3.75m heat shields don't provide any more 'shadow' than my rockomax-sized battery, so perhaps my understanding of the effect is a bit off. It's held in the other cases I've tried, though. In any case, in order to keep the heat shield in shadow, you need to keep it pointing down at the sun. Varying by more than a few degrees will cause your ship to explode. A good way to get the hang of this is to turn on 'ignore max temp' and spin the ship around to see which directions work, and which don't- you'll get the feel pretty quick! Of course when you time warp, the direction of the sun changes while your ship's doesn't, which can cause also explosions. To get around this, I made a little trick which you can see at 7:47 in the video. You can "walk" the heat shield in by rotating a few degrees west of down, time warping and repeating. I think it makes more sense just to see it, so I'll leave the explanation there.

2. It's better to not inflate the heat shield. It soaks up waaay more radiant heat that way. The ship you were using in the later pictures looked like a great one!

3. The less things on the heatshield the better. Even though they are immune to radiant heat, some objects still soak up a bit of heat from somewhere. If you look in the video at 7:59 you can see the dull red glow of the heat shield and the small decoupler beneath it. This heat conducts to and radiates out of the heat shield fairly quickly, but there's still a limit to how many of certain things you can have connected. I'm not certain the mechanism, but I know that for Kerbal heat tolerances, I was pushing it to put as much science stuff on my ship as I did. I wanted the science, though! And it looked dopey without the 60 struts. In any case, the shroud definitely adds to this heat load, so it's best to go without it.

Just to make sure I wasn't missing something silly, I went ahead and made a lookalike of your ship and spirited it out to the sun using hyperedit. The only trouble I could cause to it was by rotating it too far out of alignment with the sun.

I hope that helps!

Edit: The challenge doesn't require you to return, by the way. It's just something I did for fun.

Edited May 16, 2016 by Cunjo Carl

[cubinator]

@Cunjo Carl Thanks! I'll have to try again sometime. BTW is there a problem with me attaching the HECS probe core to the inside node? That part was usually the first to overheat, even though it was technically behind the 3.75 m heat shields. I think it needs to have a wide part like the heat shield directly attached in order for it to work right.