How Do You Deal with Inerplanetary Aerocapturing in 1.0.4?

[John FX]

I find this to be an interesting point, but is the weight in fuel to ditch 2000 m/s really less than that of a heatshield for your average vessel? Like, the wiki lists the mass of the largest 3.75m heatshield to be 2.8 tons, while a T-400 fuel tank is at 2.2 tons. As a rough guestimate, let's consider those roughly equal (or throw in another T-100 tank on top to even things out more), and I really can't think of many vessels that would be big enough to warrant a 3.75m heatshield, yet wouldn't weigh enough that they could produce 2000 m/s deltaV off a T-400.

The way I'm looking at things, you'd have to transport that mass to Jool either way to make use of it, so it essentially all comes down to what is heavier: the fuel required for an equivalent burn or the shield for the aerobrake.

Another option would be to not have a heat shield and just barely capture with fuel, then aerobrake, just skimming the atmosphere very slightly and reduce your Ap very gradually with many aero brakes, like NASA does.

IIRC they either plan to or recently did a mission with a craft that reduced it`s Ap through around 800 aerobrake manoeuvrers...

This is what I did with Jool and FAR in recent KSP versions. Capture with fuel, then lots of aerobrakes until my Ap was right for intercepting something larger like Laythe or Tylo and using a gravity assist to mostly circularise. Relatively low Dv needed to get a fairly satisfactory orbit around Jool. Took a while though.

[Geschosskopf]

Another option would be to not have a heat shield and just barely capture with fuel, then aerobrake, just skimming the atmosphere very slightly and reduce your Ap very gradually with many aero brakes, like NASA does.

But NASA has a different problem than we do in KSP, which is that they have an order of magnitude more energy to deal with. With the much lower speeds in KSP, we shouldn't have to do hundreds of passes. Besides, that doesn't sound like fun gameplay watching that play out over however many real hours instead of getting on what the actual mission you built the ship for. Not to mention the months of gametime added to travel time, which would complicate life support (especially if you had no way to predict how long this would all take), and the difficulty of doing this with more than 1 ship at a time.

[Technical Ben]

Return from the Mun was fine. I did not need the 3x heatshields I'd packed just in case. Interplanetary to test now.

[Nigeth]

The problem about "realism" is that you can't talk about realism when you are debating isolated features. If the whole game isn't designed for this all you get is a pocket of enhanced realism surrounded by a game not designed to deal with that. I wouldn't even care that aerobraking/aerocapture doesn't work if the game was designed in a way so that you don't need it and still had a fun experience.

If I could easily plot gravity assist trajectories and launch windows for my flights and the physics were scaled down so that I wouldn't need hundreds of aerocapture passes I'd be fine. Currently I can do none of this in stock. I could do this with mods (it would still be more hassle than it's worth though) but with mods I get no support from Squad whatsoever when bugs happen.

So I now have a modified aerodynamic model and heat physics and basically no tools in the stock game that help me deal with those changes. Don't even get me started on the fact that those changes haven't really been communicated to all players in a meaningful way.

So what I have:

- new scaling for engines

- new scaling of the aerodynamic models

- more realistic heat physics

- still the same crappy maneuver node system

- still the same patched conics approximation with a maximum of three conical patches

- still no advanced trajectory planning and plotting

- still no launch window calculator

- still a time warp and physics timewarp system that can't even deal with 'normal' physics without choking some of the time.

So the only thing the new system gives a normal player is even more headaches than before. To experience a new physics model you don't really need to bother with since fuel is essentially 'free'.

[oversoul]

I haven't done it yet in v104. I'm scurred.

I have aerobraked before, a large-ish space station into Eve orbit and several Duna missions but not yet here.

But I'm playing a v102 career that I set up for 50%RE; I never used DRE before v1.0 nor did I desire it. Thankfully the devs added those sliders.

- - - Updated - - -

The problem about "realism" is that you can't talk about realism when you are debating isolated features.

Maybe 'balance' is a better word than 'realism' for a game that uses toy junkyard parts to launch little green dudes into a computer generated space realm.

- - - Updated - - -

CAVEAT

and in single-player games, what other people do in their own games is their business.

Unless you're RockStar Entertainment.

Edited July 6, 2015 by oversoul

[peachoftree]

I accidentally came into jool in a retrograde orbit and tried to aerobrake to land at Laythe (I had done the gentlemanly approach to Jool capture - a Tylo gravity assist) I hit the atmosphere at around 7.4 km/s and vaporised instantly upon contact with the atmosphere. Fun times. Fun times indeed.

[X-SR71]

Interplanetary aerocaptures? If only spaceplane parts had heatshields... perhaps. Circular heatshields on Mk2 parts look terrible... I'd rather burn!

[eddiew]

Only dealth with Kerbin SoI speeds so far, but already dialled back to 70% (for now) because I'm a spaceplane/shuttle person, and there are no heatshield options for this type of craft.

Really needs some built-in ablative shielding on SP parts, because it is not funny to overheat at high altitude when aerobraking with Minmus-return speeds. Ending up with an unwieldy monster of a vessel just so's you can do some engine braking on the way home is making KSP fail the 'is it fun?' test.

[Geschosskopf]

Really needs some built-in ablative shielding on SP parts, because it is not funny to overheat at high altitude when aerobraking with Minmus-return speeds. Ending up with an unwieldy monster of a vessel just so's you can do some engine braking on the way home is making KSP fail the 'is it fun?' test.

I would only support ablative spaceplane parts if Ablator could be repaired in the field, and you could make your own Ablator in the field as well via not-too-difficult ISRU. Otherwise, the whole "reusable" thing about spaceplanes goes out the window, especially at places like Laythe where flights do not end with recovery on the runway.

I think a better idea is to just fix the broken parts of the existing system. I would also support removing the entire reentry heat system entirely from the stock game. We got along just fine without it beforehand and if you personally want it in your game, there's DRE.

[Vaporo]

For me, aerocapture has been more trouble than it's worth since 1.0.

It's easier to get into Jool orbit via Tylo gravity assist, Eve kills anything that touches it that doesn't have 5 heat shields, and Laythe doesn't take too much Delta-V after using a Tylo gravity assist. I will aerocapture at Duna because the atmosphere is thin and my relative velocity coming from Kerbin isn't too horrible high, but it's the exception to the rule.

Oh, and coming back to Kerbin I'll also simply slam into the atmosphere to slow down, but that's because it's easy to put heat shields on a return vehicle. It's not easy to shield an interplanetary mothership.

[Technical Ben]

Granted I am in sandbox, but getting to duna was fine. Even when my craft spun due to balance/drag problems. All new craft to duna will have airbreaks on the rear to stabilise.

Going to attempt gravity assists around Jool. Eve? I've decide to never go there. Never... too much DV to return. Nope. Not even going to try. Never. Large stick, end of, not even touching!

Edited July 26, 2015 by Technical Ben

[keeper]

Im playing with 100% heat, just learning about re-entry at the moment, had plenty of explosions think I'm just getting the hang of it now.

Have been experimenting with heatshields and fairings. The fairings seem more sturdy than previous versions and heatshields are a must on steeper re-entries on Kerbin. I guess it all feels about right, with the aero and heating. Not sure if the heat shields are invincible, i did a straight drop to kerbin from 200km the heat shield did its job brilliantly.

That beautiful red to golden to blinding burning sensation on the belly of my test machine was wicked.

Still wondering what those radial radiator grill things do :S Even if i put loads of em all over things still splode. Since the update I think it got harder.

I can't do spaceplanes (never have), not using FAR or NEAR (tried both & dislike), hoping they stop messing around with atmospheres or aero models so I can get used to it all again.

For KSP the aero seems fine, infact I have always liked the aero stock even before and after changes.

Heating seemed very unpredictable at first, i could see that things hitting the brunt of the atmosphere heats up more, things behind the shield/fairing are more or less completely safe, and then sometimes random things get too hot and slode, and i'll be unsure why - but i know its got something to do with where on the craft it is. On the whole, I can manage i think..

And probably worth noting i use tweakscale & mostly just part mods, and have changed my fairing max radius to something rather large.

I have very much enjoyed building ridiculously large and absurdly awkward (sp?) vessels, they ofcourse come with their own challenges.

[regex]

I would also support removing the entire reentry heat system entirely from the stock game. We got along just fine without it beforehand and if you personally want it in your game, there's DRE.

There's also a slider when you start a game, no need to rip it out and demand extra software.

[eddiew]

There's also a slider when you start a game, no need to rip it out and demand extra software.

Or if you found that heating annoys you after you've made a significant start, just edit your save file and set ReentryHeatScale to a value of 0-1 for some relief from that point forward

Thus far with it at 0.7, I've been hitting Kerbin at a moderate 3200m/s. Going in full prograde, things get very hot still, but pull up 20-30 degrees (like a shuttle shaped ship should) and the drag kills speed before the heat kills the vessel. Not a bad balance for Kerbin SoI, I think ^^

[Technical Ben]

I do feel the shields have too much "fuel". I'd be happy with the shields being nerfed a little (perhaps half or a quarter of the ablation resource) and heating from re-entry staying the same.

[Geschosskopf]

There's also a slider when you start a game, no need to rip it out and demand extra software.

Actually, the aero system should be ripped out until it's fixed. Right now, only Kerbin has an acutal atmosphere. All the other so-called atmospheres are effectively oceans instead because of their lack of wide, thin upper regions.

And yes, I do adjust the slider way down to deal with this problem. That was what I said I do in the OP of this thread . The problem is with the game's inconsistent modeling of atmospheres. It's just flat wrong everywhere but Kerbin. There are a number of ways for players to work around this basic root problem, but none of them are more "realistic" than the others because the system itself isn't realistic or even internally consistent.

[regex]

Actually, the aero system should be ripped out until it's fixed. Right now, only Kerbin has an acutal atmosphere. All the other so-called atmospheres are effectively oceans instead because of their lack of wide, thin upper regions.

Ripping out the entire system because an edge case isn't valid in the short term isn't exactly ... rational, but I totally understand your desire for more realism; it makes the game so much better.

[Geschosskopf]

Ripping out the entire system because an edge case isn't valid in the short term isn't exactly ... rational, but I totally understand your desire for more realism; it makes the game so much better.

The fact that all atmospheres bur Kerbin's are borked is hardly an "edge case". Either do it right or don't do it at all. What we have now is just as borked as what we have pre-1.0, just in a different way.

[Technical Ben]

I assume the gradual drop off of atmo could be added with a simple tweak on a line of code/ini file. So why not ask and wait and see?

[regex]

The fact that all atmospheres bur Kerbin's are borked is hardly an "edge case". Either do it right or don't do it at all. What we have now is just as borked as what we have pre-1.0, just in a different way.

It is "done right" in most cases. That fact that you can't aerocapture/brake in two places for a version is hardly cause to rip an entire system out that works great for what it was really needed for.

I assume the gradual drop off of atmo could be added with a simple tweak on a line of code/ini file. So why not ask and wait and see?

No, it's pretty deep in the system, but you could pretty easily correct it with a Kopernicus config.