Aerobrake on interplanetary travel in 1.0

[Dixi]

I took my old ship for planet exploration (works well in ksp 0.9) and went to Eve. On typical aerobrake maneuver with minimum altitude of 65km I've lost a lot of attached hardware... I'm quite scared what will happen on Jool aerobrake, since arrival velocity usually higher there as I remember. When I've tested same Eve aerobrake at 59km I've lost all sensors and ladders, and a few km lower whole ship blows due to overheating.

How I'm supposed now to build less squishy ships? On just mentioned above Eve aerobrake I've lost all ladders (retracted) on landing module and some of sensors. Ok, for sensors there is a new crate. But what about ladders?!

For correct braking altitude I was using KSP Aerobraking Calculator http://alterbaron.github.io/ksp_aerocalc/, it also do not knows about new aerodynamic in 1.0. Any other program or addon can do it correctly now?

[panzer1b]

Ive pulled off jool aerobraking with a SSTO from kerbin (and aerobrakes+landed on laythe, and aerobraked and landed on kerbin).

Its not all that hard, but the craft i happened to have had incredible resilience to overheating in general (i can pull 700m/s at sea level and not explode). Right now its a matter of 2 things, approach path and craft design. Some things (canards in particular for some reason) are notorious for exploding, some thinsg you should never have exposed (batteries, unshielded solars, RTGs, ect), and well, you need to use cooler parts often, especially on the front of your craft.

For SSTOs, the best intakes are rams, as they have 2100 degrees max, vs the other intakes 2K and 1900.

As for rockets, im guessing heat shields are the way to go, although i havent actually used heat shields at all (except when building some funny missiles that had a stack of shields on front to attain 1700m/s speeds).

[RocketPilot573]

I'd say the safest way is to just do multiple aerobrakes. Aim much higher and orbit around a few times to gradually bring the AP lower and lower.

[Gkirmathal]

I'd say the safest way is to just do multiple aerobrakes. Aim much higher and orbit around a few times to gradually bring the AP lower and lower.

How would one go about this with an interplanetary vessel/tug? If your orbital velocity is around 4000/4500, you come back to Kerbin and this higher alt aerobraking manouvre is not sufficient to capture your orbit even with retro thrusting.

Had this in 0.9, two weeks before the 1.0 release and I now wonder how the heck I would have succeeded such manoeuvre in 1.0, without disintegrating the whole ship.

[Wanderfound]

Due to the new aero, all of the old ÃŽâ€V and aerobraking calculators are now obsolete. You're going to have to do it the hard way: send a probe and test before committing Kerbals.

[Sirrobert]

How would one go about this with an interplanetary vessel/tug? If your orbital velocity is around 4000/4500, you come back to Kerbin and this higher alt aerobraking manouvre is not sufficient to capture your orbit even with retro thrusting.

Had this in 0.9, two weeks before the 1.0 release and I now wonder how the heck I would have succeeded such manoeuvre in 1.0, without disintegrating the whole ship.

You can do more expencive and longer aproach that leaves you with less relative orbital velocity on arival

[Lukaszenko]

I've done it with deadly reentry and FAR. It's definitely harder to get aerocaptured (sometimes impossible, as g-loading is also an issue), but it's definitely more realistic and fun. I would always simply aim high in the atmosphere and bring extra fuel to get captured (and keep in mind that an aerocapture has never actually been performed in real life).

Jool aerocapture was actually pretty forgiving, I presume because the planet is so big that you can spend extra time in it's atmosphere.

Edited May 1, 2015 by Lukaszenko

[Gkirmathal]

You can do more expencive and longer aproach that leaves you with less relative orbital velocity on arival

I wholy agree, but that one approach (Dres > Kerbin) just went like that and it was commited.

Maybe the new aero just makes needing aeroshields a nessecity for any interplanetary mission to planets with atmo's.

[Red Iron Crown]

Due to the new aero, all of the old ÃŽâ€V and aerobraking calculators are now obsolete. You're going to have to do it the hard way: send a probe and test before committing Kerbals.

Only ÃŽâ€V to orbit on atmospheric bodies has changed, calculators like http://ksp.olex.biz/ and http://alexmoon.github.io/ksp/ are still accurate.

[ajburges]

Don't forget, most planets also have satilites massive enough for a good gravity turn. Use that to reduce velocity WRT the body you wish to orbit.

[Gkirmathal]

Just tried a Mk2 landercan design which had NO heatshield but 4x airbrakes....could safely do a 100km orbit reentry without anything going kaboom.

Airbrakes could work on interplanetary ship design I might recon. Going to give it a try in sandbox.

[bazem]

I believe airbrakes can help a lot. I was testing an SSTO in kerbin, it would blow up as soon it went under 30k alt, where the atmosphere becomes thicker. Adding aerobrakes I could reduce speed way higher, so when i got to 30k it was slow enough to keep it intact.

[Monthar]

Has anyone figured out what drag coefficient to plug into http://alterbaron.github.io/ksp_aerocalc/to get it to be more accurate in 1.02?

[n0xiety]

I always use engine to aerobreak since its so sturdy and can whitstand almost any kind of heat. Other than that i always use utility bay to keep small parts shielded. If i have ladders i just keep them looking away from the planet and force turn my ship slightly so the other side takes the most of the heat and it works well.

[Dixi]

Tried again in 1.05

On a travel from Kerbin to Duna I did an aerobrake, starting at speed of 878.1 m/s at a distance 47'400.km, aimed at Dune PE 13km CCW, and finished on a reasonably elliptic orbit PE 12km, AP 893km.

Nothing broke except all already opened OX-4L 1x6 solar panels. They got blown away around 25km height in Dune atmosphere. Going to replace them with SP-L 1x6 panels.

Question is: is old aerobraking calculator still valid, and one just need to use different drag coefficient?

[Montag]

2 hours ago, Dixi said:

Tried again in 1.05

On a travel from Kerbin to Duna I did an aerobrake, starting at speed of 878.1 m/s at a distance 47'400.km, aimed at Dune PE 13km CCW, and finished on a reasonably elliptic orbit PE 12km, AP 893km.

Nothing broke except all already opened OX-4L 1x6 solar panels. They got blown away around 25km height in Dune atmosphere. Going to replace them with SP-L 1x6 panels.

Question is: is old aerobraking calculator still valid, and one just need to use different drag coefficient?

Can you put a pic up of your ship?  Did you have a heat shield or just relied on the engine?

[Mikki]

I wrapped all the delicate stuff in fairings an aerocaptured Jool at 192km altitude with nearly 8500m/s.
Works out now like in "2010- A space odysseey", real cool. You can save lots of dV entering Jool like this.

[NathanKell]

If the calculator dates to before 1.0, it's not valid. Drag changed totally.

[Dixi]

2 hours ago, Montag said:

Can you put a pic up of your ship?  Did you have a heat shield or just relied on the engine?

I saw no point in using heatshield in my case since I have maximum diameter fuel tanks and engine, everything else, except side fuel tanks is less base diameter, so when aligned retrogarde is protected by fuel tanks.

Here is a link, since I dunno how to insert a picture here.

http://i.imgur.com/uVAlEyz.jpg

Edited January 14, 2016 by Dixi

[David104]

On 1.5.2015 at 0:55 AM, bazem said:

I believe airbrakes can help a lot. I was testing an SSTO in kerbin, it would blow up as soon it went under 30k alt, where the atmosphere becomes thicker. Adding aerobrakes I could reduce speed way higher, so when i got to 30k it was slow enough to keep it intact.

Dont know if this is in any way helpful or its the most normal thing and it just took me ages to figure that out. .I was playing around with SSTO´s yesterday for couple of hours and figured out that, during reentry, it helps a lot to angle your craft up around 20-30°. Before I always was blowing up when entering the lower atmosphere due to overheating.
Like this I didnt need airbrakes....but maybe if coming from an interplanetary journey its different..

Edited January 16, 2016 by David104
forgot

[Snark]

6 hours ago, David104 said:

Dont know if this is in any way helpful or its the most normal thing and it just took me ages to figure that out. .I was playing around with SSTO´s yesterday for couple of hours and figured out that, during reentry, it helps a lot to angle your craft up around 20-30°. Before I always was blowing up when entering the lower atmosphere due to overheating.
Like this I didnt need airbrakes....but maybe if coming from an interplanetary journey its different..

Excellent suggestion.    The phenomenon you're describing is called body lift.  It's a great technique for aerobraking as long as you're not going so fast that you absolutely have to be hiding behind a heatshield.

Body lift can be useful to avoid burning up, in places like Kerbin.  For Duna, I find that it's also useful, but for a different reason:  not so much because of heating issues (Duna reentry is fairly forgiving; the velocity tends to be low if you've got a good transfer window), but because the atmosphere is so thin that landers have a tendency to faceplant at hundreds of meters per second, long before they're slow enough to pop chutes.  Body lift is one way to mitigate that, by helping to bleed off a lot of speed before plowing into the terrain.

(Yes, there are other things that can help with that too, like airbrakes or drogue chutes, but body lift is a very handy tool in the toolbox.)

On 1/14/2016 at 0:15 PM, Dixi said:

I dunno how to insert a picture here.

Once you have your image link (from imgur or wherever), you can insert a picture by clicking the gray "Insert other media" button at bottom right, then choosing "Insert image from URL" and pasting your image URL into the box that pops up.

Edited January 16, 2016 by Snark

[Dixi]

So there is a way to aerobrake at Duna. But what about Eve?

I came to Eve from Kerbin, and got into higher atmosphere at 5500m/s. With awful results. Eve has 90k atmosphere height. When I dive into it with 82500m PE I see whole ship temperature destruction before I reach PE point. When I fly at 85k PE I still have some modules, including main engine destroyed but loose very little speed so I do not get to any circular orbit.

I have 4 radial radiator panels on my ship, dunno are they help at all vs such extensive heating.

Should I try to use some aircraft airbrakes? 

 

On 1/14/2016 at 10:11 PM, Mikki said:

I wrapped all the delicate stuff in fairings an aerocaptured Jool at 192km altitude with nearly 8500m/s.
Works out now like in "2010- A space odysseey", real cool. You can save lots of dV entering Jool like this.

Was resulting orbit circular? Or you just lost some dV and still had to burn engines to get to circular orbit?

I think possibility of effective aerobrake and aerocapture was a cool feature of the game before 1.0. Did we lost it almost completely?

Edited January 16, 2016 by Dixi

[Snark]

1 hour ago, Dixi said:

So there is a way to aerobrake at Duna. But what about Eve?

I came to Eve from Kerbin, and got into higher atmosphere at 5500m/s. With awful results. Eve has 90k atmosphere height. When I dive into it with 82500m PE I see whole ship temperature destruction before I reach PE point. When I fly at 85k PE I still have some modules, including main engine destroyed but loose very little speed so I do not get to any circular orbit.

I have 4 radial radiator panels on my ship, dunno are they help at all vs such extensive heating.

Should I try to use some aircraft airbrakes?

Yeah, Eve's a bear.

Radiator panels aren't going to help you much, in a situation like this-- the heat load is massive and fast, far beyond what a radiator can cope with.

Airbrakes are also not going to help much for primary slowing-down; they'll overheat and explode quickly at those speeds.

The most reliable way to slow down at high interplanetary speeds is with heatshields.  But even there, it's not a sovereign remedy-- you can get stuck in a place (such as you describe) that there doesn't exist any "right" periapsis:  either you're too low and suddenly explode (even with heatshield), or else you don't get enough slowdown and go flying off into space.

The solution here is twofold:

• Make sure that every bit of your ship is hiding behind a heatshield.
• Have as many square meters of heatshield per ton of ship as possible.

The ideal shape for aerobraking is the exact opposite of the ideal shape for launch:  you want a big, flat pancake, that will let you decelerate enough to get captured, without having to dive so deep into the atmosphere that you go suddenly kaboom.

So... either lower the mass of your ship, or put a bigger-diameter heatshield on it.  And if you're already using the biggest heatshield, and have already reduced your mass as far as you can go, then add more heatshields on outriggers so that you increase your surface area.

[NathanKell]

Yep, 5500m/s is survivable, but only with a low enough ballistic coefficient. (I verified 1.05 by coming in at around 6km/sec, but that used all the ablator and had a narrow corridor---and that was with a low BC.)

[Foxster]

Here's how to get down to Eve from interplanetary speeds...

Everything is behind a heatshield. This includes the airbrakes - before AND after they are deployed, hence their rotation 180°. If you don't like the clipping that involves then you can offset them like this, but it's trickier to get them all in a compact space...