Proof why aerobraking is awesome

[dave4002000]

So here i am on an interplanetary out to Jool with the intention of landing on Laythe. I start to setup my aerobrake and notice a quick flash of an encounter node show up for Laythe. A little more tweaking with some radial translating by the RCS and i end up with this:

Maneuver node at Pe is just mechjeb's prediction of the aerobrake. I never touched the throttle during any of this.

Finished with Jool, i continue to head towards Laythe. I use about 200m/s ÃŽâ€v to adjust my Pe into the atmosphere of Laythe to setup another aerobrake which is looks like this:

Again, maneuver node is only a prediction

After that is takes me 67m/s ÃŽâ€v to raise my Pe back outside of Laythe's atmosphere into a stable, but eccentric, orbit. So all totaled up, that's only ~267m/s from interplanetary transfer speeds to a stable orbit around Laythe.

I could have easily dug a little deeper into the atmo on Laythe to try for a direct landing, but i didn't want to chance getting caught out over an ocean with no land in sight

[AustralianFries]

Wow, nice aerobreak outcome. It usually takes me a few tries before I get a solid outcome I want.

[soranno]

now try it with some deadly reentry and be sure to post pictures

[XenonSpark]

now try it with some deadly reentry and be sure to post pictures

This, please.

[dave4002000]

Well it looks like imageshack is having issues with their database...AGAIN So if anyone is wondering why there seems to be captions without any pictures, that's why..haha

You know, i've been tossing around the idea of using deadly reentry for quite a while now but never actually installed it. Maybe i'll take you guys up on your challenge and finally download it

[bsalis]

It's true, aerobraking is awesome.

However, why not just aerobrake into Laythe directly instead of lucking it.

[stupid_chris]

It's true, aerobraking is awesome.

However, why not just aerobrake into Laythe directly instead of lucking it.

Getting an encounter to a moon directly isn't always as efficient as getting an elliptic orbit that crosses that moon's orbit and then waiting for a transfer window. He just happened to have an encounter directly after setting himself in a nice orbit

[KerbMav]

Kinda bugs me that Im somehow getting the hang of aerobreaking - but thermal effects being an upcoming feature, I dont know how much of this knowledge will be put to use afterwards.

Maybe I should play around with the deadly reentry mod in my doomed 0.20 save.

[dave4002000]

I've honestly never tried going direct for it. I always setup an elliptic orbit like what you see in the first picture and then just hang out until i can do a normal Hohmann transfer. It just so happens that Laythe decided to make it easier for me this time around. Would it even be possible to aerobrake a capture directly to Laythe without retro-burning and/or litho'ing? I'm not sure you'd be able to stay in the atmosphere long enough.

::Edit:: KerbMav, the basic principles aren't going to change. You'll just have to be more careful with your entry angles and how deep you penetrate. Or just stack a dozen heat shields together...haha

Edited July 19, 2013 by dave4002000

[stupid_chris]

Kinda bugs me that Im somehow getting the hang of aerobreaking - but thermal effects being an upcoming feature, I dont know how much of this knowledge will be put to use afterwards.

Maybe I should play around with the deadly reentry mod in my doomed 0.20 save.

That's the thing. Reason why aerobraking was not used for missions like Cassini and Galileo is because the ablative heatshield that would've been needed would've been so heavy carrying it ends up being less efficient than carrying the propellant.

EDIT:

I've honestly never tried going direct for it. I always setup an elliptic orbit like what you see in the first picture and then just hang out until i can do a normal Hohmann transfer. It just so happens that Laythe decided to make it easier for me this time around. Would it even be possible to aerobrake a capture directly to Laythe without retro-burning and/or litho'ing? I'm not sure you'd be able to stay in the atmosphere long enough.

It depends where you're catching Laythe at. If you catch it as it orbits in the same direction from you, the relative speed is barely bigger than the one you had there. If you catch it on the other side though, you'll have uh, a lot of speed to bleed out. IT can still be done, you just need to set your periapsis lower, and doing it in more than one pass is recommended.

Edited July 19, 2013 by stupid_chris

[KerbMav]

That's the thing. Reason why aerobraking was not used for missions like Cassini and Galileo is because the ablative heatshield that would've been needed would've been so heavy carrying it ends up being less efficient than carrying the propellant.

Practically SCREAMS to be put into career mode: research and mine Therminium, good heat resistance, light, shiny!

I think larger/heavier ships would profit form a heat shield? They would need even more fuel to slow down.

[stupid_chris]

Practically SCREAMS to be put into career mode: research and mine Therminium, good heat resistance, light, shiny!

I think larger/heavier ships would profit form a heat shield? They would need even more fuel to slow down.

Depending on what you mean by large, maybe yes, but that's some case by case really.

[magnemoe]

now try it with some deadly reentry and be sure to post pictures

Main problem with deadly reentry is the lack of heat shields for ships. We would also need shields with hatches for engines, landing legs and other stuff like on the space shuttle.

Aerobraking works well in real world.

[stupid_chris]

Aerobraking works well in real world.

Aerobraking has never been attempted in real world, I don't know where you're taking that from.

[numerobis]

Aerobraking has never been attempted in real world, I don't know where you're taking that from.

Aerobraking has certainly been attempted in the real world. That and landing on any body with atmosphere.

[stupid_chris]

Well then I missed those. Although to land on a body, that's not aerobraking, that's called atmospheric (re)entry.

[Ralathon]

Aerobraking has never been attempted in real world, I don't know where you're taking that from.

Aerobraking has been done loads of times over the years. But what we're doing in Kerbal space program is Aerocapture, which is much more aggressive than simple aerobraking. We haven't done that yet IRL because it requires a heat shield (and as stated before, the extra weight and complexity just isn't worth it)

[stupid_chris]

Aerobraking has been done loads of times over the years. But what we're doing in Kerbal space program is Aerocapture, which is much more aggressive than simple aerobraking. We haven't done that yet IRL because it requires a heat shield (and as stated before, the extra weight and complexity just isn't worth it)

Ah there's where my confusion came from, sorry, English isn't my first language lol.

[Sof]

http://en.wikipedia.org/wiki/Aerobraking#Spacecraft_missions

"In the space simulation sandbox game Kerbal Space Program, this is a very common method of slowing a craft's orbital speed."

We're famous

[Landge]

http://en.wikipedia.org/wiki/Lithobraking

Looking at the aerobraking links I noticed this crossreference. I didn't know that lithobraking was an actual term. I thought it was a term someone in the KSP forums came up with lol!

[magnemoe]

Getting an encounter to a moon directly isn't always as efficient as getting an elliptic orbit that crosses that moon's orbit and then waiting for a transfer window. He just happened to have an encounter directly after setting himself in a nice orbit

True, usualy two ways to hit Laythe, one is to catch up with it then you pass, the other is to slingshot around Jool and get an intercept, fallback is to do an small aerobrake at Jool to get into an oribit who take you out to Val now tweak this to reach Laythe. This is also recomended if you have an fragile ship as the Laythe arobreak is high g.

[dave4002000]

http://en.wikipedia.org/wiki/Lithobraking

Looking at the aerobraking links I noticed this crossreference. I didn't know that lithobraking was an actual term. I thought it was a term someone in the KSP forums came up with lol!

Well, i think we usually use it more in the "smash into the surface uncontrollably" context. Whereas, the real context would be using airbags to soften the landing impact

[magnemoe]

Well, i think we usually use it more in the "smash into the surface uncontrollably" context. Whereas, the real context would be using airbags to soften the landing impact

Or controlled, I see the landing legs, engine, fuel tank and gear below the pod as an crumble zone, just like the front of your car.

Not supposed to be used like this but has saved lots of kerbals during landing.

However I also used the term of my first Moho landing who landed with 6km/s.

The ship was non operational after landing.

Edited July 19, 2013 by magnemoe

[Jon Tash]

Lithobraking, yeah I do that alot, purposely though.

[Tw1]

Just a thought, maybe hydrobraking could be a thing, if there's an ocean, but minimal to no atmosphere. Would be a small bit safer than lithobraking, if done with extreme care.

Anyone remember the thread where we discussed ring braking? Anyone?

Edited July 20, 2013 by Tw1