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First off, it's not my first rodeo in KSP. However, I found that one of my greatest challenges for interplanetary missions is designing a ship that is aerodynamically stable while performing an aerocapture maneuver. The primary reason for this is that rockets are naturally bottom-heavy, especially when launched from KSC. So while one can easily place an inflatable heat shield between the launch abort system and the command module, the center of mass will be so far back that the ship will tend to flip unless you add a ton of drag to the back end, in the form of literally tons of fins or more creative means. That was my first instinct, and I ended up with various semi-successful designs including turbine-like fins and infernal robotics deployed drag-inducers (heat shields). This solution isn't consistent, so I started designing ships to aerobrake engine-side first. Designs, using KIS/KAS, included using winches to haul a massive heat shield in front of the engines, assembling a heat shield in situ, or robotic arms moving radial shields into a heat shield snow plow design. Then came my most successful design concept - separation. I started designing ships to separate into two equally massive halves and aerocapture separately. Then would then rendezvous and rejoin after they left the atmosphere. The two halves were always much more stable than attempting to aero break with my typical burj khalifa looking design. My question is: what have been your successful solutions? I have a sneaking suspicion that there is a more elegant one out there.

I have a large ship made of small segments held together by docking ports, maybe 100 tons. I need to perform aerobraking maneuvers with it for its planned mission profile, so at the front end there is an inflatable heat shield. However, even with SAS and RCS set to surface prograde, the ship will flip when too deep into the atmosphere and its center of drag is likely in front of the center of mass. Flipping is a major issue with precision, but it will be even worse if the ship attempts to aerocapture at Eve and melts. How can I keep my ship stable during aerobraking manuvers? Oh,, and as a side question, how much is aerobraking actually saving me? My planned mission is to start in low munar orbit, burn straight to an Eve encounter, capture into an elliptical orbit, transfer to gilly, capture in low orbit, drop of crew at a base, directly burn to kerbin encounter, aerocapture at kerbin and brake until I can get a mun encounter, and finally capture in low orbit at the mun. If I did not aerocaptrue at kerbin, I would use the engines to capture instead.

Inline Ballutes Slow down your rocket in an upper atmosphere. Ballute = parachute + baloon = an alternative to a heatshield. Sample usage: Duna aerocapture and aerobraking, Kerbin reentry for reusable stages etc. Dependencies: stock aero = none. FAR: Module Manager by Sarbian and RealChute by stupid_chris Suggested mods: RealChute by stupid_chris - especially when with FAR aerodynamics. Config for RealChute is already included in the mod. RealHeat by NathanKell - brings the shock heat in the upper atmosphere to more realistic levels. Recommended especially for people that use Kerbol rescale mods (i.e. kscale2 / 64k). Installation instruction: Delete previous version of InlineBallutes mod. Unzip KermangeddonIndustries catalog into the KSP folder. DOWNLOAD 1.2.8[GitHub] Credits: Riocrokite - models, config Enceos - textures, testing, config ABZB - MM patch for RealChute License: CC 4.0 BY-NC-SA Changelog: FAQ: Is it even a real technology? Yes, you can read about this technology here [pdf] and here [pdf]. How to use it? Get into upper thin atmosphere (i.e. Duna, Kerbin or Laythe). Deploy it. Initially deceleration is marginal (depending on your vessel speed and mass) but it picks up quickly when you lower your altitude. You can repack it like a normal parachute if you plan multiple orbital decelerations Can I use it instead of a parachute? Rather not. Ballute drag is 4+ times lower than parachute. And then it's much heavier due to used material and shape (Zylon instead of Nylon). However since it's inline version you can use it complementary to parachute. Ballute is also great for semi-powered landing when you just need to use engines just above the surface for the final slowdown. How efficient are ballutes / how heavy rocket can be slowed down efficiently? The higher mass of the rocket the less efficient ballute is (just like a parachute). Ballute size (mass) - should work best for: - 1.25m (0.8t) - up to 20t vessel - 2.5 m (1.5t) - up to 40t vessel - 3.75m (2.75t) - up to 80t vessel - 5m (4.1t) - up to 120t vessel It is better than a heatshield? Depending on scenario it can be better than a heatshield. Shields usually have small diameter thus requiring ship to be slim and tall. With ballute you slow down in higher atmosphere when there's not much heat, thus you can have more broad vessel design. Also ballute slows you down quite effectively in thin atmosphere (i.e. above surface of Duna) whereas a heatshield doesn't have enough area to do this. There might be scenarios when you need both ballute and heatshield for optimal effect decelerating from high interplanetary speed). How it works with stock aero? Can I use it with FAR? Stock aerodynamics: In current version (1.0.5) aerobraking and aerocapture are quite effective, deceleration forces can reach 9g before a ballute breaks so watch out. However for extreme deceleration you'll also need a heatshield, otherwise the tip of your craft will melt Duna - interplanetary deceleration possible (+) Kerbin - interplanetary deceleration possible (+) Jool - it works great for even substantial deceleration thanks to reworked (much thinner) upper atmosphere in 1.0.5, it's best to aim at 170-180k m periapsis.(++) Laythe - only medium deceleration allowed due to very compressed atmosphere (starts at 50km) which gets thick very quickly so watch out.(+/-) Eve - limited deceleration due to thick atmosphere, should work for orbital deceleration, much less for interplanetary speeds(+/-). You can modify sensitivity of parachutes by modifying skinMaxTemp. You can modify drag (deceleration) values by changing deployed area. Tested max deceleration before breaking: about 9g. FAR (+RealChute) 1.0.5 aerodynamics: For FAR aerodynamics you need to install RealChute mod, otherwise FAR is overwritting parachute module with RealChuteLite module which has constant (and very low parachute-like) values. In other word ballutes with FAR won't work without RealChute. Current aerodynamics puts at least 10x more heat in upper atmosphere for ballutes than for parts so I couldn't balance it realistically so I just put unrealistic magic numbers (like 1m K max temperature) so it can behave similarly to stock. Deceleration scenarios: look above, one difference being that ballutes drag under FAR/RealChute is a bit lower than in stock (a little step towards realism;)). Tested max deceleration before breaking: about 4g. What about kscale2 or 64k mods compatibility? You probably want to install both RealChute and RealHeat mods by NathanKell since orbital/interplanetary speeds are much higher in those mods.

Aerocapture is a great way to save massive amounts of fuel on interplanetary missions. Its main downside is that it's not possible to plan very well, as your final trajectory depends on your craft, your planetary intersect, your periapsis, and what you do during the capture. Usually aerocapture involves trial and error with a couple of quicksaves/quickloads. Below I describe a technique for more controllable aerocaptures. It is applicable to Duna, Laythe, and Kerbin*; Eve and Jool would require exceptionally robust designs with creative use of heat shields at least. Designing the craft To execute this technique, your craft will need some plane-like characteristics, even if it is not an actual spaceplane. Specifically, it needs to be slippery along one axis and draggy along another axis, you need to be able to control its attitude while it is in the atmosphere, and you need to be able to survive the thermal load of the atmospheric entry (easy for Duna, a significant challenge for Kerbin, depending on where you're coming from). There are various ways to do it for a rocket-like craft -- winglets with control surfaces, big empty fuel tanks and reaction wheels/RCS -- but designing these is left to the reader. Your craft should not rely on heat shields as primary thermal protection as this significantly limits your options in executing the technique. Below we're assuming your craft has a plane-like geometry: pointy and slippery when pointed prograde, wide and draggy when pointed radial out. The technique Do preliminary research to determine a rough aerocapture altitude for your target, e.g. 15 - 20 km for Duna. Set your Pe based on that: if your craft is designed for this technique, you should be going toward the higher end of the range as it will be highly draggy when pointed radial out. Enter the atmosphere SAS set to orbit/radial out, i.e. 90 degrees. Switch immediately to map view and watch your trajectory. When your flyby turns into an orbit, set SAS to standard mode and nose down to follow prograde. Fine-tune your orbit by controlling pitch: with a plane-like craft the Ap will fall very slowly if you're tracking prograde, and very quickly if you're at radial out. Don't forget to burn prograde at Ap to get your Pe out of the atmosphere again. With plane-like aerodynamics you can get almost as precise control over your Ap as you would by controlled retrograde burns in a propulsive capture. *From relatively low-energy transfers. Mun, Minmus, and Duna are not too difficult, Eve should be doable.

Hi, Using the oft-recommended KSP Launch Window Planner (http://alexmoon.github.io/ksp/), I'm attempting to set up a mission that will take a very aggressive (totally non-Hohmann) transfer to Duna. The idea is to shave time off the transfer (and depart a good ~80-100 days before the planets are "ideally" aligned) by spending a lot more delta-v than would be "optimal". I'm about to unlock the ISRU converter and build out a Mun mining base with Extraplanetary Launchpads, so my thinking is "fuel is cheaper than time". (I don't want to time-warp through the long coast because I've got lots of contracts and station stuff to keep me busy in the meantime back in the Kerbin system.) I've built a ship with about 5300 m/s of delta-v, and have been doing dry runs of the mission in a sandbox save. Figuring I could use aerocapture to avoid the most expensive part of the trip (the braking burn at Duna periapsis to get into orbit), I put almost all of the delta-v (5000 m/s) into the ejection burn from Kerbin and used the rest to fine-tune my approach, getting a ~13km Duna periapsis on the flyby, which I've read should be enough to aerocapture. However, my best-laid plans were shattered when I actually hit the atmosphere and my entire ship burned up almost instantly. :-) In retrospect this shouldn't have been a surprise, since the navball told me my orbital speed was well over 8000 m/s when I hit the atmosphere. (Yeah, this was probably a terrible idea.) So I tweaked the design and practiced a few more aerocaptures. I found that if I use the engines to brake down to an orbital speed of 2600 m/s when I hit the atmosphere, my design can survive (even without any heatshields). But that needed a lot of delta-v, and the rocket was getting ridiculously huge; I wanted to do better. So I slapped one of the big 10m (stock) inflatable heatshields on the bottom of my lander and tried again. However, it still burned up almost instantly. It's like the heatshield wasn't even there. :-( (In fairness, some non-critical bits of the lander were clipping through the bottom of the heatshield, but if that were the only problem, I'd expect everything behind the heatshield to survive.) What am I missing here? I was sure the heatshield would solve the problem, because I've seen a Scott Manley video where he was playing RSS and aerobraked at 10 km/s on Earth coming back from a lunar free-return; surely 8 km/s at Duna should be easier??? Thanks. :-)

First off, it's not my first rodeo in KSP. However, I found that one of my greatest challenges for interplanetary missions is designing a ship that is aerodynamically stable while performing an aerocapture maneuver. The primary reason for this is that rockets are naturally bottom-heavy, especially when launched from KSC. So while one can easily place an inflatable heat shield between the launch abort system and the command module, the center of mass will be so far back that the ship will tend to flip unless you add a ton of drag to the back end, in the form of literally tons of fins or more creative means. That was my first instinct, and I ended up with various semi-successful designs including turbine-like fins and infernal robotics deployed drag-inducers (heat shields). This solution isn't consistent, so I started designing ships to aerobrake engine-side first. Designs, using KIS/KAS, included using winches to haul a massive heat shield in front of the engines, assembling a heat shield in situ, or robotic arms moving radial shields into a heat shield snow plow design. Then came my most successful design concept - separation. I started designing ships to separate into two equally massive halves and aerocapture separately. Then would then rendezvous and rejoin after they left the atmosphere. The two halves were always much more stable than attempting to aero break with my typical burj khalifa looking design. My question is: what have been your successful solutions? I have a sneaking suspicion that there is a more elegant one out there.

Okay - I'm finally getting to Eve and Jool, and I'm hitting a wall with aerocapture. I'm having ships simply explode. I've resorted to having ships just use lots of fuel, but that's making them large and unwieldy. Would be nice to have some ideas on how to best accomplish aerocapture, as well as good altitudes - is the KSP wiki still accurate on this? Thanks for any help you can give.

Hi there, Just a quick question. Is it possible to aerocapture a vessel with a direct transfer from Kerbin to Laythe using heat shields? I've been trying this all night long, but the vessel keeps exploding the minute (nay, second!) I enter Laythe's atmosphere! Below you'll find a picture of my vessel. As you can see, I'm coming in hot (orbital velocity is + 8000 m/s). The vessel consists out of 5 FL-T stacks with 5 large heat shields. Do I need more heat shields? Or maybe the larger, inflatable one? Or is it just impossible at these speeds. If I need more heat shields, thus weight, I'll bet it's much more efficient to just fiddle around with gravity slings around Tylo to get a capture with Laythe.