What is your preferred way of capturing? Part 1

[RocketSimplicity]

Hey all.

What is your prefered method of capturing at these bodies above?

I'm not very good at keeping spacecraft that are aerobraking steady, so I use the moon's gravity or I propulsively brake.

What about you?

(The reason that this isn't one big thread is that I have a maximum of 3 questions a poll)

Part 2 is here with Jool and Laythe: 

 

Edited August 25, 2019 by RocketSimplicity

[Loskene]

I'll spill the open secret: we only do aerobraking for cool points. We all do braking burns when nobody's looking because calculating aerobrakes so you don't skip out, sink low or blow up is tiresome. Mass ratio to heatshield area and atmospheric density at high altitudes and fbdbhfgh just bring another fuel tank.

[bewing]

The only time I aerobrake is when I'm bringing a full fuel tanker to LKO from my Minmus refinery. Because it's bloody heavy, and the whole point is to have as much fuel remaining as possible.

 

[Chryssalid 8492]

With Duna I find aerocapture to be easy and efficient as there is little to no risk of overheating that I've encountered. For Kerbin I aerobrake when coming from the Mun or Minmus the rest I generally burn for. Eve I mostly burn for.

[Superfluous J]

Duna I could do either aerocapture or Ike. Mostly it depends on if I'm going to do something at Ike, which I usually am.

Gilly's no help and Eve likes to murder craft, so I propulsively capture there on those odd missions where I'm not actually going to Gilly anyway.

For Kerbin, assuming I'm doing this to come home, it's an aerobrake helped with whatever fuel I managed to bring home with me. Assuming I'm not coming home... well I'm generally not going to Kerbin

[purpleivan]

I almost always do a mixture of two or even three of those options. Typically propulsive braking with an aerobrake assist (e.g. at Kerbin), but at Jool I usually swing by a moon for a little help too.

[ExtremeSquared]

Ah yes... the elusive Gilly gravity assist capture.

[Tw1]

7 hours ago, Loskene said:

I'll spill the open secret: we only do aerobraking for cool points. 

Basically.

Sometimes it might be justified, like if the heat shield structure doubles as something else.

Like recently, I sent a support orbiter to Eve, with lots of little sub-probe landers hanging of the back of the shield. The sheild was BD armor panels, so idk if more fuel and a lighter structure would have been more optimal, but I did it that way for style. 

Aerobraking might be more popular than it should be as in the pre-release days, it was by far the easiest way to capture, thanks to the Crude aerodynamic model, and lack of heating. When those came about, continuing to use the technique became a real challenge for long time players. 

Edited August 24, 2019 by Tw1

[Xavven]

Aerocapture at Kerbin makes the most sense from a dV standpoint and you don't really have to calculate it. Just aim for 30km and build an aerodynamically stable (usually a truncated cone of some sort) capsule with a heatshield. Anywhere else and I don't know the math to calculate an accurate aerobrake.

Otherwise, if you have a moon with decent gravity, it's worth it to do a powered gravity assist. This is only really an option at Tylo and to a lesser extent Ike. Gilly is too small.

[AHHans]

For me in general it depends on what I want to do: when I want to land, then I aerobrake. When I want to get into orbit, then I do a propulsive capture.

But when I want to land, I usually have some fuel left in the transfer stage. As this stage gets destroyed anyhow, I'll first slow down as much as that fuel allows. On Duna I might use the transfer stage for the final part of the landing. On Eve I might need to slow down, so that the purple monster doesn't fry my craft right through the heat-shield.

 

[esmenard]

If I want to land (and don't care about the landing site), direct reentry. If I want to go in orbit, propulsive braking (I find aerobraking too dangerous in this situations, I have no way to know in what orbit I will end up, and I don't bring a heat shield except on landers). If I want to capture at Jool, Laythe or Tylo gravity assist.

[KerikBalm]

Jool is the only planet with an atmosphere that I use gravity assist instead of aerocapture

[Loskene]

2 hours ago, esmenard said:

If I want to land (and don't care about the landing site), direct reentry. If I want to go in orbit, propulsive braking (I find aerobraking too dangerous in this situations, I have no way to know in what orbit I will end up, and I don't bring a heat shield except on landers). If I want to capture at Jool, Laythe or Tylo gravity assist.

The issue with aerobraking for anything beyond necessity is while you do have ways of knowing what orbit you'll end up in, there's a proportional tradeoff between ease of calculation and accuracy of prediction. The more you want your aerobrake to result in a deltaV vector of specific magnitude for the desired resultant orbit, the more napkin space you need to scribble on and the more babysitting you have to do with your craft's lift/drag vector during a process which may take much longer than a simple rocket burn. The trajectories mod does most of this but is limited by its assumptions and time spent on running the whole computationally expensive simulation.

Land "here"? Easy peasy, no maths needed once you brought enough ablator or spend your leftover transfer fuel on the way in.

Capture into a specific orbit and circularise? Well you might want to pause the game for a while and make a cup of tea. Then work out your time spent in atmosphere, it's density curve, the precise mass and area of your craft's air facing side, gravity losses, oberth effect, etc etc etc. Hopefully get your apoapsis down low but not too low, then do at least one circularisation burn at apo and probably a second at your next periapsis, because it's really risky to aerocapture into a very low orbit in case you end up spending too long in atmo, in which case you're landing "here" and can throw out your napkin.

So yeah I just bring the fuel tank if I'm not planning to capture and land at the same time. At least you can capture and circularise in one burn that way, instead of having it forcibly split into aerocapture/peri lift/circularise one orbit later.

Edited August 24, 2019 by Loskene

[Xurkitree]

Where's my Poll for capturing at Jool?

[Xavven]

4 hours ago, Xurkitree said:

Where's my Poll for capturing at Jool?

I'm gonna have to Bop you on the head for that bad pun.

[RocketSimplicity]

6 hours ago, Xurkitree said:

Where's my Poll for capturing at Jool?

I could only put 3 questions on the poll in this topic. Part 2 Will have Jool, Laythe and a place to add up your scores and put in the one you use the most.

Also you should know that Vall hates puns

Edited August 25, 2019 by RocketSimplicity

[Xurkitree]

4 hours ago, Xavven said:

I'm gonna have to Bop you on the head for that bad pun.

Wait, I made a pun? DAAAAMNN

[RocketSimplicity]

Part 2 with Jool and Laythe is up! Check it out!

 

[Superfluous J]

8 hours ago, RocketSimplicity said:

Also you should know that Vall hates puns

That pun was tylotally lame.

[severedsolo]

36 minutes ago, 5thHorseman said:

That pun was tylotally lame.

Laythe it out, this is getting ridiculous.

[RocketSimplicity]

30 minutes ago, severedsolo said:

Laythe it out, this is getting ridiculous.

This... This is making me sad... MohoMohoMoho 

But seriously, Kerman everyone, we should stop doing bad puns

Edited August 25, 2019 by RocketSimplicity

[Xavven]

3 hours ago, RocketSimplicity said:

This... This is making me sad... MohoMohoMoho 

But seriously, Kerman everyone, we should stop doing bad puns

I'll keep making puns and Jool-Ike it!