Gemini-like abort options

[XrayLima]

Hey there folks,

With the two kerbal Gemini-like capsule, how do you like to enable safe aborts whilst keeping mostly to the spirit of the Gemini-Titan design?  We don't have, or at least I couldn't see a stock 'eject' option and I'm not sure it would work for a pad abort with stock parachutes (I've still to play with these) anyway.  I don't think NASA were all too sure of the ejection seat abort method either......  Fitting Sepatrons makes the capsule rather heavy and wasteful.  I was just wondering what other players prefer to do to recreate Gemini?

 

XrayLima

[Tyko]

On 4/10/2018 at 3:00 AM, XrayLima said:

Hey there folks,

With the two kerbal Gemini-like capsule, how do you like to enable safe aborts whilst keeping mostly to the spirit of the Gemini-Titan design?  We don't have, or at least I couldn't see a stock 'eject' option and I'm not sure it would work for a pad abort with stock parachutes (I've still to play with these) anyway.  I don't think NASA were all too sure of the ejection seat abort method either......  Fitting Sepatrons makes the capsule rather heavy and wasteful.  I was just wondering what other players prefer to do to recreate Gemini?

 

XrayLima

A pair of Separatrons will do it and at 70ish kilos each they're not an unreasonable weight for an ejection system. A quick google of ejection seats returned that they are typically around 100 kilos each.

[XrayLima]

Hmm, I'll need to look at what can be dumped during an abort, I'm obviously too heavy.  The current design has two sepatrons in the nose, and 8 canted parallel to the cone.  This lifts the capsule, (+ 2x radial drogue, 2x Oscar-B, 4x RCS blocks, 1x Mk16 Parachute, 1x Mk2-R Radial chute, 1 x Mechjeb unit and the  heatshield) to just over 300m, from a static pad abort.  This gives the chutes just about enough time to open properly.  6 Sepatrons only get me to 190m -ish and that means, even with Smartparts opening the chutes, I hit the deck at about 15-20m/s.  Too fast for comfort.

I've just about managed to squeeze a 400km x 400km orbit and safe return (with no orbital debris, 2nd stage PE < 20km) from without deviating from the Gemini-Titan design too heavily.  It just feels very heavy and wasteful, with a launch TWR of 1.3, and 2nd Stage TWR of 0.8ish and I'm sure it could be better.

[Gogi]

Heat shield can be dumped for sure.

[Tyko]

8 hours ago, XrayLima said:

Hmm, I'll need to look at what can be dumped during an abort, I'm obviously too heavy.  The current design has two sepatrons in the nose, and 8 canted parallel to the cone.  This lifts the capsule, (+ 2x radial drogue, 2x Oscar-B, 4x RCS blocks, 1x Mk16 Parachute, 1x Mk2-R Radial chute, 1 x Mechjeb unit and the  heatshield) to just over 300m, from a static pad abort.  This gives the chutes just about enough time to open properly.  6 Sepatrons only get me to 190m -ish and that means, even with Smartparts opening the chutes, I hit the deck at about 15-20m/s.  Too fast for comfort.

I've just about managed to squeeze a 400km x 400km orbit and safe return (with no orbital debris, 2nd stage PE < 20km) from without deviating from the Gemini-Titan design too heavily.  It just feels very heavy and wasteful, with a launch TWR of 1.3, and 2nd Stage TWR of 0.8ish and I'm sure it could be better.

I only use 2 separatons, but I also don't have all that extra stuff on top. Also, as part of the abort command you can detach the heat shield as @Gogi mentioned above.

you're carrying a lot of weight up there - two tanks full of fuel alone add a big chunk of mass...Maybe rethink how your capsule is built?