Staged Parachutes

[ANWRocketMan]

This is just a small thing that has bugged me about parachutes, especially when trying to land more than just a capsule. It would be nice to have staged parachute deployment so that you don't get a sudden shock of 15+ G's 500m above the surface.

This animation of Orion's EFT-1 shows it well: The parachutes don't instantly open to full expansion.

How possible would this be to implement? Either through Stock parts or, if need be, using a plugin/mod.

[Kasuha]

In the video the capsule deploys drogues, then cuts them and deploys low atmosphere chutes. These then open pretty much all at the same time. If you want to emulate that, put drogues to one stage, normal chutes to another stage and set up an action group to cut your drogues.

But the game doesn't require you to do that. In KSP chutes can happily clip through one another.

[ANWRocketMan]

What I mean is not the drogue chute, then the main chutes open. What I mean is the time it takes the main chutes to open fully. At 2:03 they are still unopened, at 2:08 they are opened further, increasing the drag a little, then only at 2:13 do we see them opening to the full extent.

In KSP we get the first bit and then instantly at 500m the last one, but this causes 15+ G's almost every time considering you're re-entering and slowing down to maybe 90m/s when this full deployment happens. It would be nice to have another level in between at a higher altitude to decrease the G-force load.

[KerbMav]

Two ideas.

1. Look at the deploymentSpeed = 1, semiDeploymentSpeed = 1 - but I am almost certain this only affects the animation, no scaling of drag.

2. Chain the MODULEs - I did that to create a 2in1 chute that semi-deploys high up, fully deploys like a drogue still high up and fully deploys like parachute down low in the atmosphere. This was not visible, but it worked technically. (Note: the fullyDeployedDrag values seemed to get added up, so to get to the usual 500 for a chute I finally set the first MODULE to 170 like a stock drogue and the second MODULE to 330.

MODULE
{
name = ModuleParachute
invertCanopy = true
autoCutSpeed = 0.5
capName = cap
canopyName = canopy
semiDeployedAnimation = semiDeployLarge
fullyDeployedAnimation = fullyDeployLarge
stowedDrag = 0.22
semiDeployedDrag = 4
fullyDeployedDrag = 170
minAirPressureToOpen = 0.007
deployAltitude = 2500
deploymentSpeed = 1
semiDeploymentSpeed = 1
}

[YoshiFan501]

I use the Sum Dum mod that has exactly what you need

http://forum.kerbalspaceprogram.com/threads/48357-WIP-Sum-Dum-Heavy-Industries-Service-Module-System-%28Stockalike%29?highlight=sdhi

[Kasuha]

In KSP we get the first bit and then instantly at 500m the last one, but this causes 15+ G's almost every time considering you're re-entering and slowing down to maybe 90m/s when this full deployment happens. It would be nice to have another level in between at a higher altitude to decrease the G-force load.

In KSP there are four stages available:

Stage 1: you deploy drogues

Stage 2: you deploy main chutes

Stage 3: drogues open fully (at 2500 m)

Stage 4: main chutes open fully (at 500 m)

If you do it right, fully open drogues will gracefully slow you down to about 40 m/s (in Kerbin atmosphere). This will prepare the ship for the hit caused by main chutes opening.

If you want to use more stages, you can open additional drogues under 2500 m or standard chutes under 500 m. But I have never experienced problems with drogues opening all at once and if they don't slow the ship down sufficiently I usually rather use engines for additional braking.

[Supernovy]

Two ideas.

1. Look at the deploymentSpeed = 1, semiDeploymentSpeed = 1 - but I am almost certain this only affects the animation, no scaling of drag.

It does indeed scale drag, this was implemented in 0.18 to prevent the sudden shock of the parachutes opening from tearing apart spacecraft. Before then it instantly went from 1 drag (semi deployed) to 500 (fully deployed).

I'm sure you could fiddle around with those values to make a slower deploying chute.