Do you know?

[garf]

I was going for my first orbital flight. As i know by now, you have to prepare for extensive heat when reentering into kerbal. So i equipped my rocket with enough parachutes (Normal and Drogue) to savely land and also, to protect my chutes from heatdistruction, put some radiator panel on them. As i came back down i started my radiator panels seperately and waited for the heat to cool down, but form the moment the heat started my chutes where all red( would have been destroyed upon opening) and never became useable again, even after completely cooling down and reaching speeds below 700m/s. The only way to make them work again, was to turn the radiator panels of again, after cooling down..

I see no logical connection there, since the chutes are not obstructed by the panels( on or off) when launching the rocket.

Anyone know whats happening there?

Why would my radiation panel kill my chutes? (only after reentry)

Do even need to protect chutes?

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Yeah i had the wrong m/s in mind. Had even more than 500 on impact hence the "red chutes".

Thanks for the awesome replys. i learned more than just about chutes.

What an awesome game

 

 

Edited September 10, 2016 by garf

[JP76]

Hey garf, i'm a new player myself, cant help you with the radiator issue, but i can give you a nice tip i learnt by mistake the other day. 

I sent a rocket on my first orbit of Mun, and i wanted to take Bob the scientist with me to maximize science, so i added a crew cabin and science jr etc, and i wanted to arrive back at Kerbin with everything safe and attached. 

So i used the over sized Heat Shield (the 2.5 meter one i think) and it worked a charm! looked ugly as hell, but it reduced my speed massively and quickly in the lower atmosphere on re-entry, and i landed safely with all chutes etc unharmed. Infact i don't think i saw any of the little heat bars on any of the parts! 

Try that if you have it unlocked.

J

Edited September 8, 2016 by JP76
fixed wording

[Rocket In My Pocket]

You'd need to be going less than 250 m/s to safely deploy the chutes. (500 m/s for Drogues.)

The reason they all stayed red was to let you know it wasn't safe to open them yet, basically you were still going way to fast.

http://wiki.kerbalspaceprogram.com/wiki/Parachute

[Talos]

Yeah, you can't deploy parachutes at high speeds. The best use for parachutes is to deploy the drogues first to slow yourself down once you're below 500 m/s, then have the main chutes deploy at your chosen altitude.

[Diche Bach]

Some basics that reflect my approach:

1. Two drogues and two radial parachutes on any capsule.

2. Add to more radials for each significant module attached to that (e.g., the 2-Kerbal crew cylinder would get two more radials, a "service module" wouldn't [unless it was packed full of heavy stuff].

Goal is to land at around 3 to 6 m/s, and with enough aerobraking that the chutes only need to be open for a couple seconds to decelerate to that speed. I use Stage Recovery, which provides estimates of the landing speed for stages, but there are probably other, smaller apps that will give you such data. However, just following my simple rule of 2 drogues, 2 radials seems to work fine pretty much all the time.

3. ALWAYS add a heatshield on the distal (bottom) part of the reentry assembly. Radiators can help but they are not really meant for the purpose of ablating reentry heat I think. Another aspect of this is: try to have the center of mass for the reentry assembly toward the bottom end where the heat shield is attached.

4. Try to have 150 to 200 battery power at the point of the reentry burn, this will allow the pilot to use SAS to keep the capsule stable.

5. If you are really concerned about reentry speed being too high some retro-rockets can help, I've used a couple of the tiny "sepratron" SRBs, but I think those are from a mod and there is no vanilla analague

Other than that, my reentries are generally "hands off." It runs like this:

A. Do the burn to get the periapsis below 42km

B. Turn retrograde, and wait till you get to 49km altitude (where the sparks start to fly)

C. Watch.

D. Monitor the "Kerbal Engineer" (another mod) "Reentry Pane" to see if I'm landing on elevated terain, and if so, increase the height at which the chutes deploy

E. At 1800 m above the anticipated landing altitude [and ONLY if the icon for the chutes is not red] deploy the drogues.

F. Shortly after that deploy the radials.

Apart from making the reentry burn and deploying the chutes its a handsoff process once you get the hang of it.

[eddiew]

In general, you don't need to protect anything that isn't on the hot end of the air flow around the ship   In the simple case of a chute on the top of a capsule that is coming in bottom-first, then the chute will be completely fine as long as you hold retrograde. Again, in this simplest case, the capsule will do that with no input since it's weighted to be heavy at the wide end.

(Pictures of what you built will really help us tell you why it gives problems and whether it's necessary to do what you're doing!)

Edited September 8, 2016 by eddiew

[suicidejunkie]

2 hours ago, Diche Bach said:

5. If you are really concerned about reentry speed being too high some retro-rockets can help, I've used a couple of the tiny "sepratron" SRBs, but I think those are from a mod and there is no vanilla analague

Sepratrons are totally stock.

You might be thinking of the "Landertron" which is from a mod and has code to auto-ignite the SRB for a suicide burn and a soft landing without any parachutes.

[tater]

You do not want/need radiators for reentry.

 

[Hupf]

To put it simple, there's two types of heat that are tracked for each part: "skin" temperature and "core" temperature. When heat is induced from the outside of the vessel, e.g. when too close to the Sun or too close to air that was compressed to a great extend in a very timely manner and is not being pleased about this, then the skin temperature on the parts that are pointing in the appropriate direction and are not occluded by other parts wil rise (comparatively rapidly).

The core temperature rises by heat transfer between parts or from skin temperature to core temperature (diffusion, slow), also certain parts like mining equipment and the LV-N engine generate significant amounts of core heat when operational.

Radiators are good for getting rid of core temperature. During reentry, your only problem is skin temperature. The speed at which skin temperature is diffused to the part's core and from there to the radiators and back to the outside is way lower than the speed of the skin temperature rising by prolonged exposure to hot plasma. Your main chance instead is to have only appropriately sturdy parts (in terms of skin temperature) exposed in this manner (so as said above, place a sufficiently large heat shield on the nose of your vessel, or for the poor man's version turn your rocket and reenter engine-first. They usually survive a reentry from LKO better than chutes or science equipment).

[Corona688]

If your parachutes aren't literally exploding, they're OK.  The red flag is completely unrelated to heat, they're just warning you they'll rip right off at this velocity.

Edited September 8, 2016 by Corona688

[Deddly]

Great answers everyone. aaaand moved to Gameplay Questions

[Aegolius13]

I have seldom found a need for drogues when reentering Kerbin - your craft slows pretty quickly from there to safe parachute speeds.  The one exception is my suborbital tourist "ship" (aka capsule on top of thumper), which goes almost straight up and down.  Hasn't crashed yet.... Drogues are great on Duna, though.

Also worth noting that the inflatable heat shield, in addition to shielding from heat, slows you down to a ridiculous extent.  I would recommend it over the two larger conventional heat shields for most applications.

[ForScience6686]

That is not quite the purpose of the radiator.  A simple capsule should slow down pretty well on re entry to not need drogues, our a heat shield if returning from lko our even the moons.  Those are typically for larger mass craft that can't slow down fast enough.  

[Diche Bach]

I figure drogues are cheap, and I have on occasion had things not work quite as intended and needed their drag to slow down enough that the main chutes were well within the safety zone. Probably unneccessary, 95% of the time, but for a couple hundred funds (which you will likely recover most of anyway) and a bit of added risk mitigation, I'll keep using my drogues in pairs along with the main radials!

I noticed the other day that one of the capsules I tend to use (not sure if from a mod or not) has "ablator" as one of the resources in its menu pane. I guess in that case, one could even forego the heashield, but I think I'll just keep using them. The other benefit of the heatshield is that it is heavy so it tends to keep the proper end pointed at the ground.

Will be interesting when I finally get farther in the tech tree and get to check out the silica-ceramic techs for space planes.