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Can't slow down fast enaugh when reentering kerbin


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I am already in orbit and I can't go back to lunch. I can't reenter kerbin because I think my ship is too heavy. It either overheats and explode or it doesn't slow down fast enough so I can't open my parachute. I didn't put and heatshields. I tried to set the periapsis to 40k,35k,20k,10k I even tried 0k but nothing works. How can I save my astronauts?http://imgur.com/zc9w5Wn

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You ship is too heavy, and that's certainly a problem if you want to land on those legs. But it's too heavy for the chutes you used, not for reentry.

I built an exact replica (from the pic you uploaded), had it in a circular orbit at 88.5 Km from Kerbin. It is even heavier because I let all fuel with those tanks (while the pic shows your being at half fuel). Then performed the reentry this way:

- burned retrograde to aim at KSC, periapsis 50Km (yes, that high);

- turned attitude to normal (yes, it seems contrary to experience, however works). Reason it works, it exposes more on the ship surface to drag, so depleting more kinetic energy (lowers the ballistic coefficient).

- kept the ship rolling to distribute the heat on all sides.

- turned attitude to retrograde when components on the ship sides started to raise temperature too high (that was at 50 Km altitude, speed was decreasing but still about 2300 m/s).

- started burning retrograde at full throttle when lower than 40 Km (probably unnneded to decrease speed, but intent was to land without fuel).

- opened those drogue chutes when turned white, and then the Mk16 chute (had to modify the staging to have that sequence).

Even with all chutes opened, and the engine at full throttle, final speed still was 16 m/s. Too heavy and the LV-909 has too little thrust at low altitude, so had to fire the decoupler and sacrifice the lower stage. Hope you have nothing to save from that stage.

- Landed successfully with the top stage.

http://imgur.com/bwbXLiH

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33 minutes ago, diomedea said:

Even with all chutes opened, and the engine at full throttle, final speed still was 16 m/s. Too heavy and the LV-909 has too little thrust at low altitude, so had to fire the decoupler and sacrifice the lower stage. Hope you have nothing to save from that stage.

Landing legs should withstand this much. Maybe not without breaking, but them breaking should still be sufficient to protect the rest of the craft.

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3 minutes ago, Sharpy said:

Landing legs should withstand this much. Maybe not without breaking, but them breaking should still be sufficient to protect the rest of the craft.

Those legs crash tolerance is 12 m/s. Even breaking, those won't reduce speed enough for the LV-909 or the T200 tanks with that lower stage (crash tolerance at 7 and 6 m/s respectively). Parts above those tanks should survive, but then there's the danger with the vessel capsizing with no chutes to stop it, what could probably destroy parts in the top stage too.

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As stated above point normal to increase the drag your ship will produce.   this is also a moment to realize a design flaw.   you should bring back only what's necessary,  the kerbals  and the science.  leave the rest behind,  that's added mass which means more fuel for the entire journey.   minimalist building well expand your range more than anything.

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The mod Stage Recovery has a tool in the VAB that checks the expected landing speed for each stage based on the chutes you have. Handy for seeing if you have enough. Keep in mind that it computes survival based on the impact speed rating of all the parts, not just the bottom one that will contact the ground. So if you will be riding it down, look more at the expected landing speed.

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14 hours ago, hangiceren said:

I am already in orbit and I can't go back to lunch. I can't reenter kerbin because I think my ship is too heavy. It either overheats and explode or it doesn't slow down fast enough so I can't open my parachute. I didn't put and heatshields. I tried to set the periapsis to 40k,35k,20k,10k I even tried 0k but nothing works. How can I save my astronauts?http://imgur.com/zc9w5Wn

Maybe try a lighter ship. That helps. Also, try timing the parachute and maybe add heat shields. That also helps too. Maybe that will save your Kerbals. :wink:

2 minutes ago, planet-creations said:

Maybe try a lighter ship. That helps. Also, try timing the parachute and maybe add heat shields. That also helps too. Maybe that will save your Kerbals. :wink:

WAIT A SECOND...

Edited by planet-creations
I accidentally typed "sabe" instead of "save".
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