jnbspace

Have you ever collided with debris?

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7 hours ago, Geschosskopf said:

No, that's inefficient in dV and also wastes your playtime.  The best thing is to have your boosters run out of fuel exactly after completing their jobs which, if that job happens to be circularizing your orbit or kicking you out on your transfer, means you have space junk that ain't gonna re-enter by itself.  But that's why we have the wonderful TAC Self-Destruct.

Well I consider de-orbiting the junk part of launching rockets. Is the self destruct a mod? 

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12 hours ago, Geschosskopf said:

No, that's inefficient in dV and also wastes your playtime.  The best thing is to have your boosters run out of fuel exactly after completing their jobs which, if that job happens to be circularizing your orbit or kicking you out on your transfer, means you have space junk that ain't gonna re-enter by itself.  But that's why we have the wonderful TAC Self-Destruct.

Depends on what you mean by de-orbit - if you design your mission right you can deorbit as part of the mission:  Take my normal design for an early Mun mission: Booster to orbit is dropped either near the end of the gravity turn, or before the circulazition burn.  Transfer stage (which is vacuum-optimized) then circulizses, does the transfer burn, the rendezvous burn, and de-orbit burn before being jettisoned.  Lander stage lands, Kerbals do science, lander returns to Mun orbit.  At this point I usually dock to an empty return ship I've launched, which has the dV to return to Kerbin and land.

I've left one piece of debris in any orbit - the lander.  Which is reusable if I send enough fuel to top off the tanks.  Every other piece was deorbited and destroyed as part of the mission.  This also meant I used the most suited engine for every stage: Boost to orbit was a high-thrust engine, orbital maneuvers were all done with a high-ISP/low TWR engine, and the Mun landing/takeoff used a vacuum-landing engine, chosen for the design of the lander to have needed TWR.

5 hours ago, Dale Christopher said:

Well I consider de-orbiting the junk part of launching rockets. Is the self destruct a mod? 

Yep.  It adds a little box that can be staged to destroy the ship.  (Or whatever stage it's on.)  Not exactly realistic, but can be useful.

 

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17 hours ago, Dale Christopher said:

Well I consider de-orbiting the junk part of launching rockets. Is the self destruct a mod? 

Yes, TAC Self-Destruct.  I believe it's one of the myriad mods @linuxgurugamer manages these days.

11 hours ago, DStaal said:

Depends on what you mean by de-orbit - if you design your mission right you can deorbit as part of the mission:

For a given destination, as a general rule, the less mileage you get out of your lower stages, the more you must get from your upper stages, which makes them more massive, which has sort of an exponential trickledown effect on the size/cost of the lower stages.  This quickly exceeds the benefit of making short-legged lower core lifter stages ditched short of achieving orbit.  Sure, an engine optimized for liftoff won't be at its best circularizing the orbit but a bit more fuel at the bottom of the stack is way more cost-effective than more fuel higher up.  Things get much worse if you do like Space-X and make the lifter stages even bigger so as to reserve enough dV TO TURN THE THINGS AROUND after having just blasted off under full thrust, and then land them back where they started under power along with the extra otherwise dead weight of the control surfaces and landing gear.  Nice stage show magic trick technology demonstrator bur really?

That said, I agree with crasher stages.  In keeping with the idea of putting the mass as far down the stack as possible, a Munar transfer stage that also does the de-orbit and much of the descent braking, leaving the lander with not much to do but get home, is a good thing.  Plus, it provides gratuitous explosions when it crashes, to liven up the monotony of the descent.

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How much dV do you typically need to circularize?  For me, if it's more than 200 dV I've had a bad launch.  Long-range transfers I'll typically boost to a 500km starting orbit - the booster's still entering atmosphere (especially if I've put a sepratron on to help separation), but that saves quite a bit of fuel for the next stage.

Typically I'd rather boost higher and circularize with the vacuum engines then boost lower and circularize with the boost engines.  It's low fuel, keeps my orbits clear, and keeps KSP running smoothly.

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On 6/1/2019 at 7:45 PM, DStaal said:

Define 'deep'

I personally define 'deep' as < 70km :D

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29 minutes ago, DStaal said:

How much dV do you typically need to circularize?  For me, if it's more than 200 dV I've had a bad launch.  Long-range transfers I'll typically boost to a 500km starting orbit - the booster's still entering atmosphere (especially if I've put a sepratron on to help separation), but that saves quite a bit of fuel for the next stage.

Here's the real question....  At what altitude to you stop your lifter engines to get a 500km Ap off the launchpad?  If it's not at or below the +/- 40km normally needed to coast to an 80-100km Ap, then you're not really changing anything.  Rather than burning the lifter engines in vacuum to circularize, you're burning them in vacuum (or nearly so) to achieve a higher Ap.  This seems taters / totters.  And if it is at or below +/- 40km, aren't you going supersonic in the dense air?

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15 hours ago, 5thHorseman said:

I personally define 'deep' as < 70km :D

For the purposes of this discussion, the relevant number is what *KSP* defines as 'deep' - and auto-deletes under.  Which is somewhere in the 20-30km range, I believe.  ;)

15 hours ago, Geschosskopf said:

Here's the real question....  At what altitude to you stop your lifter engines to get a 500km Ap off the launchpad?  If it's not at or below the +/- 40km normally needed to coast to an 80-100km Ap, then you're not really changing anything.  Rather than burning the lifter engines in vacuum to circularize, you're burning them in vacuum (or nearly so) to achieve a higher Ap.  This seems taters / totters.  And if it is at or below +/- 40km, aren't you going supersonic in the dense air?

For a 500km launch, I'm probably dropping them at 80-140km.  They still drop to burn up however.  (Though I may have to watch them burn up if I really want them cleaned up.)  Honestly, I don't compute it down to the last dV - I launch by rule-of-thumb and the GravityTurn mod, and get launches (depending on settings, build design, etc.) costing between 3000 m/s and 3800 m/s - and that is for *either* 80km AP launches or 500km AP launches, typically.  (Admittedly, lower AP tends to lower dV.)

The point being with a reasonable mission profile you can auto-cleanup your trash, I find.  Is it absolutely perfect?  Probably not - but I'm not trying to push the boundaries of what's possible, just getting reasonable launches set up.

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I use MJ to place all sorts of craft into a 100km parking orbit, with the usual zero degree inclination.  I have about 100 pieces of debis present, generally around this altitude or 80km.  I fear the day I finally build my giant Jool mission mothership and do a slingshot or something that brings me to this altitude.

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A booster came 300 meters from my main space station the other day. Jeb had to EVA and push it away to keep the station safe.

 

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i had a collision with debris recently but ive been experiencing a bug where parts dont take damage so instead of obliterating my scansat satellite into an unsafe orbit but thankfully i had fuel to spare

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2 hours ago, Tanner Rawlings said:

Yes, I launched my apollo style rocket, staged after leaving the atmosphere, timewarped, was just about to throttle up and looked forward to see this:

https://imgur.com/a/lD9XAlo

 

:o

Oh, and by the way, you can take screenshots in game using the F1 key. They’ll appear in a Screenshots folder in your KSP directory.

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2 hours ago, Tanner Rawlings said:

Yes, I launched my apollo style rocket, staged after leaving the atmosphere, timewarped, was just about to throttle up and looked forward to see this:

https://imgur.com/a/lD9XAlo

 

Hey, you saw it: At this point you can throttle *very slowly*, hit the debris at a couple m/s, push it out of the way, and then throttle up to the full burn.  (Done that a few times, usually when doing something complicated like building a comm network.)

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On 6/3/2019 at 1:00 PM, DStaal said:

For the purposes of this discussion, the relevant number is what *KSP* defines as 'deep' - and auto-deletes under.  Which is somewhere in the 20-30km range, I believe.  ;)

The majority of my save's persistent debris on rails would impact ground in less than one full orbit due to aerodynamic losses. Regardless of the scientific definition of "deep", it's hard to argue that this adds to the simulation.

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2 hours ago, ExtremeSquared said:

The majority of my save's persistent debris on rails would impact ground in less than one full orbit due to aerodynamic losses. Regardless of the scientific definition of "deep", it's hard to argue that this adds to the simulation.

An arbitrary line which they can test for quickly.  A ship with a periapsis at 69km can probably orbit for quite a long while before it deorbits - a ship with it's periapsis at 0km isn't going to complete the orbit.  Somewhere in between there's a point where most ships would switch from 'orbit, but decay slowly' to 'impact imminent'.  KSP isn't going to compute what that is for every individual ship is in the background (it'll do it if you keep the ship in the foreground), so the devs picked a point and said 'if it goes below this, it's getting trashed'.  

They probably erred on the side of 'let it orbit' a bit more than they should, but I see the reasoning, and there's something the player can do if they set it to leave things that should de-orbit in orbit, while there isn't anything the player can do if they destroy things which should have stayed in orbit, so they're erroring on the right side.

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Posted (edited)
On 6/6/2019 at 10:16 PM, RealKerbal3x said:

:o

Oh, and by the way, you can take screenshots in game using the F1 key. They’ll appear in a Screenshots folder in your KSP directory.

Thanks, i took it on my phone cause i sent it to my brother, though admittedly, i do forget a lot of the quality of life shortcuts, max throttle, kill throttle, gui hide, ect, even though ive had the game since 2012 XD

Many a kerbal has died needlessly due to this fact.

Edited by Tanner Rawlings

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I once jettisoned the heatshield before the parachute opened. Air drag threw it back at the capsule and completely obliterated it.

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