What are my chances?

[ramses]

Just a quick question. I've done a return trip to Laythe before and that aerobraking around Jool is quite killer. This time I'm off to Vall, but am thinking of doing it in one trip as opposed to multiple trips with all my landers and rovers.

I have this to worry about...

What are my chances of it surviving Jool. (I personally don't think their good)

Edited August 24, 2013 by ramses

[SkyRender]

Depends on your technique, but I would say you'd be lucky to even reach Jool with that craft. Mainsails are good for getting into orbit, but as an interplanetary drive stage engine, they're one of the worst choices available. If you can, I suggest you replace it with an orange tank plus LV-N. It'll be slow as all-get-out, but you'll actually get to Jool with it... eventually.

[ramses]

That mainsail was just for getting me to orbit. It's got two nuke engines to get me there and back.

Just realised I've screwed up my pics. Can't see squat.

Edited August 24, 2013 by ramses

[Johnno]

What are my chances of it surviving Jool. (I personally don't think their good)

What exactly do you mean by "surviving Jool" ? Unless you're using a mod like deadly reentry then aerobraking can't damage your ship. For that very reason aerobraking is a godsend in KSP saving a craft heaps and heaps of fuel when done properly.

[magnemoe]

What exactly do you mean by "surviving Jool" ? Unless you're using a mod like deadly reentry then aerobraking can't damage your ship. For that very reason aerobraking is a godsend in KSP saving a craft heaps and heaps of fuel when done properly.

True, aerobraking put some stress on the ship but far less than the trust from an mainsail.

I only wonder if you have enough fuel, the transfer stage tank look a bit small to me. Remember you has to brake into Vall orbit to.

[Scotius]

Yeah - this ship does look a bit underfueled for a serious mission in Jool's system. I'm afraid you will have to tap into fuel tanks of landers and rovers. Consider switching one of smaller crafts for kethane mining lander.

[annallia]

Just to be on the safe side I would launch another orange tank (or one of the grey tanks that are half its size) with it to Vall just incase you do have to tap into the lander tanks. Otherwise it should be fine from the looks of things.

[Ralathon]

Why don't you just use a Tylo or Laythe grav assist to slow down instead? Skips the whole problem.

[OtherDalfite]

Why don't you just use a Tylo or Laythe grav assist to slow down instead? Skips the whole problem.

Those aren't really all that safe to use, or at least they won't be until reentry heat gets properly implemented. Slowing down with gravity can fling you onto a different trajectory, possibly throwing you right into Jool, or throwing you out of the moon system entirely. For now, it's just safer to use atmosphere's to slow down.

In regards to OP, I recommend getting a periapsis of around 112,000 meters for your aerobrake. That will get you a nice stable orbit that you can safely make adjustments to.

[Landge]

Personally I wouldn't set Jool's periapsis no deeper that 122~125km. The atmospheric drag will take you in a bit deeper than what periapsis you've set. Besides you could always make another pass and do another aerobrake.

Here's what happened to my Laythe Jet Transport Ship (J-Bird aircraft and Bird's Nest Refueling Station/Lander). My periapsis was set to 118km I think, but was dragged down to around 115~116km.

The RCS tank broke loose from the port nacelle (yes I had struts attached).

and collided with the fuel tank causing it to explode.

The RCS tank on the starboard nacelle also came loose but thankfully didn't do any additional damage.

Luckily no damage was done to the lander or aircraft. I was able to board each aircraft, separate from the transport ship, and land on Laythe. All a part of this mission.

[ramses]

Exactly what I mean Landge.With my last mission to Laythe I arrived with 5 orange tanks, but one was ripped off during aerobraking at Jool.

As far as fuel is concerned, I'll simply send some more if necessary. Landers and rovers won't be making the trip home so it'll be a lot lighter on return trip.

[Landge]

Yes it was one of those WTF? moments. I had reloaded several times but all with similar results. So I just took some pics, played it out, to see if I could make it work. I also lost a couple LV-N's on the booster stage, making my center of Thrust all out of whack on top of the whole ship's CoM getting screwed up. Every other ship made it through OK. Even though it was an exact duplicate of the first jet transport, all other ships were at a higher altitude, even my massive expedition mothership made it without a scratch. Problem was getting each ship far enough apart to bring them into Laythe one at a time.

[magnemoe]

Exactly what I mean Landge.With my last mission to Laythe I arrived with 5 orange tanks, but one was ripped off during aerobraking at Jool.

As far as fuel is concerned, I'll simply send some more if necessary. Landers and rovers won't be making the trip home so it'll be a lot lighter on return trip.

Why don't simply dock some tanks to it for the initial burn out to Jool.

It gives mission flexibility, if you have spare fuel you could visit Pol or something. If you have fuel left in the stage with the mainsail you could drain it to the nuclear engines during the first part of takeoff. Downside is poor trust however the fuel is free.