Detachable-wing spaceplanes capable of Laythe roundtrip - the Icarus and Nuculus

[ginsweater]

Okay, I am so inordinately proud of this ship that I can't bear to leave it hidden in the challenge thread - even though it's kind of tricky to launch, and it turns out to have the most common name in all kerbdom, I'm going to give it a thread.

This is a spaceplane that detaches its jets and wings just before orbit - hence I decided that this would be my Icarus, because it flies high and loses its wings. By staging, it manages to bring just enough delta-v to Laythe orbit to get the cockpit home to Kerbin.

Here's the full imgur album of its maiden flight: http://imgur.com/a/8rN6i#0

In order to manage a strict "no nukes" policy, the base craft has a very underpowered final stage and so it requires considerable luck to get home from Jool. And so I am also introducing here - the Nuculus I!

In abject defiance of mild environmentalist protests and massive outraged games-should-be-hard-dammit-ist protests, the Nuculus offers a NERVA engine and well over 3 km/s of delta-V on the final stage - enough to allow an easy return from Jool at the cost of a 7% weight increase and correspondingly more difficult landing and takeoff.

Trainer versions (plane only, no boosters) of both planes are also available - so you can try them out and practice your landings on Kerbin. (Or just crash the Nuculus trainer on Moho - it has a pretty good shot at making it there all by itself!)

I used my weird customized Kerbal Engineer Redux for design and flying, but I (think I) removed the parts for posting, so the .craft files below are all stock.

Watch out for the Space Cthulhu when you're on the pad. I decided to make this a freestanding rocket (no space for the towers) and it often loses an engine or two if you timewarp before launch. (Just end the mission and restart.)

The Jool transfer window happens when Jool is 96.58 degrees in front of Kerbin. (Thanks, ksp.olex.biz!) Your ejection angle if you go into an 85-90 km parking orbit is 114 degrees from Kerbin prograde.

Note that Jool moves about .12 degrees per hour, so if you launch when Jool's right at 97 degrees, that'll give you a couple hours to get into orbit and escape Kerbin.

I like to launch just before sunset, both because it's pretty and because I achieve orbit at about the right spot for my escape burn.

1) Landing gear up. SAS on. Throttle to full.

2) Launch.

3) When the first stage SRBs burns out, stage once to drop them and again to light the second stage SRBs.

4) Stage again to drop the second stage SRBs.

5) At 10,000 meters, begin a gravity turn to 45 degrees. BE CAREFUL. If you turn too fast, the spaceplane wings will catch the wind, and you'll lose control.

6) When the liquid boosters burn out, you should have an apoapsis of 85-89 km. Cut the engines and begin your coast.

7) Stage to separate the liquid boosters. MAKE SURE the throttle is at zero when you do this, otherwise you're likely to crash into them. Puff your engine (tap Shift, count to two, press X) to help clear the spent tanks.

8) Pitch to horizontal. Throttle back up about 30 seconds before apoapsis. Achieve orbit.

9) You'll have a little bit of fuel left - I suggest firing it off when you pass your ejection angle; it'll raise your apoapsis to 300-400 km.

10) Stage to drop the orbital insertion booster.

11) The interplanetary stage is four strap-on boosters - they should have plenty of fuel to get you to Laythe if you aerobrake at Jool. (119.5 km Jool periapsis should do the trick. I can't give you advice on a Laythe aerobraking altitude - it seems to be between 20 and 25 km. You can do a direct descent if you have to but it's really scary.)

MechJeb can almost fly this craft to orbit, but it doesn't know that it has to throttle down when detaching the liquid boosters or it'll hit them with the main engine. So to fly using MechJeb, I recommend the following:

1) Edit path, set Turn End Altitude to 40 and Final Flight Path Angle to 40.

2) Set Orbit Altitude to 85km.

3) Auto-Warp Toward Apoapsis to OFF.

4) Launch - you can stage the SRBs manually or let MechJeb do it.

5) When MechJeb shuts off the engines to coast to apoapsis, there should be only a tiny bit of fuel remaining in the boosters. Stage manually to drop them during the coast.

6) Fly normally.

1) Stage to drop your interplanetary boosters. Don't wait too long; if you do this in the atmosphere they're liable to hit something.

2) Set the plane at an angle of attack of 20-30 degrees and switch on SAS for re-entry. Once you hit atmosphere, don't touch the controls until you get under 300 m/s - the plane will be very unstable.

3) The jet engines will have switched on when you dropped the boosters - if you're going to hit water, you can always throttle up and fly to a continent to land, but you'll have that much less fuel for liftoff.

4) Continue to glide until you start to see your shadow, then flare to a 30- or 40-degree angle of attack. Try to get your surface velocity under 45 m/s if you can.

5) At the last moment, let your nose start to come down so you don't lose your jets when they hit the ground.

6) Don't hold down the brakes or you'll tip over; tap them to slow down gradually. Re-engage the SAS, or don't - it's up to you.

7) Good luck.

1) Throttle up your jets. Release the parking brake if it's set. Try to find a liftoff direction that sets your wings level - it makes it a lot easier to recover from bumps.

2) Be alert for bumps. You can recover - especially if you have a joystick - but you need to be quick.

3) At 100-120 m/s, start to pull up. If you go over a ridge at this point, you'll be airborne - be ready.

4) If you're not already heading east, turn. Pull up to 45 degrees and set the SAS.

5) Wait until your surface velocity stops increasing, then stage to fire the central engine.

6) The jets will still have a bit of power before they're totally useless. Wait until your vertical velocity starts to fall.

7) Stage to drop the jet engines. The plane's nose will jerk down from their backwash - don't worry, let the SAS recover.

8) Wait until the two side rockets burn out. You should be in a high suborbital trajectory.

9) Cut your engines to coast, and stage to release the wings. Use the final engine to establish orbit.

10) If you're using the nuclear final stage, you should have enough fuel to leave Laythe orbit, descend to a low periapsis over Jool, and burn to a Kerbin intercept. If you're using the LV-909, you'll have to be creative. Good luck.

[Resender]

I'm impressed and this has given me an idea to get my space shutlle onto new worlds

[SpaceGibsy]

Now thats a nice design! Double thanks for providing me that landingspot ..