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The K Prize - 100% reusable spaceplane to orbit and back

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Thank your very much for the great feedback! Since I apparently haven't read the thread introduction properly makes it even better to get such a great feedback nevertheless. The refueling itself happened before I found this thread and wasn't actually necessary to begin with. I then shall do another flight to orbit and back and mostly... rename it. ;)

Thanks again!



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Delivered a 45T Utility/Fuel Truck to Duna with my Falcon XC Jumbo Transport. Total tonnage was 213.64 tons, craft, fuel and payload. It has the same big cargo bay as the B version but less oxidizer and more jet fuel making it more suitable for both large and heavy payloads.


Accelerating to reach 1900m/s before climbing and going over to rocket engines.


A Kerbal checking the chutes and looks at the almost ghostly looking ship floating closer and closer to Duna.


Coming in for landing.


Payload was extremely tricky to get out. Workt fine on the first try on Kerbin but the lower gravity made it hard for it to slip out properly on Duna.


A happy kerbal reciving his new Truck.


My duna base, all delivered with the 3 sub versions of the Jumbo.


Coming in for landing at Kerbin.


Landed some where at kerbin :D Dont feel like going to KCS. seems to work in 0.20.0, landed once there with out hitting drifting hitboxes in that version but have to do more testing later.

Edited by pa1983
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Not exactly relevant to K-prize but still fun.

Flew this control tower in with my Jumbo Transporter. As you know control towers are tall. Sure My Jumbo is long so what did I do. I made it so I could erect it. Sure nothing new but it took almost a day to make it not only fit but also work properly at the same time. Once erected I jettisoned the left overs.

Theres noting an SSTO cant do :P



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After spending tons of time on rovers and probes, I wanted to tackle SSTOs again and I managed to come up with a reasonable design. It's not fully developed yet, as it has no RCS system and no docking port, but it had little trouble reaching an 80km x 80km orbit. As you can see, Jeb was pretty excited.


I used the last of the oxidizer to de-orbit, but I overshot KSC. Fortunately, I still had plenty of liquid fuel to turn around and fly back to the runway, but I was nervous about how the craft would handle under such a light fuel load. Of course, Jeb wasn't worried one little bit. As usual, Jeb was right and the craft turned around easily and held a steady course back to the runway.


With the engines at zero throttle, the craft was still quite responsive and touchdown was much smoother than I anticipated. Jeb was plainly disappointed to be back on solid ground and didn't really want to pose for the photo.


I have dubbed the craft "La Paix."


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All of which have gotten to ~100km or higher orbit and then deorbited to land at KSP again.

Craft files can be found here:


1) sweetmidge:

Vital stats:

9.12t, part count 24 (not including mechjeb)

Gets into 100km orbit with ease (even with a crappy ascent) with lots of dV (~1500+) left over, both for out-of-atmosphere and in-atmosphere stuff.

If one intentionally burns away more of the jet fuel on the ascent path, you can end up with a fair bit more dV.

Takeoff happens at around 60m/s, and landing at something significantly slower.

max turbojet-powered speed is ~1800+ m/s

This one is easy to make a VTOL as well.

Gallery here: http://imgur.com/a/tHLOE



2) sweetmite: (my favorite!)

Vital stats:

6.41t, part count 28 (not including mechjeb)

upper-atmosphere target is around 33km, where it should eventually be doing ~2125+ m/s

This puppy gets up to max service altitude and max turbojet-powered speed amazingly fast imho!

Gallery here: http://imgur.com/a/ev3vQ



3) fairfly/bat (it is itsy-bitsy!)

Vital stats:

5.18t, part count 20 for bat, and part count 24 for fairfly (not including mechjeb) (the weight difference between these two is .004 I think...)

fairfly/bat is very fuel limited, so get it up to ~1800 m/s and then head on up to orbit.

You'll need to get your reentry done pretty right, 'cause it is likely you'll have to coast down. Good thing they glide well!


Gallery here: http://imgur.com/a/iXk5u




Gallery here: http://imgur.com/a/umHTp



Technically, all ships here could be lightened with different choices of cockpit, so further weight reductions are possible.

Having played around with it, however, the crafts become difficult to control when the cockpit cannot counterbalance the jet engine's weight.

Further updates here, if any: in this thread

Edited by heavylifter
now with craft files!
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The Kiwi is back...


I forgot pics of orbit again but i did get there(easily) and had almost 300 units of fuel left! (probably enough to get to munar orbit). Future versions will have more air intakes (this one had only 6) and a more efficient flight path (I launched Aerospikes at 10K, could be held off untill 15-20K) and fuel lines will be redone. The old (17.0) version could land at Duna, refuel, get to LDO, refuel again, and come home. I plan to acheive this with this version.

EDIT: Just got into orbit with 1158 L of Oxidizer in the tank! Woop! To Duna we go!






Edited by zekes
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Hi guys, this is my first post on the KSP forums, so rather than ramble on in the welcome forum, I've got a submission for the K Prize!




(sorry if I've screenshot-spammed a bit, I don't know how much I need to post as proof)

As I suffer from a slight case of lazy designer syndrome, the Sepratrons you can see on the nose are fired at the end of the runway to force the nose up and assist in take-off. They don't decouple though.



Sadly, it takes a while to get going, and doesn't like flying up steeply or being timewarped. As a result, ascent is a bit dull.


The rockets are toggled separately from the air-breathing engines, so by leaving the jets on when the rockets are fired more air is forced into the intakes, allowing the jets to run for longer.




The HyPerformance weighs in at 13.37 tons, in case it's not clear from the screenshot. :D









Jeb insisted on planting a flag on the runway to mark his (unusually) successful landing. He is seen here daring me to run it over.

As regards a piloting guide, keep the nose pointing between 20-30 degrees during the ascent as it is quite unstable and has a tendency to do sneaky backwards loops if you're not watching. Air-breathers are toggled with key 1, aerospikes are toggled with 2. It's unlikely to have enough fuel for a high orbit, so I tend to keep it circular at around 100K. Landing at KSC isn't difficult, although I would advise keeping it in orbit and waiting until daytime to land. You will have to glide most of the way in, although there should be enough aerospike fuel for the odd descent correction burn, and don't hesitate to put the jets back on if you need a little more control during runway approach (<2000m). I'll upload the .craft file as soon as I can find out how.

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So I've been working steadily towards this challenge ever since I first brought the game, and I'm finally satisfied enough to put it to the post: :cool:

Ladies and gentlekerbals, I present the Starspeeder:


Main features are

3 Turbojets

2 LV-N nuclear engines

a set of triple wings

more air intakes than it should rightfully have (16 all told)

docking port


ejector system and parachute for the cockpit

1560 units of liquid fuel

1320 units of oxidizer

Base weight is 30,5 tons before cargo is added, so its quite on the heavy side!

It has carrying capacity for 4-5 tons extra, depending on how the weight is balanced. I normally add two extra sets of landing struts so that it can land vertically, and then tip it over onto the main landing gear. It is possible to land on the engine exhausts, but not really smart.

If I am carrying cargo, normally I put either a rover in a dorsal mount and a satellite or science unit in a ventral Mount. It can take 6 small satellites with oscar tanks and ant engines, mounted above and below the fuselage. Possibly more in fact.

Like so:


It'll go to 27k on its turbojets alone, and with careful throttle adjustment will reach 1900 m/s before starting the burn with the rockets. Normally I ascend as fast as possible to 22k with a 70 degree inclination. Then I flatten out and by the time I am in level flight it should be at 24k. At that point I start to speed up towards the 1900 m/s. Ideally I use about 250 units of liquid fuel in doing that, so there's a little more than 1100 left for the rockets.

A circularised orbit is reachable with around 1000 units of oxidiser left, having used 300 or so to reach orbit and circularize. Which, depending on the weight of the cargo, translates into around 3000 delta-v left.


This is from my first Mün landing, I had a lot of inefficient burns, so the fuel supply was quite low, but had just enough fuel left to come back to orbit and do a transfeer to Kerbin for an aerobraking.

I've gone to both Mün and Minmus with it, landing a rover of 0,9 tons on the Mün :) (Look how happy Kirgun is)


Note that these are pictures from different flights, as I was doing small tweaks to the next iteration of the craft while waiting on travel times.


It handles beautifully at all levels of fuel, allowing a glider landing on the runway at all weights below 22 tons, and a powered landing above that. It can be a tad heavy in the launch phase, and too much cargo towards the nose will mean it might require a touch of the rockets around 15k to come up sufficiently for the drag to be at good levels. Main weakness is the outboard engines are very far offset from the fuselage, meaning that any flameout on either of them is fatal.

Next step is to see if it can reach Duna! :D

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Name: The Chair

Weight: 2.85 tons

Parts: 24

Pics: Here


Re-entry effects combine with sound-barrier condensation to create a heckuva fireball.


Jebediah's having the time of his life.

Edited by sploden
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Name: Hummingbird

Weight: 1.88 tons

Parts: 35

Pics: Here

This one is tough. I had 0.30 units of liquid fuel left after circularization, so I had to do an unpowered landing after several quicksave reloads to get the aim right, because after the deorbit burn the craft circles the entire planet again in the high upper atmosphere before slowing down enough to land at KSC.


Edited by sploden
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That's amazing sploden!

Now if only there was a way to vent excess oxidizer. Would make it more practical to fly.

Turn off Liquid fuel and leave the LFEs on. It will drain Oxidizer.

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That's the same mass as my minimalist holder from 0.19, which should still work perfectly fine: http://imgur.com/a/yY9Ht#0

Ant engine is lighter than the 24-77's, and delta-deluxe wings have the best lift-mass ratio. I could cut the Oscar-B tank and several of the wings and intakes and it should still work. I'll have to try that burning off oxidizer trick, I didn't think engines use oxidizer if they're liquid fuel deprived.

Edited by tavert
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Okay here is MinLKO 6d, my updated 0.20 minimalist entry: http://imgur.com/a/5W38d#0

This was 1.68 tons, and there's still a little bit of room for improvement. Could definitely replace one of the round-8 tanks with an oscar-B, maybe both if I burn off all but 2-3 units of oxidizer first. Dropping from 4 to 2 intakes may still work, not sure.

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Thanks for your mission reports, some ingenious designs and extraordinary accomplishments. Congratulations to all K prize winners, I have updated the guest list so that Kay Kool's backstage aperture operatives will be apprised of your status and courteously grant you entry to the exclusive post performance K-Prize party... probably, just try not to wear a black tie as she gets a bit funny about those, starts accusing people of upstaging her. Artistes! pfff what can you do!?

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Here's my new entry after the forum hickup. It's a SSTO plane to Laythe and back. Rear landing gears can be toggled to allow the rover wheels to touch the ground and drive the plane on electrical power, very handy when taxiing, especially on an alien world! The mission itself was pretty straightforward, get off Kerbin on jet power, switch to nuclear when out of atmosphere, circularize and shoot for Jool encounter. When in Jool SOI i lucked out and got a Laythe encounter straight away, so i took it, aerobraked and landed the plane.

When landed I EVA'd and planted a flag (of course) and then drove up the hill. When I found a nice spot for takeoff I turned the plane downhill and took off. Once out of atmosphere I played a bit with manouver nodes, and eventually I got a nice slingshot from Vall. The slingshot took me far away but that was ok, from the new apoapsis it was pretty easy to burn for Kerbin encounter. I aerobraked again at Kerbin, circularized, and burned for de-orbit for pinpoint landing at which point I was out of fuel but luckily the plane glides very well even when out of fuel so I did make it back to KSC safely.

Jeb about to embark on a great journey!


On the beach.


Honey I'm home!


more images can be found in the imgur album here. I know it is against the rules to lose any parts during the flight, but I thought I'd submit this anyway since the parts were lost to a bug of some sort, they just went poof one by one when i was gliding towards the KSC on the final part of my flight. I did not hit ground or anything else, they just poofed. The plane went on flying so I finished the mission as planned. The landing itself was a smooth one.

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