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

[Kryten 2X4B 523P]

Ive been meaning to have a go at this for a while - So I did!

I've been playing with Rapier based spaceplanes, trying to work up a usable single engines crew transfer vehicle - and ended up with the Slingshot Mk 1 (below)

 

 

I dont do imgur, but I've got a full write up & screenshots over at my blog here : http://krytenskerblog.blogspot.co.uk/2016/07/k-prize-challenge-attempt-113.html

 

[something]

Saw this challenge only recently and had to give it a go.

When I came up with the idea of building a space plane capable of delivering crew and/or satellites into LKO, I tried to build a small spaceplane. The result was a 55.040 t vessel which was consequently christened Mjölnir as it literally was a hammer in the sky creating a lot of thunder with its four RAPIER engines. Length 24.3m  - Width 10.3m - Height 5.9m. Dorsal solar panels create the needed energy during descent when the remaining panels need to be retracted. Craft file can be provided upon request.

 

https://postimg.org/image/74pt7hq1z/

The Mjölnir on the runway - time to wait for the Kerbin Space Station to align is used to do some preflight checks. Apparently the navigation lights are fully functional.

https://postimg.org/image/51fdztq93/

Take off...
https://postimg.org/image/ijmac42ef/

The small white dot in the sky on the star side of the cockpit - that's Minmus.

https://postimg.org/image/b4wyjqgiv/

The KSC looks pretty small from that distance...

https://postimg.org/image/qro7x3uav/

Ascend profile gives rise to minor heating.

https://postimg.org/image/5kkh93hnr/

Seems we took off a little too late...KSS is gonna be ahead of the Mjölnir.

https://postimg.org/image/wwfqafmef/

Solar panels extended, cargo bay doors open - the Mjölinr in its full glory.

https://postimg.org/image/z2a14xpuv/

Those red and green lights come in handy when docking on the wrong side of the planet...

https://postimg.org/image/3wpx86t5z/

Closing in...

https://postimg.org/image/rc7udjcx3/

...and docked. The KSS grew over time and looks a little bit messy.

https://postimg.org/image/52tx6zhgn/

Undocked and preparing for de-orbit burn.
https://postimg.org/image/kctse6cyv/

Aiming for the KSC

https://postimg.org/image/kqv4drx2f/

Deorbit was during night...
https://postimg.org/image/er7da4c9z/

...so that re-entry...
https://postimg.org/image/rwmvg865j/

...provides a nice sunrise.

https://postimg.org/image/rl5f3gppj/

A high angle of attack provides maximum acceleration during re-entry. With 5.7 km/s dV left it should be no problem at all to land on the runway.

https://postimg.org/image/5ahk3hsfb/

Changing the angle of attack allows to chose the optimum landing destination.

https://postimg.org/image/uuofno36v/

Intercepting the KSC runway marker.

https://postimg.org/image/qmtnex1rb/

Cannot extend while stowed...yeah sure - the bow gear is stowed? - So either land in the water or open the cargo bay to lower the gears. Probably the most Kerbal of all features...

https://postimg.org/image/mrq9ccilj/

Wow, way too far. Missed the big white bar by almost half a runway...too bad.

https://postimg.org/image/j9e9fyhpj/

Doesn't matter - the Mjölnir has brakes, you know?

https://postimg.org/image/uzs6xcahz/

Ladies and Gentlemen, we just landed at the Kerbin Space Center. Please remain in your seat until we reached our final parking pos...what do you mean it is our final position?
https://postimg.org/image/w3cb9av53/

Apparently, nothing fell off....

[W. Kerman]

I did it, but didn't know how to upload mac screenshots, should be here now . Opps! Sorry, will make spaceplane, not rocket next weekend!

 

 

 

 

 

Edited July 19, 2016 by W. Kerman
Misunderstood

[W. Kerman]

Did the math, and my rocket weighs 172.8 tons on the pad. 52.8 landed. *Not accounting for atmosphere and gravity changing as you go higher, because that is a pain in the bum, my ROUGH estimate is the following

Stage one-center engine

Delta v= 315*9.81*Ln(172.8/64.8)=1316 m/s

 

Stage two-nuclear drive= 698 m/s ?????

 

http://wiki.kerbalspaceprogram.com/wiki/File:KerbinDeltaVMap.pngTotal delta v 2014 m/s

Conclusion, seeing as this number is HIGHER than it should be*, but is lower than is required according to this delta V map "http://wiki.kerbalspaceprogram.com/wiki/Cheat_sheet".

Now I do know that delta v maps are rough estimates of the required amount. But being 1.3 kilometers short is ridiculous. HOW THE HECK DID THIS THING GET INTO ORBIT?!?!?

Also my nuke engines used up half of their fuel for 600 m/s burn to orbit, so 1200 m/s seems rational, so did I mess up calculations, methinks moar thinking required...

[something]

You have two stages and you have varying specific impulses as you transfer through the atmosphere. The higher you get, the higher your Isp gets and hence the more dV you have at hand. You have two stages so you need to calculate at least two different values for you dV (one for the lower stage, one for the upper stage); furthermore, I do not have a clue how you do end up with these 1316 m/s in your calculation.

172.8/64.8 = 2.6666 which is almost e. Consequently ln(172.8/64.8) is approximately ln(e) which equals one. (Turns out that ln(172.8/64.8) = 0.98 in fact).

So your delta V should be around 315 s * 9.81 m/s**2 = 3090 m/s (turns out the correct value is 2845 m/s)

[W. Kerman]

1 hour ago, something said:

 furthermore, I do not have a clue how you do end up with these 1316 m/s in your calculation.

With the things I was factoring out, i.e. the atmosphere, and changing surface gravity, I should have gotten a HIGHER delta v. Retesting using google calculator.

Thanks!

[W. Kerman]

You do not want to see how many tabs I have open right now

[SuicidalInsanity]

Having entered a Gatecrasher entry a while back, I figured it was about time I did this challenge for real with a legitimate entry, so I present the SSTO Aircraft Carrier Tower of Babel:

I probably could have made it back to the KSC, but uncertainty about being able to hit a target as small as the KSC runway in an aircraft that handled like, well, a carrier, coupled with impatience - the MET flight time was something like 15m to orbit; with an IRL time closer to an hour - led me to abort and land early in the desert somewhere. The last three images aren't part of the challenge, I just threw them in for fun to show that it can actually function as advertised.

 

Edited July 20, 2016 by SuicidalInsanity

[boolybooly]

Congratulations to...

 

Kryten 2X4B 523P Advanced Pilot Precision Award 1st Class with Slingshot Mk1 SSTO.

something Advanced Pilot Precision Award 1st Class with Mjölnir.

SuicidalInsanity with Tower of Babel.

 

... for completing the K-Prize mission successfully with your researched and honed designs. Thankyou for your mission reports and welcome to the K-Prize party guest list aka the roll of honour.

If you came up with a lift off weight SuicidalInsanity then the Tower of Babel might be a maximalist contender.

 

 W.Kerman sorry to say that entering a rocket for a spaceplane challenge is definitely gatecrashing! So I linked your mission report appropriately, plus your complimentary quip! Hope you like it, you have the choice to remove it if you complete a bonafide K-Prize mission successfully in this version, or leave it, its your choice.

 

 

 

[Kryten 2X4B 523P]

Very enjoyable challenge, thanks :-)

[something]

Yeah, was a fun challenge. I never had a doubt that Mjölnir was a state of the art precision instrument which comes at surprisingly low weight

[SuicidalInsanity]

14 hours ago, boolybooly said:

If you came up with a lift off weight SuicidalInsanity then the Tower of Babel might be a maximalist contender.

it was 1269.85 tons at launch according to the SPH engineering report. Not sure what a loaded max cargo weight would be; at 490 parts by itself, attempting a Utilitarial commendation was more or less out of the question.

[boolybooly]

In which case Tower of Babel is deservedly the current maximalist record holder.

 

 

 

 

Edited July 28, 2016 by boolybooly

[RonnieThePotato]

For those who are having troubles making an SSTO.

http://wiki.kerbalspaceprogram.com/wiki/Tutorial:Basic_SSTO_Design

Good luck!

[rocketbuilder]

Does anyone know if exposed drills count as extra drag?

[Empress Neptune]

I recently modified a few SSTO's to work with 1.1.12 and also took the time to eliminate some of their undesirable quirks. I think now they are ready to be K-prize certified.

 

The 85 ton payload S-840

https://kerbalx.com/EmpressNeptune/S-840B-HSSTO-PLUS

 

 

 

And the slightly smaller 45 ton payload S-640

https://kerbalx.com/EmpressNeptune/S-640B-HSSTO

 

More images on Kerbal X. They can both reliably hit KSC from orbit, and the S-840 has been to Mun orbit, though I never landed that mission as these spaceplanes are designed as lifters rather than long range transports. I'm currently testing a version of the 840 with nuclear engines. I've been able to get 36 tons to LKO with 3000 dv remaining.

 

 

 

Edit:

 

No luck on getting my video to record, so I made an album instead. S-840 taking 85 tons of bricks to orbit

 

[imgur]8Rrv2[/imgur]

 

It looks like that is not working either. So direct link:

 

http://imgur.com/a/8RrV2

 

 

Edited July 30, 2016 by Empress Neptune
Add album

[Kergarin]

After a lot of testing... made possible the impossible... here comes antoher SSTO from Kergarin Aerospace : the Stearwing A300 SSTO  taking 20 Kerbals to Orbit, based on the stock Stearwing A300

 

 

Edited July 29, 2016 by Kergarin

[Maverick_aus]

On 28 July 2016 at 8:46 AM, Kergarin said:

After a lot of testing... made possible the impossible... here comes antoher SSTO from Kergarin Aerospace : the Stearwing A300 SSTO  taking 20 Kerbals to Orbit

Bravo, @Kergarin. Brilliant.

Here's my old ship, the ASS Mandos which served STS duties in 1.0.x. Hauled plenty of gear into space. Even wrote a kOs script to drive to orbit auto-magically. THAT was one of the most rewarding (and hard) things I've done in KSP. Sure, it's overpowered, and not very efficient, but I was so proud of that.
I should dust it off and do a proper entry here. (Well, when I finish my current Elcano attempt, and various other bits n pieces.) See how it goes in 1.1.x

Edited July 29, 2016 by Maverick_aus

[boolybooly]

I will look forward to seeing your mission Maverick_aus, in the meantime it is prize giving once again.

So congratulations are due to... 

Empress Neptune Utilitarial Commendation (85t), Advanced Pilot Precision Award with S-840.

Kergarin Advanced Pilot Precision Award 1st Class with the Stearwing A300 (undercover) SSTO.

... for completing the K-Prize with special distinctions itemised above. Thanks for your mission reports. Ore containers were a nice touch Empress Neptune and I liked the IVA scene Kergarin. Welcome both to the K-Prize party guest list aka the roll of honour. 

[McQuacker]

My SSTO spaceplane has already visited Minmus, the Mun, Duna, Ike, Dres and Laythe, where it is currently landed. I plan to visit Vall, Bop, Pol and Eelo and probably Gilly and Moho as well before landing back at KSC.

forum.kerbalspaceprogram.com/index.php?/topic/146167-ssto-grand-tour-flight-of-the-decade-thrush

[boolybooly]

Looks like a very big spaceship McQuacker and laudably ambitious mission. Thanks for sharing.

If you want it linked on the front page it will have to be as a gatecrasher because refuel is excluded for K-Prize missions.

Unless you want to do a K-Prize mission (see front page for rules) in which case you can include the grand tour link in your own K-Prize mission report post and the K-Prize committee (me!) can award the prize since a successful K-Prize mission cancels out a gatecrasher. Up to you.

[McQuacker]

I'll do a real K-prize mission then I'll post it here when it's done.

[Mycroft]

Yes! I just made a successful SSTO, took it to LKO, and landed back on the runway! First time I ever landed on the runway! I’m so happy! Anyway, I’l make an official submission with profuse screen shots tommorow.

[Mycroft]

I had only ever made one successful stock SSTO before this, and in an earlier version, so I decided to try again for this thread. I designed a craft I like to call the Shooting Star.

Here she is in the SPH: 

Not the prettiest craft around, but she works! Piloting our history-making craft today will be Megan Kerman, and co-piloting will be Katlian Kerman.

On the runway, she sits pretty low: 

Starting out we have four ‘Whiplash’ Turbo Ramjet engines, giving us a good boost. She’s rather squirrelly on takeoff: 

But we got off the runway with out mishap, pulling up at around 100 m/sec: 

Trying to ascend around 20 degrees, so we have slight acceleration and increasing engine power: 

Once we passed above 10,000 meters the engines began to fade, so Megan leveled off to gain some speed: 

Quick fuel levels check: 

Everyhing’s nominal! We are gaining speed fast! 

A few seconds was enough, now to really pitch up! 

The engines are fading, so Megan engaged the rockets.

Once the whiplashes flamed out, the intakes closed.

No turning back now! The Whiplashes seemed to have used up the fuel in an asymmetric fashion, so we had to pump some fuel around to achieve balance. 

Finally! A suborbital trajectory! 

Katlian got bored while waiting for the apoapsis burn, so she cracked out the snacks. Meanwhile, they became the first Kerbals to leave the atmosphere in a stock SSTO:

Another quick fuel check: 

And then, history was made! Megan and Katlian became the first Kerbals to reach orbit in a stock SSTO!

But the mission is not over yet! They must still return to the KSC. Katlian designed the most fuel efficient de-orbit burn possible, after having completed one orbit: 

Megan executed the burn without a hitch: 

Once the burn was complete, Megan assumed re-entry position: 

The KSC required a fuel check at this point, and Megan thought it wasn’t necessary, so Katian did it: 

Meanwhile, Megan targeted a vessel at the KSC: 

Upon re-entry, Megan realized she had forgotten to transfer fuel forward to adjust the COM: 

Never before had fuel transfers seemed to go so slowly: 

Suddenly, Megan realized that they were in sight of the KSC, leading to some desperate aerobraking maneuvers.

Fortunately, they slowed down in plenty of time. 

Katian extended the landing gear for extra aero-braking capacity:

Megan lined up a nice approach: 

Landings always made Katian nervous, so she was not able to help:

Megan was on edge, but mostly just tried to focus. A little too nervous apparently, since she flared too early.

Otherwise, the landing went fine: 

Megan’s nerves began to tell, and she landed slightly off-center, but still on the runway: 

Megan was wondering why it took engine power to taxi, until she saw that Katian had left the parking brake on. 

Katian: “Megan! you forgot your turn signal!"

Megan: [shakes head]

Megan and Katian Kerman will forever be remembered as the first Kerbals ever to achieve orbit in a stock SSTO, re-enter, and land back on the runway.

Picture time!

[Mycroft]

I literally just now realized that the name of my SSTO is the same as @eloquentJane's.  Sorry. I thought it was unique when I came up with it a week ago.