Shuttle Challenge v5 - The STS thread [Stock and Mod Friendly] - MAJOR CHALLENGE ANNOUNCEMENT! - 30.3.2020

[sturmhauke]

Yeah Goliaths don't like supersonic speeds very much.

[Kerbolitto]

10 minutes ago, sturmhauke said:

Yeah Goliaths don't like supersonic speeds very much.

I think I've never pushed them beyond the sound barrier

[Kerbolitto]

STS 1T

 

Here's the review of one of the few remaining challenges ...! I used a very powerfull plane to boost the spaceplane at almost 7000m from the Airfield Island, then slowly glided Artisan-shuttle on the edge of the runway. Everything went fine since I spent quite some time refining the wing design, many STS missions ago.. I just restarted once because I headed full north to align the shuttle on the runway.

 

 

Spoiler

Ready to take off (using the lovely thrust reverser of Goliaths) : the carrier has its tanks half full, the shuttle was dry.

Second before detaching :

Shuttle is on its own :

Slowly gliding into thicker atmosphere :

Almost finished turning onto the runway : had to retract aft elevator due to sensible pitch

Flare in front of runway :

Flight results

 

STS 2 Abort : I can't do the ascent while shutting the engines early and hit space, lifter has not enough thrust ...! Is it possible to shut them later?

Edited October 3, 2018 by Kerbolitto

[Kerbolitto]

STS 2 RTLS Abort

 

I'm on a roll this evening Finally made STS 2RTSL after second attempt, I used the shuttle as a giant airbrake and it went just fiiiine...! The lifter lacked thrust to cut engines early and still make it into space, so ... I added more boosters, and then I multiply them by 2, and it felt good.

 

 

Spoiler

Ascent profile right after detaching SRBs, just before serparating the whole ascent stage from the shuttle :

Shuttle stats :

Burning retrograde, then on the horizon more or less :

Hitting atmosphere as a big airbrake :

Artisan finally able to pitch up into lower atmosphere, using RCS as support :

Slowly gliding to KSC, Lift/drag ratio is still okay !

Flare just short of the runway

 

 

Edited October 3, 2018 by Kerbolitto

[sturmhauke]

14 minutes ago, Kerbolitto said:

The lifter lacked thrust to cut engines early and still make it into space, so ... I added more boosters, and then I multiply them by 2, and it felt good.

Yes, that is the true kerbal way.

[sturmhauke]

I see now why the NASA shuttle engine arrangement makes sense, and why I'm having so much trouble with the Buran-style arrangement:

I use the RCS Build Aid mod a lot. It's not just for RCS though, it also has readouts for engines and parachutes.

Look at the line of the CoM as it goes from full tanks (yellow) to half (orange) to dry (red). It doesn't lead straight down like it would on a traditional rocket, or even to the edge of the core booster - it leads through the rear of the orbiter. The result is highly variable torque from the thrust vector, even more so than with the NASA arrangement - on the order of tens of meganewton-meters.

I was trying to use the NF hydrolox engines, partly for coolness and partly for historical accuracy, but they don't have enough gimbal to deal with that much transverse CoM movement. Differential throttle limits might work, but that sounds tedious. I could also move the orbiter further up the stack, but that looks goofy. I might have to switch to Vector clusters.

[michal.don]

On 10/3/2018 at 2:49 PM, Kerbolitto said:

EVE STS 1

Silly me, it never occured to me to use a Kerbin-Eve-Eve aerobraking-enhanced gravity assist, a pretty good idea there! It sure helps with the heating problem. Nice two-stage probe design, too. And the pool cooling in the end is  really nice touch, I love it  So an Eve badge for you, congrats!

20 hours ago, Kerbolitto said:

STS 1T

A routine mission for a pilot as experienced as you, I'm sure  Anyway, good flying, and a confirmation that your shuttle, in fact, flies  



19 hours ago, Kerbolitto said:

STS 2 RTLS Abort

This one sure is a bit trickier, but a nice case of "moar boosters" seemed to help here....  The trajectory was a bit steep, but in your LV configuration, I think it's a must.... So, a third badge for you today:



3 hours ago, sturmhauke said:

I see now why the NASA shuttle engine arrangement makes sense, and why I'm having so much trouble with the Buran-style arrangement:

Well, the Buran had the engines on the rocked tilted, too, and the boosters compensated for the early CoM in the early stages of flight.... A similar solution, just from the other side....  

About the engines from NF - please, could you share their properies with me? I'd like to check if they are not too OP. Thanks!

Michal.don

[Kerbolitto]

1 hour ago, michal.don said:

Silly me, it never occured to me to use a Kerbin-Eve-Eve aerobraking-enhanced gravity assist, a pretty good idea there! It sure helps with the heating problem. Nice two-stage probe design, too. And the pool cooling in the end is  really nice touch, I love it  So an Eve badge for you, congrats!

 

A routine mission for a pilot as experienced as you, I'm sure  Anyway, good flying, and a confirmation that your shuttle, in fact, flies  



This one sure is a bit trickier, but a nice case of "moar boosters" seemed to help here....  The trajectory was a bit steep, but in your LV configuration, I think it's a must.... So, a third badge for you today:



 

Thanks michal

STS Eve : I had no choice to fly 2 times through Eve because the shuttle I choose had those big Bobcats hanging behind, and they really don't like heat The SSTO version would have been better.

STS 1T : No problem here, the wings were configured to (barely) land the shuttle with 40t. payload and its full tanks.

STS 2T : Actually, I think a more regular ascent would have been possible by putting lots of controls at the base of the SRBs. Main problem is that 1st stage has very little thrust and dV, Ap doesn't get above 70k. until maybe 2 minutes of flight ...!

5 hours ago, sturmhauke said:

Look at the line of the CoM as it goes from full tanks (yellow) to half (orange) to dry (red). It doesn't lead straight down like it would on a traditional rocket, or even to the edge of the core booster - it leads through the rear of the orbiter. The result is highly variable torque from the thrust vector, even more so than with the NASA arrangement - on the order of tens of meganewton-meters.

Looks like yellow / orange / red CoM are inline, is it not possible to align CoT +/- on the same line, and use the deviation to slowly achieve your gravity turn ?

[sturmhauke]

1 hour ago, Kerbolitto said:

Looks like yellow / orange / red CoM are inline, is it not possible to align CoT +/- on the same line, and use the deviation to slowly achieve your gravity turn ?

That's the thing, Buran-style means the main engines are off-axis with that line because they're not on the orbiter, which is pulling the CoM to the side.

3 hours ago, michal.don said:

Well, the Buran had the engines on the rocked tilted, too, and the boosters compensated for the early CoM in the early stages of flight.... A similar solution, just from the other side....  

Yeah, I've tried messing with the engine angles, with the core engines pointed more at the dry CoM and the strapon boosters pulling the overall thrust angle more towards the wet CoM. But at some point there's always thousands of kN-m of torque to deal with. I've been trying to minimize torque for post-booster separation, when the shuttle is nearing orbital insertion, but that's where the gimbal problem comes in.

Quote

About the engines from NF - please, could you share their properies with me? I'd like to check if they are not too OP. Thanks!

The general theme of the Near Future mods is that stuff is somewhat more advanced and versatile than stock, but not tremendously OP. There are also more tradeoffs to worry about. Like for my Buran problem, the closest equivalent to the Vector engine and its 10.5 degree gimbal is the Kite, which has only 4 degree gimbal. All the other NF engines have less gimbal than that. Anyway, I put together this little comparison album with the Vector, Kite, and one called the Odin which uses liquid hydrogen.

https://imgur.com/a/U33rjq6

Edited October 4, 2018 by sturmhauke
clarification

[Mr. Peabody]

On ‎10‎/‎2‎/‎2018 at 10:49 AM, Kerbolitto said:

 

Cockpit looks familiar for some reason...

[sturmhauke]

7 minutes ago, The Dunatian said:

Cockpit looks familiar for some reason...

It's from Nertea's Mk IV Spaceplane mod. I think he said somewhere that it was inspired by 60s sci-fi, so that would make sense. There are some Thunderbird ships based on the mod on KerbalX, even.

[sturmhauke]

So it turns out the solution is to use smaller diameter tanks for the core booster. (Or I guess a smaller orbiter, but who wants that? ) The tanks I had before were causing the CoM to shift sideways more as the fuel burned, because it started farther away from the orbiter.

@michal.don, have you made a decision about the NF engines yet? I know admins of several other challenges have considered them to be balanced, but of course it's your call.

[michal.don]

14 minutes ago, sturmhauke said:

have you made a decision about the NF engines yet?

Sorry for the slight delay, did not see your post until now.

I'll allow the use of those two engine types - they are certainly more capable than stock ones, but it's not too excessive. But, please, don't push the envelope looking for even better engines  This is probably as good as I'd allow.

Michal.don

[sturmhauke]

48 minutes ago, michal.don said:

Sorry for the slight delay, did not see your post until now.

I'll allow the use of those two engine types - they are certainly more capable than stock ones, but it's not too excessive. But, please, don't push the envelope looking for even better engines  This is probably as good as I'd allow.

Michal.don

Cool, thanks! So those aren't the only engines in the NF mods, that was just an example. But they all follow the same pattern of being a bit better than the stock equivalent.

[sturmhauke]

I'm gonna finish the actual mission later, but here's a little preview:

Spoiler

 

[Kerbolitto]

Damnit, almost done STS Cassini except I used 2 small drogue chutes for Huygens, turns out they really REALLY suck at slowing things !

[sturmhauke]

Drogues are useless for something as small as Huygens. Where they come in handy is on something like a heavy booster, to slow it from supersonic to subsonic before the main chutes.

[Kerbolitto]

1 hour ago, sturmhauke said:

Drogues are useless for something as small as Huygens. Where they come in handy is on something like a heavy booster, to slow it from supersonic to subsonic before the main chutes.

Yeah I only use them for very high speed aerobraking, but I thought they'd be capable of slowing a 0.3t. lander .. Anyway I redesigned everything, I'm trying to make something cool as this is the last STS mission !

[Petrovich]

On 10/2/2018 at 7:11 AM, michal.don said:

But before awarding the badge, I'll have to ask for a few more screenshots. Could you please provide screens showing:

- the final orbital parametres of the fuelpod orbit? (Ap and Pe to check the tolerances)

- the resource tab of the pod (just to make sure you did not use any fuel from the pod)

Thanks!

So I went back to get the screenshots needed, and found that I accidentally used some of the monopropellant in the fuel pod on ascent.

SO, I redid the mission a proper

STS-1B **CORRECTED** - https://imgur.com/a/HkJckNn       STS-1B **DOUBLY CORRECTED** - https://imgur.com/a/XqCzhRh

Sorry for the goof

Edited October 13, 2018 by Petrovich

[sturmhauke]

Finally finished STS-1a and -1b! Balance is hard, you guys.

Full album: https://imgur.com/a/obHs2ya

Spoiler

 

[Kerbolitto]

Bustard, not bad

[sturmhauke]

Thanks, lol. I tend to name my planes (shuttles too) after birds. There was also a cargo ship class called the Bustard in EVE Online.

[Kerbolitto]

STS 3T Cassini-Huygens

 

I wanted to design something special for one of the last mission of STS Challenge. I went with a heavy probe (almost 5t.) and packed the cargobay to the limit, I even had to add a trunk to the Artisan shuttle to fit a RCS bike .. This challenge took some time, as I had 2 failed Laythe landers due to excrementsty parachutes, so on the 3rd attempt I went all out with wings and a big 'chute. I also tried to use the ship as a real shuttle and not a fairing with wings, this meant quite some time in the SPH trying to figure how to place docks and stuff.

I hope you will like this time because the creation process took me some brainpower !

Cassini-Huygens injector stage :

It's made of 6 Hammers docked on a structural plate and it has 1919dV. Engines are set at 20% thrust only because the probe is a bit ... asymetrical , burn time is almost exactly 2 minutes.

Cassini :

The probe's weird shape was dictated to minize torque because of the electrical boom, with an RTG at the top. It features a probe control, Communotron 88-88 (would have love to use the big relay instead ..!), 4 Doughnut tanks, 2 Sparks, lots of batteries and a Science Experiment. Don't know the exact dV, I'd say 800m/s maybe.

Huygens :

Huygens is a buyoant lander, it has a big heatshield, 2 Science containers for buyoncy, and every experiments that could be fitted under the service module. It is also devoided of engine and was designed to be set on a crash course with Laythe (for fun).

 

Part 1 : Launch

 

Nothing special here, engines were lit up, and at some point it went into space ! I used Nervs to raise orbit at 110x110 before openning the bay.

 

Spoiler

Shuttle stats :

 

Part 2 : Assembly

 

Valentina goes to the RCS bike after openning the trunk

Cassini-Huygens is detached before being repositionned on the shuttle to facilitate assembly

Hammer free to go, one after the other

4 .. 5 .. 6 .. Nothing's missing !

The RTG boom is assembled before detaching the probe, then docked on the remaining port

 

Part 3 : Artisan's landing

 

 

Spoiler

Deorbit maneuver :

Getting a bit hot at low altitude :

 

Part 4 : Jool injection, capture, Huygens drop

 

 

Spoiler

Planned maneuver :

Deep space maneuver : the probe is set on a crash interception with Laythe

 

 

Part 5 : Huygens goes in the water

 

Huygens experimented a harsh re-entry, its trajectory was leading almost to the moon's core ! It is now a happy buoy.

 

Spoiler

Re entry performances : just a bit above 100G

Few meters before splashdown :

 

Part 6 : Cassini goes everywhere !

 

Doing flyby around Jool does not require lots of dV, it's just a bit of acrobatic maneuvers to fly from one moon to another ! The probe had lots of fuel so I forced things a bit instead of waiting years for a perfect encounter.

 

Spoiler

Capture correction after detaching Huygens !

First maneuver : almost perfect here. Passing Vall at 12k meters, change of inclination later to meet Pol a few orbits later, then a normal burn which set a direct encounter with Bop ! Only problem was that 2 encounters with Laythe did not appeared, so I had to modify things a little.

This is the correction maneuver after passing near Vall : It's a bit more costly than what was planned above but I was able to meet Bop using the same technic.

 

Part 7 : End of the mission, using Jool surface

 

 

Spoiler

Crashing on Jool required 2 Tylo's flyby : Second pass happenned below 3000m.

 

That's it for this one ! It was nice to see Jool again, I may restart a career to explore all those beautifull moons..

Edited October 7, 2018 by Kerbolitto

[4x4cheesecake]

@Kerbolitto You got a nice solution to fit everything into the cargo bay the whole mission looks pretty solid (like usual ) but I'm afraid you put too much fuel on your probes Just a single tank is allowed for each probe. I know this is a huge challenge and you definitly put a lot of time and effort in it, but I wouldn't be surprised if your entry will be rejected

@michal.don You may want to edit the challenge description to make this a bit more clear. Maybe write it in words instead of using a number, like this:

Quote

The only fuel tanks allowed on the spacecraft and the lander are: a single R-12 "Doughnut" (left) for the Cassini probe and a single "Oskar-B" (right) fuel tank for the Huygens lander

Right now, you can easily miss the '1' in front of the tank name.

[michal.don]

On 10/6/2018 at 10:06 AM, Petrovich said:

So I went back to get the screenshots needed, and found that I accidentally used some of the monopropellant in the fuel pod on ascent.

SO, I redid the mission a proper

I hate to bring bad news, but there are two major issues with your mission... First - the orbiter must land (at least mostly) intact. And losing your wing is too much damage to be considered success. And second - your orbit is not within the tolerances - at this height, the Ap and Pe must differ by less than 100 m. So, I'm sorry, but I can't award you the badge (which I'm not happy about, I really like your shuttle).  

On 10/7/2018 at 12:00 PM, sturmhauke said:

Finally finished STS-1a and -1b! Balance is hard, you guys.

Looks like you got the hang of it, this is how you do it  Nicely flown, orbit within tolerances, and KSC landing - that's two badges for you.

Congratulations!

On 10/7/2018 at 7:47 PM, Kerbolitto said:

STS 3T Cassini-Huygens

While I love your approach to this mission - the in-orbit assembled transfer stage, and the overall payload design - I can't award you the badge for reasons stated by @4x4cheesecake above: you have too many fuel tanks on your probe. you can only use 1 on the probe and 1 on the lander. I'll edit the rules in the OP so it's more obvious, it might not stand out as much as I thought it did. So, I'm sorry, but no badge this time.

 

Michal.don