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

[hoioh]

5 hours ago, 53miner53 said:

Honestly, I don’t think it would make a difference, after watching your video and comparing it to how mine went. 

https://drive.google.com/open?id=0B0eMT8zRijNmM0NONHZYR2lYb2c 

center mounted engine was shutdown, and I ended up beginning reentry backwards to use a little monoprop to slow down and make the shuttle more stable. 15t payload(I think, it was 2 rockomax 32s, dry, and 2 large ore tanks, dry, with a couple miscellaneous pieces) ended up running the lifter dry before trajectory was turned around, so I used some OMS fuel to finish that. 

It's a bit hard to see in the screenshots because of the nighttime launch, but the main difference is the engines you have on the stack, like the energia rocket. that makes your vehicle a lot more stable after the engine shutdown. On top of that I didn't shut down a center engine, but one on the side forcing me to shut down another engine. The TWR of the shuttle on launch without the boosters is 0.65 or something, so after the shutdown I'm also short on power upon separation of the boosters. I'll need to see how easily I can actualy get this thing into orbit (which I didn't test prior to the failure test, but it should be possible). I didn't even get out of the atmosphere without the proper propulsion...

[hoioh]

Ok, so it goes to orbit on a regular engine setup just fine, good to know:

 

Mun orbit with payload even, once it's in space it behaves great!

Edited May 1, 2018 by hoioh

[Ozelui]

STS test fligh 2

 

A tricky abort maneuver.  At least it showed me a small detail that I was doing wrong compared with the real shuttle.  In my case the SSME and the OMS drain the same tanks.  Quite important when you are trying to move the COM forward by burning the OMS.

Even with this configuration it is doable, but it makes sense to use a monopropellant based OMS or disable the crossfed in some way so the OMS and SSME burn fuel from different tanks(for the next time).

Edited May 2, 2018 by Ozelui
Typing in the phone with big fingers xD

[michal.don]

On 4/30/2018 at 10:56 PM, hoioh said:

Well, the RTLS abort session is a LOT harder than the 747 launch!

Yeah, it really is.... And, I've got to say, you made it a little easier on yourself   You began the PPA quite soon, and not too far downrange, and you never reached space. The real shuttle would have started the PPA around 130,000 metres, and would consume almost all the fuel in the ET.

But nevermind, these missions are for fun, so, here's your badge:

That being said, I still encourage you to do it "the right way"

 

On 5/1/2018 at 4:53 AM, 53miner53 said:

center mounted engine was shutdown, and I ended up beginning reentry backwards to use a little monoprop to slow down and make the shuttle more stable.

I think that the number of engines matters quite a lot here - when you've got plenty of them, one shutting down is not that much of an issue. In my run, I "broke" one of my three engines, and I chose one on the side. That was followed by some properly difficult flying, as the thing just wanted to go all over the place

Nice flying on your part, so, here's your badge:

[michal.don]

22 hours ago, Ozelui said:

A tricky abort maneuver.  At least it showed me a small detail that I was doing wrong compared with the real shuttle.  In my case the SSME and the OMS drain the same tanks.  Quite important when you are trying to move the COM forward by burning the OMS.

Yep, I had that issue with my shuttle as well... Solved it by burning the OMS after the ET separation, just to get rid of the fuel. Despite not reaching space, your flight looks pretty much like the real thing, good job!

 

Michal.don

[Ozelui]

1 hour ago, michal.don said:

Yep, I had that issue with my shuttle as well... Solved it by burning the OMS after the ET separation, just to get rid of the fuel. Despite not reaching space, your flight looks pretty much like the real thing, good job!



 

Michal.don

Thank you!

About not getting out of the atmosphere, I'm not sure why that's the case.  As you can see the shuttle burned all the LFO in the ascent and braking maneuvers, with just a tiny burst left that I spent just before landing ( because emergency landings and fuel are a fun mix! ).  The highest altitude was 60 km, and my attempted trajectory was more vertical than the usual launch for this bird.

In the ( not recorded ) test flights for the test flight  , without engine failures my shuttle is able to reach a 300 by 300 km orbit, dock with the space station from STS-5 - 8, and go back to the KSC.  Same fuel tanks and everything.   @hoioh 's shuttle can even reach munar orbit.  I can't avoid thinking there is something else at play.

I guess part of the difference is the low thrust and deteriorated control after loosing the SSME, that was expected.  Is KSP atmosphere higher in proportion compared to the real Earth's atmosphere?  Perhaps that's the difference.  Or perhaps the turn to retrograde was too quick?

I'd also like to try the same setup with moar SFBs.  I used a total of 6 during the video, and I'm thinking about using 10 so they fit inside the same fairings.  That setup would depend a bit less on the SSMEs and could probably make the SFB's last longer.  They are configured at 90% thrust currently to extend their duration a bit.

 

 

[michal.don]

12 minutes ago, Ozelui said:

I guess part of the difference is the low thrust and deteriorated control after loosing the SSME, that was expected.  Is KSP atmosphere higher in proportion compared to the real Earth's atmosphere?  Perhaps that's the difference.  Or perhaps the turn to retrograde was too quick?

Well, from my experience from RSS/RO, and "stock" systems, comparing ascent profiles and atmospheres is tricky to say the least.... For the size of the planet, the atmosphere reaches quite high (if atmosphere height would be scaled by the same factor as the planet's radius, it would be more like 14-20 km, not the 70 we have). The orbital speed is quite slow (2,3 km/s instead of ~7,2 km/s for LEO) too. But a bit more of TWR is needed to circularize in LKO, because you don't have as much time to do so on Kerbin. You just can't have 7-minute second stage burn to get to a nice low orbit.

I included the "must go to space" rule because of the real orbiter limitations - no agressive maneuvers could occur while still in denser parts of atmosphere, the orbiter would have been torn apart by atmopheric/structural loads on the vehicle. Some of these things don't translate too well into KSP, I guess..... 

Also, don't forget that the real shuttle had about 400 m/s of delta-V left in tanks after reaching orbit, while around here, we go happily to Duna and back....  No wonder our shuttles behave "a bit" differently.

 

Michal.don

[Alchemist]

Somehow, I ended up inspired for something very overengineered (and what did you expect?). Namely, aerial flight autopilot (with kOS). Not that simple if you consider roll control and necessity to ensure it doesn't do anything too stupid if you order it to turn around. Also added some advanced runway navigation script.

Already incorporated it for my reusable winged launcher (result is not too much different from this earlier recording, but kinda more reliable and with much less mess in return flight script), including some semi-generic landing profile (should be easily applicable to powered crafts with decent lift... just those typically land at about half the speed of this launcher, it lacks a bit in pitch authority department if you go slower). But it's not really how you reliably make unpowered glissade for low lift craft with high AoA capacity...

Yeah, properly pulling that off should require gathering some aerodynamics data in various flight modes and doing some proper maths..

OK, some thinking out loud:

Spoiler

Basically, unpowered landing consists of such phases (in reverse order, since you need to ensure start parameters for each phase):

0: touchdown after you leveled the flight - that actually should be doable with somewhat generic descent speed control
1: leveling out just above the runway (gear+airbrakes deployed, high AoA) , the "don't you crash!" part
I guess it just has to be pre-integrated. The speed determining factor is lift/weight at the final point (some extra speed won't hurt, since lift is proportional to its square, thus you can pull the same curve)
2: Straight  descent, deploying gear (low AoA). I think the angle should be the one where the speed is constant with gear and airbrakes deployed.
If speed is a bit too low, deploying airbrakes can be delayed until the end of the phase
3: turning to allign with the runway - high AoA, high roll. Now here are 4 options (2 ends of runway, clockwise and anti-clockwise turn for both) with different energy costs
Interesting fact: Buran was almost given self-destruct command when the mission control noticed large deviation from predicted trajectory. Then they realized the orbiter chose more costly turn direction to get rid of some extra speed (something they knew of, but considered it to be just several percent chance to actually happen)
4: low-AoA gliding towards landing site
5: reentry part with all the S-turns (high-AoA + airbrakes)

Yup, I'm not going to pilot the test landing on my own

[michal.don]

10 hours ago, Alchemist said:

Yup, I'm not going to pilot the test landing on my own

Because why do it the easy way......

I'm really curious how this will turn out, I have a special kind of respect for people who are able to script their own autopilots - seems almost like witchcraft to me.....

[hoioh]

21 hours ago, michal.don said:

Yeah, it really is.... And, I've got to say, you made it a little easier on yourself   You began the PPA quite soon, and not too far downrange, and you never reached space. The real shuttle would have started the PPA around 130,000 metres, and would consume almost all the fuel in the ET.

But nevermind, these missions are for fun, so, here's your badge:

That being said, I still encourage you to do it "the right way"

Thanks for the new badge @michal.don and the fact that I can keep it although my procedure was not completely "proper"

The reason it ended up like this is because I wanted to have the failure at about t30 (as specified in the mission parameters), but at that point I have not ascended enough to fully make it to orbit with an engine less. If the failure would occur, say 20 seconds later I think I would make it to orbit for a "proper" high altitude RTLS abort.

I tried with a more Energia kind of setup, but that resulted in my overshooting the runway on the way back each and every time, so this got me thinking that this kind of procedure would only be applicable with a Shuttle style launcher and would not be a feasable abort for an Energia setup for which an Abort Once Around would make a lot more sense due to the reduced loss of thrust, percentage-wise at least. But we've also seen @53miner53's procedure which looked quite succesful, so there's that to consider too.

I'm going to see if it's properly doable with my current shuttle setup with a short period in space, fingers crossed!

[hoioh]

Well, that was rediculously hard to get done! I still spun out on the way down because my vertical velocity exceeds my horizontal and I can't find a flight path for this mission that allows me to obtain enough horizontal speed to not spin out (I did like 20 takes or so and whenever I had a successful path I had the spin out).

 

[Alchemist]

9 hours ago, michal.don said:

Because why do it the easy way......

I'm really curious how this will turn out, I have a special kind of respect for people who are able to script their own autopilots - seems almost like witchcraft to me.....

Well, it is a fine balance between calculated predictions and the ability to adjust it on the fly. Not witchcraft, more like a ton of overengineering and some... alchemy

Of course, the biggest issue with shuttle landing is the fact that you can't verify and adjust the critical data in actual flight (unless you do extra maneuvering just for that) before it's too late. So need to have some aerodynamics data to predict some doable (with some reserve, of course) glissade before the actual landing.

 

And looking at the mission profile: the crew shuttle with reusable launcher I mentioned - they can easily fly on the launcher's jets if you don't take all the rocket fuel. Might fly them to  some plausible start position, set the autopilots to kick in on separation, so that the launcher dives a bit and safely flies away while the shuttle navigates to landing (and it really flies no better than my Buran)... and then quickly steer the shuttle off the runway because guess who needs it too

 

[michal.don]

I had a bit of time yesterday, so I finally checked whether another of my ideas is plausible - and it turned out it is.

So, I have a NEW "TEST PILOT" MISSION for you!

 

This one is a bit different, and much much more difficult than the previous ones. What does it include?

 

-Awesome shuttle launch? Check!

-Complex payload design? Check!

-Interplanetary travel? Check!

-SRB "kickstage"? Check!

-Gravity-assist-billiard? Check!

-Ridiculously low fuel margins? Check!

 

This mission requires a lot of gravity-assist planning, and careful fuel management, and will seriously test your navigation skills (I ended up using about ten gravity assists in my run).

 

Ladies and gentlemen, we're going to Jool, Cassini-Huygens style! All the requirements are in the OP, please read them carefully!

And of course, there's never ending glory and a new badge to get

 

I know this mission might seem a bit out of place here, but it serves its purpose, which will become apparent as the "regular" missions progress.

Good luck to you all!

 

Michal.don

 

 

Edited May 7, 2018 by michal.don

[Ozelui]

31 minutes ago, michal.don said:

Ladies and gentlemen, we're going to Jool, Cassini-Huygens style! All the requirements are in the OP, please read them carefully! < snip >

A bold mission.   Just one doughnut?  I find your lack of snacks disturbing...

 

[m4ti140]

Is Cormorant Aeronology allowed?

[hoioh]

HAHA! Guess I'm doing that twice! (again)                              https://imgur.com/a/OpWHYzV

 

Missed a rule there: -The Cassini-Huygens spacecraft + the transfer stage must fit into the long MK3 cargo bay 

And I just used the shuttle I had made for these challenges, guess I'm building a new shuttle then!

Anyway, it was a fun mission!

[michal.don]

15 hours ago, Ozelui said:

A bold mission.   Just one doughnut?  I find your lack of snacks disturbing...

It sure is a more ambitious project than the previous ones, no doubt about that.... It might keep you guys busy for a few days, at least I hope so  Despite the insufficient snacks allowed on the vessel, it is doable, but the margins are not very large....

 

13 hours ago, m4ti140 said:

Is Cormorant Aeronology allowed?

Welcome to the challenge!

Yes, pretty much all the balanced mods are allowed here! Using a part mod will place you into a "modded" category, you can take a look what people have come up with so far, some of the shuttles here are very interesting. I hope to see your entry soon, good luck!

 

12 hours ago, hoioh said:

Missed a rule there: -The Cassini-Huygens spacecraft + the transfer stage must fit into the long MK3 cargo bay 

That was a very nice mission! But, as you noticed, one of the requirements was not fulfilled.... Sorry.

But, you do not need to design a new shuttle - you can use the one you already have, just design the payload so it can fit into the MK3 cargo bay, and then you can take it to orbit in your old design!

 

Michal.don

[hoioh]

47 minutes ago, michal.don said:

That was a very nice mission! But, as you noticed, one of the requirements was not fulfilled.... Sorry.

But, you do not need to design a new shuttle - you can use the one you already have, just design the payload so it can fit into the MK3 cargo bay, and then you can take it to orbit in your old design!

Thanks! I was rather proud of the similarity with the actual ting, but yeah, too long...

So I'll need a stubbier design for the solid boosters and I'll need to see if the Huygens probe can fit on the side like that with the counterweight opposite. Other than that, in this case if I say, make a smaller booster with the same DV and manage to fit it into a MK3 cargo bay would you excuse me for not doing the whole mission again, but just the Jool encounter? (If the fuel levels on arrival are similar enough ofcourse)

 

[michal.don]

Just now, hoioh said:

So I'll need a stubbier design for the solid boosters and I'll need to see if the Huygens probe can fit on the side like that with the counterweight opposite. Other than that, in this case if I say, make a smaller booster with the same DV and manage to fit it into a MK3 cargo bay would you excuse me for not doing the whole mission again, but just the Jool encounter? (If the fuel levels on arrival are similar enough ofcourse)

Fair enough  But maybe, not just the Jool encounter, but at least an elegant gravity-assist-capture into Jool's SOI, and, if you design a new lander, land it on Laythe? Do we have a deal?

[hoioh]

2 minutes ago, michal.don said:

Fair enough  But maybe, not just the Jool encounter, but at least an elegant gravity-assist-capture into Jool's SOI, and, if you design a new lander, land it on Laythe? Do we have a deal?

I'll take that deal, let me check if the probes at least fit into a MK3 bay, if I don't have to adjust them the rest should be fairly easy to perform and obviously by "Jool encounter" I mean SOI capture similar to one from the first mission

[hoioh]

There, how's that? https://imgur.com/a/TgoZU98

Had to make some minor adjustments to the Huygens lander (for the better of it, it will land on it's legs this time around) to make it a little bit shorter without changing the weight and it fits! Also, shorter, stubbier boosters with pretty much identical DV on the boosters and no change to the probe's DV

[hoioh]

Not as good as the first transfer, This was an inferior window because of the planar difference between Jool and Kerbin at this point:

But still a succesfull launch for Jool and landing on Laythe, in the sea this time around and the right side up for a change

[michal.don]

23 hours ago, hoioh said:

There, how's that? https://imgur.com/a/TgoZU98

This time, I have nothing to add, really nice mission, so you're the first to get the badge - congrats!

 

Michal.don

[hoioh]

1 hour ago, michal.don said:

really nice mission, so you're the first to get the badge

YAY!  It's really too bad I missed the rule about the size there, it would have been great if I did that correctly right from the get go because the initial transfer window was beautiful with aligned planes and everything

Thanks for the shiny new badge!

[Mr. Peabody]

Having never built a shuttle before I thought I'd give it a try. Screenshots in spoiler.

Spoiler

 

                                                      On the pad                                                                                                                     Liftoff!

 

                                                     Gravity turn                                                                                                          Booster separation

 

                                                   Circularization                                                                                              

 

                   Secondary booster separation (later in the flight)                                                                            Orbiter in orbit

 

                                   Re-entry (approach to the KSC)                                              Down and safe. It landed on the runway but came to a stop here.

 

                                          It's still on the runway*                                                                                               Sherald pre-flight     

I hope this counts as a runway landing. Being my first time ever doing this I slightly overshot and ended up with not quite enough runway for braking.