[0.24.2] TiberDyne Aerospace R&D Division - Shuttle System 3.6 Career Update!

[Tiberion]

It sort of works. It's being replaced in the next version though, probably by ZRMs control mod.

[Chestburster]

It sort of works. It's being replaced in the next version though, probably by ZRMs control mod.

So hes adding SRB's to the calculation? Or will it be restricted to liquid fuelled engines?

[Tiberion]

Not sure, if its an issue I may just make the SRBs 'fake' and actually use liquid fuel with no throttle.

I've been busy in real life somewhat so I've only worked in small sessions, but I'll have some extended time this weekend, hopefully things come together.

[Tiberion]

Hey guys, quick update.

I got quite a bit done over the weekend. I tested the KerbCom plugin quite and bit and got it where it would fly the shuttle pretty well, minus some bugs I am hoping can be fixed. The SRBs definitely don't work currently, so if I use it I'll have to make the SRBS "fakey" and allow them to be throttled. I am undecided. The liquid buran-style boosters do work, minus the aforementioned bugs.

I also did the config work to upscale all the masses, fuel loads and thrust values to match the new upscaled parts, and got the shuttles mostly balanced and both launching and landing again.

The bad news is that they are pretty heavy now, and we all know how heavy parts act in KSP. Gonna have to use more struts to keep things attached, and needed some stronger decouplers as a result. Will also include a copy of the Heavystrut from Novapunch

Lastly I dug out the 'new' nose model I was working on months ago and finally finished it. It works just like the current one, its just smaller. I'll leave them both in so you can use your favorite. Any thoughts on the new one?

Besides waiting for word on the bug(s) I still need to do final fuel/thrust balances with respect to how much payload weight it can actually carry. Anyone who launches 2.5m payloads have a rough target weight you'd expect to be able to lift?

So more work to do, but getting closer to something I can release.

Here are some images:

Odyssey launching with Kerbcom management

Mechjeb showing the vessel info of the Odyssey/Buran stack with no payload onboard. It's heavy!

Intrepid in the hanger after it got a 'nosejob'

[KhaosCorp]

Would like to see at least 20-25ton payload capability. Seems like most the ISS modules when assembled and ready for launch are upper teens low 20s. Honestly though the more breathing room there is on that the better IMO.

[Tiberion]

So i did some research.

The gross pad weight of a NASA shuttleis roughly 2,000 metric tons (2 million kilograms)

The Buran was roughly 2,400 metric tons

The Tiberdyne shuttles are roughly 500 metric tons (pretty sure that is what MJ is displaying)

So we're looking at 1/4 to 1/5 the weight for something that is roughtly 60% the size of real life. Most of this is due to the different in fuel densities I guess.

The NASA shuttle could launch 25t and the Buran could launch 30t to low orbit, so if I were to keep it in scale the max payload would be 6 to 7 tons. That just doesn't seem sufficient to me, but I also think it might be a little silly to allow for the full 30t of Buran too.

So I am not sure where the happy medium is. I just tested an 18t fuel tank (the stock x200-32 rockomax tank) and the Buran launcher was easily able to put it in a 500x200 orbit and return empty, so the 18 to 20t range for an LKO payload seems do-able. I'm not sure it can land with that much weight, I'll need to test more. It should allow much less payload to a geostationary orbit.

Opinions?

[generalmiller]

18 to 20 seems almost perfect for the size of the shuttles. Much less then that and it severly limits the shuttles usefulness.

[KhaosCorp]

I'll be happy camper if I can lift 20tons in em. That's perfect target paylaod weight for remaking ISS around Kerbin.

[The Destroyer]

While It is realistic for 8 tons, the 18 tons sounds much more useful gameplay wise.

[hoodedarche0]

I don't really have a preference to how much it can lift (The more the merrier!) but it doesn't really bother me, I just want to have a reliable shuttle that in the past the only one I have found that accomplishes that goal is your Tiberdyne shuttle, so in short I am as excited for the re-release of this as I am for the upcoming release of GTA 5.

[Tiberion]

Okay then.

Here's a test release: https://dl.dropboxusercontent.com/u/46506740/TiberDyne3_2AlphaTEST.zip

Please keep in mind that its a TEST release, no one but me has tested it out, so you're sure to find issues.

While you guys help me find bugs and change the balancing where needed, I have a bit more I want to add to the final release; mostly some MPLM[/url style modules to go in the cargo bay to carry extra fuel and in the near future, science missions.

I also want to know which Robotic arm you guys think will work best with the shuttle, I want to get at least a craft file set up if its one that I can't redistribute with the mod.

Note, there's no plugin for the mod anymore outside of the same Mechjeb support as always. I never heard back on the bugfixes to Kerbcom, and without SRB support it simply isn't suitable for TiberDyne anyway, so we'll evaluate things later.

Honestly, it flies pretty good with the current stock SAS anyway, I think the launch sequence is pretty balanced. The most important thing is to get the main engine as "low" compared to the center of mass on the shuttle stack, so the NASA shuttle is slung low on the tank, while the Buran-style rides higher so the tank/engine setup is low. This gives the engine more torque to control the shuttle. So keep that in mind if you're building on your own.

Now, find those bugs

[Ledenko]

I tried launching it with Mechjeb and it wibbled and wobbled and suddenly I was doing an emergency EVA (without parachutes, ouch). Another time, I tried executing the roll program and it... went all over the place. It does glide like a styrofoam brick though, but from what I remember it would be completely unflyable without that. Anyway, what's the recommended ascent profile?

[FellipeC]

Don't know if I did something wrong, but the shuttle went out of electric energy once in orbit. There is need to install some RTGs or I missed something?

[Tiberion]

Ledenko: Were you using one of the craft files? Were you carrying cargo? Hit the MJ Vessel Info tab to see your total weight. Also, which MJ2 version are you using? I tested it using the "fixed' version from here: MJ Testbed thread (The dropbox link under "Install" - just grab the Mechjeb2.dll file from in there and update the old one you're using)

Here's some images of me launching the NASA-style shuttle stack with MJ

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If you do add input with your keyboard or joystick you need to be light on the controls, MJ can be touchy.

As for the gliding, yeah that's the Infini-glide bug and I hate it very much. The canards are so twitchy for rolling because they're powerful, yet they barely are able to pull up the shuttle when its coming in loaded with cargo. Sort of stuck between a rock and a hard place. if anyone finds better flight settings for the wings, please let me know.

FellipeC: How long were you in orbit? Currently the only power generation is from the Alternators on the engines, so the shuttle should be recharging during launch and maneuvers. It should use next to no power unless the Reaction wheels are active too. Open the resource meter and keep an eye on what your power usage is.

I may need to work up a fuel-cell setup to convert fuel to power while orbiting. You can also place the small solar panels on the inside of the bay doors and then open them in orbit. a Nuclear RTG seems a bit excessive on a shuttle.

[FellipeC]

I was in orbit for few hours, but yes, the reactions wheels are on.

[Guest]

Turn them off. They're prone to wasting electric charge when ASAS is on in orbit.

[Tiberion]

So we're back up (again)

Other than a couple of posts on the spaceport comments, I haven't heard much about the test release. Anyone having major issues with it? Able to lift cargo?

[Toyotawolf]

So we're back up (again)

Other than a couple of posts on the spaceport comments, I haven't heard much about the test release. Anyone having major issues with it? Able to lift cargo?

I haven't had a chance to play with it yet, but hopefully before the end of the night

[Toyotawolf]

Hmm well, this was interesting the shuttles are very squirelly, hard to control. but love seeing the docking port

[Tiberion]

Yeah with the current SAS setup it releases all axis from control when you hit the stick, so its a delicate balance. I wish there was a suitable vector management plugin I could use, but we're still waiting on the perfect one to come along I guess.

to me it seems to be pretty stable on orbit using the OMS engines and RCS (so long as you have precision mode on for RCS)

The areas I am not satisfied with is the aforementioned engine balance issue and the flight controls when gliding

The extending docking ports aren't new. They're working alright?

[KhaosCorp]

Finally got a change to run a few test flights with the new shuttles. The accent is a bit shakie, but nothing a few extra straps on the cargo cant fix. Did first few test with 15ton dummy cargo, flawless launch. Did a few at 18tons as well and seemed to work just fine.

[DoctorFoo]

I've had a couple of launch glitches, with the NASA style it wobbles to the point of shaking itself apart on launch, and the Buran has a habit of taking the center tank engine mount with it when the boosters separate (also the OMS kick in right after the boosters stage for some reason, had to rearrange the staging). The solution I found on the Buran launcher is to roll it heads-up for the gravity turn, that seems to let the boosters fall away without taking the engine mount with them.

On orbit, Mechjeb gets to within 0.3 m/s and then the target rapidly veers away and the orbiter starts tumbling to catch it. It can never seem to rendezvous with anything as a result. I've had similar problems with the Component Space Shuttle, so I'm not sure if that's a Mechjeb issue or not. I'm still relatively new at Kerbal so I might be missing something.

[Wahgineer]

Could you please get rid of the custom LOX? It really is kind of annoying that I can't use the tank for a refuel station. Before you say that the shuttle couldn't take its tank to orbit, the fact is it actually can, both in real life and in the mod. You may be wondering "yeah, so what?". Well one could utilize that capability to ship up all the components for a refuel station/OPF at once, just by slapping a docking port on the side of the ET. That is, if it used Oxidizer rather than the custom LOX. Which is used only by the SSMEs and the Bearcats. Which are only used for launch. Also, the OMEs use oxidizer, not LOX. Which also proves my point that LOX is a pointless aesthetic that gets in the way of this mods inter-compatibility with the stock parts as well as EVERY OTHER MOD.

[Guest]

In a somewhat similar vein, what would I need to change in the config files to get this shuttle to use standard fuel tanks? I want to test out George von Pragenau's alternate stack proposals, and it would require a mix of tanks to make that happen.

[Tiberion]

I can't change it because of the way engines use resources. Even if an engine runs out of one of the fuels, it will continue to burn or leak the rest of the other fuel even though its flamed-out until you thorttle down or disable the engine. It's a bug or a missing feature.

"So what?" You might ask. Well, if the main shuttle engines used regular Oxidizer, it is able to use the oxidizer stored on the actual shuttle rather than in the tank. The main engines use oxidizer at such a high rate that it basically empties the shuttle in slightly over 1 second of running time. This occurs even though the shuttle itself contains no liquid fuel (the onboard engines use mono-propellant + oxidizer in order to share fuel with the RCS system as the real shuttle did - I cheated a little, the NASA shuttles used MMH and N2O4 in both the OMS and RCS thrusters, but I left my RCS using just monoprop to keep it "stock" but also reused the monoprop +oxidizer for the OMS)

So you need to throttle down and then right-click-disable the main engines (or use an action group) before the main tank runs empty and before you can ever fire up the orbital engines on the shuttle. I don't think anyone really wants to do that.

As I sit here writing this though, I am pondering if swapping oxidizer placement might work - main engines using standard Oxidizer with the stock LiquidFuel it already uses and then the shuttle using LOX + Monoprop. That really just swaps the problem around though, as then you wouldn't be able to refuel the shuttle on orbit without having a stock of LOX on your station, though you would need less. I'll ponder the swap to see if it would have any unexpected side effects, or if it would be an improvement.

I am working on some cargo-pods for the shuttlebay to carry a variety of fuel or equipment modules into orbit, either as extra fuel or science bays to dock with a station)

As for what you need to change - LOX and stock Oxidizer are identical except in name, so you only need to edit the engine configs:

GameData\TiberDyneShuttle\Parts\EnginesAndBoosters\TD_EngBearCatSSMETriple (main shuttle engine)

GameData\TiberDyneShuttle\Parts\EnginesAndBoosters\TD_EngBroncoQuad (main engine on the 'Buran' tank)

and find 'name = LOX' in the propellant section, and change it to name = Oxidizer

And then change the fuel that's in the tanks:

GameData\TiberDyneShuttle\Parts\TanksAndFuselage\TD_SBSTank* (Long, Short, Cap, Endcap and the Orange variants)

and once again change name = LOX to name = Oxidizer

Again, remember that the shuttle engine will then immediately eat your onboard Oxidizer if its ever throttled up when the external tank is dry. Since the Buran variant doesn't have a fuel line to the shuttle, it should be fine

Edited October 2, 2013 by Tiberion