[0.25]KSP Interstellar (Magnetic Nozzles, ISRU Revamp) Version 0.13

[Tanya Sapien]

that reminds me of my first jool mission in career mode. I managed to flyby and science every single moon before terminating the mission by plunging the probe into Laythe's atmosphere, sending readings back before it smashed into the ocean. I only netted 5800 science though...if I'd included Jool in my list of targets I might have actually topped Scott...ahhh who am I kidding, he's the rocket god, resistance is futile.

[Fractal_UK]

Well you're not in a vacuum for starters, and the table is a bit our of date. Try that again in space and see what the numbers tell you, but iirc thermal rockets are less effective than the stock atomic motor until you get your reactors upgraded.

Not quite less effective, they have higher I_sp but only the largest model has competitive TWR. All of them offer more flexibility because you can use a variety of fuel types but the extra mass of the reactors is a downside that makes it a little more difficult to turn their I_sp advantage into a delta-v advantage. Overall, they are more or less comparable, as intended as they are in the same tech node.

[Tharios]

that reminds me of my first jool mission in career mode. I managed to flyby and science every single moon before terminating the mission by plunging the probe into Laythe's atmosphere, sending readings back before it smashed into the ocean. I only netted 5800 science though...if I'd included Jool in my list of targets I might have actually topped Scott...ahhh who am I kidding, he's the rocket god, resistance is futile.

Considering he mentions a number of times the specific mistakes that prevented him from simply getting the entire tree in a single mission...yeah, probably.

[Jason_25]

edit: This is just the normal throttling behavior. It would be nice to have more visual feedback on that though.

I'm back working on thermal turbojet VTOLs and have noticed a bug(s) that is making that impossible right now. The bug manifests itself in the following ways:

1. Sometimes there is no vtol thrust at all - 0.0 kn - intakeair and thermalpower show good - fixed by cycling main engines and VTOL engines on and off

2. Sometimes thrust is around half what is expected - ~60 kn - intakeair and thermalpower show good - fixed by cycling main engines and VTOL engines on and off

3. Always The main engines have an effect on the VTOL engines and vice versa - take off under VTOL power and when cycling the main engines on the VTOL engines lose thrust - intakeair and thermalpower show good - cycling does not help - THERE IS NO FIX!!!

4. As an additional clue the intakeair readout glitches back and forth while sitting on the runway with no engines running

This did not happen in earlier versions. There the VTOLs fly fine.

In other news, I finally figured out how to make a decent jet. The key was the smaller lighter reactors.

Edited November 7, 2013 by Jason_25

[Fractal_UK]

BUG REPORT

I'm back working on thermal turbojet VTOLs and have noticed a bug(s) that is making that impossible right now. The bug manifests itself in the following ways:

1. Sometimes there is no vtol thrust at all - 0.0 kn - intakeair and thermalpower show good - fixed by cycling main engines and VTOL engines on and off

2. Sometimes thrust is around half what is expected - ~60 kn - intakeair and thermalpower show good - fixed by cycling main engines and VTOL engines on and off

3. Always The main engines have an effect on the VTOL engines and vice versa - take off under VTOL power and when cycling the main engines on the VTOL engines lose thrust - intakeair and thermalpower show good - cycling does not help - THERE IS NO FIX!!!

4. As an additional clue the intakeair readout glitches back and forth while sitting on the runway with no engines running

This did not happen in earlier versions. There the VTOLs fly fine.

In other news, I finally figured out how to make a decent jet. The key was the smaller lighter reactors.

I'm going to need a lot more information than this unfortunately, screenshots with the performance of the various parts showing would be good - particularly reactors and engines.

I'll also need altitudes that all of these events are occuring at. The engines are designed to throttle down to prevent flameouts, though presently after you switch fuel types this code takes a moment to adapt. That could explain some of these instances of lower than expected thrust.

[Decoherent]

Well you're not in a vacuum for starters, and the table is a bit our of date. Try that again in space and see what the numbers tell you, but iirc thermal rockets are less effective than the stock atomic motor until you get your reactors upgraded.

Oh man. I'm not even going to tell you how long I poked around at this without ever thinking that a rocket's ISP might depend on whether or it it's in atmo. Once in orbit, that engine generated 148kN@686s, which sounds great to me. I know these engines are slightly less "effective", but the coolness of actually having nuclear power rather than just a slightly-special engine is very much worth it. Thanks!

[Jason_25]

I'm going to need a lot more information than this unfortunately, screenshots with the performance of the various parts showing would be good - particularly reactors and engines.

It was just throttling thankfully but do take a look at this series of small preview images and tell me what you think. One of them involves the "too many heatsinks needed" problem.

[Donziboy2]

zzz, I think I found a glitch with the Science lab ladders.

Once the Kerbals arms go above the top of the hatch he looses his hold on the science lab ladder. In gravity he falls, in space he floats away...

Also Fractal_UK can we get the ability to store science in the science lab?

He is actually floating in the second picture I have hack gravity enabled, half a second after I took this he floated away....

Edited November 7, 2013 by Donziboy2

[Tommygun]

I'm currently trying to get a thermal rocket nozzle to run on xenon, but nothing is happening, I can't toggle the fuel.

I am doing this in sandbox mode, do you need to upgrade the thermal rocket nozzle to be able to use xenon?

[Tharios]

I'm currently trying to get a thermal rocket nozzle to run on xenon, but nothing is happening, I can't toggle the fuel.

I am doing this in sandbox mode, do you need to upgrade the thermal rocket nozzle to be able to use xenon?

If it's in Sandbox mode, all parts should be fully upgraded. Does the thermal rocket run on Xenon at all? I thought just the plasma thruster did?

I can't check right now because I had to ditch all my mods.

[Tommygun]

If it's in Sandbox mode, all parts should be fully upgraded. Does the thermal rocket run on Xenon at all? I thought just the plasma thruster did?

I can't check right now because I had to ditch all my mods.

Yes you are right, I got the two charts at the first post mix up.

Thanks though.

[zipybug14]

I have been doing a little reading on two experimental electric thrusters, VASIMR(Variable Specific Impulse Magnetoplasma Rocket) and PIT(Pulsed Inductive Thruster). They both claim variable Isp. Any thoughts?

[Fractal_UK]

I have been doing a little reading on two experimental electric thrusters, VASIMR(Variable Specific Impulse Magnetoplasma Rocket) and PIT(Pulsed Inductive Thruster). They both claim variable Isp. Any thoughts?

Much earlier in the development cycle, I was thinking about different electric engines and what I might implement. I decided to use realistic engine Isps as well as use relatively realistic values of power outputs/masses for the initial (unupgraded) nuclear reactors albeit scaled down somewhat in volume terms to something more acceptable to Kerbals.

All electric engines have very high specific impulses and very low thrusts. Because the game doesn't really support people use extremely low thrust, high Isp engines at this time, I decided it was best to go for the high thrust / low(er) I_sp pick of the bunch. A VASIMR might have a minimum specific impulse a little higher than the MPD, up to a maximum of around 10x as high. Of course, the thrust goes down in the same proportion. Until something changes with the game (e.g. better, faster, physical timewarp), I don't anticipate too much demand for that kind of thing.

You can, however, vary the I_sp of the MPD downward (and consequently the thrust upward) by using a different propellant: Lithium, Argon or Xenon.

[Makeone]

Hmm, is Lithium in KSPI for MPD fuel, i though it had some other use?

And a though of thermal 'jets', shouldn't they be only operating once the plane is up to speed, as they don't have(?) compressor part, like normal jet engine? I know it could be a limit of the game, although there is a (s)ram jet engine that starts providing power once there enough speed.

[Donziboy2]

I have been doing a little reading on two experimental electric thrusters, VASIMR(Variable Specific Impulse Magnetoplasma Rocket) and PIT(Pulsed Inductive Thruster). They both claim variable Isp. Any thoughts?

Near Future Propulsion Pack has both of those I believe.

[wasmic]

Page number 300!

EDIT: Yes, I was lurking, waiting for the perfect time to strike...

[zipybug14]

Near Future Propulsion Pack has both of those I believe.

Indeed it does. I shall try it out later today.

[Fractal_UK]

Hmm, is Lithium in KSPI for MPD fuel, i though it had some other use?

It does, you can use it to breed Tritium for Vista engines too.

And a though of thermal 'jets', shouldn't they be only operating once the plane is up to speed, as they don't have(?) compressor part, like normal jet engine? I know it could be a limit of the game, although there is a (s)ram jet engine that starts providing power once there enough speed.

No reason for them not to have a compressor particularly, they weren't designed to be nuclear ramjets. You could build a nuclear ramjet but there isn't any design constraint that forces you to adopt either approach.

[Eadrom]

Just unlocked warp drives in my career save! Had to send a few lander probes out to make back the science I invested in some computer cores. Just launched my first warp ship in this save (probably only my 3rd warp ship total as well). Took a stroll over to Eve. Mission was to aerobrake to make orbit. Had to reload once because a 70k meter periapsis coming in at over 10k m/s just bounced me out of the atmo. lol Reloaded and came in with a 49k meter periapsis and bled off enough speed so that with a 300 or so m/s burn, I was able to make a nice circular orbit at 1.5 million meters around Eve.

Was a lot of fun gathering the extra 20k science needed to unlock all the KSPI nodes. Forced me to visit all the planets and moons and land a few probes as well. Now to build an antimatter factory at Jool and design an FTL antimatter freighter! Thank you again for the fun, Fractal.

[BananaDealer]

Hey Fractal, any news on when we can expect that new drive you showed us a picture of awhile back?

[db48x]

That's a great looking ship. Would you care to share it?

db48x

[Fractal_UK]

That's a great looking ship. Would you care to share it?

It might be nice if we could get a thread going over on the spacecraft exchange of various craft people have built that they want to share.

Hey Fractal, any news on when we can expect that new drive you showed us a picture of awhile back?

Not really. All I can say is 0.8 is proving to be a large and complicated update, there is no ETA at the moment.

There is a lot to tackle, the microwave launch system is obviously taking a lot of effort, as a sole feature, it's basically done but the atmospheric limiting code (to prevent flameouts) is a bonus feature with most engines, with microwave engines it's an absolute neccessity because the power output can change fairly significantly even over a fraction of a second. That means, I really need to get the code functioning perfectly otherwise bad results quickly follow.

I'd also really like to tackle some other outstanding shortcomings, including having no options at all for refueling nuclear reactors. Obviously I also want to add the Sabatier ISRU process, geared towards Duna, for methane production and the liquid methane + oxidiser engine.

Edited November 7, 2013 by Fractal_UK

[Tharios]

There is a lot to tackle, the microwave launch system is obviously taking a lot of effort, as a sole feature, it's basically done but the atmospheric limiting code (to prevent flameouts) is a bonus feature with most engines, with microwave engines it's an absolute neccessity because the power output can change fairly significantly even over a fraction of a second. That means, I really need to get the code functioning perfectly otherwise bad results quickly follow.

Is this system likely to have the side-benefit of permitting more effective solar power networks?

[theSpeare]

Fractal would it be too much to request for the warp drives (and possibly every other part) to be upgradable "retrofit" style for a third level? Forcing it to be retrofitted compels us to retrofit every new craft that comes out, but it also lets us keep using science when it pretty much just becomes useless and pointless as soon as you hit warp drives.

[BananaDealer]

It might be nice if we could get a thread going over on the spacecraft exchange of various craft people have built that they want to share.

Not really. All I can say is 0.8 is proving to be a large and complicated update, there is no ETA at the moment.

There is a lot to tackle, the microwave launch system is obviously taking a lot of effort, as a sole feature, it's basically done but the atmospheric limiting code (to prevent flameouts) is a bonus feature with most engines, with microwave engines it's an absolute neccessity because the power output can change fairly significantly even over a fraction of a second. That means, I really need to get the code functioning perfectly otherwise bad results quickly follow.

I'd also really like to tackle some other outstanding shortcomings, including having no options at all for refueling nuclear reactors. Obviously I also want to add the Sabatier ISRU process, geared towards Duna, for methane production and the liquid methane + oxidiser engine.

Alrighty... No rush!