nyrath
-
Posts
604 -
Joined
-
Last visited
Content Type
Profiles
Forums
Developer Articles
KSP2 Release Notes
Posts posted by nyrath
-
-
With an automobile, there is friction. Because of that, we talk about how many miles a car can drive on a fuel tank of gasoline. We can't do that with a rocket. Instead we use delta-V.
There is no friction in space. Here on Terra, if you are driving a car and take your foot off the accelerator, the car will coast to a stop due to the friction of the road. In space, if a spacecraft turns off its engines it will maintain its current velocity for the rest of eternity (unless is crashes into a planet or something). In the movie 2001 A Space Odyssey, you may have noticed that the spacecraft Discovery was traveling to Jupiter with nary a puff coming out of the rocket motors.
This is why it makes no sense to talk about the "range" of a rocket. Any rocket not in orbit around a planet or in the Sun's gravity well has a range of infinity. In theory it can do a burn and travel to, say, the Andromeda Galaxy, it is only that it will take millions of year to get there. Instead of a rocket's range, one should talk about a rocket's delta V capacity.
The important thing is that a mission can be rated according to how much delta V is required. For instance: lift off from Terra, Hohmann orbit to Mars, and Mars landing, is a mission which would take a delta V of about 18,290 m/s. If the spacecraft has equal or more delta V capacity than the mission, it is capable of performing that mission. The sum of all the delta V requirements in a mission is called the delta V budget.
-
We might know two. If we confirm methanophiles on Titan, it'd be a huge breakthrough in our understanding of life in this universe. It'd take us from total uncertainty about life elsewhere and bring us to an almost absolute certainty that universe is filled with life.
There might be five. Exobiologists think there is a chance of life on Europa, Enceladus, Ganymede and Titan.
Which has implications. If our solar system has one hot-life planet (Earth), and four cold-life planet, it could mean that on the average cold-life outnumbers hot-life four to one throughout the galaxy.
-
A complete and conclusive report ialdabaoth ! Good stuff.
I'm probably going to have to make some sort of jury-rigged system in order to allow my Orion Drive to handle propellant and fuel in the form of nuclear charges. If it can be done at all within the bounds of the current program.
-
The best antimatter fuel is the fuel you can contain, that is, hold in some container so it does not touch any of the matter walls. Otherwise it is a worthless fuel.
This may put a severe restriction on what form the fuel can take. Dr. Robert Forward spoke of storing antimatter in the form of a frozen snowball of anti-hydrogen at temperatures below two Kelvin, levitated in a magnetic field to avoid contact with the chamber wall. In a vacuum, of course. The cold temperature is to keep the blasted stuff from sublimating any anti-atoms from the surface and starting an annihilation reaction with the chamber.
Anything heavier and non-ferrous is probably a non-starter.
http://www.projectrho.com/public_html/rocket/spacegunexotic.php#id--Antimatter
-
That I can see being made much more practically. You effectively only need to shield the nuclear core when disengaging the NTR / engaging the LOX.
Ummmm, I fear you do not understand. In LOX mode the nuclear core is still running. The only difference is that the hot exhaust has LOX injected into it as an afterburner.
-
Recovered the code! Certain not to work with the latest version of ksp and woefully unfinished, but it should serve as a starting point!
NovaSilisko thank you so much! This will be a huge help!
-
Yes, Scialytic has it correct. For an NTR you want the lowest molar mass possible. And Giggleplex777 is correct as well, you can toggle the LOX injection. That is the point of LANTR, it has a low-gear and a high-gear. In those cases where you suddenly need more thrust, you can shift into high gear by toggling the LOX. You get more thrust with the expense of a lower specific impulse. Kind of like an afterburner.
-
though natural antilog is a silly name for what I always just call the exponential function
Yes, it is true that is its real name. But when trying to explain it is not intuitively obvious that the exponential function is the inverse of natural logarithm. Which is what you have to do when solving for Mp
-
twotoes02, the opposite of the natural log of a number is called e^x or natural antilog.
For example:
deltaV = (g*Isp) * ln[massRatio]
deltaV / (g*Isp) = ln[massRatio]
massRatio = e^(deltaV / (g*Isp))You sort of confused me because I'm used to seeing the letter R to symbolize Mass Ratio, not thrust to weight ratio.
Now, below, Mp is the mass of the propellant, Me is the mass of the rest of the rocket, deltaV is delta V, Isp is specific Impulse
MassRatio = (Mp/Me) + 1
deltaV = (g*Isp) * ln((Mp/Me) + 1)
deltaV / (g*Isp) = ln((Mp/Me) + 1)
e^(deltaV / (g*Isp)) = (Mp/Me) + 1
e^(deltaV / (g*Isp)) - 1 = Mp / Me
(e^(deltaV / (g*Isp)) - 1) * Me = Mpso the last equation will give you the mass of propellant, given the other variables.
The total initial mass is Me + Mp, divide the mass of the propellant by that to get the propellant fraction.
-
In my quest to make the series of explosions I did run across this
http://forum.kerbalspaceprogram.com/showthread.php/16497-0-16-Oi3-Demolition-Inc-TNT-Pack
However, examining the source code, it apparently just calls the
part.explode()
function on a part. I guess if I can create a new part to represent each new explosive charge, I can explode it and send a message to the pusher plate to run one cycle of the pusher animation. I guess.
Meanwhile in Kerbin...Yes, Captain Kalawang, I respect the purists who do everything with only stock plain vanilla. I will try that.
But any hacker gets an itchy feeling with something doesn't quite do what they want. Currently there is no stock Project Orion engine.
-
The Rocket Company
http://www.amazon.com/The-Rocket-Company-ebook/dp/B00BWEEWOI/
Very realistic, the rocket described inside is patented. And it might give you some ideas for Kerbal rockets.
-
So I sort of figured it out. I unwrapped it like an orange instead of a ball, and that gave me a png that was much easier to paint. However, I should have four black parts and four white parts on the model and instead I have three of each? I don't know why and tried all sorts of things. You can see in the small preview (top right) the ball has four of each, but in the model view it has three of each.
Fiddlestyx, did you apply seams to your mesh before you unwrapped it? You can set the seams so that you have 8 parts instead of 6.
http://wiki.blender.org/index.php/Doc:2.6/Manual/Modeling/Meshes/Editing/Edges
-
I was talking about, well, shock waves. The Orion engine requires a directed pulse of energy in the form of high-speed ions generated by the explosion in the direction of the pusher plate, right? A nuke, going off in-atmos generates a large shock wave, but less 'push' from the perspective of the plate. That also would damage the ship, as the shock waves would ripple around the plate... Causing explosions.
Very kerbal indeed
Orion drive ships use nuclear shaped charges. The blast is not isotropic, it is directed.
http://www.projectrho.com/public_html/rocket/enginelist.php#id--Pulse--Orion
Also, while in the atmosphere, the charges are much smaller. For example, the 4,000 ton Orion would use five kiloton nuclear charges while in space, but during the climb out of the atmosphere it would use charges that were only 0.15 kilotons. The atmo charges would also not need the tungsten propellant required on the vacuum charges, the atmosphere would provide the propellant.
-
Just a note- the Orion drive would only be feasible if in space already.
Depends on how you define "feasible".
It will take off from Earth or Kerbal and travel into low orbit just fine.
It is just that some people have a problem with how it pops off 200 or so five-kiloton nukes in the process.
It actually is not utterly hideous, if you take off from a huge steel plate covered in graphite, with the lift-off point located near the north or south magnetic pole.
-
Yes! I have waited so long for such a mod:D Thank you nyrath:)
Don't thank me yet, this is going to take a while to get it working. But I'm glad you are eager for it.
-
Nice model, but to be even slightly realistic, it would need to be at least 4 or 5 times the size.
I'm not sure you need to code anything. You could use a "Pellets" ressource that uses one unit on each pulse and calculate the Isp accordingly. Thrust vectoring should be disabled.
Five times. For the NASA-USAF Orion study, the pusher plate was 10 meters in diameter, the one I have is only two. I used two because that is the standard stack element diameter. And because I was unsure if it would break anything if I made it 10 meters in diameter. Because I am a total noob at this sort of thing.
I'm sure this thing is going to undergo plenty of revision.
Thanks for the tip about the "pellet" resource, and thrust vectoring. But I wanted to see if I could animate a series of explosions synchronized with the pusher-plate animation.
Can you please tell me the relationship between heatProduction and maxTemp? The emissive texture tutorial I read said that the emission animation should be 60 seconds long, and the view at 30 second should be "normal" operational heat. Is the animation at 60 seconds what you get when temp = maxTemp? I assume that the temp has heatProduction added to it periodically, but how often, and what level triggers overheating?
So far I have failed to find this info in the wiki or in the forum.
-
Fiddlestyx, I believe you are trying to use Blender's vertex painting feature
http://wiki.blender.org/index.php/Doc:2.6/Manual/Materials/Special_Effects/Vertex_Paint
I am pretty sure that technique will not work when making Kerbal mods.
Instead, you should use Blender's UV mapping feature. It is more work, but it makes it easier to keep in the lines.
http://wiki.blender.org/index.php/Doc:2.6/Manual/Textures/Mapping/UV
http://forum.kerbalspaceprogram.com/showthread.php/18376-First-part-in-blender
-
MOD EDIT : Appears to be licensed according to this post. Nyrath, please confirm or deny as soon as you see this.
What is Project Orion?
A totally insane propulsion system. It is based on the old "firecracker under a tin can" principle. Except the tin can is a spacecraft and the firecracker is a nuclear bomb.
And it was real. The project was cancelled in 1963 due to the nuclear test ban treaty.
Details here:
http://www.projectrho.com/public_html/rocket/enginelist.php#id--Pulse--Orion
http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29
Why a Kerbal Orion mod?
Because everybody wants one. I found no less than four prior Orion projects, all of which ended in failure.
Which means there is a demand, but it is freaking hard to do.
Since the mod is based on actual project Orion data, it is very scientifically accurate. You will find that it can boost absurd amounts of payload into orbit, and it has shocking amounts of delta V. Of course Kerbals are immune to radiation, which is why this engine is not used by NASA.
Why Me?
Because I'm the Atomic Rocket guy, and my life will not be complete without KSP equipped with the ultimate insane atomic rocket.
I used this document as my primary reference for the mod.
Alpha version ready for test
Download here
version 0.18 (9.7MB)
Instructions and history are in the readme file
WARNING:
This version is broken in KSP 0.90
As a temporary fix, after you install the mod, get the modified DLL here and install it
https://github.com/cerebrate/USAFOrion/releases
I will merge the fix as soon as I get some free time.
With version 0.12, mod is now in KSP 0.20 format. Before installing, be sure you have removed any pre-0.12 Orion mods.
[1] from \Kerbal Space Program\Plugins\ delete the file USAFOrion.dll
[2] from \Kerbal Space Program\Plugins\, delete entire folders
\USAFOrion3Engine\
\USAFOrionEngine\
\USAFOrionMag0_8kt0_88mn\
\USAFOrionMag15kt400mn\
\USAFOrionMag1kt2mn\
\USAFOrionMag1kt3_5mn\
\USAFOrionMag5kt80mn\
\USAFOrionMagazine\
Bug fixes:
With KSP version 0.21, suddenly the Orion vessels were blowing up on the launch pads. This is a fix for that.
WARNING: if your ship is "tippy", that is if it is massive enough so that if it rests on its bare Orion pusher plate you see the ship gently swaying back and forth, launching under Orion power will make the ship explode despite the bug fix. To avoid this, launch with the vessel supported by TT18-A Launch Stability Enhancers or with LT-2 Landing Struts that have been extended by pressing the G key.
If anybody is interested, the problem was the little bomb module that you see shooting through the pusher plate and exploding. Trouble was it was programmed to detonate 23 meters below the pusher plate. Which is a problem if the plate is resting flat on the ground. So the little bomb hit the launch pad at high speed, and the resulting shock broke the vessel apart. This is because as far as the physics engine is concerned the little bomb and the Orion engine are the same thing, it thought the entire engine hit the launch pad at high speed.
Now the plug in is smart enough to check the bomb's travel path for obstacles, like planets.
------------
If you load a .craft file and get an error about missing part USAFOrionmag1kt2mn, that was removed in version 0.14. It is present in version 0.13
old version 0.13
http://ubuntuone.com/44qIfp6I86yoWzHtAwNW1b
If version 0.18 breaks revert to version 0.17
old version 0.17
http://ubuntuone.com/6Xmgy59yKQ2FgSBxPMaSUq
-------------------------
(SketchFab image below, if your browser does not support it, you will just see a blank space)
-------------------------
Quick video
Scott Manley's review of the mod
-
This is also called a "Clarke" orbit, after Sir Arthur C. Clarke who first proposed it. He often wistfully wondered if he could have patented the idea.
Around Earth real-estate in the Clarke orbit is next to non-existent. Everybody and his brother wants to put communication satellites there, and the satellites cannot be too close or their radio broadcasts interfere with each other. The orbit is packed to the gills with satellites, and competition for empty slots is beyond cut-throat.
-
I have wondered why there isn't a design that combines nuclear and chemical power.
If you're using a fuel that burns, why waste the chemical potential energy? There must be design challenges that make it impractical.
There is one. It is called LOX-augmented Nuclear Thermal Rocket. The chemical and nuclear parts interfere with each other.
What it boils down to is that when it is in Nuclear mode, it has an Isp of 940 seconds, but a thrust of only 67 kiloNewtons. In LOX augmented mode, it has an Isp of only 647 seconds but a thrust of 184 kiloNewtons.
In other words, in LOX augmented mode it trades reduceds Isp for increased thrust.
http://www.projectrho.com/public_html/rocket/enginelist.php#id--Nuclear_Thermal--Solid_Core--LANTR
Once you start dealing with liquid and gas core nuclear thermal rockets, the chemical part is superfluous. It is sort of like attaching a firecracker to the side of a nuclear warhead: yes, the explosion will be bigger, but not enough to measure.
-
SunJumper, did you read Dr. Slough's papers on Magneto Inertial Fusion?
http://msnwllc.com/propulsion-publications
The fusion fuel is compressed by lithium foil rings, which do a good job of containing the radiation. Then the lithium acts like propellant, , with much more mass than a thin stream of He4.
-
Nerds seriously, are you all math professors or something like that?
Well, it does help when one is playing a game that is literally rocket-science.
-
1 ion requires 12 units of electricity per second.
RTG's used to provide 1 per second, but were nerfed and now only provide 0.75/s.
12 units * 1 RTG / 0.75 units = 15 RTG's required to power a single ion engine.
15*0.08t = 1.2t : the mass of all these RTG's. Not large in comparison to some of the engines/fuel tanks, but when factoring the ion engine (0.25t), xenon tank (0.12t), and lightest probe core (0.04t), we get a total mass of 1.61t.
One ion engine produces 0.5 kN of thrust, so this gives us a Kerbin TWR of 0.031--which would take an eternity to change orbits!
I guess you could just put it on 4x time warp, then go watch TV or something...
Great analysis!
Things will be much worse if the game implemented the VASIMR. Compared to the ion drive it is a power hog. Solar cell arrays and RTGs are too weak, you'll need something like a small nuclear reactor. Since reactors components are all constructed of fantastically dense elements, this makes for truly pathetic thrust-to-weight ratios.
-
It seems to me that the sticky bit is the old problem that fuel is not propellant. Except in odd cases like chemical rockets.
Chemical Rockets: fuel is fuel+oxidizer, propellant is combustion products
Ion rockets: fuel is electricity (solar cells or RTG), propellant is xenon
Fission nuclear thermal rocket: fuel is uranium/plutonium, propellant is hydrogen
Magneto Inertial Fusion: fuel is deuterium, propellant is lithium foil liners
VASIMR: fuel is lots of electricity (nuclear reactor), propellant is argon or xenon
Orion aka "Ol' Boom-boom"
in KSP1 Mod Development
Posted
Great! Thank you so much, that would have taken me weeks to find in the docs.
Hrrmph. You might be right. I tried a version with a full 10 meter plate. Perhaps a bit excessive...
Landing gear is going to be a bit of a problem. Not to mention getting the Kerbals down to the ground. I'll have to think about this.