nyrath
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Posts posted by nyrath
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Well, the main thing is I'm not sure the delta-V values for the various missions is correct.
The chart was plotted by a Python program I wrote using nomograph theory.
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There are actually two space projects called Orion.
- The Orion project, the megalomanic nuclear pulse propulsion project from the 50s and 60s
- The Orion Multi-Purpose Crew Vehicle, which is a capsule with conventional propulsion designed for up to 6 people and is currently in development by NASA.
Actually, I think there was a third as well. There are too many blasted projects with the name "Orion."
Don't simply believe everything you see on the internet, what's the source?Aerospace Projects Review vol2, number 2
Scott Lowther always does meticulous research, you can trust his results.
The "doomsday Orion" mentioned was more of a theoretical idea. The departments in charge of the Orion project were becoming a little desperate to find an application for the blasted thing.
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What's a nomogram? It is an obsolete calculating device about the same vintage as a slide rule. You do not see them much anymore because I wasn't kidding about them being obsolete. But educators on a budget might find this useful. Or not.
It is printed piece of paper optimized to do one single mathematical calculation. It is a series of printed scale that you place a ruler or other straightedge over to solve the equation. Download this and print it out. And if you spot any mistakes, let me know so I can fix them.
http://ubuntuone.com/1kD39BCoV38WP1QeG6MtO6 version 1.1
This particular nomogram solves the delta-V equation: dv = Ve ln®
That is, there are three variables: delta-V, Isp (or exhaust velocity), and mass ratio (or fuel percentage). Given any two variable, the nomogram will tell you the value of the third.
Example: Say your spacecraft has engines with a specific impulse (Isp) of 320 seconds. You want to do an orbital transfer from Kerbin to Dres (1,300 meters per second). Place the nomogram on the table. Lay a ruler over it so that on the Specific Impulse scale (the one on the left) it crosses the 320 second mark. Pivot the ruler so that it simultaneously crosses the Delta V scale (the one in the middle) at the 1,300 mark (labeled "Kerbin-Dres xfer 1,300 m/s). Look at where the ruler crosses the Mass Ratio scale (the one on the right), and you will see it does so at Mass Ratio 1.51 (a tad less than 34% fuel).
Now, there is one application where a nomogram has an advantage over a calculator. It allows you to visualize a range of solution. If the mission is an orbital transfer from Kerbin to Dres, you can place the ruler on the 1,300 m/s mark on the Delta V scale, and pivot it there. This allows you to see how changing the specific impulse of the engine affects the propellant fraction, and vice versa.
Remember that exhaust velocity equals specific impulse times 9.81, and propellant fraction = 1 - (1 / massRatio)
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Scratch that lost though, i figured the problem, but how do i fix this issues with the kerbal's texture
Hard to tell what is going on there. Try editing the Kerbal, doing a "remove doubles", and recalculate the normals.
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I've got some notes on Orion here:
http://www.projectrho.com/public_html/rocket/enginelist.php#id--Pulse--Orion
In the pulse unit table, divide jet velocity by 9.81 to get specific impulse.
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In Blender you model with quads by default, save for cylinder caps. All you need to do is ctrl+f and select "Quads to Tris". It has its own hotkey but I forgot it, so this method is just as valid. Thats what I usually do, as Unity only likes tris, I just model with the quads and then I Quad -> Tri that stuff.
{ smacks forehead } D'oh! Now that you remind me, I knew that years ago, but promptly forgot it. Since Blender doesn't really care, I never used that function.
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I have no idea.
I do know that in the real world the available power produced by a solar cell array decreases in proportion to the cosine of the angle the array is off from face-on to the sun. So if the array was 75 degrees (1.30899694 radians) off from face on, it would produce Cos(75°) = 0.2588 or 26% of maximum.
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Also I know people constantly debate the merits of nuclear electric vs solar electric vs NTR; my understanding 'high-thrust' electric drives (relative term, a huge 200 kW VASIMR provides 5N of thrust) will need on the order of 200 MW to be used for fast human piloted Mars missions. Unfortunately no space nuclear reactor has yet been flown with power greater than 10kW, so an improvement of 20,000X is required, alas an improvement for which development if currently unfunded. In the case of solar IRC the ISS 8 arrays provide less than 100 kW, and they are not light weight
Not to mention the fact that solar electric arrays suffer from that pesky inverse square law. Here in our solar system, a given size of solar electric array that produces 100% power in Earth orbit will only produce 42% power at Mars orbit. And the power drops off rapidly the further away from the sun you travel.
EnergyPercent = 1 / Dist^2
where
Dist = distance the spacecraft is from Kerbal, measured in KAU, or units where 1 = distance between Kerbal and Kerbin
EnergyPercent = percentage of power the array will produce as compared to what it produces at 1 KAU (1.0 = 100%). Of course the array will produce more than 100% of the power if it is closer to Kerbal than 1 KAU.
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I don't know if it has been posted before, but it should have been. I've been watching that site for almost a decade, wish they could get some funding.
I like this trailer as well. Always brings a tear to my eye.
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EDIT- Just to let you know, I am now bookmarking that site. Thanks for the link!
Ummm, you do realize, do you not, that is my site?
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Well, if you have added a curve, selected it, and hit the TAB key to enter edit mode, you should see the two end points, connected by the curve (which has arrows along it). Each end point has two control points, that is, the point will be at the center of a line connecting the two control points.
Placing the mouse over one of the end points, then clicking the right mouse button should select it. The point should get brighter, a circle appears around it, and maybe some colored arrows. In the diagram, point B is selected.
Be sure to select the point, not the control point.
If right click does not do it, hit B key and move mouse near point, hold left mouse button and drag a square over the point, then release.
In a newly added and edited curve, move the mouse over the 3D window, and hit the 7 keypad key (to get the top view). You can see that the control line for Point A is skew. You want it pointed along the line connecting it to point B. To fix it, select point A with a right-click, R key (for rotate), move the mouse so that the line spins until it is aimed at point B, then hit the Return key to set that rotation.
For your manipulations, it will be easier if you only use either the top, left, or front views (7 keypad, 1 keypad, or 3 keypad).
Move control points by selecting them, hitting the G key, moving them with either the mouse or arrow keys, then setting it with the Return key.
Add new control points by selecting two points (right click on first point, hold shift key while right clicking on second point), then hitting "Subdivide" (several ways but you can go to "Curve" menu at bottom of screen, select "Segments", then select "Subdivide". This points a new point inbetween the selected points.
Change the sharpness of the curve around a point by selecting the point, hitting S key (for scale), moving the mouse while watching the curve, then return to set the scale.
Change the angle of the curve by R key.
Once you have the curve the shape you want, hit the Tab to exit edit mode. Then go to the Object menu at the bottom, select Convert To, select Mesh.
Hit Tab key to re-enter edit mode. The object is now a series of vertices.
Go to the view centered on the axis you want to spin the object around (probably 7 keypad). Make sure the cursor is on the spin axis (probably want it at origin, Shift-S select Cursor to Origin). Make pivot point the 3D cursor (pivot point control on lower menu, select 3D cursor). Select entire mesh with A key, so entire thing is lit up. Open mesh tool tray on left edge of window, if not visible hit the tiny gray "+" on left edge. In Mesh Tool section "Add", click on Spin button. On lower part of mesh tool tray will be the spin controls. Set the steps to what you want (probably 12), the angle to 360, and be sure the Dupli checkbox is NOT checked. Do A key to select entire thing. In mesh tool tray go to "remove", and click "Remove Doubles."
You are done.
Feel free to ask questions.
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Outstanding work MarcRan17! The results are both attractive and useful.
I might toy with making a nomogram for delta-v, just for fun.
http://www.projectrho.com/public_html/rocket/engines.php#id--Handy_Aids
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Perhaps not Hubble velocity. But certainly you'd have to match the "peculiar velocity"
http://en.wikipedia.org/wiki/Peculiar_motion
in the same way a Kerbal has to match velocity with the destination planet.
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Well right, my physical dissertation was just to get a general idea (even for myself) of just how powerful this is. But I'll be honest, I think its better to have a "spiked" nuclear engine (burning liquid/oxidizer + a bit of magic from a third fuel) which provides a much higher dV but at much more doable levels.
Oh and, by the way, thanks for your website, you just showed me an array of propulsion methods that I can think about and dissect using my vast knowledge of physics. Mmmm, I'm never really bored, especially when mind boggling stuff like this comes into my path.
You are welcome! I'm glad you found my propulsion list useful.
Spiked? Do you mean LOX-augmented Nuclear Thermal Rocket (LANTR)? Yes, another way for a rocket engine to trade Isp for Thrust. Comes in real handy for a host of applications.
I decided to fool around with Blender to see what sort of Orion mesh I could make with minimal polygons. It was annoying because Blender wanted to create faces that were 4 vertex n-gons instead of 3 vertex triangles. Just for fun I might try taking it into Unity and see how far I get. I'm a total noob at this.
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I wonder how momentum is conserved through the warp. It seems to me that even if you have this warp drive you would still need 30-50km/s of delta-v to match Hubble velocities with other star systems (unless you didn't mind hurtleing past them post-warp).
As far as I know it is conserved. So yes, you will need an auxiliary propulsion system to match Hubble velocities with your destination.
In the old E.E. "Doc" Smith Lensman novels, this was called a ship's "intrinsic" velocity.
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Weapon fanciers should thank their lucky stars that the devs allow weapons in KSP mods. The developer of Orbiter will not allow weapons at all. I heard this was due to the fact he was a pacifist.
As for no enemies cause they're all kerbals in the same space programme... What happens if the probe bodies rise up like cylons?
Hah. That may yet happen.
Darpa Robots Will Turn Dead Satellites Into a Zombie Orbital Array
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The Discovery II is some aerospace engineers trying to recreate the Discovery from the movie 2001 A Space Odyssey with modern technology. Helium3-Deuterium Fusion, Isp = 35,435 sec, Wet mass 1,690 metric tons, Dry mass 883 metric tons, delta-V 223 km/s, thrust 18 kiloNewtons, initial acceleration 1.68 milli-g. And you though ion drives had a low thrust.
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Alcubierre's warp drive would totally ignore orbital trajectories, it would move along a direct geodesic. Since it is making a pocket universe to cut off the effect of relativity, it would also cut off the effect of gravity.
Problems include:
- There does not seem to be any way for the ship inside the warp to stop the warp
- creating the warp takes about 12 times as much energy as is contained in the entire universe
- When the warp is released, a huge blast of radiation vaporizes anything in its path
- There does not seem to be any way for the ship inside the warp to stop the warp
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The RC controller board didn't have an arduino. I think my project was the first to use an arduino to link to KSP but I may be wrong. I've been designing the circuits for use in the main board now that I have the parts I needed. I've just got to get the DSKY etched and drilled which is on hold until I finish my PCB precision drill mod. It's funny but I'm currently at the "making the tools to make the tools to make the sim" stage.
Is the Arduino the best solution? I'm a total nubie with them, but they sure seem to do all the heavy lifting for you when it comes to interfacing to sensors, controllers, or other microprocessors.
The last time I asked about something like that on an electronics forum they just sniffed at me and said I'd be better off with a bare AVR microprocessor, after I had built a burner.
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Well, one of my favorite space games is one of the most scientifically accurate: High Frontier.
But it is not a computer game, it is a tabletop game.
Still good, though, just read the reviews.
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Depends on your point of view.
The concussive impacts of the Orion system can cause damage to the rocket, and a lot of energy is release sideways and lost in the detonation of the bombs.
Ummm, no, that turns out not to be the case.
The propulsive charges in an Orion Drive are nuclear shaped charges. About 85% of the energy from the nuke is directed into the pusher plate.
If they were not shaped charges, only about 10% would hit the plate.
Details on my website
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If forced to choose between Saltwater and Orion i would take Salty every time. For some reason this whole idea of propelling a spaceship by detonating atomic bombs (even small) near its tail looks bad to me
Ummmmm, I fear that you do not understand the nuclear salt water rocket.
Orion is a nuclear rocket driven by a series of detonations near its tail.
Nuclear salt water rocket is driven by a CONTINUOUS NUCLEAR DETONATION near its tail.
So the salt water rocket is worse.
If you have problems with detonating nuclear devices near the rocket's tail, it might be better trying detonating them in front.
http://www.projectrho.com/public_html/rocket/enginelist.php#id--Pulse--Medusa
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Anybody know any Makers? I lack the skills to do this, but I though it would be a hoot if somebody could figure out how to make joystick-like input devices for your computer to remove the need to use one's keyboard. Specifically, if one could dock one's spacecraft by using something similar to the Apollo mission controllers.
The handgrip thingy is a rotation hand controller (for yaw, pitch, and roll), while the T-bar thingy is a translation hand controller.
I mean, why should flight simulator software get all the love?
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I agree with everybody else, the video is utterly stunning. I'd suggest that the powers that be in Squad consider using it in an ad campaign. Something about it draws the viewer in, and gets their blood pounding.
I had seen this video some time ago, and had placed it on my website in the KSP section. I just assumed it had been posted here on the forum a long time ago. Silly me.
Kerbal's with beards
in KSP Fan Works
Posted
Yes indeed, that is an urban legend
http://www.snopes.com/business/genius/spacepen.asp
Among the bad things that graphite does is get into the wiring and cause short circuits. Conducts electricity, y'know.