silent_prtoagonist
Members-
Posts
215 -
Joined
-
Last visited
Content Type
Profiles
Forums
Developer Articles
KSP2 Release Notes
Everything posted by silent_prtoagonist
-
I like to think of 1 unit of "electric charge" as being equal to 1 MJ, based on the ion thruster. The PB-ION produces 500 N of thrust with an exhaust velocity of 41,202 m/s (insert rant about the units of Isp here), and draws 14.548 ec/s (according to the wiki). Thrust power for a reaction engine is: thrust power = 1/2*thrust*exhaust velocity = 0.5*500N*41202m/s = 10.3E6 W Assuming it's drawing 14.548E6 W of electrical power, this corresponds to an efficiency of 10.3/14.548 = 70.8%, which seems reasonable. Interestingly, 1 MJ is also equal to about 240 food calories. Thus, in order to reduce confusion about charge vs. power, I hereby recommend rebranding the unit of electrical power in KSP as "snacks."
-
Ideal Ascent Profile
silent_prtoagonist replied to SiliconPyro's topic in KSP1 Gameplay Questions and Tutorials
My standard ascent profile is pitching over 15 degrees every 7500 m, putting you level to the horizon at 45 km. It seems to work pretty reliably for most designs, although occasionally I'll modify it to 15 degrees every 6000 or 10,000 m, for unusually high- or low-thrust designs, respectively. -
Show off your awesome KSP Pictures
silent_prtoagonist replied to Capt'n Skunky's topic in KSP1 Discussion
Aha. I've been using protractor for a couple of days, but I never noticed that before. Thanks. -
Show off your awesome KSP Pictures
silent_prtoagonist replied to Capt'n Skunky's topic in KSP1 Discussion
What's the little calculator icon in the bottom left of your image? -
Show off your awesome KSP Pictures
silent_prtoagonist replied to Capt'n Skunky's topic in KSP1 Discussion
My first successful round trip to Duna This ship was designed as the lander stage of a two part mission, intended to land on another planet and reach orbit again, then rendezvous with a return ship in orbit. However, since this was my first attempt at designing a full round trip mission, I over engineered it just a wee bit... The flight was originally just supposed to be a test flight to see if my design had enough dV to reach Duna, however after discovering that my transfer stage had about three times the dV needed (courtesy of the new nukes), I decided to try in hit Duna anyway, even though I was nowhere near the right phase angle. After pushing my ap out halfway to Jool I finally got the intercept. A long wait and a very fast aerocapture (many quick loads) later, I was in orbit. I finally touched down in a broad valley in the northern hemisphere. With seven almost full tanks in the lander, making it back to orbit was never a question, but I was curious if I could make it all the way home. Reaching orbit left me with a little over one tank full, just enough to escape and drop back down to Kerbin. I was a little late for the launch window, but I decided to try it anyway. I was able to pick up the intercept, and then eek my Kerbin pe down to about 3,500 km before my tanks ran completely dry (again, many quick loads). With no rcs or other alternative propulsion, it looked like I was stuck, until I remembered that plane change maneuvers are most efficient 90 deg from target intercept (I had been doing them just outside DUna's soi). Waiting 1/4 of an orbit later I was able to easily dip my pe into Kerbin's atmosphere with plenty of fuel to spare, which turned out to be a very good thing. Since I had originally designed the lander to never return to Kerbin itself, it only had one parachute, which had been used on Duna. Fortunately I had just enough fuel left to slow my descent. The time was tricky (many quick loads again) but by slamming on the throttle just as I passed 500m I was able to slow down enough that the capsule (but nothing else) survived. Riblas, Bartburry, and Gergun Kerman were finally home. Album: http://imgur.com/a/61QbS#0 Just before entry interface for aerocapture at Duna On the surface Close pass by Ike on the way home Almost there... Home The same design on the pad. -
What do you think about new nuclear engine?
silent_prtoagonist replied to Pawelk198604's topic in KSP1 Discussion
I love them, swapping out the transfer stage engines on my 0.16 interplanetary designs makes them ridiculously over-powered. Burn times can be a bit...tedious, but it's a small price to pay. An interesting point, a combination of a 1 kerbal pod and 1 meter half-tank has almost exactly the same dv with a nuke or a small lander engine. The extra weight of the nuke almost completely offsets the extra efficiency. -
Kerbal Space Program Trajectory Optimization Tool
silent_prtoagonist replied to Arrowstar's topic in KSP1 Mod Development
Yep, that fixed it, working great for me -
Kerbal Space Program Trajectory Optimization Tool
silent_prtoagonist replied to Arrowstar's topic in KSP1 Mod Development
Yea, I'm on Win7 64-bit -
Kerbal Space Program Trajectory Optimization Tool
silent_prtoagonist replied to Arrowstar's topic in KSP1 Mod Development
I'm getting an error that says "Unable to load JavaFX runtime" when I run the .jar. This happens with both version 0.1 and 0.2. I'm running Java 7 Update 7 (7.0.70) 32 bit on Windows 7 Pro x64. I also ran into this problem running 64 bit java. -
Haha that's an awesome idea, lob yourself out of the atmosphere on a sub-orbital capsule and then make up the rest with EVA, very kerbal I tried getting a kerbal into orbit from the surface of Mun once, and he fell just a few m/s short of reaching orbit, so they have at least 550m/s dV, and maybe up to 700 or so (I'm not sure how much I lost to gravity drag). Keep in mind though that you'll need a little in reserve. Even if, once you get him in orbit, the kerbal is the passive member in the rendezvous, he'll still need a little to reach the hatch. Trying to maneuver the ship that close and then switching sounds like somewhere between maddeningly difficult and impossible. Hmm...I feel a challenge coming on
-
[UNOFFICIAL/FANMADE] 0.17 Discussion Thread 2
silent_prtoagonist replied to kacperrutka26's topic in KSP1 Discussion
Here's an interesting thought. What if, just for lols, Jool had the same diameter and mass as Earth? I think it would be in about the right ballpark to be in scale with the rest of the Kerbol system: Kerbin is ~1/10 the size and ~1/100 the mass of Earth, and Earth is ~1/10 the size and ~1/300 the mass of Jupiter. And it would make a fun easter egg for people who looked closely at the numbers... -
Ok, some back-of-the-envelope calculations: Kerbin properties: surface gravity: 9.807m/s^2 GM: 3530 km^3/s^2 radius: 600 km Eve properties: surface gravity: 9.807*1.7m/s^2 = 16.66m/s^2 radius: 700km. assume a 200km orbit to be safely above the atmosphere Law of Gravity: g = GM/r^2 => GM = g*r^2 = (16.66E-3km/s^2)*(700km)^2= 8164 km^3/s^2 for Eve (as a side note, this means Eve has a mass = 1.223E23 kg, about 2.3x Kerbin) Circular orbital velocity: g = v^2/r => v = sqrt(g*r) = sqrt(GM/r) => At surface: v_700 = sqrt[(8164 km^3/s^2) / (700km) ] = 3415 m/s At 200km altitude v_900 = sqrt[(8164 km^3/s^2) / (900km) ] = 3011 m/s Gravity drag: Find an altitude above Kerbin equivalent to 200km above Eve; reaching this altitude should incur the same gravity losses in either case. specific energy change to go from Eve surface to 200km: dE = GM/r2-GM/r1 = (8164 km^3/s^2)/(900km) - (8164 km^3/s^2)/(700km) = -2.592 km^2/s^2 equivalent altitude above Kerbin: r2 = GM/(GM/r1+dE) = (3530 km^3/s^2) / ((3530 km^3/s^2)/600km - 2.592 km^2/s^2) = 1073 km Air drag: This is a bit trickier. Drag force scales linearly with density, but I'm not sure how that translates into drag losses. Maybe the best way to deal with this is to modify a small part (maybe a parachute) to add the appropriate extra drag for each design. Oi, that was more complicated than I thought. I'm doing all of this off the top of my head, so feel free to check my numbers, but these seem about right. So in total, a normal rocket that can launch from Kerbin and reach a speed of ~3000 m/s at an altitude of ~1000km (which would put it in an escape trajectory and then some) should be able to reach low Evonian orbit, not accounding for drag...
-
[UNOFFICIAL/FANMADE] 0.17 Discussion Thread 2
silent_prtoagonist replied to kacperrutka26's topic in KSP1 Discussion
Either way I'll be happy. The other three planets look great, more than enough to keep me occupied. I'm happy to wait for Moho to be done right if that's what the devs decide to do. -
Specific impulse?
silent_prtoagonist replied to robly18's topic in KSP1 Gameplay Questions and Tutorials
Another way of looking at it, specific impulse is the amount of time, in seconds, that an engine producing 1 kgf (kilogram of force) would take to burn 1 kg of fuel. -
I've found that the most efficient trajectories are almost the same as the ones I use for rockets. For instance, try pitching up to 60 degrees as soon as you've cleared the runway, then slowly pitch down as you ascend, aiming to be at 45 degrees at 15km altitude. Turn on your rockets at ~12 km, turn off your jets at about 15 km. After that, just keep pitching down, aiming for 30 degrees at 30 km, and level at 45 km, then keep accelerating until your apoapsis as where you want it, coast and circularize. Also, don't try those super tiny designs at first. I find a reasonable one-kerbal design to reach orbit without too much difficulty usually has about 5 standard tanks of fuel (2000L), to give you an idea of what ballpark you should be in. Once you've figured out how to get that into orbit, start optimizing your ascent, and shaving off fuel until you've worked it down to super-tiny.
-
[UNOFFICIAL/FANMADE] 0.17 Discussion Thread 2
silent_prtoagonist replied to kacperrutka26's topic in KSP1 Discussion
I've actually found that it's not too hard to do them in the Mun-Minmus system, as long as you're not terribly picky about where you go or when. The longer times involved with interplanetary flight would make this method tedious, though. There are a few tricks that should be fairly easy to eyeball, though. For instance resonant encounters (where you hit the same planet multiple times in a row, ala the vidoes that LukeTim posted) should be fairly straight forward. Just eject into an orbit who's period is a nice multiple of the planets--2x, 1.5x, 2/3x, etc--coast out the the opposite apsis, and adjust your orbit to make sure you're at another nice multiple for the next time around. -
Lagrange points are really outside the scope of KSP. But if you're really ready to start talking about building lagrange point space stations, then you're probably ready to make the jump to Orbiter. It has pseudo-n-body physics, which accurately simulate lagrange points, in addition to allowing other interesting things like sun-synchronous orbits and solar sails. It also, given that it has docking support, is currently a much better simulator for building space stations to begin with (at least until docking makes it into KSP). There are also numerous full n-body simulators out there that are fun to play around with. Universe Sandbox (which is pretty, but costs money) and Gravity Simulator (which is ugly but free) come to mind... EDIT: In retrospect that really sounded like an add...I promise I don't work for Martin Schweiger
-
I have a kerbal down, on the moon.
silent_prtoagonist replied to iCharles's topic in KSP1 Discussion
I've had similar troubles with kerbals not being able to get up when the fall while standing on a part, but quitting and reloading the game usually fixes it... -
Space-themed TV shows (that care a little about realism)?
silent_prtoagonist replied to Nikolai's topic in The Lounge
Artificial gravity (other than by acceleration) is about as impossible as ftl, which is to say there a few oddball theories that explain ways in which it might be done without completely throwing the laws of motion, thermodynamics, etc out the window, but they either require new physics or are simply many orders of magnitude beyond our current technical ability. If you want to include them in your sci-fi that's fine, but most authors/writers don't bother to explore the consequences of these technologies. For example, if the civilizations in Star Trek can routinely convert matter to energy and back again (transporters and replicators) why do they bother with the obvious safety hazards of powering their ships with antimatter? That's not to say that shows like Star Trek are bad shows (I'm a trekkie through and through), but I tend to find stories that at least acknowledge the presence of reality (such as the one scene in the new Star Trek movie with no sound in space...it's a step in the right direction at least) more rewarding that those that don't. Btw, a great website on the topic of realistic sci-fi that y'all should look at if you haven't already: http://www.projectrho.com/public_html/rocket/index.php -
Space-themed TV shows (that care a little about realism)?
silent_prtoagonist replied to Nikolai's topic in The Lounge
**spoiler warning** As has been mentioned, Firefly has no ftl, everything happens at sublight (albeit probably very high, by modern standards) speeds, so relativistic effects don't apply. I also have to give Firefly props for having no sound in space, and requiring ships to rurn around to slow down/change direction. It even has reentry heating Where Firefly gets it wrong is anti-gravity, propulsion systems that are "optimistically efficient" at best, and the general "space is bigger than you think" problem, among others. However, I usually tend to forgive live action tv shows for having artificial gravity, since most don't have anywhere near the budget necessary to make every single interior shot an effects shot, just to make the characters float (but props to Babylon 5 for doing AG right). As for the propulsion systems, the "firefly drive" is apparently ridiculously efficient, since Serenity isn't a flying gas tank...even assuming that 500 years in the future, we are capable of building such a drive that doesn't instantly vaporize itself with waste heat, you still have to deal with the problem of thousands of private ships flying around with weapons of mass destruction on their tails (but at least the show does acknowledge this in the pilot ) Finally, there are a couple of occasions in the show when the writers forget just how big and empty space really is...most notable in the pilot when the ship "just happens" to have a close call with a Reaver ship. The chances of such a close encounter happening by chance in interplanetary space, or even cis-lunar space, without one or both parties trying specifically to make the rendezvous, are astronomically low (literally)... -
I put a couple muon detectors in polar orbit back during my quest to find all of the monoliths. Basically they're useful anytime you want your satellite to pass over every point on Kerbin...mapping, communications, etc.