Gaarst

#bringbackthelaunchtower

Just out of curiosity, how much time do you spend on your creations on average?

You basically want to find z numbers such that the complex part of the polynomial is zero. Define z = a + ib with a,b real. Your polynomial becomes: P(z) = z3 + 8iz2 - z + 42i = (a + ib)3 + 8i(a + ib)2 - (a + ib) + 42i Develop the cube and square and rearrange a bit to obtain the polynomial with separated real and imaginary parts: P(z) = (a3 - 3ab2 - 16ab - a) + i(-b3 + 3a2b + 8a2 - 8b2 - b + 42) If you want your polynomial to return real numbers, you need to find a number z = a + ib such that the imaginary part of P is zero: Im[P(z)] = -b3 + 3a2b + 8a2 - 8b2 - b + 42 = 0 This is basically all you need to solve this kind of problem, there are methods that are more efficient but this one is reliable and fairly simple as it gives the imaginary (real) part of z as a function of the real (imaginary) part, so you won't need to find roots (except maybe for the domain of b). For this particular polynomial, the solution is z = a + ib with: b ∈ ( -∞, -7] ∪ [-3, -8/3) ∪ [2, ∞), and a = ± √[(b3 + 8b2 + b - 42) / (3b + 8)] You could also use the variable r as you did, and solve z3 + 8i z2 - z + 42i - r = 0 for z directly. This amounts to solving a third order polynomial for z, keeping in mind that z may be complex. If you seek a numerical solution, this is probably easiest/fastest method since root-finding algorithms are pretty efficient. If you want a function that maps z to r, you will need to solve it analytically. 3rd order polynomials are doable but surprisingly annoying for what they're worth. The solution for a and b is quite complicated in itself (a being the square root of a rational function), so I don't expect the math to be trivial.

Top right of the screen, click on your username, Ignored users, and add their name there. http://forum.kerbalspaceprogram.com/index.php?/ignore/

The GSLV first stage is the same as the PSLV (S139 solid stage), and their second stage is very similar, both powered by Vikas 4 engines. My guess is that using this architecture, large boosters were the easiest way to push the design to 2.5t GTO. Being limited in power (India currently only produces Vikas variants in that range of thrust), bigger boosters meant longer burn times. Using proven components meant a cheap launcher and therefore they could allow losing a bit of efficiency by arranging the staging as they did (it's actually more "not exploiting possible efficiency" that "losing efficiency" since the launcher fills its role which is enough).

I've added the link to the old downloads in the HGR Community Fixes entry. Thanks for making me notice the name change, I've changed it.

And no typo anymore! Thanks for noticing!

Pictures of RSS? I have quite a bunch of these somewhere, a few in the spoiler.

The N1 didn't kill anyone. And even if there was people in it it had an LES. Part of a rocket's standard abort procedure is to terminate all propulsion, which has to be done explosively on SRBs, there was no way for the crew of the Space Shuttle to survive a SRB failure. Bringing an upper stage to LEO and lighting it there is less efficient than launching straight for an higher orbit. Besides a conventional launcher doesn't require a crew and 70t of dead mass for a few tons of satellites. Meaning that you need to bring crew on any commercial flight, and that you bring 70t of dead mass each time you get people to space. Being able to do the two is a good thing for particular situations, but doesn't make up for the constraints. Yes. They are being adapted, because the Space Shuttle program was terminated. At no point during the Space Shuttle program was it planned to use hardware for another launch system. This allowed the components of the Shuttle to be more specific in their roles, and more efficient: but reduced the possibilities for alternative use. For example the SSMEs are the most complex rocket engines ever created in order to be reusable over dozens of missions, and they worked fine in that role, but using them for single launches is simply a waste of money. Energia's adaptation for alternative payloads was to be much more simple, because it was designed for it. No engine or boosters upgrades were needed, and no additional components were to be manufactured: quite like a regular rocket, you would have been able to strap a payload to the launcher and launch it. Regular expendable rockets are better for the role of crew transportation. Regular expandable rockets are better for the role of heavy payloads transportation. The Space Shuttle was better for the role of crew and heavy payload transportation at the same time, but it's a niche use, besides SpaceLab missions and Hubble servicing, this combined capacity was never required. The ISS could have been built by regular unmanned rockets, just like MIR was by Protons. The Space Shuttle was better for the role of mass returns. In my opinion it's the only effective advantage, with in orbit servicing, of the Shuttle over regular rockets. Being able to bring back large objects protected from reentry is a real asset, but it doesn't justify the entirety Space Shuttle program, especially the parts were it was to be the only US launch system to try to make it economically viable.

Yes.

Good point. But SLS doesn't have the public/political support Apollo had. It painfully passed government approval over arguments that it could reuse Space Shuttle hardware and facilities, but I feel like the program is very frail.

A 1% payload fraction is pretty terrible, even for real rockets. And you don't need 2000t of rocket to send 7 people. Soyuz can do it in 900t, and that's using 3 different rocket, with one almost empty. Dragon v2 is designed to be launched on a Falcon 9, 4 times lighter than the Space Shuttle, and a lot more than 4 times cheaper. Falcon 9 can also bring its 20t payload to orbits other than 28° LEO. cf Challenger. Energia-Buran was a single program. Being able to use Energia for something else means better commercial possibilities, and acquiring more experience on the launcher, overall helping the program as a whole. The impact on the Buran itself might have been rather limiter though. It could have but it didn't. Regular expandable launchers remained better for the role over the 30 years of the Shuttle.

If SLS fails on its first launch, consider the program to be over. Especially if it is manned.

OK, I didn't know that. Though I don't see the point of using an absolute path (with GameData as root) over a relative path starting from the config (or mod folder) inside a mod. I can see why it would be needed for dependencies but not for a single folder.

[slightly off-topic because it used to reply to a post that was removed] Even though there is no absolute proof that climate change is caused by human activities, the general scientific consensus is that the climate change we are experiencing right now it is very likely caused by human activities. One cannot state whether or not it definitely is the case. If you do, it's nothing more than an opinion, whatever it may be. Considering the possible consequences of a man-driven climate change and the likeliness of man's role (and the adage "Better safe than sorry"), the safest choice is to act against the possible human sources of climate change. Slightly aside: ecology != preventing climate change. Climate change is a big risk, but even if it is not true, other kinds of pollution cause a risk to health and biodiversity. Both sides of the debate tend to reduce the pollution problem to climate change. Industries argue that climate change being a hoax allows them to pollute the environment with non-greenhouse products, and "mainstream ecologists" happily shoot back on the same line.

That's the issue. This old lady probably doesn't even know what an ellipse is, and yet challenges 400 years of evidence in many fields of science (from observational to mathematics) by claiming geocentrism is a thing. I'm sure she is a very nice person, but this is beyond ignorance (I'd say a mix of stupidity and arrogance). People need to accept that they might not know some things and that they may be wrong on other. Unfortunately, politics has a long history of dividing people through ideologies and dogmas, doing little to unite other than shouting they are the best louder that their neighbour. Now that scientific issues are becoming politicised (climate change, health issues...) people are applying this way of thinking onto science, and effectively removing all the "scientific" part of the public debate. I feel like the fields of research are too far from ordinary people's preoccupations and this causes ignorance on the matters (I didn't even know how scientific articles are written until I got halfway through my degree in physics). Science in general needs to become more "popular" in order for people to appreciate the true meaning of it because stupidity stems from ignorance. Teach people that science isn't a matter of opinions or beliefs, and some people will no longer be able to manipulate it to support their claims. Problem is challenging one's way of thinking is pretty hard so I don't expect this change to happen anytime soon; plus there is a fair bit of disinformation out there, and as we all know, a random YouTube video backing your opinion is a better argument that centuries of scientific consensus on the matter...

I think planets are the element of KSP that got the least improvement during its development. Other than adding new bodies or reworking terrains, nothing has ever been done AFAIK. I support these improvements, though at this level it would probably require a complete rewrite of the planets generation. Fingers crossed for 1.5! (1.4 has to be a graphics/rocket parts revamp)

One of the earliest game I remember playing was Halo 2 or some Medal of Honor (couldn't tell which, probably AA). I've also played some CoD (up to MW) and Battlefield (1942 and BF2). Thinking about it, besides these oldies and CS:GO, I haven't played that many FPS.

AFAIK you could nest a mod folder inside 20 folders named "fnjkhghvinhekv" and it will still work. KSP just browse through all folders and subfolders it finds in GameData; as long as you don't touch anything inside the mod folder itself (ie: renaming textures/models folders...) your mod should work fine as long as it doesn't have dependencies. If it does (eg: a planet mod and Kopernicus) I guess it depends on how the mod is written. If the mod is written such as to wait until all Kopernicus stuff is loaded it should be fine, but if it has to get the Kopernicus files it needs manually, you might have problems if you move your mods around. I'm not a modder so I don't really know how dependencies are handled. I'm an idiot again, see below for actual answers.

Idiots thinking watching a video on YouTube or reading a random website makes them better qualified about a subject than several generations of scientists dedicating their lives to it isn't anything new. To be fair I couldn't care less about these. Clever people exploiting them are the problem.

No.

OMG they found life on Earth! On a place slightly drier than average! Remove 99% of the atmosphere (air, radiation protection...), the few droplets of water still hanging around, and about 100K and we almost have Mars! Better start packing our stuff for Mars right now!

You can interpolate a n-th order polynomial for any set of n+1 points: the curve will pass exactly in every points, but the variations in between may not reflect what you want. So you could find a 7th order polynomial such that f(1) = 0, f(2) = 1, f(3) = 4, f(4) = -13 and so on. If you don't want random oscillations between you defined points or a curve that is not a polynomial, you can use splines, which are lower-order polynomials patched together to form a smooth curve.

A few guidelines: 1.2 TWR is a bit on the low side. You want something closer to 1.5 at liftoff otherwise you will lose much dV to gravity drag. Try to always put the more efficient fuels up in the rocket, ie: (down to top) a hypergolic-kerolox-hydrolox rocket will be more efficient than a hydrolox-kerolox-hypergolic rocket. If you need hypergolics on your orbital stage for restarts try keeping as little as possible I like having 2-2.5 stages designs for LEO: a powerful 1st stage (+ boosters if needed) to get me off the pad, and an efficient upper stage to get me in orbit. For anywhere beyond LEO I add a third stage. The best upper stage fuel is hydrolox, because it is very efficient. But if you use it, mind boiloff. It is good from anything you have to do in LEO (insertion, transfer or ejections) but you will start losing a lot of it if you try taking it further. For GTO-GEO insertions or outer planets exploration, hypergolics are the best (infinitely storable and many restarts). You don't need TWR > 1 for the upper stage. A weaker engine means a less massive engine and therefore more dV. With a bit of practice you can reliably and efficiently achieve orbit with 0.5 TWR upper stages on 2 stages designs. Lower TWR is doable but requires more practice. Start with comfortable thrusts (TWR about 1) and reduce it as you get more confident when launching. The lower the upper stage TWR, the steeper the trajectory. If you are close to apo when igniting your second stage, you will have to burn off prograde in order to avoid falling back to Earth, and you will lose considerable amounts of dV. 3 stages designs can use even lower TWR for the upper stage, and so they are good for beyond-LEO launches. You don't need TWR in space. Once you're in a stable orbit, very low TWR (>0.1) are enough for small adjustments. For insertions into higher orbits, you don't need that much TWR either, as long as your burn times are under 10min, I find that accuracy and efficiency are good enough. Launch in the right orbit. Inclination changes in RSS are extremely expensive, so 20° plane changes once in LEO are usually not an option. For lower stages, the best fuel depends on the dV you need. The more stages you have, the less dV per stage you need, and you can allow less efficient but denser fuels (hypergolics or kerolox). If you have only 2 stages, an hydrolox upper stage is almost mandatory if you want a decent payload fraction. Solid fuel is good in boosters and that's it. Because it's so inefficient (and therefore heavy) having it in upper stages will reduce your dV. Having a perfectly tuned solid upper stage that gets you in the perfect orbit is great but keep it for later. Solid first stages can be useful, but you will need large boosters and 3 stages. 2 stages can be done but your upper stage will either be a pain to fly due to low TWR during the ascent, or way too powerful and inefficient. A useful design trick that I still use is designing your launchers in two parts: the booster to LEO and an upper stage to wherever. Aim for 9.5km/s (9.3 when you get more experience) dV in the booster and ditch it in LEO, no matter how much fuel you have left in it. Design your upper stage to that it can do its task even from a fairly low LEO. Direct insertions to further places requires experience anyway to nail the timing, so keep them for later as well. These are guidelines that I use in my game, and AFAIK they work pretty decently. Note that I don't play with the full RO/RP-0 suite (I have most of the RO mods, but installed manually and separately), so there might be subtle differences of which I am not aware. The RSS/RO people are always happy to help regular KSP players get into it (probably because we are all elitists who subconsciously think that RSS is superior), so don't hesitate to ask more questions!

Parts designed for a specific purpose in a spaceflight game? Absolute nonsense! Everyone knows rockets should be stacks of fuel tanks taped together!