Horn Brain

Saturn V, not Falcon. Falcon is SpaceX stuff. The LM looks like this: It used hypergolic fuels, not monopropellant, and had two engines, both in the center of the vehicle. You can see the ascent engine is recessed into the cabin area. If I were you, I would cut way back on fuel for both stages. You only need about 700 m/s max to land on the Mun from LMO, and that's granting a generous saftey margin. Likewise, you need the same dv to get back up.

We really do need electric propellers for Jool/Laythe/Eve/Duna exploration. On Laythe it's possible to bring jet fuel, but for the others it's basically rovers or tons of rocket fuel. And just to preempt: I know about firespitter, I'm saying it would be nice to have this stock.

I've done everything but a return mission to Tylo (and Jool and the Sun, but duh). I don't see the point in it anymore. I did Eve, which is harder, and Tylo would just be more fiddling and tweaking to get the stages to cut out at just the right times. There's also nothing cool to see on or from Tylo that I'm aware of, except maybe the Cave. To me, the cave seems too much like a glitch to be worth checking out. If they had implemented the resources system, they could have given Tylo some special resource that is relatively rare everywhere else and then maybe it would make sense to go there... BUT NOOOOOOOOOOO...

This is fantastic! So much fun, it's like an instant mission control. Very useful for helping others learn the game, since I can tweak their maneuver nodes if they get stuck. One thing I think would make this even better is correcting the following: 1.) The navball doesn't seem to be working in the map view, it kind of just lolls around randomly. 2.) The ship part count, weight, etc. don't update in the info box on the right side of the map. I was impressed that the maneuver node delta-v works great, though. Kudos for a great mod. A little bit of polishing (and a few words in the readme to help newbs like me figure out how to connect over IP) and this will become a "must have" mod. I would even venture that something like this is a better direction for multiplayer to go than multiple independent players whizzing around thousands or millions of kilometers away from each other. Thanks again!

I think a New Horizons-style mission would be pretty easily within our grasp even now. Whip around Jupiter with a 20 year lead time and we'll be out there waiting for it to scream past. By the time we are ready to launch this mission, however, we will hopefully have some much more exciting options. Maybe we can send a nuclear electric driven craft out there with enough dv to actually orbit Sedna, or even bring a lander to examine the surface. The dv to return to Earth from Sedna would be something like 4 km/s - not actually too crazy when your Isp is 5000 s. I would think that a sample return would be a goal worth aiming for by this time. The mission wouldn't need to be much more dv intensive than the JIMO

As a rule of thumb: The best scope to buy is the biggest one you can afford that you will feel like taking the trouble to set up and use frequently. However, it does have to meet some basic standards of quality. There's no way you'll be able to figure out if your scope is a lemon or a pearl until you get it out and use it yourself, so you're going to have to read lots of reviews from independent sources (i.e. not the people selling the thing!) to get a good idea. Here is a link that helped me when I was buying my first scope: http://www.skyandtelescope.com/astronomy-equipment/types-of-telescopes/ (I ended up buying binoculars until I was sure I liked going out enough to spend much more for a larger scope). Also, don't forget to factor in the cost of the necessary accessories! Your scope is useless if you don't know where to point it, so you'll have to either get some star maps or software to be able to figure out what's up there when it's dark out and where to find it. While they aren't strictly necessary, they are much more convenient than having to have your computer around to help you find planetary nebulae. There are lots of add ons depending on your type of scope, as well. Know what they are! Manage your expectations. When you find the Eagle Nebula, you aren't going to see this: http://www.spacetelescope.org/static/archives/print_posters/screen/hst_print_poster_0029.jpg, you're going to see this: http://spacemandan.net/astronomy/Deep_Space/Eagle_Nebula/Through_A_Telescope-small.jpg However, you will be AMAZED at how much detail you can actually get out of a faint fuzzy image like this if you learn how to observe. Observation is a skill, and so far I've found it to be one part knowing what to look for, one part knowing how to use your scope technically, ten parts dark adaptation, and ten parts patience. Finally, READ. To tell you everything you really ought to know about telescope hunting and observing would be to write a very thick book. Read reviews of telescopes in your price range, browse astronomy websites for tips on how to observe, how to use the scope, how to figure out magnification/field of view/limiting magnitude/etc., and how to keep from doing something stupid like cleaning your optics with a paper towel. There's a ton to know, but to me that's part of the fun of the hobby. Best of luck to you in finding your new scope/binos!

Just so people know, the Kepler Problem refers to the restricted two body problem, which is the basis for all of the game's orbital mechanics. The primary body is the sole source of gravity that is considered when computing trajectories of any secondary or ship. With this simplification, there is a known solution to the trajectory. The solution is not in fully explicit form however, because of Kepler's Equation, which relates time to a body's position along the orbit. That equation is transcendental and must be solved iteratively. Luckily, it (in practice) almost always converges very quickly using a standard approach and a standard initial guess. That iterative procedure is not necessarily impossible to do in Excel, but it does immediately mean that you're into the area of math where you ought to be using something better than Excel. Anything written in simple Matlab should be easy to make work in Octave, which is open-source. Ideally, you should be using a compiled language for this because of the indeterminate end conditions on the loops required when using a converging process, but they are often too tedious for anyone to sit down and do the coding. If I'm not mistaken, Julia is a new thing which is supposed to be like compiled Matlab, and may be ideal for this.

Yeah, I'll say.

Do you mind if it's in Matlab? I've already got something like this written for that.

Suppose this works great. You're still SOL because Xenon is an extremely heavy atom, which means that your exhaust velocity will be much lower and therefore your rocket will be much less efficient than it could be otherwise. This is partly why H2 and O2 are the top of the line fuels: they produce H2O as exhaust, which has a molecular weight of 18, compared to what I'm assuming will be Xe + 2O2, which has a combined molecular weight of 131+2*32=195. Divide by three for the average and you get 65 or so. Roughly speaking, for the same temperature you're going to get about 1/2 the molecular velocity (on average), which means 1/2 the Isp!

I don't want to make ten, but my most important rule for beginners is BUILD BACKWARDS! First put together the thing you want to land back on Kerbin, then build a thing to get that back to Kerbin from the target, then build a thing to get that from LKO to the target, then build a thing to get that into orbit. Once you do this a few times, you'll get a much better feel for how important it is to save weight on the later stages.

Single Stage to Space Station! This thing can just barely get to orbit on its own, and so I made it look like Skylab. Bob enjoyed it.

Glad you solved it. I was wondering how to do it without hacks. Is it possible to park the rover about halfway into the sea and then have the kerbal swim up to the correct side of the pod and grab on?

Hastily conceived challenge does not forbid wings... >:-|

Idea: Can we just sticky post a "Space Shuttle Opinion Thread" so that people can just be redirected when they get off topic?

Is it ethical to wash your hands with soap, knowing that you'll be killing millions of bacteria? People >>>>>>>>>>>>>>>>> bacteria. Even Martian bacteria. We do what we need to ensure our survival, and in the case of Mars that means colonizing it to ensure that we can't be wiped out by a comet or other cataclysmic event on Earth. Any measures that are possible should be taken to preserve samples of any Martian life we find, but even if we do find active microbial life on Mars, it should not prevent us from colonizing it at the risk of destroying Martian life. The only utility that Mars life provides is its value for scientific study (unless we discover that it can do cool useful stuff that our bacteria can't).

Who knows what would happen? Anyone with about two seconds to spare thinking about this problem. Mars would explode from centrifugal force looooooooong before you ever even noticed the added gravitational effect of the extra energy. Mars doesn't need more gravity, just a magnetic field. And that's only for the long-term (hundreds of thousand or millions of years). If we warmed up Mars right now and added some extra atmosphere to get it up to safe levels, you could have oceans and atmosphere for longer than our civilization has existed so far.

Faith, if it's defined as believing something without or in spite of good evidence, is directly opposed to science. You can't have a science show that doesn't at least implicitly argue directly against that kind of belief. It's just not possible. Science is the rejection of faith in that sense. Most people use faith to mean other things, like "religion", "confidence in yourself", etc. Cosmos has nothing to say about these things really. It never says you can't be religious and do science. The "hero" of the first episode, for instance, was very religious, as was Newton. All Cosmos wants is for people to use science when they have the option, because science is always the best way to find out the truth about nature (almost by definition, since if there was a demonstrably better way discovered to learn about nature, science would incorporate it). As long as you keep your mind open that what you believe may be challenged and proven wrong, then you can do science. So be careful when you say things like Cosmos is picking on people's faith, because in some sense it couldn't do otherwise, and in some sense it's absolutely not.

I'm really enjoying it. In fact I've been blogging about it and trying to use little oversimplifications used in the show as jumping off points to learn more about some of the things brought up in each episode. There are some really fascinating things you can learn if you just keep your eyes open during the show. This goes hand in hand with what I view as the show's goal: It's not so much about teaching people all kinds of crazy facts as it is exposing them to the breadth of the knowledge that science provides us, and especially pointing out the frontiers. Every child who grows up in a "FOX family" and who sees this show and breaks out of their tiny little life bubble and discovers the universe is a victory for all of humanity. I can't wait to learn the things that some of these kids will grow up to discover about our universe.

Hey and welcome to the game! You should take a look at the amazing KSP Wiki. It will teach you just about everything you need to know to get started in the game. Take this for example: http://wiki.kerbalspaceprogram.com/wiki/Vehicle_Assembly_Building#Interface That should explain how to save and load ships in the VAB. What have you done so far? Made it to orbit yet?

Don't do the gently skimming the atmosphere repeatedly thing. When you finally dip the apoapsis into the atmosphere you start from too high up and dive too steeply. It would be nice to plot a maximum g-force vs. periapsis altitude graph from running this experiment but I don't have time. I've learned that there is a sweet spot for low g reentry. If you start with a periapsis of zero and raise it by increments, the maximum g force encountered on each reentry will decrease up to a point, and then you'll start to see it increase again once you get to the point where you lose horizontal velocity too fast and too high and end up dropping more like a brick. Hope that helps. The numbers people are giving you in here are about right. Around 30km to 40km is what I aim for, depending on how fast I'm coming in.

First of all I meant "force" less than literally. I mean to force people to confront the fact, stated very bluntly, that out here, we're all humans, earthlings, similar. Second of all, I can think of nothing that has caused more violence in human history than people seeing each other as members of different groups, as opposed to human beings. So it might not be such a bad thing if people took their cultures a bit less seriously down here. Not that they can't enjoy their culture, just that it would be nice if they saw themselves as humans first. This goes for all cultures, including dominant ones that see themselves as "normal" compared to the minority cultures which are seen as "special".

Space needs to be free of political boundaries. Everyone can use space so long as they don't interfere with anyone else's use of space (no orbital littering, demolishing other countries' infrastructure on other worlds, etc.). It would be good to force humans off the Earth to think of themselves as humans and not as Americans, Russians, Chinese, etc.

The amount of air that an object can push aside at hypersonic speed is something like it's own mass. This is Newton's impact depth approximation and it works pretty well. This works out to be a relationship between the density of an asteroid that can pierce a given column of air and it's radius. If you look up air mass, you'll see that at the horizon, the column of air you're looking through has about 38 times as much mass as the column of air directly over your head, which has an areal density of about (sea level density) * (atmospheric scale height). So 2*38*(sea level density)*(atmospheric scale height) is about 824 tons per meter squared of cross-sectional density for an asteroid. Since the asteroid's mean cross-sectional density is approximately (4/3)*(density)*(radius) (divide mass of a sphere by pi r^2), we get a relationship between asteroid density and minimum radius to pierce the atmosphere. The denser the asteroid (x axis) the smaller it can be (in meters on the y axis). If we have an iron asteroid, the radius would have to be around 80 km. That's the minimum size from a purely momentum-based view. It may have to be bigger to handle the heat load, it may have to be unphysically strong to avoid being ripped apart. If you notice, this 160 km rock sitting 1m off the surface of the ocean has its top in space. So it's pretty much not going to happen the way you're imagining it.

I never thought of Whackjob as a pragmatist.