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?