satnet

Methane and oxygen are great for main propulsion, but for this application would not be very suitable. Basically in a spacecraft you have two main rocket categories: main propulsion (where most of your delta-v comes from) and RCS/maneuvering thrusters. For RCS you want it to fire quickly and accurately since it is used for fine control of direction. Hydrogen peroxide and hydrazine variant (either as a monoprop or a bi-propellant) have both of these traits and as @Reactordrone said H2O2 is much safer in proximity to people. OF2 and CH4 don't have these properties: they aren't hypergolic so you need to provide some ignition source and they need to be pumped which means you need time to spin up and spin down. They are also cryogenic, which is OK when you have vast quantities for main propulsion and the square cube law means that you aren't paying too much for the insulated tanks (as volume increases you need proportionally less insulated surface area), but prohibitive when you need a small volume and therefore need a relatively large insulated surface area. P.S. I'm not saying methane and OF2, can't be used for RCS just that they aren't well suited to it. I believe the BFR will use CH4/O2 for at least some of its thrusters, but it has a reason to have large tanks of the stuff and is massive enough that even with spin up/spin down time it can be considered fine control. I agree with this, though relative to other monoprops it isn't very dangerous (though anything which has enough energy by itself to be a viable rocket fuel is arguably dangerous). You can come into contact with small quantities and it is just unpleasant with no real long term effects (which is not true of hydrazine). The main danger is when it is in large quantities where it can get enough energy to explode or you can come into contact with enough of it you can't escape to remove it in a reasonable time frame. Its main issues are spontaneously undergoing exothermic decomposition and it is catalyzed by just about everything (meaning your tanks must be obscenely clean to avoid it decomposing much faster than 200 days).

The Russians also use Fisher space pens. Also the pens are cheaper than the mechanical pencils that NASA was using to replace wooden pencils (wood being a fire hazard). On a more serious note I'm glad the crew is safe.

Your guess is as good as mine. The sources I found actually said oxygen pressurized air, so I don't think it was pure oxygen, though it sounds like a higher than normal concentration of oxygen. It struck me as both counter intuitive and interesting, but I don't know exactly why. https://www.spacetelescope.org/about/general/gyroscopes/

The gyros were replaced in Service Mission 3A (1999) and again in Service Mission 4 (2009), so it is maintaining its 9-10 year period between gyro failures. Three of the 6 gyros installed in the last service mission were of a newer design that was meant to be more resilient. The older ones used a pressurized oxygen to deliver the suspension fluid which corroded the wires, but the newer ones were constructed with nitrogen and were expected to be more resilient. Two of these new gyros are still up and running. The one they are trying to activate is the third one of this new design, but it does not seem to be operating correctly. Hopefully they can get it back up and running, it would be a shame to lose functionality, especially with JWST still on the ground.

As with a lot of engineering endeavors there isn't one "best" option. You have a bunch of competing criteria and your trying to optimize for your highest priority ones while being acceptable in the lower priority ones. What is a high or low priority depends on what you're trying to accomplish. For rocket fuels methane is on a short list of pretty good in most criteria, though it isn't THE best in very many it just happens to be the second or third best in many of them. Depending on what a rocket is designed for, methane's broadly "good enough" status may win out or you may want hydrogen's lower molecular mass and higher energy and put up with its irritatingly low density and low boiling point. RP-1 is easier to handle being a liquid at room temperature, it has a long history in the industry, and is probably cheaper (I don't know for sure). Methane has relatively low molecular mass, high energy, OK density, OK boiling point, and is clean burning. You can probably find a better fuel in each category, but most of them are noticeably worse in another. For deep space missions methane has the advantage of having a boiling point close to oxygen or OF2 which means that you don't have to worry as much about the temperature of the tanks equalizing over time. It should also be possible to manufacture in-situ. For right now I'm guessing that the reduced risk of coking in the engine is what is pushing SpaceX and Blue Origin in this direction since they both want to re-use their engines, so a cleaner burning fuel is huge asset to them (though the deep space considerations are probably a significant factor given their long term plans). I was curious what Ignition! had to say and it found this in the chapter on "Halogens and Politics and Deep Space": "All the hydrocarbons were good fuels, but methane was in a class by itself as a coolant, transpiration or regenerative, besides having the best performance. The OF2-methane combination is an extremely promising one. (It took a long time for Winkler's fuel of 1930 to come into its own!)"

Actually they did weave it physically in the ROM. They just wrote it in assembly first, then wove the resulting binary program into the memory. Curious Droid has a pretty good video on the subject:

As I understand it no, though they are similar and likely to have similar (dire) consequences. Cavitation occurs is when voids form in a liquid due to forces acting on it. It generally occurs in the pumps themselves (though any condition that causes a rapid change in pressure can produce it) and doesn't require a pre-existing void. Vapor lock due to ullage occurs because the liquid is separated from the fuel system by voids in the tank. They both produce voids that interrupt the flow, but are produced by different phenomena. Cavitation is particularly nasty since it generally occurs right next to moving parts and when these voids collapse they often produce shock waves powerful enough to damage parts. This can cause micro-pitting that eats away at blades and other parts of the pump. This is in addition to mass flow and combustion issues.

There is a site called the cosmic train schedule (http://clowder.net/hop/railroad/sched.html). It has Hohmann transfers for a number of bodies including Earth to Mercury. If you want to work from first principles you might look at http://www.braeunig.us/space/interpl.htm, since alexmoon's launch window planner used it as a guide.

I find it interesting to compare the BFS capabilities with a 747 freighter. They are close enough to be somewhat comparable: 747-8F - 137 metric tons, 858 m^3 cargo volume 747-Dreamlifter - 113 metric tons, 1840 m^3 cargo volume BFS - 100 metric tons, 1000 m^3 cargo/crew volume It sort of puts the vehicle in perspective for me even if we are comparing aircraft to spacecraft.

A couple people have alluded to Ignition!, which you can download here: https://archive.org/details/ignition_201612. It is definitely worth reading if you have any interest in rocket propellant chemistry or enjoy explosions. Chapters 3 and 8 are probably the most relevant. Basically the reason gasoline, diesel, etc. are not used is because rockets are unforgiving beasts with refined tastes and a nasty temper. You can get gasoline to work (probably diesel too) and we probably don't need to be as refined as RP-1, but the expense of the payload and rocket justifies a fuel you can be reasonably sure won't destroy them. As @MinimumSky5 said RP-1 was developed to be remove the impurities, but still have something petroleum based so it was reasonably attainable and affordable after many failed attempts to use gasoline or jet fuel (the military wanted something they already had on hand, but reluctantly had to concede that it wasn't going to happen). Probably the most relevant passage is in chapter 8 talking about JP-4 (jet fuel) with liquid oxygen: "But there were troubles. The sloppy specifications for JP-4 arose to haunt the engineers. It burned all right, and gave the performance it should —but. In the cooling passages it had a tendency to polymerize (you will remember that the specifications allowed a high percentage of olefins) into tarry substances which slowed the fuel flow, whereupon the motor would cleverly burn itself up. And in the gas generator it produced soot, coke, and other assorted deposits that completely fouled up the works. And, of course, no two barrels of it were alike. (Also, believe it or not, it grows bacteria which produce sludge!)". Also in chapter 3 he talks about the issues with both gasoline and JP-4 with acid (generally some nitric acid variant): "It (JP-4) was acid-gasoline all over again —a coughing, choking, screaming motor, that usually managed to reduce itself to fragments, and the engineers to frustrated blasphemy. Everything was tried to make the stuff burn smoothly, from catalysts in the acid down —or up —to voodoo."

It sounds like you're talking about an Mars cycler (you may also see it called an Aldrin cycler due to "Buzz" Aldrin's contributions) with a rotating section. This is more akin to a station than ship, though that distinction can be fuzzy in space. You can justify more mass because you get to use it over and over again, but this justification has its limits. Like a lot of space infrastructure you're problem is not so much technical feasibility, but the economics and politics. For this one you have to justify 100 BFR launches which could have been put to other use. If the BFR can get to mars with 1 crew/cargo launch + 5 refuel launches that is the equivalent of trading ~16 BFR direct missions for this one cycler. If we do have a colony that might make sense because we'll be sending cargo and people for the foreseeable future, but for the early missions it is going to be overkill. If it were me I would downscale this quite a bit. First, if this really only makes sense if we have permanent habitation we must have established that martian g is sufficient for long term, so target 1/3rd of a g instead of a full earth g. You can always design it with connectors so you can expand it out to a full g. I would also make them arc segments instead of full rings (again you can plan for expansion to a full ring). Put only the things that benefit from gravity in there: gym, dining areas, medical, and sleeping quarters (some of those are debatable, but you get the idea). Those are just my first thoughts. p.s. Rendezvous is slightly more delta-v than the direct mission. The benefit of a cycler isn't reduced delta-v, but the ability to re-use the high mass cycler while only boosting the much smaller rendezvous craft up to that speed.

I'm releasing this to linuxgurugamer if he is still interested (if not he is now free to release it to someone else). Sorry for the long delay. I took a break from KSP and only recently came back.

RealGecko contacted me before hand so he's in compliance with the license. I apologize of abandoning it without nominating a new maintainer, but I kept telling myself I'd come back to it. I've finally concluded that isn't going to happen and it is past time for me to pass the torch. I appreciate RealGecko making this available for people.

I'm looking for a new maintainer. Let me know if you're interested.

I'm looking for a new maintainer for this mod. Let me know if you're interested.

Take a look at Keptin's design thread: http://forum.kerbalspaceprogram.com/index.php?/topic/47818-basic-aircraft-design-explained-simply-with-pictures/. Now for a some specific advice on your plane. The CoL is above the CoM which is more stable, so you might lower your wings. I'm not sure how much wing aspect matters in stock aero, but you might want to give a lower aspect ratio (stubby instead of wide). Your CoL is nearly on your CoM, which is good for maneuverability though you could probably afford to have the CoL a little further forward if the rest of the changes aren't enough. As far as making the wings more solid it mostly comes down to reducing the number of wing segments involved if you can. Using larger pieces would help. Reducing the aspect ratio would also help since more of the wing would be attached to the plane fuselage instead of a wing attached to a wing attached to a wing (you get the idea). P.S. Keptin does NOT pay me to plug his thread, I just find it immensely helpful and worth sharing.

I would also suggest http://alexmoon.github.io/ksp/ for planning a transfer burn. It is similar to olex's, but it tells you the in-game time when the transfer window will occur. It also makes it obvious that it is a window where you have times that are really optimal and some around it that are not as optimal, but OK. There is also a mod that does nearly the same thing (Transfer Window Planner?).

Thanks for the suggestion. I just posted 0.31 which supports this.

Version 0.31 Minor Update: LEST-1 - Now triggers when using FAR and an aerodynamic failure occurs.

It is often a good idea to check the KSP.log file (created in the same dir as your KSP executable) when a part won't load. There will usually be some hint why it isn't loaded.

Version 0.30 New Parts: TRS-1 - Terrain Radar which scans the ground below your ship and gives you a color coded view of the terrain. LEST-1 - Launch Escape System Trigger that will auto abort if a part is unexpectedly destroyed.

There is "collider.bounds" on the Part. I believe that will give you want you want. You might also look at "collider.ClosestPointOnBounds".

I saw this post and was inspired, so I put together a part/plugin that does this and added it to my mod for flight safety tech. I just uploaded the new version of The RAT Pack (Dev Thread) with it included. I had some other significant changes in this release, so it will probably be a few days before it makes it into an official release. I'm sure I'll make it more sophisticated, but for now it will trigger the abort action group when any part is unexpectedly destroyed which seems to work pretty well.

Version 0.21 is up. -Terrain Radar - See how terrible your landing spot is before you touch down. -Launch Escape System Trigger - Detects a rocket failure and triggers the abort action group. -TAWS alert sound is now configurable. The TAWS.cfg file has a "terrainAudio" field. Within that there is a clip field and a next field (optional). The clip can be any *.ogg or *.wav in a GameData sub-directory. The terrainAudio field is an AudioSequence, you can fill out the next field and stitch together different audio clips which will be played sequence on a loop while there is warning triggered.

Posted 0.20. New Parts: EPM-Mk3 - Emergency power unit for Mk3 aircraft. Contains a RAT, Fuel Cell, and APU. Changes: Reworked RAT calculation. Now takes into account orientation and occlusion. Reworked the atmospheric pressure handling. Completely new power curves thanks to some great input from Reiver on the Dev thread. More varied and realistic. A graphing function to show off the new power curves and make it easier to compare one RAT to another. Fixed the animation rate when generating power. Other small tweaks.