wumpus

That sounds like more than a few of my attempts to get into orbit using NERVs for circularization burns. I'm a bit more embarrassed about my first trip to Duna (sandbox, after far too much experience flittering around the Kerbin system). I barely needed my NERV stage to Duna, and it deleted the thing while it was in orbit. I managed to get there and back without the majority of my delta-v.

Any idea what takes so long? Does it have to compile the C# each time? I know mine isn't fast, data comes of an SSD and runs into a potato CPU (AMD Bulldozer) but I'm not running many mods. Back when this thread was new Harvester mentioned a Unity bug. But that was long before 64 bit mode and the ability to go wild with mods.

But does it make more sense to send up reactor than solar panels? Granted, the ISS has this big old planet occulting the Sun every 45 minutes or so. My understanding is that reactors are for Mars and beyond (especially beyond). Stuffing a multiple falcon heavies with solar panels sounds like a trivial task (both politically and packaging wise) than sending up a reactor.

You think that would ever stop a government worker protecting his "turf"? This sounds a lot like the reason that Spacex cameras had to cut out when nearing space. As far as I know, there have been plenty of "trade secrets" lawsuits over things publicly available, and as long as they weren't leaked in a completely legal way (and trace such a leak to the defendant) the "owner" of the secret could still sue.

There was a recent plea for help to avoid a Kraken attack on a spacestation. Some suggestions: Reaction wheels should be in the center. I theory it doesn't matter, but the numerical means KSP uses for physics calculations mean that the effects start at the reaction wheel and propagate out. Moving things toward the center helps reduce resonant effects. RCS have similar issues: don't have them fight each other nor push hard on unstrutted parts. Beyond that, go wild.

Does Earth have a backstory? I guess the [presumed] Theia collision was impressive (producing the Moon), but beyond that it mostly cooled and cultured life. What kind of backstory would Mars have? We can suppose that some ancient culture caused a runaway greenhouse effect on Venus, but that is projecting modern scientifically important theories on little data much the way Victorians assumed that such a cloudy planet must have dinosaurs. I can't imagine gas giants having a backstory, although the various moons might have more interesting stories involving their capture. I'd especially avoid giving stock Kerbol planets backstories. Long before release somebody simulated the Jovian system and it ejected a moon in under a year. It is just gives you a place to go, and has little more justification than "because they're there".

My understanding is that hydrogen is already used this way in current hydralox engines. They run fuel rich to include hydrogen in the output (as well as water), this helps both keep temperatures from melting all known materials and increase Isp. As far as I know, I think the materials are at thermal limits, so using an increasingly rich input won't help much (unless you want to build a cheaper engine with slightly less Isp and not quite so thermally constrained). Building a turbopump for a source of hydrogen is likely too complicated for any currently used engine, while hydralox engines are simply designed for a different oxidizer/fuel ratio. As far as the nuclear thermal reactor (or possibly solar thermal reactor), hydrogen is the key and the achilles heel. They might list a 4 digit Isp, but don't expect that from anything but hydrogen. Water will give you less Isp than chemical hydralox, but might be easier to find in space. Keeping hydrogen in your tanks beyond Earth orbit is easier said than done. I don't think anyone as worked with fluorine or lithium in rockets since Ignition! was published.

I was under the impression that monatomic hydrogen was up there (along with metalic hydrogen) as wildly superior to ordinary rocket fuels. The issue is that monatomic hydrogen isn't stable enough to even have the horror stories in this thread, you simply can't make it without it decomposing into H2. Presumably you meant simply compressing hydrogen gas, as that is pretty pointless. It takes up too much volume, needs to be refilled right before launch, and is unlikely to deliver more impulse than compressed nitrogen (which is trivial to work with, although dangerous in large volumes. I'd guess you'd include some oxygen to avoid asphyxiating technicians). Don't forget that beryllium as a metal has some amazing strength to weight ratios. You might want to use that more to decrease dry mass than to increase Isp. Just be careful what you expose it to and how you mix it in an alloy.

Gotta love that 4-4-4 triangle (Magnemoe beat me to it). Flash point: 30C? Not for use near Cocoa, Florida (KFC), Santa Maria, California (Vandenburg), and even winter use is iffy in Chincoteague, Virgina (Wallops, Island). Can't tell if the 50mg/kg LD50 really means milligrams, the concentration LC50 values imply you wouldn't need close to that to kill you. Explosive limits of .42%? Does that mean any significant concentration explodes if you look at it funny?

How much does dynomite (nitroglycerin stablized in a clay substrate, i.e. Alfred Nobel's invention) add to the weight? Of course, I wouldn't recommend going through a search like Al did to find a means to stablize ozone (one son was blown up, the other was rather convinced he deserved the inheritance).

New spacecraft (whether probes or satellites) fit somewhere between the cost of developing a whole new launch vehicle and hitching a ride on a fully developed one. I strongly suspect that "no new orbital platforms" and "no new probe platforms" will need to be added to keep costs coming down. - this is of course orthogonal to SLS whose mandate is largely to spend money in specific Congressional districts.

I suppose there are aero engineers here to correct me, but exceeding "velocity not to exceed" is a good way to get your aircraft to shake itself (flutter) to death in a second (I don't think it is modeled in either KSP or Ferrum). I suppose there are aero engineers here to correct me, but exceeding "velocity not to exceed" is a good way to get your aircraft to shake itself (flutter) to death in a second (I don't think it is modeled in either KSP or Ferrum).

The problem remains the same: is the motor sufficiently efficient (and massive) to put 510km/s to the wheels before it cooks itself due to lack of cooling. Both the Tesla and Roadster absolutely require that atmosphere for continual use, in this instance we can cut the motors once we are inertiaborne (like airborne, only via orbital mechanics in a vacuum). Electrics tend to want to be cooler than fossil fuel heat engines, so be careful how much you use them. My understanding is that drag racers can do the 1/4 mile on empty radiators (not what I'd think is a good idea, but not all of them feel like plumbing the thing up, nor eating the nasty aero penalty an exposed radiator inflicts). I'd expect a Tesla S would be well over 155mph [70m/s] (with the limiter removed) in 402m, but going beyond that is asking for heating issues. https://www.youtube.com/watch?v=F76-npz0CeI [Jason Fenske discusses the issues of extreme speeds in production cars. Electrics should be mentioned in passing, because they have the same issues]. -

The problem is that Teslas lack a transmission and are limited to around ~100mph (might be slightly higher to allow winning a drag race). You would have to change the gearing and software to get them to go fast. Heating would also be a difficult issue, for the engines, batteries, and tires. Judging from what I've heard of Bonneville salt flat runs, you can't do anywhere near orbital velocity with tires and will have to switch to solid aluminum wheels (moreso since they won't be cooled by air). After that it is a relatively simple calculation to work out how hot the engines/motors can get, how many Joules of heat it takes to heat them up to that level, and then use the efficiency of a Tesla to figure out how much energy has been transmitted to the tires to get it to that speed, then convert that energy into speed (and I'm sure that Al wheels have resistance as well).

I went and checked the escape velocities of each of them and found that the closest the Cessna got was about 1/4th of Charon's escape velocity (202 TC302R doesn't have one listed). And I'm likely using the most common (of recently made) Cessnas max speed rather than cruising speed (I used .063km/s).

I'm guessing that they have a pretty good idea what Spacex went through to do this and know it simply won't work on a Govt/DoD contract schedule. Come to think of it, it could cost $100 to do and it *still* couldn't be done on a Govt/DoD contract schedule, at least not without technically committing multiple felonies (and for any real price it wouldn't be "technically").

Which means that the boundary temperature gets nasty, and if your fluorine/ozone mix gets any hotter the blades are in big trouble. I'd hate to think what would happen to turbine blades on Venus, and have always considered this a "burn nitrogen on Earth" thing, so use a scramjet to >mach 10 or so (first stage). I guess it allows for heavier craft than 1kg helicopters on Mars, but fixed wing craft there doesn't sound any more sane. Do any of the moons of Jupiter (or Titan) have atmospheres (at least more than Mars)?

While I'm fairly sure the local Level 4 biohazard research facility (Ft. Detrick in Maryland, not the CDC) withstood yesterday's 5" of rain in two hours + nasty hail (said to be "baseball sized" in places within a few miles of the Fort), I'd sleep a lot easier if the various biohazards couldn't make it back to Earth without burning up. Yes, it is a superfund sight (although that likely dates back to when it was used for offensive disease capability research. This is the same place that found a depot of nerve gas while the Army was looking for such things in Iraq). I'm sure it provides plenty of good jobs, but the place is exactly what you would describe as "not in my backyard".

According to the FAQ, it is available for 64 bit Linux (and only 64 bit Windows and Mac). If you aren't running Ubuntu you might need to compile, and it might also be picky about libc and such.

Sounds like a way to reduce the problem of building a SCRAMJET booster into a single problem: keeping the fuel from exploding. Oh, and launch your scramjet from a ground-based SRB, we don't want to lose a carrier aircraft as well.

So there's you, Scott Manley, and at least one NASA Principle Investigator that showed up on the forum. All the rest of us likely followed a path similar to Randal Monroe (of XKCD fame). There's always Principia if you want to get your understanding of orbital mechanics more accurate.

Never mind Teddy, but I think William Gladstone has Nibb31's idea beat by about 100 years... The canal still is a better plan.

They didn't admit to it, and the USSR wasn't about to admit that U-2s were flying over them without being shot down. From what I've heard of the news in Pravda, you wouldn't think that there had been any U2 flights before Gary Powers. They certainly wanted the publicity of launching the first satellite (it did wonders for Soviet science PR) which makes a huge difference.

Everything I've heard was that Boeing really overdid it for Dreamliner (subcontracted the entire plane) and this nearly turned into a disaster (it often made much more economic sense for subcontractors to blame other subcontractors than to fix the problems). Don't forget that the subcontractor-based infrastructure grew up in an environment of multiple airline manufacturers which was hugely influenced by military purchasing requirements (which often require specific subcontractors). Musk may have rightly decided that he could afford a "clean sheet of paper" approach to building spacecraft, and that the less bits of the rocket controlled by subcontractors (the way the Military Industrial Complex has always done it) the better. It isn't clear that you really could build an airplane this way, but there is certainly less infrastructure for rockets.

Combustion tap-off cycles don't appear to be built for "indefinite" lifespans. Especially when start/stop methods are considered. Yes, Raptor's staged combustion engine might have similar issues, but at least it doesn't subject turbines to the full temperature of the combustion chamber. Is there anything to indicate that this is more than just a throwaway powerpoint bullet to get a few staffers off their back? If they were serious about it, wouldn't the be already doing testing runs with helicopter capture? I know smaller things have been air captured, but some indication that ULA had any capability to capture an entire engine might indicate that they were serious. I've heard a lot of marketing about rocket reuse (wasn't Ariane originally supposed to be reusable, or maybe that was a bad translation), but so far only the Shuttle and Falcon 9 if off while going to orbit (X-15, Spaceship 1, and New Shepard have all done it suborbital). I'll believe it when they launch a second rocket for 65% of the price of the previous rocket. Right now it sounds too much like "me to" and spacex's plans for asparagus on Falcon Heavy (which sounds much, much easier. I'm guessing they could do it with a restart on the center engines, but 6 restarts was considered too high a price).