Spica

Purple algae as they may have evolved on Earth would face many obstacles today and in the future. First being that green plants reflect away the green light that purple plants need. Green plants dominate the productive regions of the Earth, leaving little room for purple plants to take hold. Additionally green plants produce oxygen which would have been highly toxic to any purple plants that came before, just as elemental chlorine is toxic to green plants and other aerobic organisms around today. And anyway, green-plant photosynthesis as it stands is such a "hard" process to evolve that it seems very unlikely that a new, dramatically more efficient process would arise in the future without drastic changes to Earth's chemical environment.

Take a look at this page for guidance on and ideas for laser guns: http://www.projectrho.com/public_html/rocket/sidearmenergy.php There's plenty of reading on this topic to do on this page and the page for "convectional weapons"

Shocks are highly nonlinear and definitely not smooth processes, so potential flow solutions should not be valid across a shock. The flow across an oblique shock isn't irrotational as far as I am aware, which would also break any potential flow solutions across one.

A wing whether finite or infinite in span still sheds a starting vortex upon the onset of lift generation, and therefore there still must be real bound circulation about the wing. Of course there isn't a little tornado attached to the wing in flight, but if you were to photograph the induced flow around a wing section near the root you would still see an overall vortical flow pattern. I am fairly sure you could photograph this in a water tunnel if the camera and water were stationary, and the airfoil was moved down the test section. Tracers (dust, glitter, bits of dye...) could be used to visualize the induced flow. I have never found such a photograph though, only renders.

Cooling is a minor problem for SSTOs, since they're required to be super bulky to fit all the hydrogen fuel needed to reach orbit. That large volume comes along with a large surface area which makes re-entry heating much milder. Lower ballistic coefficients allow the bulk of atmospheric braking to happen at higher altitudes, trading a large reduction in heating intensity for a greater heating duration. The real problem with SSTOs is, and I can not stress this enough, structural weight. Nuclear powered air-breathing SSTOs suffer doubly from excess weight, since they need to carry heavy air-breathing engines, wings, excess structure to support multiple load paths, and heavy reactors and their requisite shielding. Additionally any NTR powered SSTO will almost certainly use hydrogen propellant, which will invariably make the structure even larger and heavier due to its extremely low density.

The coming possibility of high-powered battlefield lasers might shift the balance away from missiles. The F-35B for example has a little over 21 MW of available shaft power that normally drives the lift fan, even 10% of that energy as a laser beam ought to be able to do significant damage to any incoming missiles. Remember, simply destroying any externally mounted sensors is enough to severely degrade or destroy the performance of any incoming missile, and that will certainly take less energy than outright destroying the incoming threat. A collection of high powered pulsed lasers aboard a spacecraft should make a very potent missile-defense system.

One thing to also be aware of is the surprisingly limited range of laser weapons. At visible light wavelengths and "sane" primary mirror diameters they're typically limited to a few tens to hundreds of kilometers at most. If you've played "Children of a Dead Earth" on Steam you'll get an idea of the implications of this. It forces engagement ranges down significantly enough that guns (be they electromagnetic or chemical) become useful as weapons. This is a very good idea, Atomic Rockets is absolutely full of useful information for hard sci-fi spacecraft design.

Compact, maneuverable spaceships may definitely exist, but they will almost certainly take the form of unmanned missiles. Realistic close-quarters space combat engagements are likely to happen too quickly for a human-in-the-loop to be useful. They may be powered by chemical rockets or high performance NTRs. Low performing nuclear pulse drives or even nuclear salt water rockets might be seen on larger drones with higher ∆v capability, assuming of course that riding a criticality accident can be made a useful form of propulsion. Lasers, electron beams, dustguns, kinetic missiles, and nukes are all fair game, which ones in particular are used depends on the size of the spacecraft and the amount of power it has available. Even old-fashioned bullets are viable, again it all depends on the details. One thing that will probably not be seen is conventional chemical explosives, since inert matter travelling at orbital speeds can easily contain more kinetic energy than even the most theoretical high-power chemical explosives. If non-relativistic kinetic weapons dominate the setting, armor in the form of whipple shields will almost certainly be useful. Actively cooled and reflective laser armor may also be useful depending on the laser wavelength and whether or not the beam is pulsed or continuous. Nukes in space are effectively x-ray flashbulbs which makes them very powerful against lightweight armor. A whipple shield with unusually thick and wide-spaced layers will be better than nothing. Good luck armoring up against weaponized electron beams. The larger and more complex a given spacecraft is, the more likely it is to be reusable. It is hard to draw specific lines that separate what would be manned and unmanned vessels, since that is ever so dependent on the details of the setting. Now this is not knowable any more than the objectives of any earthbound war are. Any and all of the causes you listed may well be possible objectives, and they will all influence ship design. Jousting is not a terrible analogy for how space battles may look. Relative velocity is your friend, as it increases the potency of any kinetic weapons you have and makes you vulnerable for less time. Just as in modern war, outranging your opponent provides you a tremendous advantage. If we're only concerned with engines with Isps on the order of thousands of seconds you may see hyperbolic engagements, but orbital mechanics are not totally irrelevant. I doubt boarding will be a likely occurrence, since any ship carrying cargo worth boarding for also has the capability to thoroughly destroy itself, and likely anything within boarding range of it. Now, one major difference between terrestrial war and space war is the element of surprise. Since space is pretty empty and orbital mechanics keep things moving, there are exceedingly few places to hide. Additionally, any powerful weapons and/or propulsion systems will likely be detectable far beyond weapons range, making surprise attacks difficult and rare but not totally impossible. Current technology can detect cold rocks millions of miles away, bright radiators, exhaust plumes, and future imaging technology only make that task easier. Just as modern war machinery takes a variety of forms (aircraft carriers, submarines, tanks, jet fighters, bombers, missiles, and more), so will military spaceships.

Unfortunately photon thrusters are anything but infinite propulsion. If the energy to be used in powering your thruster is carried along with your ship, you will not be very impressed by its performance. A 100% efficient photon rocket powered by uranium can reach no more than ~250 km/s under it's own power. That's plenty fast for getting around the solar system, but a terrible waste of the energy contained in the uranium. If the rocket instead uses that energy stored in the uranium to accelerate exhaust you can go much, much faster. If the same amount of energy that the photon rocket used was instead used to accelerate normal exhaust, your rocket can now reach more than 10,000 km/s under its own power. That amounts to a 40-fold increase in speed, all at no increase in the total amount of energy consumed.

I think the problems you're facing come from the fact that all orbits in KSP are measured in a plane parallel to the ecliptic. However, the reference plane that inclination and LAN are measured about for planets is the equator of that planet, not the ecliptic plane. The angle difference between the ecliptic and planetary equator is messing up the orbital elements.

I'm probably doing something wrong with my install, but for me the 1.2.0 release doesn't work (no axial tilt appears on any planet), the exception that I see in the console is: Exception: TypeLoadException: Could not load type 'TiltEm.TiltEm' from assembly 'Tiltem, Version=1.2.0.73, Culture=neutral, PublicKeyToken=null'. I'm using it in a fresh KSP 1.7.3 install with the latest Kopernicus and required dependencies, and no other mods for testing. I have also tried KSP 1.7.1 with and without Kopernicus, and KSP 1.7.2 without Kopernicus.

RSSVE does not support KSP 1.7.1 from what I can tell, so if you want it to work properly you should use KSP 1.6.1 Moreover, if you are trying to use Realism Overhaul, you should definitely use 1.6.1 as well. RSSVE works perfectly if you follow the instructions on the github wiki perfectly.

That would create just as many issues as it would solve, as syncing with some planetary reference date and time that differs from your own would make all the planets suddenly change places, along with anything orbiting them. If you had any other vessels en route somewhere they would immediately miss their destination, as all the planets and vessels would have to change places as the date changed.

I assume RO means Realism Overhaul here. There is no 1.6.1 version of Realism Overhaul, and the DLC is not supported by RO, thus you can expect all sorts of problems with installing RO in ksp version 1.6.1 The most recent version that RO is compatible with is 1.4.5, but it works much better in 1.3.1

Absolutely magnificent job there CobaltWolf on that Gemini and Titan booster. The ablative nozzle skirt on the LR-91 looked strange at first, but I've come to like it.

Community Resource Pack provides a set of common resources (fuel types and more) that mod authors can use to prevent conflicts/duplicates and also to allow easy inter-mod interaction. B9 Part Switch is what enables many parts in the Near Future suite to have multiple variants, say one with and one without an integrated mount. I'd strongly recommend not touching either CRP or B9 part switch, as that may break the subset of parts you want to use.

Jesus H. Christ that's quite a throwback. Never thought I'd be mentioned directly, especially over a glitch I found five years ago.

359 a gap of 6 is no longer unusual at these values.

I tried the first version of this mod in 1.3.1, and it seemed to work with no other mods installed. When I installed other mods that modify planets (Kopernicus+Principia) the game still loaded, but no celestial body had axial tilt. This was in no way surprising.

Regarding your first question, after a little bit of poking around encyclopedia astronautica I found the following: http://www.astronautix.com/m/m55tx-55tu-122.html : Minuteman I ICBM first stage, Isp 237 s at sea level http://www.astronautix.com/s/sr19.html : The second stage of the minuteman II has a pretty high Isp, 288 seconds in vacuum. The early versions of the Sprint ABM seem to have used a polymer bound fuel grain containing ammonium perchlorate, nitrocellulose, and small bits of zirconium metal. http://up-ship.com/blog/?p=4971 NGNC is most likely a mix of Nitroglycerin and Nitrocellulose, and HNIW is another name for CL-20. https://en.wikipedia.org/wiki/Hexanitrohexaazaisowurtzitane

In general, you can get away with just merging the new version with the old one. However, there is a very slim chance that this may not always work as a situation could arise in which this could break a mod. (note, I have never had this happen to me in all my four years of playing KSP). You should be fine with just merging though, but if that really breaks things, just delete and reinstall it. Unless a mod undergoes a major update, your craft files should remain intact.

If I had to pick a favorite spacecraft, it would be the Agena Target Vehicle.

-46 Not so fast, part three

Nickel Carbonyl Ni(CO)4 Basically the most toxic inorganic compound there is. Its LC50 in humans is only 30 parts per million in the atmosphere, causing death within 30 minutes. Its also a highly volatile liquid, so be incredibly careful around it.

I go for as many realism enhancing mods as I can possibly install before KSP just dies. That is, Real Solar System, Realism Overhaul, RSS Visual Enhancements, all manner of realistic engines available (KW, soviet engines, CMES, KOCMOC), TAC LS, Remotetech, Deadly Reentry, FASA, procedural parts, FAR, Mechjeb (provides more and more accurate info than KER), engine igniter, RPM + VV, and any other well known realism-enhancing mod out there.