p1t1o

As far as I know, the US air force is capable of developing+launching its own stuff without NASA at all.

One word: Insurance. Its much easier to just insure the payload for 10billion, or however much. https://en.wikipedia.org/wiki/Satellite_insurance

Well with these parameters, you dont need to do any science at all, you dont even need a calculator. Once you have said the words "unlimited" and "exponential", of course the universe will be destroyed!

The OP was clearly writing in a somewhat satirical manner, but the OP, and your description of it, matches some scientific "journalism" quite closely.

We ARE Von Neumann probes. Think about THAT.

Yes.

My favorite example of such weirdness - https://en.wikipedia.org/wiki/Elitzur–Vaidman_bomb_tester A method of observing an object without interacting with it in any way whatsoever, without even bouncing a photon off it. And practically demonstrated in the real world as well! Apparently one school of thought hypothesises that there is communication/interaction with other versions of our universe (a-la the many worlds interpretation) and extracting information from them.

So like, King Arthur, according to some legends, will return when Britain needs him once more. So what if I am King Arthur in a sort of "rest life"? That'd be cool. It would explain why when I see railings like this: I think: "Good. Spear storage for the coming of the Great Dragon is preceding apace."

"Photons themselves" is a troublesome concept when looking very closely, they aren't really little physical particles, they just behave that way under various circumstances.

This is a pretty cryptic one XD What is he doing? Manually soldering new components onto a microchip? Fighting a war with ants?

@Johnnyc"relativistic mass" only exists in the reference frame of an observer. The passengers on the ship do not experience an increase in mass, nor can they detect any change in inertia of any objects. They do not collapse under their own gravitational pull as their mass approaches infinity. This is the crux of "relativity", things change "relative" to something else. Consider the kinetic energy of a tennis ball. Stationary, its KE is zero. But the Earth is whipping around the sun at several thousand miles an hour. The KE of the tennis ball is measured relative to its reference frame, from another reference frame, say a heliocentric one, its KE can be completely different and almost unrelated to its KE measured in another frame. So with relativistic mass. Two co-moving masses at high relativistic speed will NOT start to gravitate towards each other (any more than they were before, anyway), because their relativistic mass is NOT increasing relative to one another. A mass moving at high relativistic speed past a stationary object, however, will have a larger gravitational effect on said object than is described by its rest-mass alone. Consider the relativistic mass of the stationary object from the perspective of the passengers on the ship though. From their perspective, the stationary object is moving past them at high relativistic speed. They will experience the "stationary" object having the increased mass and will experience its effects. An admirable statement, but it doesnt work quite that way when discussing such fundamental concepts as superluminal travel. It really is analogous to arguing that there is a slight probability that unicorns abound. Dark matter and dark energy already are attempts to explain apparent gaps in our knowledge, we already know that our understanding of gravity is incomplete, not only are there whole, huge fields of science dedicated to just that (hence dark matter, dark energy) but the finer theory has even been recently revised to take into account discovered discrepancies at very low accelerations. The light speed limit also, explains AN UNIMAGINABLE amount of stuff - tinkering with the idea that superluminal travel just might be possible, digs a rather large whole in all of the underlying physics that you'd also have to explain. You cant just rely on the wiggle-room in less-than-absolute-proof, because almost our whole body of science agrees that it must be a rule. If you attempt to explain what happens to a superluminal particle, with our current science, it gives you garbage results that cannot be translated to reality. You cant just say "but what if it did?" because there is no body of knowledge to explain it. Literally the only thing you can say is "But what if it did?" and after that, you are free to make things up - hence, its not much use in scientific discourse. tl;dr - there is not much that is certain in the universe, but as far as things go, the lightspeed limit and the laws of thermodynamics are about the most certain concepts in the entirety of human knowledge.

I'd put my money on economics. That is usually the answer when something does not match the engineering paradigm. Possibly it was faster to construct it this way, maybe there was a deadline to meet? Slightly inefficient design made up for by meeting a contract?

I'd go for a magnifying glass and a radiant heat source, like the sun or a light bulb.

These "people" are dead wrong. You dont grow out of lego until age 99, officially:

Is it large and far away, or small and close?

NO!

OH. MY. GAWD. WANT. http://gizmodo.com/live-out-your-astronaut-dreams-with-legos-meter-tall-na-1794714699

I think the most important parameter in spot size is the size of the lens, what size were you using? Its possible that both calculations (CoaDE and whatever the calculator I am using is called) are using different maths or parameters. But at 50,000km, 40cm still represents a tiny divergence angle, and the ability to keep the spot on target is a significant challenge. Miniscule vibrations, at 50,000km, will spray your laser all over the shop. I think its still obvious from the results that: Yes, a sufficiently powerful laser can do cool stuff. Sufficiently powerful lasers are very, very large and technically demanding.

If we are talking real life, and not hypotheticals, then orbiting battlestations are right out. Nobody wants foreign battlestations closer to their heads than their own borders are. They are too likely to start a war by themselves to be considered. Otherwise, other factors make them less desirable than terrestrial solutions, namely cost effectiveness. Though I do not doubt the realism of CoaDE's physics, I do not consider this a realistic weapon. Its all well and good scaling things up until you get really impressive performance, but other factors rule it out. NB: the calculator I used before (http://www.5596.org/cgi-bin/laser.php - linked from project rho) gives different, more disappointing results from your parameters, I dont know which version is more correct. input parameters: 77nm 416MW output 1 second burst 10metre radius lens Results in, @ 50,000km - 0.5MW/cm2 0.23m radius spot size at target 2.6cm of aluminium vaporised No impulsive shock Still capable of taking out missiles though. IF you can keep your 40cm wide spot on target at this range.

But a silo can withstand all but a direct hit from a high-yield nuclear strike, a satellite can be taken out by a ball bearing. Or at the very least, much much less than that required to knock out a silo. There are political advantages to having your weapons easily observed as well, and disadvantages to stealthy less-readily-identifyable ones. I dont imagine that the identification of battlestations would be that much of a difficulty for a determined adversary, there are specific things about them which make them stand out - size, thermal signiture, orbital parameters etc. It is probable that they will be tracked by significant players from the moment thy are launched.

"Feasible" as in physically possible, yes, but can it outperform much much cheaper terrestrial options? Dollar-for-dollar, capability-for-capability, no IMO, by a decent margin. That is...quite far...I wonder what sort of effect you will get spreading 1GW across the sort of spot-size you can expect at 100,000km. I cant see the picture from here unfortunately, where is this laser from? Using this calculator: http://www.5596.org/cgi-bin/laser.php 1GW at 50,000km vaporises 0.5mm per second of aluminium. Its not great. At 1000km though, it vaporises 6.2metres of aluminium per second. However, this laser requires a 10metre lens and will generate megawatts of waste heat. Along with a Gigawatt powerstation... Further to that, the simple calculation ignores things like material blow-off which will significantly impact penetration. These capabilities dont come cheap, which is the problem. Whilst "technically" "feasible", as weapons they may be worse than useless. Yes, Salyut 3: https://en.wikipedia.org/wiki/Salyut_3#On-board_gun Also, google "POLYUS" which was a bona-fide orbital battlestation, albeit lightly armed. Unfortunately, when they launched it, it flipped over mid-ascent and failed to make orbit, in a most Kerbal manner XD

Provided you can get your warships within 1000km of your target this is fine. CoaDE kinda of glosses over that part. For orbital bombardment, or space-to-space orbital applications, 1000km range still means you need a hundred-to-several-hundred stations for reliable coverage, depending on the required effects at-target. 1000km is not that far in space.

10/10 would watch

Well first off, some of those concerns can be offset with proper experimental design. For example, some bodies around Jupiter receive considerable energy from Jupiter itself. Or one could include a large RTG to warm the general area of the landing site. And you could specify cold-hardened species in your organic soup. If there is a bit of liquid water anywhere going spare, environment will not be an issue. But mostly, Even if everything is soundly sterilised, multiple times no matter how you set it up, at the very least this would enable us to start thinking of exploring other places with less fear of contaminating them.

There is actually quite a lot of literature that is available. During the cold war there was a lot of interest and a surprisingly large amount of well funded research into the feasibility of orbital weapons. Much of it is declassified today. Sadly, the news is not great for orbital weaponry with todays technology, and for many of the reasons, an increase in technological capability might not make them any more feasible. Firstly, if the intention is to strike the ground from space: You have put a huge slab of armour in between you and the target, namely the atmosphere. It is quite thick and substantial, so any weapon must penetrate this first, this is non-trivial whether you are talking physical warheads or directed energy weapons. You have put a decent bit of distance between the weapon and the target, at least 100miles, probably more. This complicates targeting, yes there are ways to do it, but accuracy will certainly suffer compared to other platforms. Your platform is also moving rapidly, it may not seem like aiming a weapon at the ground from a satellite would be hard, but hitting small targets (ie: smaller than a football stadium) would be non-trivial. Many platforms required for global coverage, if you dont want there to be a chance that you will have to wait days for a platform to be in the right place. IE: extremal expense. *** Other issues: Lasers - dont get too excited (HA! PUN!) by these, physical constraints mean that to have any decent range, they must be very large and power hungry. And even with ranges of thousands of kilometres, against space targets, you still need a large number of them, and against ground targets you still have to penetrate the atmosphere. Even well-transmitted frequencies will have a hard time with cloud cover. Hypothetical high performance technologies only reduce these disadvantages by an increment. Kinetic weaponry - against space targets actually pretty effective, the only complication is targeting and identification. Against ground targets, sure, viable, but you'd get better results with conventional weapons. The atmosphere is a significant obstacle here. Nuclear weapons - already banned in space, see below: Politically destabilising - countries - friendly and enemy alike - dont like having flying battlestations hovering over their territory. Their presence can destabilise arms races and negatively affect any peace negotiations. There is a non-zero risk of accident causing international incident. This is especially an issue if you are considering nuclear weapons, as this system would closely resemble a "FOBS" or "Fractional Orbital Bombardement System", once fielded by the Soviets, they have been soundly banned across the board for a host of obvious reasons. Due to the nature of the weapon system in question, this may be the most significant obstacle. The bottom line is - though an effective orbital bombardment system could be constructed, if you have the (very large amount of) cash required - for there to be any point to it at all, it must be better at its job than anything else we can already field. Want an explosive payload on a target quick-smart? We've got various technologies from cruise missiles to aircraft carriers that can put a substantial amount of firepower down at very short notice. We may not currently be able to strike anywhere on the globe within hours, but we can do almost that. For an orbital system to match this, it would have to be very comprehensive and therefore expensive, to improve on it, even more so. Want to nuke something? ICBMs are already pretty good at this and are far less controvertial/destabilising. Even with modern ABM systems, modern missiles and warheads still pose a very potent threat. And they already have the range to hit most targets in less than an hour. Want to stop someone from nuking you? For this you need complete temporal coverage, or your opponents will simply fire through the gaps. This makes it, again, very expensive. For the same investment, other solutions would be as effective. Why pay a trillion dollars so that you have at least one or two interceptor platforms in position over your country, when you can instead, for a fraction of the price, build a complete ABM shield that will be in place constantly, have a similar probability of a kill, and have a larger number of available interceptors? And also not be vulnerable to ASATs. Maybe you are interesting in orbital weapons for their sheer firepower? There is no laser or kinetic RV currently on the drawing board that can pierce the atmosphere from 150miles up and match the destructive energy of a 2000lb LGB dropped from a fighter jet or a Tomahawk cruise missile. And we can launch thousands of those. Launching an ASAT is very, very, muchly less expensive than launching an orbital battlestation. Taking warfare to space significantly increases the risk of closing off space for everybody due to the well known Kessler Syndrome. This would be bad for all sides, nobody wants this. My position: with the current state of the art, orbital bombardment weapons are not a viable idea. Largely due to cost, politics and the fact that terrestrial weaponry is already very capable.