monophonic

That's just under 2 years completely under wrap. A-12 first flew in April 1962 and YF-12 was publicly announced in February 1964. I'll give you that they kept the original Oxcart variant a secret a lot longer, but that was only plausible because the other variants existed and were publicly known about.

It's really hard to chooce between A9/A10/A11, UR-700 and Sea Dragon. They all share the same feeling of trying to push technology a little bit too much, yet still don't look like they couldn't have worked had they been built. For actually built rockets, I dunno, most rockets feel like all the others to me. Like, that one is different color or a little bit different shape but they all get the job done. Maybe I have some fondness to the Shuttle and Ariane 5, mainly because they were the main contenders for mentions in the medias when I grew up.

Yes. Yes it really is called that. Well, very close anyway. https://en.wikipedia.org/wiki/People's_Liberation_Army_Naval_Air_Force

Thoughts on one of the older ways of rocketry: composite tanks inside a metal hull? How about a definitely counter-intuitive variant: metal hull-tank walls with composite bulkheads?

The opposite does not follow either. If profit culture wasn't so prevalent no-one would have ever been fired for raising concerns about safety issues. Yet that has happened repeatedly. People can do extraordinarily stupid things if they are pushed for results. I wouldn't believe anyone would have done such a thing again after SK751, but am certain that I do not know it. NASA can't leave astronauts lives hanging on beliefs and thinkings, they have to do better than that. They need to know. Of course political pressure has been mentioned, but all that means is even weaker arguments suffice for an excuse to conduct an investigation. Not even Boeing gets unanimous love in the senate. Maybe a couple of senators threw a bet over which of their respective pet companies does safety better? Should we have waited for a final report on Mr. Musk's smoking habits before taking that up too? I did mention they were allegations didn't I? It doesn't look as bad if the omission was only in the differences training material. Then again what point does a "differences training" serve if it doesn't train one on all the differences? Luckily there are smarter people than I looking into that. Oh and just to make one thing clear I wouldn't cancel a flight for getting scheduled on a 737MAX.

Yes, they share the same corporate leadership. Ergo they potentially share corporate culture including corporate safety culture. Therefore potential safety concerns at Boeing's aviation side can be a reason to do an audit of the safety culture at their space side. You are right in that NASA does not have to concern themselves with actually inspecting the aviation side. As long as things are known to be fine in the space side of Boeing, it would not matter for Commercial Crew if 737s were dropping like flies... Plus FAA will be doing a number on the aviation side anyway if the allegations are found to be true. Of absolutely no relevance to the allegations raised. Whether a design is a derivative or a cleansheet one it is not a factor in choosing what to include in the operating manuals. None. Cancelling CC would leave Orion the only crew bus in the west. Thus Orion would have to be integrated to other launchers because SLS cannot provide the launch cadence to support the ISS. Then credibility of SLS' published reason of existence would get compromised. The rest is politics and thus out of bounds on this forum.

Wait? Three pages about Musk and safety in general? But no-one has mentioned even in passing that the other company under scrutiny has recently been implicated in omitting safety critical information from the operating manuals of a flagship product? And that has possibly contributed in a loss of passenger lives event? Of course the investigation is still very much ongoing so the officials cannot openly mention it - just as they cannot openly mention the other one's substance use habits. Just reminds us that there are more than one side in a coin.

Decoys are physical things, although they do belong under the broader concept of jamming. What you have been describing is better categorized into deceptive jamming techniques. Have you considered how your technique behaves in non-trivial acoustic environments e.g. surface duct or bottom bounce conditions? And especially when some emitters are in a different region from others? (a quick reference of sound paths for those who want one: http://www.oc.nps.edu/~bird/oc2930/acoustics/summary.html )

Both of these thoughts were confirmed in the article.

"The constantly-changing acronym" would fit in the Culture names theme SpaceX has had going with the barges pretty well. I like that! Because when they do... third reich.

These guys might be interested in cheaper bricks. Most 3D printing building systems seem to extrude concrete like materials though.

Do we know that that part is bent and not extruded? Also should one want to tap a thread in the hole wouldn't that have to be done after painting? Otherwise paint would clog the thread right?

I wouldn't jump quite that far just yet... First, pilot holes are a standard drilling technique. That is, you first drill a smaller (pilot) hole that is easier to get in exactly the right (or wrong as the case may be) spot which then helps keep the bigger drill bit at the right spot. Second, if you start a hole and stop (for example because you realised you are drilling it at a very wrong spot) before the tapered point of the bit is entirely inside the material being drilled you end up with a hole smaller than the bit you had. In thin materials that can even be a nice through hole, albeit one with a tapered edge (like you would want for counter-sinking a screw head). So even though no 2mm holes are needed that does not prove at all that 2mm holes are not drilled in manufacturing. I may just be that any of that size are to be immediately enlarged to a required size. Or it happened as a consequence of abortive misplaced drilling attempt. Also who would benefit from sabotaging a Soyuz?

Maybe there is a second hole across the room from the now patched one?

Add noisiness to that mix and you are getting close. Active noise cancellation and other advances mean flow noise now dominates over machinery noise. Exact priorities over each other depend on the class; a bomber values maximal silence over all others while an attack boat needs to be fast enough to be useful.

100 pax is regional airliner size. They are typically boarded and unboarded through a single, narrow one person at a time sized door. This happens in a reasonable time thousands of times every day. That access arm will not be the limiting factor for boarding time regardless of the destination and attire (casual or space suit).

From pocket change to small country budgets. Cheap end can be say a smartphone on an ocular holder and a small scope on a motorized mount. Fancy coordinate seeking scope mounts, specialized cameras and powerful computers for processing can be as expensive as you can imagine and more. This is doable at every price level.

And that, kids, is why you must be very careful with how you use quotation marks.

But was that dV calculated with an atmospheric nozzle? If so would a vacuum nozzle bring enough extra to allow a LOR profile mission? I am intrigued as the idea of using NS as a LEM has occurred to me too.

Paywalled, can we have a 1 sentence summary?

"Flying in weird trajectories to burn out excessive fuel" is exactly what GEMS is. You would use a D-5 (or Bulava) on Mars for exactly the same reason you would use a BDM-1 or Armata in place of a bespoke Mars optimized fighting vehicle.

Yes, Armata would be a better starting point. You wont even do extra work vacuum proofing the power train, since you have to fix that first anyway. Some newer IFVs feature unmanned turrets too, if you need more space and/or don't need that extreme armor protection or big gun an MBT has. Of course ground drones are a thing and there are armed ones too. So, maybe you can just do away with the meatbags and their cumbersome needs entirely.

D'oh. Obviously the other kid exists in a quantum superposition of a boy and a girl. Therefore the probability of him being also a boy is 1 until we try to observe him. At that point he will collapse into one or the other gender and is not also a boy any more.

Unfortunately no. The deep wading kit includes a giant pressurised rubber ring to seal the turret ring against water leak. Other openings including the muzzle of the cannon are likewise sealed shut. These preparations make moving the turret or shooting the cannon impossible, which in itself is only a problem if you plan to engage in combat of course. The engine air intake and exhaust are directed to and from the surface through a snorkel. There is also a bilge pump to remove any water that still manages to leak in. Many a military has decided this is too much of a hassle and risk to bother, compared to e.g. building pontoon bridges. So the tanks are not completely airtight. The NBC protection system works by pulling in air from the outside through a filter system. It pulls in enough to keep a small overpressure inside the vehicle, which ensures any leaks flow from inside to outside therefore keeping any toxic and/or radioactive materials outside the vehicle. In a vacuum you would be hard pressed to store enough air in the vehicle to last any useful lenght of time. Now those submarines are a better bet on that front. For a few days at least, I suspect the vacuum and abrasive dust would do a number on the seals. Harder to get them moving without liquid water on the surface though. Workaround is to program the missile so the PE of that orbit is underground and the trajectory crosses the surface downwards at the target point. It's just math, even if it's hard math.

Deep wading equipment is available for at least Abrams and Leopard 2 tanks. So yes. But the operation itself is not nearly as useful as it is often depicted. You don't normally have concrete entry and exit ramps and smooth solid bottom in rivers, like e.g. soviets liked to use in their demonstrations. Nor is the equipment itself armoured to any degree, so using it under fire is not a good idea. Therefore few armies practise with nor even acquire this equipment for their tanks.