sevenperforce

My areas of expertise are history, physics, and law, not biology or genetic engineering, but it was my understanding from the research that the size of the adaptations was larger than this type of function testing could have produced. In other words, there needed to be something between bats and humans to ease the transition.

As @insert_name said, that COPV isn’t for pressure-feeding. It looks too large to be the nitrogen tank for the cold-gas thrusters so it has to be the helium ullage tank. The Merlin Vacuum engine uses the same gas generator turbopump as the Merlin SL engine, but you still need something to replace the lost volume in the tanks, and so they use a helium tank. The helium passes through a heat exchanger near the engine to warm up before being exhausted into the tanks to maintain ullage. Both stages of the Falcon 9 use this system. This was the cause of the failure that exploded AMOS-6. Starship won’t use helium COPVs because it uses autogenous pressurization — a small portion of the LOX and liquid methane are vaporized in a heat exchanger downstream of the turbopump outlet and routed back into their respective tanks. You can’t do this with kerosene because kerosene doesn’t vaporize as nicely as methane. Starship will, however, use COPVs to hold gaseous methane and GOX to supply the pressure-fed hot-gas thrusters and to restart the engines after coast.

Frankly, human beings are simply not yet capable of that level of genetic engineering. We could create a virus more dangerous than SARS-CoV-2, sure. But we can't create a virus that functions this efficiently. Not even close.

I think everyone here probably agrees that SARS-CoV-2 was not purposefully created/genetically engineered. Rather, I think the "lab leak" theory is SARS-CoV-2 originated from a naturally-collected sample which was sent to the Wuhan lab and then somehow infected someone there. As I said above, though, I don't think this fits. If SARS-CoV-2 originated in the wild, was sent to the lab, and then escaped, we would be able to find it in the wild. We don't. And the mutagenic differences between the nearest wild coronavirus and SARS-CoV-2 are too significant to have taken place in a lab, not unless there was deliberate engineering (which, as you note above, there was not).

@KerikBalm lays out a few of the reasons for the lab leak scenario on the previous page. I find it plausible because I had actually heard about concerns with the Wuhan lab a year or so before Covid was on everyone's radar. There were several articles suggesting that the government / educational groups running the lab were rushing things and not following protocols expected of BSL-4 labs. I'm willing to consider the lab leak hypothesis, but I don't find it particularly plausible, mostly because of the nature of SARS-CoV-2. SARS-CoV-2 isn't like norovirus or measles, where even a couple dozen virions are enough to infect someone. Fomite transmission of COVID-19 is possible, but infrequent, and only happens when a surface is touched by someone who is seriously infected. Most transmission requires relatively close personal contact. Even if the Wuhan lab had a breach, it wouldn't have just "gotten out" into the public, not without going through basically everyone at that lab first and all of their families. It seems unlikely that one person at the lab became infected asymptomatically, DIDN'T give it to anyone else at the lab, and then caused a superspreader event at a wet market 42 km away. Further, the lack of genetic diversity in the virus and its mechanism of action strongly suggests a natural origin and a spillover infection event. Coronaviruses need to jump around a lot to mutate significantly, so if this was simply a sample of a wild bat coronavirus which was sent to the Wuhan lab, it wouldn't have had any real way of mutating much in the lab. Yet the closest known wild relative to SARS-CoV-2, RaTG13, is only 96.1% similar to SARS-CoV-2, and since early 2020 repeated sampling and serum testing of the Yunnan region where RaTG13 was found shows nothing closer.

I don't believe the EmDrive generates any total photon pressure, but that the LemDrive (the one that uses a laser resonator) does generate photon pressure. I think what they're saying, though, is that their measurement accuracy was greater than the amount of photon pressure which would be produced if you used the same amount of energy to directly power a photon drive. In other words, suppose you were trying to operate the EmDrive at 50 W. A photon drive operated at 50 W would produce a thrust of 1.67e-7 N. They are saying that they have ruled out any thrust for the EmDrive to well below 1.67e-7N. For the LemDrive, which is expected to generate photon pressure but claimed to produce additional thrust, they're saying the difference between the photon pressure it is expected to generate and its actual thrust is lower than 1.67e-7N. So yeah, in either case a laser pointer would do better.

Love it. This bit cannot be understated: His theory (…we limit ourselves here to the laboratory standard and not to his astronomical claims), as well as the experiments cited by him are excluded by 4 orders of magnitude. With both the EmDrive and the LemDrive, we have achieved a measurement accuracy that is below the photon pressure. That is, even if one of these concepts worked, it would be more effective simply to use a laser beam as a drive. Obviously proponents can still try to claim they "did it wrong" but any claim that NASA's tests support the EM Drive can no longer be maintained.

We saw that engine on fire during ascent, with the primary burn area around the turbopump outlet to the cold fuel manifold (A in the image below). That is the single highest-pressure point in the entire engine. Setting aside the cause of that fire -- if the burn weakened the main fuel valve, then it could have failed during engine spin-up. Because helium is used to spin up the turbine, the upper impeller would have already had quite a bit of inertia and a sudden failure at the valve would have caused it to rip itself apart, sending a shockwave and shrapnel straight up the liquid methane feed line (B in the image below) and into the methane downcomer. Fragging the methane downcomer would have introduced GOX into the methane line, and with shrapnel flying, the immediate detonation wave would have traveled straight up the downcomer and popped the methane header around its circumferential seam like a balloon.

Theories....

Exactly. A crackpot talks about science but never does the math. A scientist knows the math is necessary to do science. But it takes real skill to understand the math but talk about science without it.

Who even came up with the "change your DNA" business? Someone at some point apparently said, "This isn't like ordinary vaccines; it changes your DNA so that your cells can no longer be attacked by COVID-19. This is gene therapy." It's SHOCKING how many people believe that's what mRNA is. Obligatory:

I hope they still accept this submission -- I didn't realize the time zone was JST.

The foreshortening in that photo is extreme. The booster looks less the size of BN1 and more like the size of Falcon 9. But shiny.

That seems close to this post which apparently has inside info from SpaceX employees: That suggests FTS was activated from the ground rather than self-activated on the vehicle. This relight thing seems consistently tricky. DC-X never had to relight its engines in flight, let alone relight from a weird angle. The header tanks were a good idea and seem to work okay, but they may just not work well enough. Elon will be mad if they end up having to pause and dev the hot-gas thrusters just to execute the flip.

Right, same basic idea. The original Ares I was supposed to use an SSME on the second stage but they would have had to rebuild for air-starts.

I imagine they'd need to build the frag shield directly around the turbopumps below the gimbal. They won't do it at this time, obviously, because they need video view of the engines for diagnostics. I mean, falcons are raptors....

No, no, just #dearmoon haha

Obviously I am not a rocket scientist (although reasonable minds may differ) so I could only guess... ...but if I had to wildly speculate based solely on Elon's tweets and the available footage, I would say that Engine 2 had some sort of ground debris damage or a burn-through affecting the cold fuel manifold at the CH4 turbopump outlet. This started an external fire. Engine 2 is the second engine to shut down, so the fire continued for quite some time (you can see this later in the video, from another angle). They were having video issues and so we do not see Engine 2 shut down. As SN11 crosses 1 km altitude, we have a split-second shot of Engine 1 beginning to ignite, and then it freezes. Because Elon says that Engine 2 "didn't reach operating chamber pressure during landing burn", I suspect this means Engines 1 and 3 did reach full chamber pressure, but Engine 2's turbopump failed catastrophically at startup due to the fire damage and fragged the other two engines. Falcon 9's octaweb includes frag shields between engines, but there are no shields between engines on Starship. Losing the other two engines would have resulted in the system immediately realizing it couldn't land and triggering the FTS. The poor video was probably just the result of fog and no other issues. Huh. The Dragon docking port is androgynous so I would have expected that free-flight missions would still retain the port for contingency.

This looked less fuel-rich and more engine-rich. That pipe with the little silver wrap around it is the manifold that takes cold liquid methane from the turbopump outlet and pipes it into the regenerative cooling channels. It is the highest-pressure point on the fuel side of the engine. I'm not sure if that's what was burning or if that's just where the flames ended up swirling. But it's definitely off-nominal. And you can see that they switch to the LOX tank view almost immediately.

Whoa. What the heck?

Vulcan pathfinder sitting on the pad.

Looking back at how DIRECT was admittedly overpowered for LEO work (not that the Shuttle wasn't), I wonder if it would have been possible to do a smaller version with just one SRB for launching Orion Lite to the ISS. One SRB strapped to a smaller tank -- maybe something like the Delta IV Common Booster Core? Lots of gimbal action to keep the COM in the right place on the way up. And then just a single SSME.

You better believe I will. Which reminds me, I still owe Astrobotics a sea shanty......

Everyone knows I dig SpaceX but I'm going to limit myself to aesthetics on this. For the sensation of rugged unbridled power, Delta IV Heavy with the long fairing is just breathtaking. For launching people, the Soyuz-FG is glorious. Gorgeous curves, hot staging, the launch pad that opens up like a flower, and the neat verniers for control. It's a rocket that looks good at every stage (no pun intended) of flight, like every single part is just doing what it is supposed to do and nothing else. And there's something just so amazing about 32 separate combustion chambers igniting at once. I'm not a fan of the Atlas V with the small fairing, but with the 5 meter fairing and a handful of SRBs, it's really really sharp. Most Chinese rockets seem ungainly to me (and of course I deeply dislike hypergolics), but the Long March 5B just looks very satisfying. Finally, for ridiculously bad ideas that nonetheless just looked awesome, there's always the Ares I.

Haha!! No, I don't want to pigeonhole myself as a singing science guy. I'll probably do a video that introduces myself and talks about what I like, but in a format that illustrates public communication ability. That's my schtick, anyway. "Hi, I talk about science and people listen to me because I act like I know what I'm talking about, but also I know what I'm talking about."