Bill Phil

We've had the tech to synthesize diesel since the 40s at least... Fischer Tropsch process can do it. Germany did it during WWII due to lack of oil, but they had plenty of coal to turn into fuels. Of course it only provided about 9% of their fuels during the war, but it's an old process.

Both large airship aircraft carriers (Akron and Macon) crashed before the Hindenburg did. This was around the early 30s. It ended up being poor for offensive tactics, but had some potential for reconnaissance and searching for targets. Airships were used to help defend the US coast during WWII, but this was after the crashes of the Akron and the Macon and used small blimps, not rigid airships.

Yeah. Synchronized rocket landing is way more fun.

Very. I remember seeing a drone helicarrier that some guys built. Some RC plane pilots were challenged to land on it.

Sure, but you'd be hard pressed to cool anything down. It probably would be better to use the heat to heat up a fluid and pipe it into the ground. Even on Mars. Just because its temperature is low, it isn't necessarily a good medium for heat rejection.

Not when there's barely any atmosphere to speak of.

There's one, but it's not very helpful. You can find it by googling "Blue Origin Blue Moon" and searching under the images tab. It may not be an actual image of the vehicle though.

Reminds me of the Cessna(?) that reported a flight level of 3000. In terms of distance, that's 300000 feet, or, very near to the edge of space. Of course a Cessna can't fly that high, the pilot just reported altitude instead of flight level.

The idea is to make it so cheap to operate that they can replace the F9 family entirely. It's possible, albeit unlikely, that a BFS could be used as an SSTO or be used to take a kick motor to near orbit, potentially orbiting payloads near F9 size without a booster being necessary. Even if it needs a booster for every launch, if they can get the cost to a level less than a current F9 launch, then if someone wants to launch a small payload they can do so at a cheaper cost than today, but going bigger would be better for the customer.

It only takes about 2.5 km/s of dv to land on the Moon from LLO. That's less than hydrolox's exhaust velocity, but hydrolox is difficult to store. It's also less than kerolox, methalox, and a few hypergolic propellant combinations. If we can get a moonbase going and harvest oxygen from lunar regolith and bring some hydrogen with us, we could refill the LOX tanks on the Moon. Some margin would be good to have, of course. Maybe a multi-stage system could work, but make them reusable, like a sort of mini BFR system optimized for lower dv to orbit?

Well, the armor is basically useless in the anime series (if not in real life...), the armor only exists to protect it from small arms fire. What's funny is that they have shields (not sci-fi deflector shields, literal shields) to protect against more powerful weapons, but the only protection against the most powerful weapons is to not get hit.

What would be funny is if in the future there's a space junkyard filled with BFS-es and other bear future concept vehicles.

If it ends up working then it ends up working. I suspect that governments will be a large customer if it becomes operational. I personally think that there are better ways to get to space, but if they can reduce launch costs and potentially inspire reductions in payload costs, then everyone benefits.

Space has very little matter in which to have a temperature...

We can tell the difference. But John Q. Public may have some trouble. NASA's Mars program has a big rocket, and it hasn't flown yet. SpaceX's future general purpose vehicle hasn't flown either. Yes, it could go to Mars, but that's just one of many possibilities. Almost no one here thinks it will be sending people (or anything, for that matter) to Mars before the early 2030s, at the earliest.

In that article it gives a ballpark estimate of the first mission costing 230 billion. One mission. 230 billion. Not trillions. That 1.5 trillion estimate is for 9 missions, and it assumes that the vehicle is expended for each mission. Which is not likely. There are known methods to make reentry less demanding on the vehicle. A ballute system could do the job, making the transfer vehicle reusable and lowering the cost to less than a trillion for the program.

2.1 trillion is too low for colonization, but a flags and footprints mission should only cost hundreds of billions, not trillions.

Ironically, I think Gundam (at least the early Universal Century timeline) deserves some praise. It gets a lot wrong, but it does very well regardless. The ships have handles that people grab onto to move around within the vessel while in free fall, the artificial gravity is from rotation, the deck alignment on some of the ships is technically justified since the ships also function on/above Earth (they do have magical rocket engines though...), and even then some more space aligned characters point out how impractical it is for a spaceship. Even the combat being within visual range is justified in-story, as in real life it would never happen. It's got fictional science, but at least they tried to make something with a decent scientific background. Of course, the giant robots aren't really excusable.

Yeah. The decision to use "off the shelf" technology really shot the whole program in the foot. They had to essentially redesign the SRBs and have to re-engineer the SSME/RS-25. Not to mention develop two upper stages (even though one is based on an existing upper stage). And all without enough payloads to really justify its existence. Even the Shuttle technically had payloads to fly, and it could fly at much higher rates. All SLS has is Orion. I sure hope that NASA will be able to move on after this whole debacle. It should be flying by last year. Yeah. That's part of why they're using SSMEs, since you could technically take the core all the way to orbit. The core is the orbital insertion stage, basically, but they're going to fly a trajectory that can dispose of it.

RS-68s would require even more work to get them to work on SLS. It's designed for SSMEs. So they're basically stuck with building new ones. The RS-68 isn't an option. It is a hydrolox engine, but its isp is less than the SSME by a decently sized margin. Yeah. They've got 16 in storage. And none of them are really consistent with each other. Which means that individual engine choices will impact vehicle performance.

Welcome to the adults club. I still haven't gotten my check though...

The most difficult aspect of rocket development is funding, followed by rocket engines. It just so happens that the Raptor is well on its way on its development and they'll probably make a bunch of cash off government contracts and commercial launches. If they want to develop BFR, and they do (at this point in time), then they'll develop it. One of my engineer acquaintances who works at MSFC has repeatedly told me about how screwed SLS's development has been. The core is underpowered, the RS-25s are inconsistent, and they're trying to eek out extra performance from Block 1, about ten tonnes. They're even having issues with potentially damaging the Orion's solar panels with the thrust from the upper stage. It's getting pretty bad...

To be fair, the RS-25 is an excellent engine. It has decent sea level isp and high vacuum isp. With 70s technology. It's behind the curve in the modern world, yes, but it's performance is quite high. It's not really fit for reuse, though, as they learned from the Shuttle program.

Conglaturation.

Very. QED