Nibb31

If the whole point of an SSTO is to make space cheap, then using massive amounts of highly toxic, corrosive and violently reactive fuels is not going to help you. Any cost reduction you might get by saving a stage is going to be offset by the costs of producing, handling, and storing propellants.

It required airports to upgrade their runways and boarding facilities. It's the biggest airliner in service. What's not to hype?

Similar requirements produce similar designs.

The entire ITS is supposed to be reusable. It's pretty much the whole point. That simulation doesn't make much sense at all. If the ITS can put 90t into LEO as an SSTO, then there really is no use for the booster at all. You could do the refuel runs without it, you would just need to do more of them, but it would save a huge effort. 90t to LEO as an SSTO is more than the SLS Block I, which is multi-stage. It really doesn't make any sense at all.

Probably as much difference as with the Breguet Deux Ponts, a french-built double-decker that predated the MD12 by several decades.

If it could get 90 tons to LEO as an expendable, then it could probably get at least 20 tons and carry enough propellant to land. I haven't looked into the details, but it sounds fishy to me.

I think that experience with the Shuttle has proven twice that parallel staging isn't a good idea. I mentioned the ITS general configuration, not necessarily the exact vehicle. There are several possible abort options that you could fit into that design, including higher-thrust engines or a separable capsule with a pusher ring.

I'm not sure why it can't be discussed in your original thread. I think that for a fully reusable multiple-stage launcher, the ITS configuration makes the most sense. Although it could be smaller. You would need to combine the F9 upper stage and the Dragon into a single lifting body design

The French Revolution also tried to adopt a metric calendar (12 months, 30 days, 10 days in a week, plus 5 or 6 extra days to catch up), but it was abolished after Napoleon in 1806. They even tried a metric 10-hour day, but that didn't work.

A moving ship is more stable than a landing ship. It doesn't make much of a difference in terms of avionics as long as the rocket and the deck are both at the right place at the right time. Everything is relative anyway.

No they don't. This is what an Earth-centric solar system would look like: From the Earth's point of view, you would see planets accelerating and slowing down and getting bigger and smaller as they follow those weird trajectories. Which, incidentally, is how the Sun-centric model appears to us.

"Universal attraction" is another name for gravity. I'm not sure what an electron or people in the Roman Senate have to do with gravity. So you don't illustrate much. I'm really not sure what you're trying to demonstrate. Science is a method, not a belief system. You can criticize a method, but you have to offer an alternative method. Do you have something more convincing than the scientific method for understanding the laws of the universe? No. It can be explained too. Just because you haven't researched or understood a subject doesn't mean that others haven't. It sure is. I don't think you even understand what science is, therefore trying to discuss epistemology is going to be hard.

They used a converted Myasishchev M-4 bomber to transport Energia tanks and even Buran. I don't know if the plane is still operational or how difficult it would be to build a new one. Russia could still rent the AN-225 Mriya from Ukraine like Airbus and Boeing do. However, in the current political climate, that might be difficult...

Absolutely. The N1 was a product of many compromises that no longer exist. It used spherical tanks because they couldn't ship large cylindrical tanks to Baikonur. It used a multitude of small engines because the USSR wasn't interested in making an F-1 equivalent. Each stage wasn't tested separately because they didn't have large test facilities. And so on. These requirements actually made things more complicated for the design bureau and don't make any sense today. The same is true for Saturn V. Some of the parts were designed to reuse existing tooling and hardware to save costs at the time. Nowadays, those savings don't make any sense. Techniques and materials have evolved a lot. Parts are made with CNC machines that require digital CAD/CAM files, so old drawings would all need to be manually converted to digital, old materials would need to be converted to new materials with different properties, and therefore reassessed and retested. You would basically be better off designing a new rocket that takes advantages of current tooling and hardware, which is basically what SLS is.

And as I mentioned earlier, Boeing had to completely reinvent how to build an airliner with the 787. It required a new factory, new tooling, new suppliers, new techniques, new procedures, new tests, and a lot of that didn't work as planned as they suffered many unexpected technical problems and delays. It cost them $32 billion to develop, which kinda makes sense if you expect to sell thousands of units. The A380 and A350 programs both cost around €11-13 billion. These are both rather conventional aircraft that apply proven technology. The A350 uses composite wings but a conventional fuselage. As a comparison, the Ariane 6 development program has a budget of €2.6 billion. Development of Vulcan will probably be around $2-3 billion too. REL claims that Skylon could be developed for $12 billion, which is less than half the cost of the 787 and about the same amount as the A350. That's absolutely unrealistic. Even with the best estimates, a total fleet of 5 Skylons would exceed the world's entire launch market, which would put the unit price of one Skylon at $2-3 billion. The economics simply don't work.

The same way Falcon 9 lands. It is all automatic. Rockets are always flown by computers on a predetermined trajectory, even when they are manned. It makes no sense to introduce human error. Falcon is just a launcher. Dragon is the spacecraft. Dragon 1 is un unmanned cargo vehicle. Dragon 2 will be the manned version, but it hasn't flown yet.

It took a 115-ton S-IVB to push a 30-ton CSM+LM stack into a lunar flyby. The Shuttle Orbiter was 90 tons, so you'd probably need at least 300-tons of propellant to get it into lunar orbit.

No way. You have to wrap your head around the idea that a vehicle designed for LEO is wildly different to a vehicle designed for BEO or circumlunar. The Orbiter would actually need another ET to reach the Moon. It also didn't have guidance systems, comms systems or radiation shielding for such a trip.

It's difficult to calculate. It depends on atmospheric pressure, of course, but also on thrust, azimuth, gravity, propellant usage, aerodynamic forces, and mass. I think that in real-life mission planning, they simulate hundreds of iterations of flight profiles until they find the best one.

I don't think it's possible to dock with something with such low mass. There needs to be a minimum force applied to the IDS docking rings for them to connect. If the target is too light, you risk bumping it away. It's not like in KSP with magical magnets. At the very least, your orbital module is going to need its own attitude control and batteries to stay steady. Once you've fitted all that gear into the trunk, I'm not sure that the extra habitable volume is really worth the hassle.

Nobody does. The entire Skylon airframe is nothing like any modern aerospace design. It requires new tooling, new construction techniques, new sourcing, and fundamentally different skillsets to those actually employed in the industry. The industrialization effort would be similar to Boeing having to completely reinvent how to build a composite 787, including going through all the pitfalls. For Boeing, it was worth it, because they plan to sell thousands of 787s in the future, and they'll probably extend those techniques to smaller jets too. For Skylon, it makes no sense at all.

That would require designing a whole new upper stage, as well as a whole new refueling vehicle. That would take years of development and would side track all their other projects.

Atlas V

People are discussing this as if nobody was doing anything about it. In fact there already is strong governance in place for the most crowded orbits. GEO slots are strongly regulated and you don't get one without filling out the requirements for disposal of your satellite. In GEO, everyone is travelling in the same direction and the same speed, and everyone is sticking to their assigned longitude, so the risk of a collision is low. Even if a bird dies before it's boosted to its graveyard orbit, then the risk of collision remains low. If there ever was a collision in GEO, it would be at a very low speed, therefore it wouldn't cause generate much in terms of debris. Any debris would either remain at the same speed, or fly off into a different orbit. As for LEO, drag clears up most of the debris. This is why the ISS is in LEO, because it's much safer. The risks are in higher orbits, between LEO and GEO, but there are much less sats out in that space, so the likelihood of a collision is low. Also, those pics of the Earth surrounded by a cloud of debris are wildly exaggerated. Every dot is blown up to the size of a major city, which makes it seem much worse than it is. In reality, each most dots are smaller than a refrigerator and you definitely wouldn't see them on the graphic.

Because graveyard orbits are perfectly adequate.