sevenperforce

I am highly skeptical that they can get better performance than if they just air-dropped the same exact LV. No possible way that air-dropping is more expensive than this setup.

Just looked that up. Fascinating! Not sure if human activity would produce more or less though. I read that the formation process involves primarily solar heating. And regardless, those thrusters are obviously thrusters.

I don't see how this wasn't blindingly obvious from the word go.

With damage kicked up all the way, two large ore tanks hitting the VAB above 289 m/s will destroy it. Trying to see if lower mass and higher velocity will do it too. EDIT: A single large ore tank will destroy the VAB at 417 m/s but not at 414 m/s so that's probably about our cutoff. Terminal velocity of a large unshielded ore tank is about 310 m/s. EDIT II: A single large ore tank with fairings on the nose and tail impacts at well in excess of 900 m/s when dropped from orbit.

All right, here you go. Took a little doing but I figured it out. My Jeb ship: My rescue ship: The mission: Final Score 13:39. Shockingly, look what ended up surviving quite by mistake:

I already built it without, so.....

Can the "stranded" ship use RCS?

Yes

The OMG particle is 50,000 slower than this. But I could be wrong.

I love these kinds of questions. So here's an idea. When you jump from one point to another, you are not just changing position. You're also changing a lot of other things. You're going from one gravitational potential to another and from one gravitational gradient to another. Remember that every massive objects exists inside a gravitational potential well with a particular depth (potential) and a particular slope (gradient). Together, they give you the vis-visa equation, which tells you how much specific mechanical energy the object has. There's also the underlying velocity of the gravitational potential well, since the object you're orbiting is itself moving through space. This isn't an issue if you are jumping from one orbit to another around the same object, but if you are jumping between objects (say, from Earth to Jupiter), then you have to model the whole thing as the superposition of the two planetary gravitational fields WITHIN the solar gravitational field. If you want to jump from one star system to another, then you have to model it as the superposition of the two stellar gravitational fields within the galactic gravitational field. To use this in the story to limit FTL -- you can say that the hyperdrive/jumpdrive/etc. can only execute a jump that crosses two spheres of influence. So you can jump from one planet to another, but not from a moon of one planet directly to another planet. You can jump from one star system to another, but not from one planet directly to another star system. You can jump from Ganymede to Europa but you cannot jump from a random Jovian orbit to Europa. You can also say that the energy requirements for any jump depend on the difference in the vis-visa energies of the two orbits, taking into account all involved gravitational fields. For example: if you want to jump from a low lunar orbit to an orbit around Titan, you'd first have to use regular chemical propulsion to burn out of lunar orbit until you were free. Then you'd need to calculate the vis-visa energy of your Earth orbit PLUS the vis-visa energy of Earth's orbit around the sun, and compare it to the vis-visa energy of a Titan-crossing Saturn orbit PLUS the vis-visa energy of Saturn's orbit around the sun. The jump energy would be the difference in the vector subtraction of all those energies. Then you'd need to burn to enter orbit around Titan. I, too, wish he'd just use one thread for all of these. But it's fun to answer regardless.

The issue is the solution to the ladder paradox: simultaneity. If you are hitting a thin-disk earth at nearly the speed of light, you will not necessarily have time for simultaneous force interactions. Back of the envelope estimate says you'll have frame-dragging effects (which might actually be rather extreme) but nothing else.

BOTE says no, but YMMV. See the Ladder Paradox.

Here's the render that SpaceX did themselves:

I wonder if you could make a passively-stable design and just go with damn thrusters (and maybe some pumped CoM-management) all the way down. The best system is no system....

Agreed. I'm curious what that looks like. It's not an easy problem to solve. In that vein, I'm still uneasy about the final flip. The fact that the ship needs all four flaperons and either engine power or thrusters to execute the flip seems like a disaster waiting to happen.

In a hearing before the House subcomittee on science and tech (Space Science and Applications subcommittee) in 1982, Culbertson (NASA's deputy administrator at the time) said that the planned sustained launch rate was 40 flights per year with a fleet of four to five orbiters, and up to 50 flights if demand was there. It was expected that a Shuttle orbiter would be capable of flying 8 times per year or up to 10 in extraordinary circumstances. As we know, the program ran for 30 years with no more than four operational orbiters at any time and 135 launches, or about ten months between each flight on average. The fastest-ever turnaround was 54 days. There's a LOX tank up there but no CH4. I am also unsure whether there are meth-gox accumulators or if RCS is run straight off tank head pressure. It would make sense to have some sort of separate meth-gox accumulators and pumping mechanism for on-orbit loiter. Any cabin-based launch escape system would need an independent landing mode, which adds additional complexity. Having that LOX tank up in the nose means extra weight if you're trying to abort, which is not helpful. A proper bipropellant liquid thruster will have much higher TWR than a meth-gox thruster, so it would make sense to design some pressure-fed mini-Raptors, particularly if you already have accumulator tanks up in the nose with you. You'd have to add a CH4 header tank, though. The high-thrust regime is only necessary for the actual abort, so those tanks can burn to depletion and then hopefully you can shutter them and use remaining pressed gas in your hot-gas thrusters to control trajectory. Then you have to figure out whether you're using chutes for landing or what. He is not good at this, haha.

Yeah I have been dropping ore tanks on it with increasing weight and it's shocking how durable it is.

I would want to see it recover and land safely after sustaining some sort of damage or other malfunction. Stuck fins, a bad engine, whatever. Show that you can sustain failures and still keep the crew alive, and THEN I'll get on. No one ever seriously suggested that the Shuttle would have less than a week of turnaround time. Certainly not multiple flights per day. I wonder if they could use a head pressure reservoir (usually tapped for RCS) to run pressure-fed methalox thrusters.

Right. There are part redundancies and there are modal redundancies. Airliners are safe because they have modal redundancies...they can land in water if they lose an engine, they can belly-slide if need be, they can use differential engine thrust to compensate for a stuck rudder. Even the Shuttle, for all its ills, had redundant landing modes for contingencies (although they all required successful booster separation, which was a problem). Starship has only one landing mode and it has to work exactly the same way every time. You can try to make all the parts redundant so that it works every time, but there are still no contingencies.

All make it into space but the FH center cores are still closer to a 747's speed than they are to orbital speed. Agreed. The final powered touchdown of the Falcon 9 boosters has never been the problem, not since they got it working. It's the other stuff that keeps tripping them up. A jammed grid fin. An engine that doesn't restart when it's supposed to. A GPS signal with the wrong path length. A landing leg that doesn't deploy all the way. SpaceX has got the hoverslam landing maneuver solved. No question about it. It's all the other stuff that scares me.

Yeah, if the skydive-kick-flip-burn maneuver was backup (for low-altitude aborts or something), that would be one thing. Making it the baseline landing mode just seems scary.

Like, none of the stock designs.

Indeed. I don't think it's possible to fit an SSTO into one of the above categories. If you can do it on the first go, more points to you!! But it would be a shame to have to abandon the mission because of a small problem on the pad, so I will say once it is launched it cannot go back to the hangar but you can definitely re-try from launch.

This is a fairly simple challenge. Build an orbital spaceplane and launch vehicle entirely in the VAB and SPH, without any testing and without using any stock game modules. Fly it into LKO and return it to a rolling landing at the KSC, without reverting to the SPH or VAB. You can turn on "no crash damage" and "unbreakable joints" in the cheat menu because lots of times part force limits get messed up if you have a big rocket and a small computer, and it would suck to lose out for that reason alone. This challenge has four categories: X-37 Simple: Build a spaceplane that launches inside a fairing on a traditional launch vehicle. Dyna-Soar Tough: Build a spaceplane that launches with crew, without a fairing, on a traditional launch vehicle. Buran Incredible: Build a spaceplane that launches with crew, slung on the side of a 1.5-stage launch vehicle like Energia. STS-1 Impossible: Build a spaceplane that recovers its own engines, slung on the side of its own drop tank, like the STS. You can also buff with these achievements: Safe and Sound: Equip your crew vehicle with an independent launch abort system that will eject them safely at any point from the pad all the way to touchdown. Must be demonstrated AFTER your successful flight. Pay Lode: Carry cargo that is deployed into LKO. Far to Go: Send your spaceplane around the Mun. True Life: Use no reaction wheels, no monopropellant on ascent, and only monopropellant once in orbit. Impossi-Ball: Land your spaceplane on the Mun or Minmus. Elon-gate: Recover your first stage.

There's planned amortization. You expect reusable parts to degrade beyond the point of reuse eventually.