sevenperforce

It could be something exotic like this. A subcritical reactor or a critically-boosted RTG that uses the propellant as a heat sink to generate power and then ionizes and accelerates it. No. The force from the exhaust gases collecting on the tarp is equal and opposite to the force from the exhaust gases pushing against the nozzle on their way out of the engine. There would be zero forward thrust in this situation. There would be 220.2 kN of tension on the ropes towing the tarp, but that is beside the point. Ok? Why is this a bad thing assuming it has already done its intended job, that intended job is to accelerate the craft via going through the nozzle That's the problem -- if you don't "let go" of it, it hasn't done its "intended job" at all. If you do not lose the propellant you do not have any thrust at all. There can be no reactionless thruster. Imagine that you are inside a sealed boxcar on a frictionless railway. You have a collection of tennis balls and you have a few other friends inside the boxcar with you. There is NOTHING you can do with those tennis balls inside that boxcar to make the boxcar accelerate down the track. Whether you throw them, bounce them, roll them, or spin them around with magnetic butterfly nets, moving the tennis balls around inside the boxcar does nothing whatsoever to actually accelerate the boxcar with respect to the track. I would urge gentility. Newton's laws are harsh mistresses and it can take time to appreciate the extent of their dominance.

Equal and opposite reaction, remember?

Then the impulse would be imparted back to the magnets. Zero net thrust.

That literally will not work. **cough** They could be doing an experimental low-thrust, high-efficiency RTG-based rocket. Direct-pass RTG radioionization of the working fluid in a heat exchanger; use the heat exchanger to drive a dynamo for an accelerating magnetic nozzle. But probably just an NTR. If it has any appreciable thrust, definitely an NTR.

Wonderfully fantastic submissions! I'll get to scoring and those badges -- was out over the weekend.

For those wondering... Tonight's mission sent the payload into an orbit much higher than a normal GTO. Rather than a Hohmann transfer, the payload is now in a more efficient bi-elliptic transfer. Once at apogee, high above GEO altitude, the satellite will correct its inclination and raise its perigee to GEO altitude. It will then coast back down to GEO altitude and then lower its apogee to circularize. Even though this is two burns rather than one, it ends up being more efficient because more energy is provided by the launch vehicle with the advantage of the Oberth effect. Congratulations to SpaceX for a triple-booster recovery!!

Obligatory:

Chomp, doors, or roll up -- the primary issue is going to be failure modes. They want it to work every time. Again and again. You can see the fine line for articulation on the winglets. I'm still curious how they will handle heating on those. Is it just me or is the "static" point off from a 120-degree tripoint?

Yes but there are optimal and suboptimal windows in terms of inclination.

Ridiculously impressive.

Spectacular job! I checked your scoring and you are correct; my Don't Chute bonus says not to use any chutes, so having a vehicle with chutes onboard at launch is still okay as long as they aren't used as part of the mission. Accidentally bringing Jeb along is no big deal.....spectacular job having him ride a fairing base down from orbit. I'll get that mission badge to you briefly.

In theory, they wouldn't be. You'd have the same (or lower) force, just much longer burn time.

https://forum.kerbalspaceprogram.com/index.php?/topic/175525-leave-a-legacy/&do=findComment&comment=3391331

I know off-hand that they have not.

Abfraccckinsurd.

The Schwarzschild radius is proportional to the mass of the object, unlike ordinary objects, wherein the radius is proportional to the cubed root of the mass given constant density. I have a tattoo of Earth's schwarzschild radius on my shoulder. It is smaller than a dime.

Either they began construction of this core before they stopped painting the interstage (early b5), or they painted this one with ablative paint.

Indeed it is. It seems unlikely unless the core stage tankage has been designed for more than two boosters from the outset. I’m no rocket engineer but I’d think those SRBs are putting a lot of force through whichever part of the tank they’re attached to - welding a couple of extra decouplers on the side for the extra boosters and calling it done, will probably end badly. That's one of the big advantages of liquid boosters...they have no more thrust than the SRBs (actually lower thrust) but they burn for so much longer that they add a lot of dV. Lower thrust means the core doesn't have any more stresses than before so you don't have to redesign the core to accommodate them. Adding more SRBs or more energetic SRBs means bigger loads going through the core, which means a redesign.

Raptor uses an augmented spark igniter. It can restart whenever it wants, as many times as it wants, as long as it has electricity and props. They haven't done a full-duration test fire of Raptor but they fired the last one continuously on the test stand for a few minutes, I believe.

Yep, that's the equation for the energy of a particle in an infinite square well. The energy can only change as the square of multiples of the lowest energy state.

A little more detail on QM and ground states... Consider a ball bouncing back and forth between the walls of a well. Left to right, right to left, left to right, ad infinitum. Although there is energy (the "zero-point energy" of the system) in the system, the system does not change states with respect to time. Now, let's imagine that instead of a single particle, we have two identical particles that are coupled together: Now, because these two subsystems are coupled; energy can be transferred between the two particles if they happen to bounce against the central "bar". In certain configurations, there could be additional energy in this system, so that even though one of the particles is above its individual ground state, the overall system is in a ground state. The energy would be transferred back and forth in a reliable, predictable way. Even though the entire system is in its ground state, we now have a system that is changing with respect to time. The reason this is interesting is that time is defined rigorously in reference to entropy. The only way to say that a system is moving forward in time is to show that a system is moving from a state of low entropy to higher entropy. This is a system which seems to be changing with respect to time -- energy is moving around -- and yet there is no increase in entropy. Thus, the system can be seen as moving forward or backward in time.

Actually, motion is the case for all quantized systems. The lowest possible energy state is not rest, but an oscillating "ground state". The simplest possible quantum system (and the first one you learn to evaluate in QM or MP) is the infinite square well, in which a particle is trapped within an infinitely deep potential well with no energy gradients. If such a particle loses all the energy it can, it will still retain a "zero point" or "ground state" energy which is nonzero; in essence it is "bouncing" back and forth between the walls of its energy well, forever. The "time crystal" is much more complex than a particle in an infinite square well, but it too has a collective ground state. The individual particles would have their own individual ground states if they were not in a crystal form, but the ion disequilibrium in the time crystal means that the overall system has more energy in its minimum ground state than the sum of the energies of the ground states of its particles. As a result, the "extra" energy of the system's ground state ends up being transferred back and forth between the particles, forever, and there is no way to extract any of that energy, so it will continue ad infinitum. Of course it is not an overunity system. There is no energy being produced. It's just a system in which there is lossless oscillation between states.

Looking forward to the submission! I always build most of my missions in reverse anyway.

Correct; I was simplifying. The majority of the gravity drag happens while the vehicle is still mostly-vertical...tautologically, of course. It is still a huge impact. Adding fuel to the first stage is only a second-order improvement to final dV; adding thrust is first-order. Yeah someone is going to make sure it has extra. I hadn't heard it was boosting back to near the coast -- is OCISLY positioned differently? Have they posted a near-coast NOTAM?

You never cease to amaze.