Hmmm .... all very interesting there, Jolly Roger. I may be wrong, but I always thought that the solar wind of charged particles also exerted pressure, same as sunlight. And that a sail could be used for either/both. I know that when the Apollo astronauts visited the Moon on one of their missions, lunar dust was observed being kicked - up by the solar wind. Due to the Moon’s lack of atmosphere, it did not make dust clouds, but almost immediately settled back down again. But the magnetic bubble idea for utilizing solar wind as a possible supplement to an onboard fusion - powered thruster also sounds interesting. Both the thruster and the magnetic field bubble could perhaps all be powered by focus fusion.
Hmmm .... all very interesting there, Jolly Roger. I may be wrong, but I always thought that the solar wind of charged particles also exerted pressure, same as sunlight. And that a sail could be used for either/both.
Sunlight has thousands of times more momentum than the solar wind. The thrust contribution of the solar wind on a solar sail is extremely small. The problem with a solar sail is that its size is limited by the weight of the sail material. A magnetic bubble sail does not have the same constraint, and can be expanded to the enormous size needed to catch the feeble solar wind.
Again interesting, would the charged particles from the solar wind be drawn into the the sail? And other matter around the spacecraft?
Just thinking if there is a need to carry mass to maintain the sail.
ETA: other than the power supply systems of course.
From what I’ve read, there will be some absorption of particles from the solar wind into the plasma sail, but not enough to make up for leakage. So, yes, there is still a need to carry mass to maintain the sail.
Again interesting, would the charged particles from the solar wind be drawn into the the sail? And other matter around the spacecraft?
Just thinking if there is a need to carry mass to maintain the sail.
ETA: other than the power supply systems of course.
From what I’ve read, there will be some absorption of particles from the solar wind into the plasma sail, but not enough to make up for leakage. So, yes, there is still a need to carry mass to maintain the sail.
Come to think of it, there’s just no end to the creative ideas and ways you could possibly have hybrid FF reactor / other propulsion for a spacecraft to make it more flexible and versatile.
Come to think of it, there’s just no end to the creative ideas and ways you could possibly have hybrid FF reactor / other propulsion for a spacecraft to make it more flexible and versatile.
Its the holy grail of spaceship technology development atm, and electric based propulsion system that can get you into orbit.
It states that we may expect a Hydrogen-Boron rocket engine to have an exhaust velocity of 980 km/sec, thrust of 61 kN and engine mass of 300 metric tons.
We expect an FF engine to have a mass closer to 3 tons, but perhaps the other numbers are in the ballpark. If so, our spacecraft will have a top speed of 980 km/sec or 0.33% of the speed of light. I think that relativistic effects will be minimal.
With a top speed such a small fraction of the speed of light, extra-solar missions will be limited to robots, sleepers or generation ships. However, it should do fine for getting around the solar system, even out to the brown dwarf, Barbarossa, thought by some amateur astronomers to be orbiting the Sun, currently at about 218 AU.
The critical factor then is the thrust. At 61 kN, our 100-metric ton ship will have an acceleration of 61 cm/sec^2. It would hit top speed in a few weeks, but it would still take 13 months to accelerate, coast/cruise, and decelerate to Barbarossa. A larger ship, with the 2,000 ton mass of the Space Shuttle, would take 25 months for the same journey.
The brown dwarf Barbarossa is not to be confused with the asteroid of the same name. Barbarossa may be the Dark Star Marduk/Nibiru that author Andy Lloyd is looking for.
... Therefore, if 10 N= 1G of acceleration, a 100-ton ship would require only 1kN for 1G. For clarity, that would be tons of mass, not earth weight. 100 metric tons of mass would still be a sizable (and hefty) 1,000 metric tons or 3,200 tons (US) weight.
I don’t understand your math. I will explain mine.
1 Newton (N) of thrust will accelerate 1 kilogram (kg) of mass by 1 meter per second per second (m/sec^2).
10 N will accelerate 1 kg by 10 m/sec^2. 1 Gravity (G) = 9.8 m/sec^2, so 10 N/kg = 1.02 G = ~1 G.
1 metric ton mass is 1,000 kg, therefore it would take ~10,000 N (10 kN) to accelerate it to 1 G.
100 metric tons mass is 100,000 kg, therefore it would take ~1,000,000 N (1 MN) to accelerate it to 1 G.
The Space Shuttle has a mass of ~20,000 metric tons. It needs ~200 MN thrust for 1 G.
Thanx for explaining it more clearly than my texts, Jolly Roger. I was “thinking” I’d seen a typo.
A couple of points/questions:
Tacking is not possible against the solar wind, because there is no parallel to a keel or water medium for the keel to push against. If you draw the forces that operate in sailing, you will see that the forward motion comes from pressure on the keel being pressed against water resistance at an angle to the incident wind. There is no water or equivalent to press against for a spacecraft.
Second, I fail to see how any angle of a solar sail could slow the ship down (unless it is already heading inbound towards the source). The incident force is away from the sun/source; you can angle the sail to get some sideways pressure, but no possible angle gives you reverse pressure.
Magnetic reconnection and the strorage of an ultra dense plasma matter in a magnetic confinement would be the ultimate power to go where no man has gone before, deep space far far away.
Magnetic reconnection and the strorage of an ultra dense plasma matter in a magnetic confinement would be the ultimate power to go where no man has gone before, deep space far far away.
The attraction of sailing has always been the lack of propellant mass required. While the acceleration is low, it is constant and long-lasting, permitting high velocity over time, riding a laser or (e.g.) diffraction-lens-focussed beam.
I suspect that at human scale, “storage of ultra-dense plasma in magnetic confinement” is going to require more mass and power than can be managed. It is also inherently risky, as the failure of confinement leads to very nasty local effects.
The genius of FF is that it uses natural magnetic effects and processes at sub-microscopic scales to achieve strongly positive energy payoffs, not hard-driven superconducting magnets. And the local dangers are minimal by comparison; there is some toxic gas (decaborane) involved, but no particular explosive potential to breach containment.
Focus Fusion Society 
