81–90 of 90 posts
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A million square metres is one square kilometre. It could be built but it would be heavy. A circular sail with a radius of just over 600 metres would do it.
wouldn't a million square metered be a megametre and not kilometre?
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Sci-fi-grade engines are always fun. If you want to jump straight into a stable orbit, just add the right velocity component to your exit point. Or select a synchronous orbit. Any sci-fi-grade navigation computer can do that.
Even a Geo orbit is an orbit. I guess you could drop out at a Lagrange point. Of course depending on hour your Sci-Fi FTL engines work you could build up speed by stopping up high in the gravity well, let the planet accelerate you to orbital velocity, then jump sideways into an orbit once you're moving fast enough.
These functions are a hard requirement for passenger transportation anyway because you need to match orbit with the station you are docking with. Protocol is to jump to a random position a couple light seconds from the port, get authorization, then short jump to your assigned docking exit point.
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Micrometeors and radiation would be the major problem. Also, it's not just time dilation that would help. At relativistic speeds, space contracts quite noticeably in the direction of travel, so the actual distance you need to cover diminishes as well.
That's because you won't be locally faster than light. You may cover 4 light years in one, but only because those light years will be much smaller from your point of view. You'll never "feel" faster than light.
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Even a Geo orbit is an orbit. I guess you could drop out at a Lagrange point. Of course depending on hour your Sci-Fi FTL engines work you could build up speed by stopping up high in the gravity well, let the planet accelerate you to orbital velocity, then jump sideways into an orbit once you're moving fast enough.
Or you can just use the automatic preset that puts you in a stable orbit depending on the distance from the surface you chose. The default is synchronous (a.k.a. "standard orbit"). These functions are a hard requirement for passenger transportation anyway because you need to match orbit with the station you are docking with. Protocol is to jump to a random position a couple light seconds from the port, get authorizat…
Thoughts: We need a functioning ITER -- in space...
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Or you can just use the automatic preset that puts you in a stable orbit depending on the distance from the surface you chose. The default is synchronous (a.k.a. "standard orbit"). These functions are a hard requirement for passenger transportation anyway because you need to match orbit with the station you are docking with. Protocol is to jump to a random position a couple light seconds from the port, get authorizat…
I guess it comes down to the details of your fictional FTL drive. A lot of times normal space momentum is not maintained in FTL, and gaining normal space momentum requires conventional rockets where delta-V is hugely expensive in terms of mass and volume.
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The idea isn't ludicrous, although the torch-ship speeds of 39-day transits are definitely out of reach for now. The basic idea is, let's attach a nuclear reactor to an ion engine. Further, let's make the propellant hydrogen so we can refuel anywhere in the solar system. If we want to get serious about exploiting the solar system, we'll eventually have to give in and embrace nuclear technology, whether something like…
Physics, logic, and economics preclude interplanetary trade. There's no realistic space propulsion that would enable interplanetary trade to be in any way economically feasible. It's economical to ship finished goods and even raw material around the surface of Earth because it costs less than a dollar per pound by sea, rail, or road. Air freight is more expensive at around two dollars a pound. SpaceX's best price to…
From what I heard from industry people, overheating is an unsolved problem for VASIMR. It is 60-70% efficient, meaning that 60kW of thermal power has to go somewhere. Waste heat management for 200MW system in space is firmly outside the realm of present-day technology.
Could you use the waste heat to boil something and then spray it out the back as extra reaction mass?
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In all fairness modern naval reactors like the A1B are pushing more like 700 MW thermal (unclassified, probably higher) and float in what amounts to an infinite heatsink of excellent liquid coolant. Of course lifetimes and decades of experience produce the A1B, The First Torchship is not going to do as well. The real problem for a spacecraft isn't generating 700 MW of thermal heat, which is pretty small and light, bu…
Space is an infinite heatsink if, and becomes an actually very good one once your radiators can reach 2000K+ Not a problem for a glowing plutonium plasma. Here is a quote on one project from sixties: > a spaceborne electric powerplant dubbed EU-610, with an electric output of circa 3.3x106 kWt, specific power 0.7x105 kWt/kg/sec (sic), relative mass 18.7 g/kWt, length 10000 mm.
The Carnot heat engine efficiency is not nice at a cold side of 2000K and the working fluid will be a problem. Maybe gaseous helium or argon to reduce leakage, I guess.
The only place I found EU-610 was a Russian thermal rocket. Which is kind of like saying all you need for a coal electrical plant is a lightweight pile of charcoal.
Its a different type of technology, sorta like the difference between burning in a cast iron stove to boil tea, vs using a microwave oven to boil tea.
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In all fairness modern naval reactors like the A1B are pushing more like 700 MW thermal (unclassified, probably higher) and float in what amounts to an infinite heatsink of excellent liquid coolant. Of course lifetimes and decades of experience produce the A1B, The First Torchship is not going to do as well. The real problem for a spacecraft isn't generating 700 MW of thermal heat, which is pretty small and light, bu…
Space is an infinite heatsink if, and becomes an actually very good one once your radiators can reach 2000K+ Not a problem for a glowing plutonium plasma. Here is a quote on one project from sixties: > a spaceborne electric powerplant dubbed EU-610, with an electric output of circa 3.3x106 kWt, specific power 0.7x105 kWt/kg/sec (sic), relative mass 18.7 g/kWt, length 10000 mm.