Penoyre and Sandford offer a novel twist. Instead of anchoring the cable to Earth, they propose tethering it to the Moon and extending it toward Earth. This would take advantage of the Moon’s slower orbital rotation and the gravitational equilibrium between the two celestial bodies.
At a critical point known as the Lagrange point, the gravitational pulls of Earth and the Moon cancel each other out. This region would serve as a pivotal part of the spaceline. Below the Lagrange point, Earth’s gravity would pull the cable downward.
Above it, the Moon’s gravity would draw the cable upward. This setup significantly reduces the tension forces on the cable, making the concept viable with current high-strength materials like carbon polymers, including Zylon.
According to Penoyre and Sandford, these materials could support a cable extending from the Moon to geostationary orbit. Such a structure, with a diameter no greater than a pencil lead, could feasibly be constructed at a cost comparable to other large-scale space missions—around several billion dollars.
They claim it can be constructed with present day materials and engineering techniques.
I wonder how much an underground bunker on the moon would cost. The risk of nuclear fallout and marauding hordes would be greatly reduced. Sealing all doors and windows would suck. Suiting up for a walk would take time. The clothing would be expensive. However, the view would be out of this world.
7 thoughts on “Build a Spaceline Instead of a Space Elevator”
A bunker on the moon? You think finding all your AR-15 brass is hard now….
Loading...
Did you forget about the brass catcher I showed you? And 2,000-yard shots with an AR will be child’s play.
Loading...
Three problems. Installation, high-velocity debris, static charge.
Loading...
It’s possible in theory. So is FTL with a warp drive. The trick is the engineering and manufacturing. How much would such a filament….some 240 thousand miles long weigh? How would you get it into orbit? Can’t use a rocket? Guess you have to manufacture it in space. That means building factories in space which requires launching all the materials necessary via rocket. And so on and so forth. Just because something appears to work….ON PAPER….in no way means it will work in the real world. It’s like people saying we can turn Mars into another Earth. They don’t get it. We MIGHT be able to put small colonies on Mars that are supported by Earth. But Mars can NEVER replace the Earth. Neither can the moon. The lack of a magnetosphere on either body alone makes things exceedingly limited as to what can be done.
Loading...
Well, windage adjustments wouldn’t be a factor, but anything some distance 2K meters would probably involve taking into account the surface curvature arc. I’m too lazy to do the math, but any idea what orbital velocity would be? You might wind up with all sorts of LLO (Low Lunar Orbit) “debris” after a Boomershoot-type event.
“Shoot, then watch out behind you in 20 minutes if you miss….”
Loading...
I think he was referring to the lower gravity => less bullet drop at a given distance.
Loading...
And if an industrial accident or terrorist attack breaks it below the Lagrange point, 200,000 miles of super-cable falls to Earth at terminal velocity. Not sure if it lands in one huge pile or wraps around the planet half a dozen times, but neither sounds like fun.
A bunker on the moon? You think finding all your AR-15 brass is hard now….
Did you forget about the brass catcher I showed you? And 2,000-yard shots with an AR will be child’s play.
Three problems. Installation, high-velocity debris, static charge.
It’s possible in theory. So is FTL with a warp drive. The trick is the engineering and manufacturing. How much would such a filament….some 240 thousand miles long weigh? How would you get it into orbit? Can’t use a rocket? Guess you have to manufacture it in space. That means building factories in space which requires launching all the materials necessary via rocket. And so on and so forth. Just because something appears to work….ON PAPER….in no way means it will work in the real world. It’s like people saying we can turn Mars into another Earth. They don’t get it. We MIGHT be able to put small colonies on Mars that are supported by Earth. But Mars can NEVER replace the Earth. Neither can the moon. The lack of a magnetosphere on either body alone makes things exceedingly limited as to what can be done.
Well, windage adjustments wouldn’t be a factor, but anything some distance 2K meters would probably involve taking into account the surface curvature arc. I’m too lazy to do the math, but any idea what orbital velocity would be? You might wind up with all sorts of LLO (Low Lunar Orbit) “debris” after a Boomershoot-type event.
“Shoot, then watch out behind you in 20 minutes if you miss….”
I think he was referring to the lower gravity => less bullet drop at a given distance.
And if an industrial accident or terrorist attack breaks it below the Lagrange point, 200,000 miles of super-cable falls to Earth at terminal velocity. Not sure if it lands in one huge pile or wraps around the planet half a dozen times, but neither sounds like fun.