Hamartia Antidote
ELITE MEMBER
- Joined
- Nov 17, 2013
- Messages
- 35,188
- Reaction score
- 30
- Country
- Location
Could an inflatable kevlar tube make space elevators practical? | ExtremeTech
Honestly, it’s really more of a stratosphere elevator than a “space” elevator, but a new space elevator concept from Canadian company Thoth Technology has some in the space industry buzzing. It’s an odd design, even by the standards of lifts to the heavens, and it makes some key compromises that make it less useful than a traditional space elevator design. But those very compromises mean that it might just be feasible enough to make a debut in the real, actual world.
Space elevators usually refer to devices where cars, or “climbers,” pull themselves up a long, flexible metal ribbon stretching from Earth to geosynchronous orbit, and held taught by the centrifugal force of a huge anchor weight at the end. The idea is to make “launch” to orbit several orders of magnitude cheaper and safer, so next-gen space projects like the colonization of Mars might become practically possible. A space elevator would allow us to power a launch to space with electricity, rather than explosive chemical energy, and thus beat the majority of Earth’s gravity for far, far less investment.
This new concept, however, is different, in that it allows an electric climb past a far smaller portion of the Earth’s gravity well. Topping out at about 12 miles (20 km), the elevator features a commercial space launch runway at the top, where single-stage reusable spacecraft can launch and land in thin atmosphere, and slightly reduced gravity. This would be well matched with other next-gen space technology programs, like several ongoing reusable spacecraft from companies like Lockheed and SpaceX, including those that can do vertical takeoff vertical landing (VTVL) maneuvers.
A “traditional” space elevator concept keeps itself rigid with centrifugal force, since it’s so long and heavy that the rotation of the Earth keeps it taught. At just 12 miles in length, however, this concept doesn’t generate enough outward acceleration to stay straight, and thus the engineers have come up with an alternative: gas pressure. They plan to make their huge cylinder out of kevlar rings stitched together and then blow it up — like the aerospace industry’s version of those inflatable car lot dudes. Thoth wants to fill it with either hydrogen or helium, but it’s not a matter of making the elevator float like a helium balloon — they plan to add enormous pressures of the gas, keeping it rigid through mechanical stress. On the one hand, hydrogen is flammable, on the other helium is expensive…
The elevator will purportedly feature a system of gyroscopes so it can detect large bends and keep itself stable. Cars will likely climb the tube itself, rather than using a cable or ribbon, and the creators are still deciding whether those cars should go on the insider or outside of the tube. The inside would seem to provide a bit of extra safety, and consistent buoyancy through gas pressure, but climbing the outside of the tube would certainly increase the appeal to space tourism.
Amazingly, the company thinks it could begin on a scale version quickly, hoping to finish a prototype at just under a mile in height within five years. They estimate a version could reach the 12-mile mark within a decade, for about $5 billion. That’s just a fraction of what it cost to build the international space station, mostly because this space elevator can be built on the ground and slowly erected higher and higher, rather than having to be built space, then unspooled down to the surface.
Still, I do wonder what the economic argument would be in favor of their 1-mile pilot project; spacecraft would still be subject to the vast majority of the Earth’s gravity, at that height, and thus the scale version might not save enough on launch budgets to justify investment. That’s honestly a potential problem for the full-scale version as well: will a 12-mile launch advantage be enough to offset the cost of construction? Thoth says the full version could cut fuel needs by 30% — will that be good enough to justify billions up front?
Space elevators are a big topic of discussion, which ought to show you how broken the aerospace launch industry is, given how totally hypothetical the devices really are. Places like NASA have a hard time imagining figurative (or literal) moonshot projects when there is such a stark price and difficulty barrier between them and the cosmos they study. The next great space-based mega-project might not be a space elevator, but you can bet it will address this problem somehow
---------------------------------------------------------------------------------------------------------------------
New diamond laser 20 times more powerful
Researchers from the MQ Photonics Research Centre joined with fiber laser experts from the Fraunhofer Institute for Applied Optics and Precision Engineering in Jena, Germany to demonstrate a diamond laser 20 times more powerful than previous diamond lasers.
Average power levels were less than 20 Watts, with the new laser now providing up to 380 Watts of output power – the equivalent of approximately 400,000 laser pointers and enough power to easily cut through steel.
High-power diamond lasers are well-suited to applications that require beaming power over long distances, such as optical communications in space, laser ranging, and the tracking and removal of space debris.
Diamond is a relatively new material for creating laser beams, but it is rapidly becoming a technology leader in terms of generating powerful, high-brightness beams at wavelengths, or 'colours', where traditional lasers are not able to shine.
"Just as x-rays pass through flesh to enable us to see bones within a body, different colours of laser radiation can interact or be transmitted by different target materials," said Dr Robert Williams, the lead researcher on the project.
The wavelength of the new diamond laser, at 1240nm, has high transmission through the atmosphere, and is safer to use because of its reduced transmission through the front of the eye and lower risk of damage to the retina.
Diamond lasers have progressed enormously over the last few years due to advances in synthesis of high quality diamond – better than what can be obtained naturally.
"Diamond is an ancient material, yet only now many of its extraordinary properties are becoming evident. High power lasers is one such area that diamond looks like providing a major advantage," said Rich Mildren, Associate Professor in the MQ Photonics Research Centre.
"Diamond crystals seems to naturally fit to high power fiber lasers. It's interesting to see that such a development is now possible and I'm sure much exciting research will follow," said Thomas Schreiber, group leader for the fiber laser research at the Fraunhofer IOF Jena, Germany.
"Around the time of its invention, the laser was famously labelled 'a solution in need of a problem', but now it has penetrated so many aspects of industry, science and our daily lives that the number of applications are countless. A key to unlocking many more applications of lasers will be the development of high-brightness beams at new wavelengths, and diamond is providing just that," said Dr Williams.
Honestly, it’s really more of a stratosphere elevator than a “space” elevator, but a new space elevator concept from Canadian company Thoth Technology has some in the space industry buzzing. It’s an odd design, even by the standards of lifts to the heavens, and it makes some key compromises that make it less useful than a traditional space elevator design. But those very compromises mean that it might just be feasible enough to make a debut in the real, actual world.
Space elevators usually refer to devices where cars, or “climbers,” pull themselves up a long, flexible metal ribbon stretching from Earth to geosynchronous orbit, and held taught by the centrifugal force of a huge anchor weight at the end. The idea is to make “launch” to orbit several orders of magnitude cheaper and safer, so next-gen space projects like the colonization of Mars might become practically possible. A space elevator would allow us to power a launch to space with electricity, rather than explosive chemical energy, and thus beat the majority of Earth’s gravity for far, far less investment.
This new concept, however, is different, in that it allows an electric climb past a far smaller portion of the Earth’s gravity well. Topping out at about 12 miles (20 km), the elevator features a commercial space launch runway at the top, where single-stage reusable spacecraft can launch and land in thin atmosphere, and slightly reduced gravity. This would be well matched with other next-gen space technology programs, like several ongoing reusable spacecraft from companies like Lockheed and SpaceX, including those that can do vertical takeoff vertical landing (VTVL) maneuvers.
A “traditional” space elevator concept keeps itself rigid with centrifugal force, since it’s so long and heavy that the rotation of the Earth keeps it taught. At just 12 miles in length, however, this concept doesn’t generate enough outward acceleration to stay straight, and thus the engineers have come up with an alternative: gas pressure. They plan to make their huge cylinder out of kevlar rings stitched together and then blow it up — like the aerospace industry’s version of those inflatable car lot dudes. Thoth wants to fill it with either hydrogen or helium, but it’s not a matter of making the elevator float like a helium balloon — they plan to add enormous pressures of the gas, keeping it rigid through mechanical stress. On the one hand, hydrogen is flammable, on the other helium is expensive…
The elevator will purportedly feature a system of gyroscopes so it can detect large bends and keep itself stable. Cars will likely climb the tube itself, rather than using a cable or ribbon, and the creators are still deciding whether those cars should go on the insider or outside of the tube. The inside would seem to provide a bit of extra safety, and consistent buoyancy through gas pressure, but climbing the outside of the tube would certainly increase the appeal to space tourism.
Amazingly, the company thinks it could begin on a scale version quickly, hoping to finish a prototype at just under a mile in height within five years. They estimate a version could reach the 12-mile mark within a decade, for about $5 billion. That’s just a fraction of what it cost to build the international space station, mostly because this space elevator can be built on the ground and slowly erected higher and higher, rather than having to be built space, then unspooled down to the surface.
Still, I do wonder what the economic argument would be in favor of their 1-mile pilot project; spacecraft would still be subject to the vast majority of the Earth’s gravity, at that height, and thus the scale version might not save enough on launch budgets to justify investment. That’s honestly a potential problem for the full-scale version as well: will a 12-mile launch advantage be enough to offset the cost of construction? Thoth says the full version could cut fuel needs by 30% — will that be good enough to justify billions up front?
Space elevators are a big topic of discussion, which ought to show you how broken the aerospace launch industry is, given how totally hypothetical the devices really are. Places like NASA have a hard time imagining figurative (or literal) moonshot projects when there is such a stark price and difficulty barrier between them and the cosmos they study. The next great space-based mega-project might not be a space elevator, but you can bet it will address this problem somehow
---------------------------------------------------------------------------------------------------------------------
New diamond laser 20 times more powerful
Researchers from the MQ Photonics Research Centre joined with fiber laser experts from the Fraunhofer Institute for Applied Optics and Precision Engineering in Jena, Germany to demonstrate a diamond laser 20 times more powerful than previous diamond lasers.
Average power levels were less than 20 Watts, with the new laser now providing up to 380 Watts of output power – the equivalent of approximately 400,000 laser pointers and enough power to easily cut through steel.
High-power diamond lasers are well-suited to applications that require beaming power over long distances, such as optical communications in space, laser ranging, and the tracking and removal of space debris.
Diamond is a relatively new material for creating laser beams, but it is rapidly becoming a technology leader in terms of generating powerful, high-brightness beams at wavelengths, or 'colours', where traditional lasers are not able to shine.
"Just as x-rays pass through flesh to enable us to see bones within a body, different colours of laser radiation can interact or be transmitted by different target materials," said Dr Robert Williams, the lead researcher on the project.
The wavelength of the new diamond laser, at 1240nm, has high transmission through the atmosphere, and is safer to use because of its reduced transmission through the front of the eye and lower risk of damage to the retina.
Diamond lasers have progressed enormously over the last few years due to advances in synthesis of high quality diamond – better than what can be obtained naturally.
"Diamond is an ancient material, yet only now many of its extraordinary properties are becoming evident. High power lasers is one such area that diamond looks like providing a major advantage," said Rich Mildren, Associate Professor in the MQ Photonics Research Centre.
"Diamond crystals seems to naturally fit to high power fiber lasers. It's interesting to see that such a development is now possible and I'm sure much exciting research will follow," said Thomas Schreiber, group leader for the fiber laser research at the Fraunhofer IOF Jena, Germany.
"Around the time of its invention, the laser was famously labelled 'a solution in need of a problem', but now it has penetrated so many aspects of industry, science and our daily lives that the number of applications are countless. A key to unlocking many more applications of lasers will be the development of high-brightness beams at new wavelengths, and diamond is providing just that," said Dr Williams.
