5 ms·

This is either total scam or the founder didn't do school physiscs. Most of the info is quoted as "founder said to CNBC", hence I see no material proof. A scho

This is either total scam or the founder didn't do school physiscs. Most of the info is quoted as "founder said to CNBC", hence I see no material proof. A school-level physics calculation is enough to debunk it in a minute. Earth orbital velocity is roughly 8000 m/s. To achieve even a small fraction of it by spinning, the projectile and the device must withstand centrifugal acceleration: a = V ^ 2 / r Let's assume we obtain 1/8th of the orbital velocity, which will give a significant fuel reduction, thanks to fuel is exponential to delta V. r of the full-scale should be 136 m (small-scale diameter is 91 m as in the article, scaled by 3 as said there too, divided by 2) 1000 ^ 2 / 136 = 7352 m/s^2 = 750 g. I leave to the others to calculate how many RPMs should the device make. There's no material that can withstand such forces for extention. Many projects of energy conservation with flywheel were cancelled because sighnificantly heavy and large flywheels (couple of tons and just about 1 meter in radius) tear themselves apart at 2-3K RPM. I've not heard of any devices handling 100g over any significantly long periods of time.

antimatter15 5y ago
iPhones can survive 1000G's
- sandworm101 5y ago
  Not for more than a microsecond.
sandworm101 5y ago
Fan blades in jet engines regularly see 100+ g, in tension. Artillery shells, even the fancy ones with guidance hardware, can handle such loads too, in compression.
- culebron21 5y ago
  Good point, thanks!
jillesvangurp 5y ago
Have you considered it might be you that's lacking in knowledge rather than the investors and founders? You seem quick to call people out on being scammers for something you clearly don't fully understand. Yes you can cite high school math but than you start making assumptions/assertions, drawing conclusions, etc. that are clearly wrong/baseless. Very sloppy arguing. You, "leave to the others to calculate how many RPMs should the device make"; like the people behind this company that clearly did that math, build a device and then proceeded to launch an object several tens of thousands of feet up. Clearly their math is better than yours. "I've not heard of any devices handling 100g over any significantly long periods of time." You just did.
- culebron21 5y ago
  Let's give your insult a benefit of a doubt. Show me a complex mechanical device, like a rocket, with fuel tanks, fuel pumps and ball bearings, that withstands >100g continuously for >10 seconds. Turbine blade that has 100g at its tip, is not one. "Don't learn physics, and you'll live in the world of wonders!"
  - JorgeGT 5y ago
    It is certainly a good question. The closest I found was the guidance and control system for the HARP project (shooting satellites into orbit). According to Wikipedia: The components of the guidance and control assembly were integrated into a 6.25-inch diameter test projectile. Sun sensors, horizon sensors, telemetry packs, receiving/transmitting antenna, hydraulic systems, logic modules, and gas thruster attitude control systems were all test-fired to approximately 10,000 g's https://en.wikipedia.org/wiki/Project_HARP#Martlet_4_Control_Systems https://en.wikipedia.org/wiki/Project_HARP#Martlet_4_Control...
inglor_cz 5y ago
IDK if they can make it work on Earth, but the Moon would still be valuable - and with zero atmosphere to slow things down. Production of chemical fuel on Moon is going be tricky, there are no fossil fuel deposits there and water is much scarcer than on Earth. Our contemporary chemistry isn't completely ready for such conditions, at least not on industrial scales. If we could use a mechanical / electrical mechanism to throw things onto the Lunar orbit, it might be much more efficient than, say, making methane in situ using Sabatier reaction. Solar panels are much more productive on the Moon than on Earth.
- culebron21 5y ago
  Back in 2012, before seeing Kerbal Space Program, I thought of it too. Well, if we build a tower 1 km tall (or find a suitable mountain), have two bobines with 5-10 km cable rotating and gradually increasing the radius while keeping the weight above the ground, then it could launch the vehicle at reasonable g's and within reasonable radius. But still the centrifugal force formula is cruel, and the size of the device is huge. Actually, I wonder if cold gas thruster can do the same job. (https://en.wikipedia.org/wiki/Cold_gas_thruster https://en.wikipedia.org/wiki/Cold_gas_thruster) At least some gases are extractable on the Moon surface.
- culebron21 5y ago
  Regarding cold gas, I found this analysis [1], that essentially says that within 40% of vehicle mass will get you to 500-1000 m/s, dV growing as square root. So it won't make it into lunar orbit. [1] https://digitalcommons.usu.edu/cgi/viewcontent.cgi?filename=0&article=1225&context=smallsat&type=additional https://digitalcommons.usu.edu/cgi/viewcontent.cgi?filename=...
h2odragon 5y ago
they speak of the planned system to launch 200kg payloads at 10,000g launch forces. Did we need to orbit fluidized electronics?

antimatter15 5y ago

iPhones can survive 1000G's

sandworm101 5y ago
Not for more than a microsecond.

sandworm101 5y ago

Fan blades in jet engines regularly see 100+ g, in tension. Artillery shells, even the fancy ones with guidance hardware, can handle such loads too, in compression.

culebron21 5y ago
Good point, thanks!

jillesvangurp 5y ago

Have you considered it might be you that's lacking in knowledge rather than the investors and founders? You seem quick to call people out on being scammers for something you clearly don't fully understand. Yes you can cite high school math but than you start making assumptions/assertions, drawing conclusions, etc. that are clearly wrong/baseless. Very sloppy arguing. You, "leave to the others to calculate how many RPMs should the device make"; like the people behind this company that clearly did that math, build a device and then proceeded to launch an object several tens of thousands of feet up. Clearly their math is better than yours. "I've not heard of any devices handling 100g over any significantly long periods of time." You just did.

culebron21 5y ago
Let's give your insult a benefit of a doubt. Show me a complex mechanical device, like a rocket, with fuel tanks, fuel pumps and ball bearings, that withstands >100g continuously for >10 seconds. Turbine blade that has 100g at its tip, is not one. "Don't learn physics, and you'll live in the world of wonders!"
- JorgeGT 5y ago
  It is certainly a good question. The closest I found was the guidance and control system for the HARP project (shooting satellites into orbit). According to Wikipedia: The components of the guidance and control assembly were integrated into a 6.25-inch diameter test projectile. Sun sensors, horizon sensors, telemetry packs, receiving/transmitting antenna, hydraulic systems, logic modules, and gas thruster attitude control systems were all test-fired to approximately 10,000 g's https://en.wikipedia.org/wiki/Project_HARP#Martlet_4_Control_Systems https://en.wikipedia.org/wiki/Project_HARP#Martlet_4_Control...

inglor_cz 5y ago

IDK if they can make it work on Earth, but the Moon would still be valuable - and with zero atmosphere to slow things down. Production of chemical fuel on Moon is going be tricky, there are no fossil fuel deposits there and water is much scarcer than on Earth. Our contemporary chemistry isn't completely ready for such conditions, at least not on industrial scales. If we could use a mechanical / electrical mechanism to throw things onto the Lunar orbit, it might be much more efficient than, say, making methane in situ using Sabatier reaction. Solar panels are much more productive on the Moon than on Earth.

culebron21 5y ago
Back in 2012, before seeing Kerbal Space Program, I thought of it too. Well, if we build a tower 1 km tall (or find a suitable mountain), have two bobines with 5-10 km cable rotating and gradually increasing the radius while keeping the weight above the ground, then it could launch the vehicle at reasonable g's and within reasonable radius. But still the centrifugal force formula is cruel, and the size of the device is huge. Actually, I wonder if cold gas thruster can do the same job. (https://en.wikipedia.org/wiki/Cold_gas_thruster https://en.wikipedia.org/wiki/Cold_gas_thruster) At least some gases are extractable on the Moon surface.
culebron21 5y ago
Regarding cold gas, I found this analysis [1], that essentially says that within 40% of vehicle mass will get you to 500-1000 m/s, dV growing as square root. So it won't make it into lunar orbit. [1] https://digitalcommons.usu.edu/cgi/viewcontent.cgi?filename=0&article=1225&context=smallsat&type=additional https://digitalcommons.usu.edu/cgi/viewcontent.cgi?filename=...

h2odragon 5y ago

they speak of the planned system to launch 200kg payloads at 10,000g launch forces. Did we need to orbit fluidized electronics?