3 ms·

1 megawatt of continuously absorbed power would require a lot of mass to dissipate without melting. But since we're talking about gram-sized objects, there's no

1 megawatt of continuously absorbed power would require a lot of mass to dissipate without melting. But since we're talking about gram-sized objects, there's no chance. Even kilowatt would be a problem for object that small.

marcosdumay 2y ago
> 1 megawatt of continuously absorbed power would require a lot of mass to dissipate without melting Hum... I would require a lot of surface area, that's certain. There's no constraint at all at the mass.
- bufferoverflow 2y ago
  Yes, there's a constraint on mass. Surface area is for dissipation. Mass will have to store the absorbed energy until it's dissipated. Mass determines the temperature. And every material has a limit on that temperature.
EthanHeilman 2y ago
Starshot which is the above proposal is likely based uses 10 meter square solar sails that are 100 atoms thick. > In order to reach relativistic speeds, the Starshot lightsail should have an area of ~10 m2 and be kept to a mass of under ~1 gram, which translates into an equivalent thickness of approximately 100 atomic layers ... With radiative cooling being the sole mechanism for passive thermal management in space, we quantify stringent requirements on material absorptivity that enable the lightsail to withstand high laser intensity and prevent excessive heating and mechanical failure. They seem to think that heat dissipating is within the realm of plausibility Materials challenges for the Starshot lightsail, Nature Materials, 2018, https://daedalus.caltech.edu/files/2018/05/Materials-challneges-for-Starshot-lightsail.pdf https://daedalus.caltech.edu/files/2018/05/Materials-challne...
- barbegal 2y ago
  It's a nice idea but surely any variation in mass of the lightsail will result in significant forces which will literally pull the sail apart. And with a thickness of 100 atoms that variation might be just a few atoms. I can't see how this can be manufactured to take such high forces and be so light and thin.
  - EthanHeilman 2y ago
    That's why it is a research project, it is hard to do.

marcosdumay 2y ago

> 1 megawatt of continuously absorbed power would require a lot of mass to dissipate without melting Hum... I would require a lot of surface area, that's certain. There's no constraint at all at the mass.

bufferoverflow 2y ago
Yes, there's a constraint on mass. Surface area is for dissipation. Mass will have to store the absorbed energy until it's dissipated. Mass determines the temperature. And every material has a limit on that temperature.

EthanHeilman 2y ago

Starshot which is the above proposal is likely based uses 10 meter square solar sails that are 100 atoms thick. > In order to reach relativistic speeds, the Starshot lightsail should have an area of ~10 m2 and be kept to a mass of under ~1 gram, which translates into an equivalent thickness of approximately 100 atomic layers ... With radiative cooling being the sole mechanism for passive thermal management in space, we quantify stringent requirements on material absorptivity that enable the lightsail to withstand high laser intensity and prevent excessive heating and mechanical failure. They seem to think that heat dissipating is within the realm of plausibility Materials challenges for the Starshot lightsail, Nature Materials, 2018, https://daedalus.caltech.edu/files/2018/05/Materials-challneges-for-Starshot-lightsail.pdf https://daedalus.caltech.edu/files/2018/05/Materials-challne...

barbegal 2y ago
It's a nice idea but surely any variation in mass of the lightsail will result in significant forces which will literally pull the sail apart. And with a thickness of 100 atoms that variation might be just a few atoms. I can't see how this can be manufactured to take such high forces and be so light and thin.
- EthanHeilman 2y ago
  That's why it is a research project, it is hard to do.