Jun 16, 2016 07:36
michael.million@sky.com
Posted on: Centauri Dreams
We could make MEM's particle accelrators and ion engines to move the sail around, these MEM's can handle massive 'g's and can be made by mass production methods we currently use for silicon.
http://lmts.epfl.ch/MEMS-ion-source
When can we start building these sails?
Jun 21, 2016 09:43
michael.million@sky.com
Posted on: Centauri Dreams
If we had a rim that was highly positively charged to deflect oncoming ionised gas and dust (edge on) we could also turn it slightly to one side using a small power drive and the sail will be deflected to one side using the ISM as the reaction mass, just like a sail would do.
Jul 16, 2016 00:18
margaritalopezmm82@outlook.com
Posted on: Centauri Dreams
A few days ago I have watched a video on YouTube about this but unfortunatelly my english is not strong so I could not understand.
Jul 23, 2016 21:03
Breakthrough Initiatives
Posted on: Breakthrough Initiatives
Apr 13, 2016 03:20 Dan Ward Posted on: Breakthrough Initiatives:
"Here's a very uninformed question/suggestion: if the sail is a reflective material, doesn't the incident light produce a sidewards pressure component on an angled surface? In effect, can't a mirrored sail be used to 'tack' within the laser beam? No need then for thrusters.
Unless the thrusters are to re-angle and stabilize the sail. In that case, why not use voltage-controlled shuttered sections (varied opacity with LCD-type material) along the sail's edges. Assuming the sail is spun to maintain it's shape, those shutters would be timed to precess and stabilize the whole craft to the desired angle. That would draw a lot less current than diode lasers."
Yes, tilting the sail relative to the laser could induce a force perpendicular to the beam as you have suggested. The main issue here is that the sail will only be “riding the beam” for the first few minutes of its journey. We will need to be able to alter the sail’s attitude (orientation) and possibly make small course corrections throughout its long journey. This will require some other form of propulsion.
– Zac Manchester, Breakthrough Starshot
Jul 23, 2016 21:04
Breakthrough Initiatives
Posted on: Breakthrough Initiatives
Apr 14, 2016 15:42 Michael Atkinson Posted on: Breakthrough Initiatives:
"How about altering the charge on the spacecraft and using interaction with interstellar magnetic fields and target star magnetic fields to alter the trajectory?"
It sounds like you’re suggesting using the Lorentz force (https://en.wikipedia.org/wiki/Lorentz_force) to alter the craft’s trajectory. The issue here is that the Lorentz force is generally very weak. The strength of a magnetic field decreases with the cube of the distance from a dipole source (https://en.wikipedia.org/wiki/Magnetic_dipole), which means you need to be extremely close to the source of the field and need a very large charge on the spacecraft to achieve any meaningful delta-v. This might be possible on a close flyby of a planet or star with a very strong magnetic field, but not in interstellar space.
– Zac Manchester, Breakthrough Starshot
Jul 23, 2016 21:07
Breakthrough Initiatives
Posted on: Breakthrough Initiatives
Apr 23, 2016 23:11michael.million@sky.comPosted on: Breakthrough Initiatives
"Might be better to have a radioactive source emitting alpha particles onto a steerable deflecting sheet which can then be used to move the sail around. Or have radioactive material sprayed onto the sail and then use electrical impulses to twist the sheet so the radioactive particles give directional thrust."
Answer:
Yes, there may be alternatives to photon pressure. The problem I see with a radioisotope source is in deflecting the particles in the direction you want, which could require very dense materials and mechanical actuators. Both would add significant weight to the spacecraft.
– Zac Manchester, Breakthrough Starshot
Jul 23, 2016 21:08
Breakthrough Initiatives
Posted on: Breakthrough Initiatives
May 05, 2016 17:43Maryna TsybulskaPosted on: Breakthrough Initiatives
"Perhaps this thing could be useful, if it can be made to fit somehow?
http://arxiv.org/abs/1603.03015";
May 07, 2016 12:32Dmitry NovoseltsevPosted on: Breakthrough Initiatives
"Combining Magnetic and Electric Sails
(http://arxiv.org/abs/1603.03015)?
Or combining light and electric sails
(http://spacecolonization.info/issues/issue-8-2014/)?
(it was non-relativistic (low-speed) nanocraft)"
There are two main issues with something like the magnetic and/or electric sail concepts proposed in the paper. First, as you have pointed out, is the added mass they would require. Second is the power needed to operate them. Adding a large power system would again add more mass. Minimizing the mass of the spacecraft is crucial to our ability to accelerate it to high speed.
– Zac Manchester, Breakthrough Starshot
Jul 23, 2016 21:10
Breakthrough Initiatives
Posted on: Breakthrough Initiatives
Jun 16, 2016 07:36michael.million@sky.comPosted on: Centauri Dreams:
"We could make MEM's particle accelrators and ion engines to move the sail around, these MEM's can handle massive 'g's and can be made by mass production methods we currently use for silicon.
http://lmts.epfl.ch/MEMS-ion-source
When can we start building these sails?"
The main issue with something like the MEMS electrospray thrusters you have pointed out is that they require expendable propellant to operate. On a multi-decade mission, the fuel will eventually run out. A photon thruster, on the other hand, only requires power supply.
– Zac Manchester, Breakthrough Starshot
