Aug 17, 2016 14:07 Breakthrough Initiatives Posted on: Breakthrough Initiatives

Apr 13, 2016 06:39 Theodore Kim Posted on: Breakthrough Initiatives:
"I believe one reason for the choice of this design (having lasers on the ground, at a high altitude in Chile's Atacama desert) was because it would prevent someone from having a 100GW laser canon in space that could be used as a weapon! That, and of course the much lower costs of basing it on earth rather than on space. However, it would still be a fantastically powerful anti-sat weapon capable of (literally) blowing away anything the passes overhead (almost everything except geo-sync orbits over the other hemisphere). That's why governments will need/want to be involved (if they secretly aren't already :(
However, there is another application that I propose. Not only would it be, as a telescope, be able to spot any potential asteroids heading our way but a 100GW laser could do serious damage to them, "pushing" them or more realistically ablating their surface so that they are gradually nudged off course. Think of it as an "earth-defense" laser :)"

Answer:

Indeed, all possible auxiliary uses for the beamer.
As you mention, asteroids in a range of masses and Earth closing vectors could be moved off course by ablating the surface; see work of Prof. Lubin and team on DE-STAR.
http://arxiv.org/pdf/1604.03511v2.pdf
http://www.deepspace.ucsb.edu/projects/directed-energy-planetary-defense

Additional applications are space debris cleaning (diffraction limit at 1000 km is only 1 mm) and as laser source for “BEAMED ENERGY FOR ABLATIVE PROPULSION IN NEAR EARTH SPACE”, a very promising idea for future space launches.
http://nsstc.uah.edu/essa/docs/iac/Bergstue-Grant-IAC-11.C4.8.2.x11495.pdf

– Prof. Sasha Buchman, Breakthrough Initiatives

Aug 17, 2016 14:08 Breakthrough Initiatives Posted on: Breakthrough Initiatives

Apr 13, 2016 10:43 Angeliki Kapoglou Posted on: Breakthrough Initiatives:
"How much simpler the laser-beamed interstellar probes concept would be (both from policy and technical perspective) if we built the array on the Moon? Maybe not much. but someone needs to check this :)"

Answer:

A moon based station would require GW power generation an advanced technical capabilities team, a km size telescope and a significant technical team. As mentioned in other comments thus is an endeavor of even larger scale than StarShot and thus not available on the same single generation time scale.

– Prof. Sasha Buchman, Breakthrough Initiatives

Aug 17, 2016 14:09 Breakthrough Initiatives Posted on: Breakthrough Initiatives

Apr 14, 2016 17:58 Louis Scheffer Posted on: Breakthrough Initiatives:
"The policy objectives (can't be used for attack of Earth or its satellites) could also be achieved by a space-based laser, if solar powered and outside the Earth's orbit. The architecture would be a thin plate with solar cells on one side and adjustable lasers on the other. With no storage, it would need to be somewhat bigger (say 5 km on a side) which would give less power but longer acceleration times (since it's a bigger aperture it can keep focus longer). Phasing would be much easier. Expense is an obvious problem."

Answer:

The expense and technical challenges would indeed be the problem; see previous comment. A 5 km on a side array/beamer with 20% efficiency would generate about 7 GW, but would also, as you mention, deliver a tighter beam. An Earth orbit around the Sun will ensure that the beamer will maintain its position with respect to Earth, never coming closer. However, at a distance of less than 2 AU, the power density delivered at Earth by the 5 km beamer will be in excess of 1 MW/m2. This will increase the temperature of a targeted body by a factor of more than 5, i.e. ~1,500 K.

– Prof Sasha Buchman, Breakthrough Initiatives

Aug 27, 2016 19:08 benedictrodgers@hotmail.com Posted on: Breakthrough Initiatives

This is an excellent project and I hope that it inspires Earthlings to look up and get a sense of perspective.

However I think that the "policy" challenge, the most utterly mundane and tedious of all the challenges ("obtain permission from the government"), may well turn out to be the one with the longest timescale.

The truth is that, as the world order is presently constituted, it is and will remain impossible to obtain a worldwide consensus on the construction of a laser with the power of a hundred nuclear power stations. Whose laser, they will ask, will it be? Will it be a Chilean laser? An American laser? Chinese? Russian?

Until we have established a worldwide legal framework which makes these cretinous questions otiose, the project is not going to happen.

I mean not to rain on this parade! I mean merely to say that those of us who are not blessed with maths, may have a role to play in realising this project.

Sep 09, 2016 21:05 michael.million@sky.com Posted on: Centauri Dreams

All of humanity, it is our time to create a stellar empire upon which Suns never set.

Nov 18, 2016 23:44 Breakthrough Initiatives Posted on: Breakthrough Initiatives

RE:
"Aug 27, 2016 19:08benedictrodgers@hotmail.comPosted on: Breakthrough Initiatives
This is an excellent project and I hope that it inspires Earthlings to look up and get a sense of perspective. However I think that the "policy" challenge, the most utterly mundane and tedious of all the challenges ("obtain permission from the government"), may well turn out to be the one with the longest timescale.

The truth is that, as the world order is presently constituted, it is and will remain impossible to obtain a worldwide consensus on the construction of a laser with the power of a hundred nuclear power stations. Whose laser, they will ask, will it be? Will it be a Chilean laser? An American laser? Chinese? Russian? Until we have established a worldwide legal framework which makes these cretinous questions otiose, the project is not going to happen. I mean not to rain on this parade! I mean merely to say that those of us who are not blessed with maths, may have a role to play in realising this project."

Answer:
Thank you for your interest. The issue of policy is indeed a grand challenge. Striving for mutual understanding on the topic of space exploration requires a global discourse as does the guarantee of safe operating procedures. There is ongoing research into how one would tackle the concerns you have addressed and such research will likely become a key component of this programs future.

Jan 08, 2017 12:10 michael.million@sky.com Posted on: Centauri Dreams

We may have to build two, one in the southern hemisphere in Chile and another one say around China/India/Russia in the northern hemisphere. If we use it for asteroid/comet defence at least we have greater coverage to cover more space directions and it makes it less likely one side will use it against space borne assets as there is likely to be a retaliatory response from the other.

Feb 02, 2017 19:02 Breakthrough Initiatives Posted on: Breakthrough Initiatives

RE:
"Jan 08, 2017 12:10 michael.million@sky.com Posted on: Centauri Dreams
We may have to build two, one in the southern hemisphere in Chile and another one say around China/India/Russia in the northern hemisphere. If we use it for asteroid/comet defence at least we have greater coverage to cover more space directions and it makes it less likely one side will use it against space borne assets as there is likely to be a retaliatory response from the other."

Answer:
Thank you for your consideration. Yes we are considering Hawaii and the Tibet as possible sites.

– Pete Klupar, Breakthrough Starshot

Nov 08, 2017 07:35 Nathan Bemis Posted on: Breakthrough Initiatives

A big bonus of the array is that it could be used to clear orbital debris. That should be a very intriguing to governments.
There should be international involvement in making sure the technology and purpose is used for science not as a weapon or some political bureaucratic bargaining chip. Keep the ugly politics out of it.

Dec 11, 2017 19:34 Breakthrough Initiatives Posted on: Breakthrough Initiatives

RE:
"Nov 08, 2017 07:35 Nathan Bemis Posted on: Breakthrough Initiatives"

Reply:
Thank you for your comment. Your idea has been shared by others and could potentially be useful for said purpose. The primary focus of the initiative remains to accelerate small spacecraft to high enough velocities to reach the Alpha Centauri system.

- Team, Breakthrough Initiatives