Communication | Sending images with laser using sail as antenna

Images of the target planet could be transmitted by a 1Watt laser onboard the nanocraft, in a ‘burst mode’ which uses the energy storage unit to rapidly draw power for the power-intensive laser communications mode. Upon approach to the target, the sail would be used to focus the laser communication signal.

For a 4m sail, for example, the diffraction limit spot size on Earth would be on order of 1000m. A kilometer-scale receiving array would intercept 10-14 of the transmitted signal. The main challenge is to use the sail as diffraction limited optics for the laser communication system. This would be achieved by shaping the sail into a ‘Fresnel lens’ upon approach to the target. The sail structure could be different at the launch and communication phases. In order to maintain a high transmission through the Earth’s atmosphere, the communication would need to operate at a wavelength shorter than that used by the launch laser system, due to the Doppler shift of the nanocraft relative to the Earth.

May 02, 2016 19:16 Karl Loh Posted on: Breakthrough Initiatives

If an extraterrestrial civilization were observing us with gram-scale devices and sending data back using a laser, how would we detect it?

If extraterrestrials were sending commands to their gram-scale devices, scrambled to blend into background noise, how would we detect it?

May 07, 2016 16:54 Karl Loh Posted on: Breakthrough Initiatives

Regarding above-mentioned query about the possibility of extraterrestrial gram-scale devices in our system, where might they be? Below lunar orbit, above, or on the moon, or in lunar-synchronous orbit? Might they be in geo-synchronous orbit, but, under constant lightsail propulsion, higher than our satellites are? Or lower, for closer observation? What would we do if we were them?

Jun 15, 2016 07:39 michael.million@sky.com Posted on: Centauri Dreams

Using MEM's we could deform the sail to form an antenna, these MEM's (electrostatic actuators) could be etched onto the dark side of the sail using modern silicon fabrication technologies.

Jun 15, 2016 09:57 Carl Hinton Posted on: Breakthrough Initiatives

If wormholes are possible, then ordinary subluminal methods of communication could be sent through them to achieve superluminal transmission speeds - reducing significantly the return message time. Considering the immense energy that current theories suggest would be required to open a wormhole only atomic-scale wormholes would be practical to build, limiting their use solely to information transmission. Some theories of wormhole formation would prevent them from ever becoming "timeholes", allowing superluminal communication without the additional complication of allowing communication with the past.

Sep 17, 2016 16:25 michael.million@sky.com Posted on: Centauri Dreams

We may be able to do this if we had stacks of laser diodes in which the light is transmitted in a plane, now on the sail we have mirrors which are erected so that the light shone in the plane is reflected off the mirrors.

http://newscenter.lbl.gov/2015/10/20/exciting-breakthrough-in-2d-lasers/

http://slideplayer.com/slide/9193031/

http://cdn4.explainthatstuff.com/laserdiode.png

http://spie.org/Images/Graphics/Newsroom/Imported-2010/002555/002555_10_fig1.jpg

Nov 05, 2016 04:40 Breakthrough Initiatives Posted on: Breakthrough Initiatives

RE:
"May 02, 2016 19:16Karl LohPosted on: Breakthrough Initiatives
If an extraterrestrial civilization were observing us with gram-scale devices and sending data back using a laser, how would we detect it? If extraterrestrials were sending commands to their gram-scale devices, scrambled to blend into background noise, how would we detect it?"

Answer:
Detecting the beamer is an interesting possibility which was recently studied in the following paper
https://arxiv.org/pdf/1508.03043.pdf

Detecting 1 gram nanocrafts with existing telescopes is not feasible even within the solar system.

- Avi Loeb, Breakthrough Starshot

Nov 05, 2016 04:40 Breakthrough Initiatives Posted on: Breakthrough Initiatives

RE:
"May 07, 2016 16:54Karl LohPosted on: Breakthrough Initiatives
Regarding above-mentioned query about the possibility of extraterrestrial gram-scale devices in our system, where might they be? Below lunar orbit, above, or on the moon, or in lunar-synchronous orbit? Might they be in geo-synchronous orbit, but, under constant lightsail propulsion, higher than our satellites are? Or lower, for closer observation? What would we do if we were them?"

Answer:
Thanks for your interest. Our intention is to stay at least 1 AU from the target planet. As we learn more about the systems we may move closer

- Avi Loeb, Breakthrough Starshot

Nov 05, 2016 04:41 Breakthrough Initiatives Posted on: Breakthrough Initiatives

RE:
"Jun 15, 2016 07:39michael.million@sky.comPosted on: Centauri Dreams
Using MEM's we could deform the sail to form an antenna, these MEM's (electrostatic actuators) could be etched onto the dark side of the sail using modern silicon fabrication technologies."

Answer:
Thanks for the response. This is a wonderful idea and will be traded during the design phase.

- Avi Loeb, Breakthrough Starshot

Nov 05, 2016 04:41 Breakthrough Initiatives Posted on: Breakthrough Initiatives

RE:
"Jun 15, 2016 09:57Carl HintonPosted on: Breakthrough Initiatives
If wormholes are possible, then ordinary subluminal methods of communication could be sent through them to achieve superluminal transmission speeds - reducing significantly the return message time. Considering the immense energy that current theories suggest would be required to open a wormhole only atomic-scale wormholes would be practical to build, limiting their use solely to information transmission. Some theories of wormhole formation would prevent them from ever becoming "timeholes", allowing superluminal communication without the additional complication of allowing communication with the past."

Answer:
Thanks for your interest. We will watch the development in wormhole technology and use it as soon as it is available. For now the idea is considered highly speculative.

- Avi Loeb, Breakthrough Starshot

Nov 05, 2016 04:41 Breakthrough Initiatives Posted on: Breakthrough Initiatives

RE:
"Sep 17, 2016 16:25michael.million@sky.comPosted on: Centauri Dreams
We may be able to do this if we had stacks of laser diodes in which the light is transmitted in a plane, now on the sail we have mirrors which are erected so that the light shone in the plane is reflected off the mirrors.

http://newscenter.lbl.gov/2015/10/20/exciting-breakthrough-in-2d-lasers/
http://slideplayer.com/slide/9193031/
http://cdn4.explainthatstuff.com/laserdiode.png
http://spie.org/Images/Graphics/Newsroom/Imported-2010/002555/002555_10_fig1.jpg

Answer:
Thanks for the response. These are exciting developments and we will incorporate as much as we can.

- Avi Loeb, Breakthrough Starshot

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