Breakthrough Starshot Initiative *Live Feed HAS ENDED*

[p1t1o]

Clearly the answer is to build 1000 laser stations so that we can up the probes to 1kg.

[AngelLestat]

9 hours ago, The Yellow Dart said:

I don't understand how a nano-satellite is supposed to beam data to earth from +4ly away. It takes a decent sized antenna/transmitter to go from Earth to Mars, and the whole probe was only supposed to be like the size of a quarter, right? I didn't watch the talk, did they talk about that at all?

These sails will have a diameter of 1 to 4 meters, that can be used as a descent parabolic, the parabolic will always point forward, with a light receptor in the focus point, then you relay that transmission with a laser to the next sail, these sails are 99.999% reflective, they only need to get few photons with a complex error proof algorithm, and they dont need to achieve high bandwidth because their instruments will be simple without much resolution.
They transmit only in one direction, so is not a connection link.  You can not sent info or ask anything.
The normal distance between sails will be neptune to earth distance, but they should be able to transmit 5 times that distance in case something happens.

2 hours ago, p1t1o said:

Clearly the answer is to build 1000 laser stations so that we can up the probes to 1kg.

They want to keep this project between the 100 billion margin, if you need 1000 times that power, it will also increase a lot that budget to the point that the  government and investors will just said "no". And we get nothing..

Maybe there is a way just increasing a bit more the laser power and sail area keeping the budget low reducing the amount of sails you sent and increasing the acceleration time with extra laser in the way and using mirrors to get multiple bounces of the photons when the sail is closer to the laser.
In this way you place low powered lasers over all the way from here to mars orbit, but allowing to bounce the light in each laser around 100 times. 
Then you include a tiny wire in the sail that it will work as mag sail to be used as brake to at least reduce the speed from 20% c to 5% c, then you make a close dive with the 2 stars from the binary system to slow down the 5% leftover and stay in the system, going to any planet you want (because it also works as a solar sail).
If the sail is bigger, it can transmit over higher distances and even receive commands.

Edited April 15, 2016 by AngelLestat

[PB666]

28 minutes ago, AngelLestat said:

These sails will have a diameter of 1 to 4 meters, that can be used as a descent parabolic, the parabolic will always point forward, with a light receptor in the focus point, then you relay that transmission with a laser to the next sail, these sails are 99.999% reflective, they only need to get few photons with a complex error proof algorithm, and they dont need to achieve high bandwidth because their instruments will be simple without much resolution.

Solar wind travels at several hundred km per second outward,145,000 m/s ( 0.0005c), your vessel is traveling at 0.2c. The density at earths orbit is 1E9kg/4pi*150000000000^2 = 3.5E-15 per square meter transient or 2.4E-20/cubic meter. Why I throw out this trivia is that a craft traveling at 0.2c, the solar winds are all but a static drag force. So if the sail was 4 square meters, and travel 60,000,000 meters per second it would encounter 5.76x 10-12 kg of protons/second which would deflect around the sail as it built up positive charge (more so than the payload because of its size). The differential energy is 1.8E15/kg therefore the and if we assumed that in deflection 10% of the photons energy was transferred, then we would see an energy in the form of sun facing force on the sail of  1036 joules/second (basically a kilowatt). The work done per unit time is F*d and interaction distance is 60,000,000 then the force 17 micronewtons per kilogram mass, and so if the whole device weights a gram its 17 ma of acceleration which declines at the k * SQRT(d_sun/150,000,000,000) .

The bottom line is that the device will turn, the convex surface of the sail will face the sun, because there is gas density all the way to aC, it will stay facing the sun, any signal it sends will be sent away from the sun. The only way to stop this is to charge the sail so that it bottom is negatively charge and top is positively charged, since the sail is decelerating and the payload is not the sail would fall into the center of the payload and the sail would collapse around the payload reducing the force. To prevent this the payload would need to be positively charged to push it away from the sail.

 

Quote

They transmit only in one direction, so is not a connection link.  You can not sent info or ask anything.
The normal distance between sails will be neptune to earth distance, but they should be able to transmit 5 times that distance in case something happens.

They want to keep this project between the 100 billion margin, if you need 1000 times that power, it will also increase a lot that budget to the point that the  government and investors will just said "no". And we get nothing..

 

What they could do is charge the device and turn it, transmit to the next IS ship one the way, which is set to receive by default force then turns around and sends it message to the next one back. And alternative is to move a nuclear based ship into Interstellar space (IOW no orbit relative to the sun) with a huge antenna, very low frequency signals (long wave, of low power can transmit almost perfectly between heliopauses), and a very high gain antenna could be made a mile wide with widely separated wires, you could potentially receive such weak signals. The problem with such a receiver is that you would have to have an active cooling system that was very close to absolute zero. The other problem, data transmission would be in baud, like 20 baud or so. 

The way to do the is set up tracking arrays with lasers in elliptical orbits that have the same periods as Earth, then you can repeatedly accelerate a larger craft and you are not bound by the limits of earth tracking. In addition since velocity is lower you would have less of a challenge with the solar wind. One way to create a huge antenna is ro roll out wire (like the wind sail in the other post) and rotate the wires, using a tether pull the ends toward the center, These wires could be .01 mm in length made of memory material that assumes a certain shape, again the frequency so low that the great distance of the wires would reflect the signal in the desired direction.

Another way is this, create a extra-heliopause ship that sends out sorted poly-chromatic light, telling the ships were they are relative to the center. The ships when launched retract their sails to slightly alter velocity. The first ships leave their sails out, the last ships retract their sails, They steer using their sails to the center of the light path based on the wavelength of light they detect, once at the center they search out other ships, which then can send signals out in parallel each ship sharing data with the next and each ship gathering its own bit of science.

If you launched millions you could actually have them build a robot that then collects other ships that build an antenna.

 

[YNM]

5 hours ago, PB666 said:

(speaking from the big underground cave i currently digging for no particular reason)

Are you recreating this ?

[AngelLestat]

@PB666 Lets start from the base that solar wind produce 5000 times less pressure over 1m2 mag sail than photons (1360w/m2 normal irradiance at earth orbit) over 1m2 solar sail, a normal sail if is not designed to work like a magsail, the charge is not the same,  would not do much.. the force and effect is negligible.

The benefics with electric sails is area, they are also very good to kill relativistic speeds, not so much low speeds, a craft traveling at 0.95c, it may take few days to brake to 0.5c without propellant.
That is why I consider a good idea to include some charge wires in a normal sail, so even if is not enough to brake, your time in the system increase.
About your concave shape concern due pressure, you dont need to transmit inside the solar system, and shape will be easy to control if you add some contraction rings over the sail, that it will contact when a electrical current is applied. (Ok now I read your next paragraph and you had a similar idea).

You mean a continue beam?  I did not understand the part of "once at the center they search out other ships, which then can send signals out in parallel each ship sharing data with the next and each ship gathering its own bit of science".

Choramatic light in the edges of the beam is not possible, because all beams diffract, in no time you have that chromatic light in the center of the beam and way beyond the edges.
 

[PB666]

18 minutes ago, AngelLestat said:

@PB666 Lets start from the base that solar wind produce 5000 times less pressure over 1m2 mag sail than photons (1360w/m2 normal irradiance at earth orbit) over 1m2 solar sail, a normal sail if is not designed to work like a magsail, the charge is not the same,  would not do much.. the force and effect is negligible.

 

Yes but photons are only used breifly as soon as the force is release the sail will turn, if you miss-target it turns. So there is no way to keep from turning except constantly applying force all the way to aC, in that respect its impossible.

 

[todofwar]

http://www.sciencemag.org/news/2016/04/russian-billionaire-unveils-big-plan-build-tiny-interstellar-spacecraft

Not sure if that link will work since I read it on a network with a science subscription, but apparently this billionaire wants to send a space craft to a nearby star, and he plans on making it weigh a gram. Apparently it will work by getting pushed by lasers based on the earth.

Edited April 18, 2016 by todofwar

[Spaceception]

6 minutes ago, todofwar said:

http://www.sciencemag.org/news/2016/04/russian-billionaire-unveils-big-plan-build-tiny-interstellar-spacecraft

Not sure if that link will work since I read it on a network with a science subscription, but apparently this billionaire wants to send a space craft to a nearby star, and he plans on making it weigh a gram. Apparently it will work by getting pushed by lasers based on the earth.

 

[AngelLestat]

On 15/4/2016 at 6:00 PM, PB666 said:

Yes but photons are only used breifly as soon as the force is release the sail will turn, if you miss-target it turns. So there is no way to keep from turning except constantly applying force all the way to aC, in that respect its impossible.¡

Yeah, It could be used as attitude control over the whole trip, but not sure the amount of energy you will need to waste in this matter, because you need to turn on and off the charges in the wires, so even if you use superconductors does not help much.

Edited April 18, 2016 by AngelLestat

[PB666]

You would only need to turn it on to communicate.

[Aethon]

Can the sail be used as the antenna?

[AngelLestat]

6 minutes ago, Aethon said:

Can the sail be used as the antenna?

As i comment before, if you use lasers (instead of radio waves) to communication, then sails will act as a parabolic mirror in where you can place a photon receptor in the focus point.  You can turn your receptor to just a very narrow range of frequencies to avoid noice.

[Aethon]

Yeah.  That's where I was going.  I commented at the end of page 3, thinking i had read all unread posts.

To be clear about all of this..  The $100 million dollars won't fund this project, it's just seed money to work these concepts out.  

There were some pretty smart people on the stage during the presentation,  I assume they are confident we have the technology to make it so, and they probably have some tricks up their sleeves- having said that, I'd love to see a more fleshed out version of how they plan to do all this.

[Shpaget]

9 hours ago, AngelLestat said:

As i comment before, if you use lasers (instead of radio waves) to communication, then sails will act as a parabolic mirror in where you can place a photon receptor in the focus point.  You can turn your receptor to just a very narrow range of frequencies to avoid noice.

How do you send the transmission back?

[PB666]

14 hours ago, Aethon said:

Yeah.  That's where I was going.  I commented at the end of page 3, thinking i had read all unread posts.

To be clear about all of this..  The $100 million dollars won't fund this project, it's just seed money to work these concepts out.  

There were some pretty smart people on the stage during the presentation,  I assume they are confident we have the technology to make it so, and they probably have some tricks up their sleeves- having said that, I'd love to see a more fleshed out version of how they plan to do all this.

No, that we have the technology for some aspects and evolving technology for others, I think the 100 million dollars is to do the following, to kick the thinking about space travel out of the ion-drives are the limit of ISP and even with that we cannot get very far. So 100 million dollars says we can make mega-big energy/mass stuff (with reality) but we not sure at the moment if we can control it, so you guys figure it out.

 

[AngelLestat]

8 hours ago, Shpaget said:

How do you send the transmission back?

the transmission is one way..

You can not send commands or instructions to the sails, and even if you can it will be pointless.

 

 

[Shpaget]

Ok, it seems there was a glitch in our coms. I thought you were suggesting the usage of lasers for sending instructions from Earth to the probes.

I thought we've already established just how not feasible sending data back from probes to Earth is. Power requirements still sound a few orders of magnitude outside the "gram scale" platform capabilities.

[Spaceception]

 

[PB666]

1 hour ago, Spaceception said:

 

Where is the not-like button?

[Exoscientist]

I've been thinking of ways we can get such nanocraft to link up through
self-assembly and form larger structures that can do more detailed
observations and experiments. This could work even for visits to far off
destinations still in the Solar System such as Kuiper belt objects like
Pluto or the Oort cloud.

The main problem is getting the many objects flying independently and
getting further apart the further out they go to gradually be drawn to each
other and link up. Once they link up, I don't it would be too difficult to
then get them to do self-assembly.

But it's that drawing together step that is the sticking point.

   Bob Clark

 

Edited April 28, 2016 by Exoscientist

[Shpaget]

3 hours ago, Exoscientist said:

I've been thinking of ways we can get such nanocraft to link up through
self-assembly and form larger structures that can do more detailed
observations and experiments. This could work even for visits to far off
destinations still in the Solar System such as Kuiper belt objects like
Pluto or the Oort cloud.

The main problem is getting the many objects flying independently and
getting further apart the further out they go to gradually be drawn to each
other and link up. Once they link up, I don't it would be to difficult to
then get them to do self-assembly.

But it's that drawing together step that is the sticking point.

   Bob Clark

 

Drawn to each other? Drawn by what?

If you can have multiple crafts close enough to each other for them to touch (even eventually), then you might as well launch them together (as a single probe) in the first place and save quite a bit of mass by not including propulsion, coms and navigation needed for the merger.

[Exoscientist]

 The reason why the Hawking probe is going to use nanoprobes is because it is hard to get a large size vehicle to relativistic speeds even when using laser propulsion from the ground.

 As to how they might be made to link up, perhaps the light sails can be angled so that so that they would be directed to conglomerate at a common point. It is known that solar/laser sails can do "tacking" to change their direction.

 Another possibility is that there will be the ionized solar wind and interplanetary and interstellar dust that the nanoprobes could react against to be directed to a common point. 

 BTW, I don't think it would too difficult to do the self-assembly, still I'd like to get some feedback on how it could be done. Note the nanoprobes are considered to be about the size, and complexity of, say, a virus, or RNA molecule. This also raises the possibility of alien species using this to seed other star systems with life.

 

  Bob Clark

 

 

Edited April 29, 2016 by Exoscientist

[KerbMav]

Someone in this thread mentioned a 60 years long mission - decades to wait for an answer ... gave me a dystopian story idea somehow ...

On 13.4.2016 at 4:19 PM, Robotengineer said:

Stephen Hawking's chair is not your average wheelchair. 

Hawking, cousin of Commodore Pike.

[Exoscientist]

Assuming we can get the nanoprobes to link up this may be something we can do now. The Hawking proposal is for a 100 gigawatt laser to send multitudes of 1 gm probes. Then scale down the size of the probes to get a more feasible laser power requirement. See the list of typical values of the mass of different objects here:

https://en.m.wikipedia.org/wiki/Orders_of_magnitude_(mass)#10.E2.88.9212_to_10.E2.88.927_kg

 A human ovum weighs in the range of a few micrograms. This would require a laser only 100 kilowatts. With the nanoscale engineering currently used to make integrated circuits, we can make a quite complex "cell" of the same mass of a human ovum that can be used to build a more complex system.

  Bob Clark

[sal_vager]

Pinned for May @rodion_herrera