# Breakthrough Starshot?

I am trying to find out if there is any reason other than cost that Breakthrough Starshot is only looking at Alpha Centauri. It seems to me that once the laser system is in place that creating more nanocraft to go to other, even more interesting, places would be just a matter of mass production. I also wonder if a space-based laser satellite may be better as it may be able to accelerate the ships more slowly for a longer period of time. Is such a laser satellite using nuclear or solar power not feasible or again just too costly? I tried to find answers on their website, but was unsatisfied.

• There are several different questions here. Can you try narrowing it down a little? Jul 5 '16 at 15:39
• Perhaps this could be split into 2 questions: Why is Breakthrough Starshot only looking at Alpha Centauri, and Why aren't they considering using space-based laser satellites. We ask for questions that are narrow and specific enough for a fairly brief answer, and so the information is easy for others to find later. Jul 5 '16 at 15:51
• At 0.2c-0.3c, Alpha Centauri is 15-20 years away, so it will take 20-25 years to get a result. More interesting is further away, making the wait longer, not to mention the need for more durable technology, and the further you go, the harder it will be to detect the signals sent back. But I think the key point is that it is described as proof of concept, and Alpha Centauri, being the nearest star, is the lowest bar to prove the concept. Jul 6 '16 at 1:30
• but I don't want to wait 25 years for proof of concept Jul 7 '16 at 14:36
• @JackR.Woods That's easy to say when it's not your money funding the project. Jul 7 '16 at 19:29

The laser needs to be very powerful. The largest powerplant we have in space today is the ISS, with about 200 kW peak power. Breakthrough Starshot are talking about GW of power. We'd have to ramp up the space industry by a factor of 1000 to make a space-based laser that large feasible.

• Why does the laser have to be space-based? Yuri Milner is reportedly considering the Atacama desert as a site.
– gerrit
Jul 25 '16 at 18:06
• I was answering the question 'I also wonder if a space-based laser satellite may be better (than a ground-based laser)'. The advantage of a space-based laser is you need ~1/10th the power of a ground based system, and you don't have the atmosphere dispersing the beam. Jul 25 '16 at 19:19

Our current best estimate for the Star Shot ground-based approach is it will cost on the order of \$10 B. We estimate the space-based approach to cost on the order of \$100 B.

We intend to send probes to planets in the habitable zone around nearby stars. The Alpha Centauri system is the closest sun-like star, which is why it is our first target. About 80% of the nearby stars are dwarf stars; there is a debate if life is possible in these systems.

• For context, Pete Klupar is the Chief Engineer at Breakthrough Prize Foundation, and formerly the engineering director at Ames Research Center. Jul 29 '16 at 17:05
• @Pete Klupar .. But you forget we will have a space elevator in the 2030s and the price of doing things in space will drop tenfold. (Not serious) I am really excited about any project like this happening in my lifetime and wish the Breakthrough projects best of luck. Aug 1 '16 at 15:55