
Just how dangerous is it to travel at 20% the speed of light? - redman25
http://arstechnica.com/science/2016/08/could-breakthrough-starshots-ships-survive-the-trip/
======
TheMagician0
Another aspect of the project's challenge is funding. While technically
plausible in principle to develop such system, the total funding needed is on
the order of $5-10 Billion. There is a relevant discussion about this on
[Metaculus]([http://www.metaculus.com/questions/208/to-the-
stars-1-will-t...](http://www.metaculus.com/questions/208/to-the-stars-1-will-
the-private-investment-in-laser-sail-extra-solar-travel-be-matched-by-a-
comparable-amount-within-5-years/)), for those who are interested.

~~~
TheMagician0
There is actually a "Beam Propulsion Series" on
Metaculus([http://www.metaculus.com/questions/#/search/series--beam-
pro...](http://www.metaculus.com/questions/#/search/series--beam-propulsion/))
addressing relevant questions about the Starshot Project.

------
scrumper
Charlie Stross wrote recently about the threat of beta radiation to these
small probes[1]. This isn't discussed at all in this article or the associated
paper[2] which focuses on purely mechanical collision effects. Anyone know if
this is a separate consideration for another research group?

[1] [http://www.antipope.org/charlie/blog-static/2016/08/san-
trom...](http://www.antipope.org/charlie/blog-static/2016/08/san-trombone-
exoplanet-reality.html)

[2]
[http://arxiv.org/pdf/1608.05284v1.pdf](http://arxiv.org/pdf/1608.05284v1.pdf)

~~~
T-A
Alpha, not beta (beta radiation is just electrons):

> Roughly 1% of the ISM consists of helium atoms, and we have a technical term
> for an ionized helium nucleus travelling at roughly 2% of the speed of
> light—6000km/sec—we call it an alpha particle.

The article pretty much debunks [1] by concluding that heavier atoms do most
damage, but are still manageable.

~~~
scrumper
Thanks for the correction! Bad memory on my part.

So the article refutes [1] because the relatively easy to manage mechanical
effects of those alpha particles on the spacecraft exterior mean that it
actually functions as an effective, long-term shield against alpha particles?

------
posterboy
> The main problem with running into an atom isn't the physical collision but
> rather the energy deposited in the spacecraft by the impact

Where is the difference? I don't see none except for level of detail.

~~~
noselasd
They mean the physical damage isn't the big issue, but added heat from the
collision is - You don't want a spacecraft to accumulate heat - it's hard to
get rid of.

------
Koshkin
> how dangerous

I would think it's just as dangerous as having something traveling at 20% the
speed of light _relative to you_.

