[ExI] fermi paradox- weighted summary

[Rafal Smigrodzki]

On Dec 6, 2007 4:35 PM, Eugen Leitl <eugen at leitl.org> wrote:

> > You need the equivalent to stop at the other end.
>
> Multiple answers to that. It's a bootstrap issue. You could
> launch the first probe with is heavy enough for braking. You
> could use a sacrifical sail, which outsources the complexity
> and the power.
>
### The sail is the answer. If you have the capability to digest your
black sail (which is likely to be mostly carbon), and reform it into
reaction mass for an ion drive, you should be able to brake from 0.1 c
to orbital in a few years. Of course, assuming that you at first have
multiple drives, and as your reaction mass gets used up, more and more
drives get converted to reaction mass, until you glide into orbit on
your last few kg of carbon.

To the best of my knowledge, this is strictly an engineering problem,
in the sense that no new science, no new physical phenomena have to be
discovered to allow this technology to exist. All you need is a design
for good ion drives (already here), a fusion energy source (in
development), and robotic or nanotech devices (ETA - 30 to 50 years
from now) to digest the black sail, and transform it into reaction
mass and ion drives.

Rafal