[ExI] No mirrors, was Deceleration mirrors

[Rafal Smigrodzki]

On Mon, Sep 21, 2015 at 8:23 AM, Anders Sandberg <anders at aleph.se> wrote:

> My calculations convinced me that there is simply no point in sending
> flesh to the stars. AI/nano probes, rather thin javellins and not
> superrelativistic, seems to be the way to go. Colonizing around denser dust
> clouds rather than trying to spam through them looks like a good strategy;
> in many cases remote galaxies are easier to reach than stars in the thin
> galactic disk.


### Absolutely, no flesh. But I have doubts about nanoprobes - I am
assuming you mean devices the size of bacteria rather than beer cans. Can't
think about a good way of slowing them down. Could you use ablative
shielding and atmospheric braking? Won't this fry any conceivable
structure? Atmospheric braking at 25% light speed would produce an
acceleration in the 10 million g range (if my calculation is correct), so
it looks like a non-starter.

There is a substantial premium to maximizing speed. Even a 1% difference in
speed translates into thousands of years advantage in reaching targets at
the other end of the galaxy, and even more so when flying to other
galaxies. The first to arrive at a planetary system could homestead and
settle it with trillions of minds in a few hundreds of years. Latecomers
would be a minor footnote.

I would imagine that swarms of small but non-microscopic probes would be
launched at 2000+ g on a single beam extended by lenses, and then coalesce
into a formation with sacrificial shielding components for the long flight.
Close to target the devices would reform to build a laser, or ion engine,
and use up 99.9% or more of their mass to brake. The final colonizer swarm
would be tiny, possibly with bacteria-like digestor devices that would
transform matter into computational substrate for the minds to be
downloaded from distributed storage.

Rafał
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