[ExI] new job

[Adrian Tymes]

On Wed, Dec 18, 2024 at 5:28 PM Keith Henson via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

> On Wed, Dec 18, 2024 at 1:58 PM BillK via extropy-chat
> <extropy-chat at lists.extropy.org> wrote:
> > On Wed, 18 Dec 2024 at 20:54, Adrian Tymes via extropy-chat <
> extropy-chat at lists.extropy.org> wrote:
> >> What would it take to nudge Apophis from "might impact Earth later"
> into a stable orbit around the Earth, or perhaps the Moon (and thus around
> the Earth)?
> >
> > Perplexity AI thinks it is an impossible task.
>

And makes a few mistakes in the data while doing so.  But yes, this is
certainly not a task to be done before 2029.


> With current technology, I agree.
>
> With self-replicating nanotechnology, you could turn the whole thing
> into a light sail and fly it wherever you want.
>

You wouldn't even need self-replicating nanotechnology, just something that
can grind up asteroid mass and turn it into solar sail material, along with
assembly robots to put it in place.

If we're consulting with AIs, Claude.ai gives the following if 1% of
Apophis was turned into about 270 km^2 of solar sail material:

Solar radiation force at 0.9225 AU:
Pressure = 9 μN/m² × (1/0.9225)² = 10.57 μN/m²
Total force = 270,000,000 m² × 10.57 × 10⁻⁶ = 2,854 N
Delta-v per year:
a = 2,854 / (27 × 10⁶) = 1.057 × 10⁻⁴ m/s²
Yearly delta-v = 1.057 × 10⁻⁴ × 31,557,600 = 3,335 m/s per year

...one year's worth of which might be a bit more than is needed to capture
Apophis.  Launch the machinery during a close pass, perhaps 2036.  Give it
several years to make, deploy, and test the sail.  Start capture operations
a bit over a year before the next close pass, in this case 2051.  (Maybe
two years, since the 2029 approach will put it in a slightly longer orbit
with lower solar radiation force available.)  Maybe do have
self-replicating factories, but with macrotech rather than nanotech.
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