Re: [Starlink] Hitting an atira asteroid with a spacex starship?

[Bruce Perens <bruce@perens.com>]

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On Thu, Nov 3, 2022 at 5:52 PM Dave Taht <dave.taht@gmail.com> wrote:

> Space is a big place, and I'm pretty sure the orbit, impact, and debris
> could be tracked.
>

Actually, no. The Space Shuttle got a very concerning bulls-eye in its
front cockpit window a few decades ago from a tiny paint chip. The speed of
two objects in counter-rotating orbits when they hit imparts a  truly large
amount of energy. And there are now so many such things that there is a
significant risk to suited astronauts on EVAs.

NORAD will not actually tell us how small an object it can track, nor how
many, this being something potentially of interest to enemies. The
Satellite Catalog that they publish covers objects of 10 cm diameter and
larger, a 1U PocketQube satellite is 5x5x5 cm plus antennas that bring it
to 10 cm, and the early ephemerides published by NORAD for such objects can
be inaccurate. We aren't allowed to launch anything smaller.

We also are now required to provide a position-changing ability to avoid
collisions, and active re-entry at the end of the life of a satellite. This
is mainly about the potential for Kessler Syndrome.

The 60 years of thinking that orbital space is so big that we don't have to
concern ourselves with debris are definitely over.

What would you do with a starship that after launch, due to lost tiles, or
> other problems is certain to burn up on re-entry? Why not test getting out
> of orbit?
>

Put it somewhere that you can use the habitable volume. Starship
potentially has a larger habitable volume than ISS. That is *without*
converting the tanks.

Otherwise, if you have the delta-V to get there, there is a junkyard orbit
above geosynchronous. Things will stay there for a really long time. The
other option is a controlled re-entry with a known termination in the
middle of an ocean.

China drops entire stages on farmers fields and rural roads in their own
country quite often, but this is not thought well of by others.

That takes all the fun out of it. Impact is so much easier. Our knowledge
> of the solar system is only skin deep.
>

People are even starting to get annoyed about stuff that hits the moon,
although this doesn't create orbital debris unless the energy is really
huge.

    Thanks

    Bruce

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