[Cerowrt-devel] spacebee

[Jonathan Morton]

> On 13 Mar, 2018, at 7:31 pm, Dave Taht <dave.taht at gmail.com> wrote:
> 
>> Size, until the object gets really small, really doesn't matter.
> 
> The odds of a collision drop proportionally (what's the math?) to
> size. Imagine useful sats this small, or smaller, in lower orbits that
> burn up in a few years, and constant replacement and technological
> refreshment...

Observation: we're talking about an object that's substantially bigger than a bullet, substantially heavier than a bullet, and travelling *faster* than a bullet.  Collisions with such an object would be extremely high-energy, and spacecraft don't have the weight budget for the tank-grade armour required to survive such an impact.

I don't think the occupants of the ISS would be very happy with being hit by a titanium cricket ball at 10,000 kph relative.

Also, the probability of collision, given random trajectories, depends on the sizes of *both* objects involved - and rather more strongly on the size of the *larger* object.  If you reduce the size of a 10cm object by 50%, it has much less effect on the combined collision radius than reducing the size of a 10m object by 50%.

 - Jonathan Morton