[ExI] Asteroid on track for possible Mars hit

[spike]

> -----Original Message-----
> From: extropy-chat-bounces at lists.extropy.org [mailto:extropy-chat-
> bounces at lists.extropy.org] On Behalf Of Eugen Leitl
...
> 
> You'd need to launch the bird (that doesn't exist) NOW in order that
> it can intercept and deflect (by assymetric ablation, perhaps a series
> of such) the impactor weeks to months before impact. The earlier you'd
> get him, the less deflection you'll need...

Ja.



> We don't have any such standby capabilities right now. It wouldn't be
> necessarily that expensive, given that you'd have to accelerate a payload
> of less than 100 kg, potentially much less than 100 kg...

Hmmm, ja, but I don't expect it to be much less than 100kg.  We need a
spherical plutonium core surrounded by high explosive with a damper shell,
next to a heavy hydrogen device.  For this application, I expect it to
exceed 100.




> if it's just
> a naked fusion device sans guidance but a detonator. Can we do such
> precision shots right now?

We do, but it would need a combination ground based or space based radar
with ground guidance, combined with some pretty tricky endgame guidance
on-board as is done with the THAAD missile.  I expect the entire package to
be closer to about 400 to 500-ish kg, since you need guidance propulsion,
attitude control, antennas etc. 
 



> Delta-v is probably 10 km/s at least...

Ja we would need all of 10 km/sec methinks, but I need to do some BOTECs to
figure out how we would do this.  I think we would need to get as close as
possible to coming the exact opposite direction of the rock, otherwise I
don't know if our endgame guidance authority would be sufficient for a hit
with current technology.  

I doubt we could get out to the object, match its velocity and attempt a
soft landing (the required delta V is way too high.)  So the biggest
technological challenge might be how to detonate the device within the time
tolerance when the closing speeds might be in access of 20km/sec.  The
precision needed to do this is tech we don't currently have.  At 20 meters
per millisecond, if the device detonates 10 milliseconds too early, 200
meters might be too far away to do much.  A millisecond too late and the
impact destroys the device without detonating.

spike



 






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> Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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