Re: ASTRONOMY: Nuclear bombs will not save the earth

From: Doug Jones (
Date: Sun Jun 25 2000 - 18:06:35 MDT

Everitt Mickey wrote:
> >> Doug Jones wrote:. The total delta-V needed to divert an object from
> >> collision given 20-30 years advance notice is only a few millimeters per
> >> second. This impulse would be delivered, not by a cratering surface or
> >> subsurface explosion, but by a series of many blasts, each at an
> >> altitude of .4 radius from the surface....
> That being the about a laser instead?
> Wouldn't a properly placed laser beam of the correct intensity cause a
> similar spalling effect with similar changes of orbit?......I would think
> that an orbital 'droid watch laser station would be much cheaper and more
> practicle.....

Yeah, it has been proposed and analyzed, but it takes a honkin' BIG
laser to do enough spallation to achieve the mission delta-V. This
laser would have to work at the job for years, with no expendables and
no resupply. The technology for lightweight long life solar powered
multimegawatt (kilojoule pulsed) lasers just doesn't exist. Nukes, even
an array of smaller ones instead of just a few big ones, are A) cheap
B) off the shelf C) low mass.

When & if the need arises, there probably won't be time & money to do
the needed development of lasers, but it would be quick & cheap to use

Doug Jones
Rocket Plumber, XCOR Aerospace

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