[ExI] Power sats as weapons

[Keith Henson]

On Tue, Sep 11, 2012 at 5:00 AM,  John Clark <johnkclark at gmail.com> wrote:
>
> On Sun, Sep 9, 2012 at 2:03 PM, Keith Henson <hkeithhenson at gmail.com> wrote:
>
>>> we already have an excellent method for instantly vaporizing cities and
>>> I don't see what additional advantage a laser would provide in
>>> accomplishing that task. And a huge but delicate power satellite powering a
>>> enormous laser in geosynchronous orbit would be a sitting duck for anybody
>>> who didn't like it.
>>>
>> > I don't exactly see how.  Perhaps you could explain.  To me, trying to
>> target a propulsion laser satellite is a bit like a rock fight between
>> someone on the top and someone on the bottom of a well.
>>
> If military history has taught us anything its that fixed fortifications
> don't work because the enemy always knows exactly where they are, and
> lethal lasers run from huge power satellites have the additional
> disadvantage of being delicate.  And if your new way of getting into space
> is as cheap and works as well as you say it does (and if it doesn't then
> there's no space laser in the first place) then the difference between the
> top and bottom of a well becomes far less important.

Granted that power satellites and platforms for propulsion lasers are
relatively delicate.  But in order to damage one, you have to deliver
the agent of damage.  Now, the laser beam from one of them will
certainly put another one out of operation--assuming there is more
than one of them.  Even a laser beam from the ground might be able to
destroy one.  But GW lasers are not easy to hide and cost way more
than a terrorist operation could afford.

Nukes require physical delivery.  Launching one from the ground as an
attack against a propulsion laser is possible, though very expensive.
It will take hours to get there and the hostile intent will be
obvious.  Many years ago Lowell Wood thought about this in the context
of armored space forts.  It will take a combination of lasers and
impact missiles to defend against a high velocity bomb inside a
tantalum carbide laser shield.  Of course with propulsion lasers,
powering defensive missiles with lots of delta V should not be hard.

> It would take months
> for a space laser to deliver as much energy to a target as a H bomb could
> do in less than a millionth of a second, so I just don't see the advantage
> from a military perspective.

The trend for a long time has been precision rather than raw power.

> And I can't picture a terrorist organization
> like al-Qaeda launching a power satellite and a giant laser, but
> unfortunately I can imagine them making a H-bomb, or at least a A-bomb.

True.  But getting it to the target when the target is in GEO and is
defended would be a much harder task.

Keith