Date: Fri, 26 May 2000 21:27:15 -0700
From: Doug Jones <random@qnet.com>
Newsgroups: sci.space.policy
Subject: Re: SDI is back!^

Kelly McDonald wrote:
>
> Upon launch detection you have what 5-10 min to not only detect and

Detection takes only seconds (the USAF understandably doesn't advertise
the exact capabilities of the DSP sats).

> track the launch, you also have to move into a position to intercept.

Kinetic interceptors would either be in position, or not.  The cross
range vs constellation size would be selected to give continuous
coverage.  Beam weapons would have very long range, essentially line of
sight- no movement needed at all.

> Plus and the most important delay is making the decision to fire or
> not. Is it an incoming ICBM, or a half billion dollar com sat launch,
> or a bunch of tourists on thier way to Hotel Mir. This is the hardest
> part of a boost phase intercept.

If it's rising from a known missile field or from open ocean other than
the SeaLaunch or San Marco platforms, identification is very
straightforward.  If many launches are seen within a short time, again
the assumption is that they are legitimate targets ("many" in this case
would be of the order of four).  In the event that commercial (ie
tourist) flight rates increase dramatically, prudence would suggest
voluntary disclosure of ascent data for collision avoidance- so a
straying "Q-ship" launch would be quickly detected.

When you come right down to it, a single launch could be tracked and
observed for many minutes before a decision must be made whether to
attack it- but if a massive salvo launch is seen, you shoot first and
ask questions later.

--
Doug Jones
Rocket Plumber, XCOR Aerospace
http://www.xcor-aerospace.com

Date: Sat, 27 May 2000 10:44:38 -0700
From: Doug Jones <random@qnet.com>
Newsgroups: sci.space.policy
Subject: Re: SDI is back!^

Some general notes about target detection, tracking, and interception:

* all launches can be detected no later than when they climb above 25 km
* a LEO constellation can also be used for confirmation and tracking
* boost-phase intercept is useful, but not needed for small attacks-
  a "rogue" launch could be saturated with enough shots to nail all
  the decoys, the RV, and the bus, too.

Rules of engagement can have multiple inputs:
* massive salvo launches are hostile and are engaged immediately
* single launches can be watched until burnout, then engaged in
  midcourse if needed
* extremely lofted trajectories are probably hostile
* certain azimuths from certain sites are probably hostile
* lots more that I won't bother to reinvent

Please spare us the squirrel cases about stealthy takeovers of civilian
launch sites (and how long would it take for the bad guys to swap
payloads and bring in their own trustworthy launch crew?).  A "small"
attack would still be classified as an attack with plenty of time to
intercept (as if three salvoed solid-fueled launchers on a northerly
azimuth from North Korea would not scream "SHOOT ME DOWN").

Using a computer virus as a distraction would require a fantastic degree
of penetration of the ABM control system, and the attack planners would
have little way of knowing whether their software attack was
successful.  An ABM system wouldn't be the freaking internet, begging
for a DDOS attack.

> But it is true, you have many minutes.  This is both good and bad, however,
> because exercises have shown that often the military types would wait so
> long as to not shoot during boost and post-boost phase when success
> would be highest.  The DoD is still trying to streamline the process of
> authorization to shoot; it takes too long as it is.

Once again: a small attack could be countered after boost phase, and a
large attack would make the shoot/no shot decision much easier and
faster, enabling the boost phase intercept.

--
Doug Jones
Rocket Plumber, XCOR Aerospace
http://www.xcor-aerospace.com

Date: Sat, 27 May 2000 10:53:54 -0700
From: Doug Jones <random@qnet.com>
Newsgroups: sci.space.policy
Subject: Re: SDI is back!^

Kelly McDonald wrote:
>
> "Jeff Greason" <jgreason@hughes.net> wrote:
> >
> >This is why IFF was invented.  This is not a new problem, and no
> >new solutions are required.  When there is space defense, there has
> >to be space traffic control -- to paraphrase Harry Stine; you are
> >either squawking the correct transponder code and on a filed flight
> >plan, or you risk getting smoked.
>
> So every nation in the world is going to have to put IFF transponders
> on thier sat launchers?? Whats to stop them from putting them on
> ICBM's??

An ICBM with an IFF squawking is a fat, juicy, target- the IFF
transmission would include the vehicle's guidance and navigation
output.  A bogus navigation transmission would become obvious in under a
minute, at which point the ABM system would get *very* interested.
Strangling the parrot would be another big red flag, much like a
gangbanger turning and running from a police cruiser.

Commercial air traffic carries transponders for traffic safety- refusal
to do so marks you as an antisocial sort to be watched closely.  There
is little reason to omit launchers from this paradigm.

--
Doug Jones
Rocket Plumber, XCOR Aerospace
http://www.xcor-aerospace.com

Date: Thu, 22 Jun 2000 09:31:53 -0700
From: Doug Jones <random@qnet.com>
Newsgroups: sci.space.policy
Subject: Re: RV Decoys

Jonathan Stone wrote:
>
> In article <3954ad8b.84604291@news.seanet.com>,
> Derek Lyons <elde@hurricane.net> wrote:
> >jonathan@DSG.Stanford.EDU (Jonathan Stone) wrote:
>
> >>So how about tethering a large flock of heated-mass decoys and real
> >>warheads, and releasing them as a bundle?  What would _that_ do to the
> >>suggested optical id'ing of decoy/warhead t release time and tracking
> >>them separately until intercept, ad not intercepting targets?
> >
> >Congratulations.  You've just downgraded your expensive MIRV weapons
> >into a MRV.  Not A Good Idea
>
> *What* Chinese MIRVs? Indian?  Pakistani?  You dont think that NMD
> will make the Russians reconsider dismantling their MIRVS?

The point is that tethered decoys would be usable with only one RV,
*reducing* the number of kills needed to defeat the attack.

> >>Or (to counter laser-puncture of decoys) using quick-setting
> >>inflatable decoy structures, instead of gas-rigidized balloons?
> >>Doesn't exactly sound like rocket science to me.
> >
> >Ok, this can be offset by observing the recoil when hit by the laser.
>
> How much energy are these lasers delivering, and how far through the
> warhead/cluster trajectory? what's the delta-v from vapourizing the
> decoy?  Where are the resources to track the decoy/warhead cluster
> from laser delta-v to intercept?

The laser discriminators would use pulses of about 100 joules; if these
produce hot vapor pulses at 50% efficiency and Isp of 200, about 25E-6
kg of material is ablated and .05 N-s of impulse is delivered.  This
would change the velocity of a 10 kg decoy by .005 m/s, easily
detectable by simultaneous doppler radar.  The delta-V induced on a
massive Rv would be far less.

> What's the mass penalty for a small gas jet to add delta-v from, say,
> an acceleromerter calibrated to react to laser deflation of a balloon?
> (how tightly does this have ot be synched with the laser pulse to fool
> the defender's tracking system?)

The exhaust from these cold gas jets can be seen- take a look at
http://www.ll.mit.edu/ST/sbv/ballistic.html for example images from
tests.  This was a rather primitive late 1980s imager with fewer pixels
than a modern medium-price digital camera.

> Without details it sounds no different to what someone pooh-poohed
> as "school science fair project".

Then look at the details available instead of putting up strawman
arguments, eh?  It appears that your objection to NMD is more
ideological than technical, and your technical arguments are a series of
retreats from one poorly prepared position to another.  Discrimination,
target cueing, and target tracking are all problems that have had a
*lot* of resources put into them, much of it classified.  That
significant amounts of information are available suggests that many
concepts not discussed here are probably in development.  Thousands of
man-years have been put into analysis of these issues, do you really
think you've come up with major obstacles not detected by the red
teams?  There's a lot of people paid to do that job, with lots of
support.

As with MAD, the key contribution of NMD is to put uncertainty into
enemy attack plans- if the efficacy of a particular attack is unknown,
the likelihood of it being mounted is reduced.

--
Doug Jones
Rocket Plumber, XCOR Aerospace
http://www.xcor-aerospace.com

Newsgroups: sci.space.policy
From: henry@spsystems.net (Henry Spencer)
Subject: Re: Thor satellites.
Date: Thu, 10 Feb 2000 22:27:45 GMT

In article <Lhno4.7378$pH6.229425@newsread1.prod.itd.earthlink.net>,
Scott Robinson <windspear@earthlink.net> wrote:
>reasonable amount to spend on a weapon that using tech borrowed from THAAD,
>satellite guided cruise missles, and the more interactive camera guided
>missles, should be relatively easy to develop to a high accuracy rate. Why
>are we not doing this already?

Probably because it's not as easy as it looks.  For example, there are
real problems in making those guidance systems work with the necessary
accuracy at high hypersonic speeds:  GPS isn't quite accurate enough, and
the "more interactive camera guided missles" don't have cameras which can
look through a plasma sheath at Mach 15-20.

There are potential ways of solving these problems -- for example, there
are substances you can (theoretically) inject into the plasma sheath to
soak up electrons and make it at least partly transparent at some
wavelengths -- but it's not as simple as just throwing a few pieces of
off-the-shelf hardware together and having it work.
--
The space program reminds me        |  Henry Spencer   henry@spsystems.net
of a government agency.  -Jim Baen  |      (aka henry@zoo.toronto.edu)

Date: Thu, 10 Feb 2000 21:24:51 -0800
From: Doug Jones <random@qnet.com>
Newsgroups: sci.space.policy
Subject: Re: Thor satellites.

Scott Robinson wrote:
>
> Henry Spencer wrote:
>
> > Probably because it's not as easy as it looks.  For example, there are
> > real problems in making those guidance systems work with the necessary
> > accuracy at high hypersonic speeds:  GPS isn't quite accurate enough, and
> > the "more interactive camera guided missles" don't have cameras which can
> > look through a plasma sheath at Mach 15-20.
> >
>
> Do you need to look through a camera on the actual projectile? Couldn't you
> guide it in remotely from the satellite or (if our imaging capabilities still
> aren't capable of less than say a meter of resolution) by a UAV communicating
> with the satellite?

This would make shooting down the UAV an effective defense- but
communicating with the hypersonic projectile through that same plasma
sheath would be even tougher than finding one optical wavelength that could
see through it.  Plasmas are pretty much by definition conductive- and the
very dense very hot plasma around the projectile would make a mighty
effective Faraday cage.

--
Doug Jones
Rocket Plumber, XCOR Aerospace
http://www.xcor-aerospace.com

Newsgroups: sci.space.policy
From: henry@spsystems.net (Henry Spencer)
Subject: Re: Thor satellites.
Date: Sat, 12 Feb 2000 02:00:30 GMT

In article <38A39812.CC2183A8@earthlink.net>,
Scott Robinson  <windspear@earthlink.net> wrote:
>> real problems in making those guidance systems work with the necessary
>> accuracy at high hypersonic speeds:  GPS isn't quite accurate enough, and
>> the "more interactive camera guided missles" don't have cameras which can
>> look through a plasma sheath at Mach 15-20.
>
>Do you need to look through a camera on the actual projectile? Couldn't you
>guide it in remotely from the satellite or (if our imaging capabilities still
>aren't capable of less than say a meter of resolution) by a UAV communicating
>with the satellite?

The huge advantage of guiding with data from the projectile is that such
data gets more precise as the projectile closes on the target (because the
sensor is also getting closer).  I'd have doubts about doing it with pure
command guidance; that approach was abandoned long ago for things like
antiaircraft missiles.  If they can't make it work at Mach 2...

I don't think a UAV would have the necessary view.  Knowing the location
of the projectile is just as important as knowing the location of the
target, and then you have to subtract the two, which drives up the needed
precision still further.  The view from the projectile implicitly reports
the result of the subtraction.
--
The space program reminds me        |  Henry Spencer   henry@spsystems.net
of a government agency.  -Jim Baen  |      (aka henry@zoo.toronto.edu)

Newsgroups: sci.space.policy
From: henry@spsystems.net (Henry Spencer)
Subject: Re: Thor satellites.
Date: Mon, 14 Feb 2000 16:10:24 GMT

In article <38A782C7.9D44D564@nortelnetworks.com>,
John Beadles  <beadles@nortelnetworks.com> wrote:
>> ...Knowing the location
>> of the projectile is just as important as knowing the location of the
>> target, and then you have to subtract the two, which drives up the needed
>> precision still further...
>
>I'm thinking the plasma sheath around the projectile should be fairly
>radar reflective, right?  A UAV track that. So you use a UAV for
>terminal target guidance and a separate UAV for thor projectile radar
>acquisition...

Oh sure, you can track both.  But again, this has to be done very
precisely, because you've got to subtract the two sets of data to get what
you really care about, the aiming error.  Some early antiaircraft missiles
did work that way, but that approach was rapidly discontinued in favor of
homing systems using on-board sensors, which proved far superior.
--
The space program reminds me        |  Henry Spencer   henry@spsystems.net
of a government agency.  -Jim Baen  |      (aka henry@zoo.toronto.edu)