🚀 go-pugleaf

uunet!eros.calpoly.edu!jgreen writes:
> I've heard a rumor that some organization (SSI?) has actually
                                             ^^^^<--- (see signature line)
> built a large railgun somewhere in the SW USA.  It's apparently
> supposed to be big enough to put small payloads (>5 kg) into
> orbit, though I don't know if they've done that yet.
>
> Is this a rumor or is there some truth to it?

I can state with some certainty that it wasn't us.

Seriously, I saw a public demonstration of a rail gun on the tube a few
years back, but it was intended as an onorbit weapon for SDIO (this
whas when they where fighting their "No, we're really not a pipe dream"
funding battle).  I think this was in So. California, which is
certainly SW USA.  As I recall, it fired something about the size and
shape of a hockey puck (there's that Canadian influence again, eh
Henry?).  I haven't heard anything about a ground based version.

Personally, I don't know that a railgun is going to be worth much for
anything other than ASAT and ABM applications.  The problem is that a
ground launched body can't attain orbit (at least, not an orbit that
doesn't intersect the surface) without a circularizing burn at
periapsis.  This means that you have to carry propulsion (motor and
fuel), GNC hardware (star trackers or a gyro/accelerometer platform,
momentum wheels or an RCS, guidance computer and control hardware),
power and cooling, a shroud capable of protecting the whole shebang
when it exits the launcher in sea level air at better than 17,000 mph
(orbital velocity at 150 mi), aerosurfaces to prevent tumbling, and
probably active control of same, and still retain enough mass
capability for a payload.

On the other hand, if all you want to do is intercept incomming
missiles, you can scrap most of this except the shroud and the
aerosurfaces.  Approriate sensor technology in the nose and a
"bang-bang" control system for terminal homing, and you have enough
payload space for a fuze and some plastique (although the entire
vehicle becomes a warhead at the kind of intercept speeds involved).
Of course, a rail launcher certainly wouldn't be portable, and the
power generating equipment (if not the rail itself) would be pretty
noticeable from orbit.  Might as well put up a big sign that reads
"Please Nuke Me".

Seems to me that something like Pegasus is a better investment for both
types of applications in this payload mass category.

Lou Adornato                 |    "Sure, the cow may have jumped over the
Supercomputer Systems, Inc   |      moon, but she burned up on reentry"
Eau Claire, WI               | The secretary (and the rest of the company)
uunet!ssi!lfa or lfa@ssi.com | have disavowed any knowledge of my actions.