This thing seems to have some unusual failure cases, relative to other
launch systems. Where are they going to put it? I assume their design makes
it impossible (or unlikely) to fail and launch off-axis, but given the
structural requirements, I'm not sure a standard range safety charge will
disintegrate a premature (low speed) launch as easily as the comparatively
energetic and fragile rockets we're used to, so it'd better be somewhere
with a very long safety corridor.
On Fri, Feb 23, 2018 at 9:43 AM, Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Fri, 23 Feb 2018, Jake Anderson wrote:
A tricky part would be circularising the orbit though, whatever you do to
do that needs to survive the launch...
Yeah, even if your catapult/gun can give you *all* of the initial velocity
(and it sounds like this one maybe can't), you need perhaps 2km/s to
circularize if you launch upward at enough of an angle to get clear of the
thick air relatively quickly. The circularization stage turned out to be a
major cost driver for John Hunter's gas-gun launch system.
Rocket stages that can survive gun launch are routine production items, so
I'm sure one that can survive this ride is possible, but it's not trivial,
especially if it needs to produce serious delta-V.
And if the catapult can only give you the first 1-2km/s, then as John
says, the question is whether it's worth the trouble at all compared to
making the rocket a little bigger, and the answer is probably no.
We need more people trying even weird things -- some of them are likely to
work -- so I'm reluctant to call this one a total lost cause, but the odds
don't seem good.
Talk about noise abatement though. What's the SPL of a few tonne
projectile at mach 35 at low altitude?
Jordin Kare once mentioned that one gas-gun concept would kill most of the
*bacteria* within 100m of the muzzle, never mind anything bigger...
Henry