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Old January 31st 20, 01:03 PM posted to sci.space.policy
Jeff Findley[_6_]
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Default Inside SpinLaunch, the Space Industry?s Best Kept Secret

In article , says...

On Jan/30/2020 à 17:02,
wrote :
See:

https://www.wired.com/story/inside-s...t-kept-secret/

How practical is this idea compared to conventional rocketry?


Totally impractical. Try travelling at a speed near orbital velocity low
in the atmosphere. It is hard enough to do so at 50 km altitude, doing
it low in the atmosphere is quite unlikely. If you launch at an altitude
of 7.5 km (that would be in Asia, you can't find such a mountain outside
Asia) the atmospheric pressure would be about 150 times higher than at
50 km.

My opinion is that this is a scam.


I wouldn't go so far as to say it's a complete scam, but it's certainly
a niche solution looking for a problem to solve. You're only going to
be able to launch payloads which can take *a lot* of Gs (i.e. crew
launch is right out, as well as most satellite launches). And when the
vehicle (supersonic projectile really) exits the launcher, you're going
to get one hell of a sonic boom in the area surrounding the facility, so
you can't really build a spin-launcher anywhere near people or animals
(so desert or remote island launch?). So, anything you launch will have
to be transported to a remote site to begin with! Not terribly
practical compared with other launch options.

So, what's left that's remotely practical to launch with this thing?
Bulk cargo and warheads. And even with bulk cargo, you're going to
either need a tug in LEO to get the payload to somewhere useful, or this
thing is going to be resupplying a LEO fuel depot or similar.

More likely this company is hoping to do a smallish demo "launch" in
order to attract a military contract so they can go "full scale".
Because, to me anyway, it really doesn't make much sense given the
practicality of first stage reuse (i.e. Falcon 9) or even air launch
(Pegasus, Stratolaunch, or Virgin Galactic). Air launch is far more
practical, IMHO as it can be responsive and can use existing airports
for its aircraft operations. And as Virgin Galactic has shown, you can
easily convert a 747 into a carrier aircraft by simply using the spare
engine mounting point, so you don't have to go all one off aircraft like
Stratolaunch.

In summary, I'd say it's a scam in so far as they're seeking investors
by marketing this thing as a practical commercial launch vehicle which
it will never be. This would do far better as a DARPA funded project,
as that's the only practical use I see for the thing.

Jeff
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