[AR] Re: Ozone layer was Re: Removing Coking Deposits
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Tue, 27 Sep 2016 11:43:25 -0400 (EDT)
On Tue, 27 Sep 2016, Peter Fairbrother wrote:
I hope you haven't joined the SSTO club though :)
I hate to disappoint you, but I'm a lifetime member. :-)
Oh dear -perhaps you might explain?
To cut a very long story short: (a) it would have major operational
advantages; (b) although it's not easy, it shouldn't be impossibly hard
either, despite the superstitions (the performance levels needed for
*expendable* SSTO were achieved in production hardware fifty years ago;
the only serious challenge is making it reusable); (c) the main reason it
has never been done is that nobody has ever been able to get adequate
funding to *try*.
...I think it means you'll need rocket thrust vectoring (or a
very hefty RCS) for control. I don't think that's ever been done in a
rocket aircraft before; the X-15 high-altitude flights were all
ballistic trajectories, with the noisy flamey part :-) finishing at much
lower altitude where aerodynamic controls still worked...
Didn't the X-15 have a HTP RCS? Perhaps they didn't use it for high altitude
flights, though I can't think why.
The X-15 indeed had an HTP RCS, for the *ballistic* part of the
high-altitude flights. It was nowhere near beefy enough to be used for
attitude control during a main-engine burn in vacuum (something the X-15
never did).
Spacecraft with solid-fuel kick motors often were spin-stabilized for
kick-motor burn, but the ones that weren't, typically had two sets of RCS
thrusters: little ones for normal operations, big ones for attitude
control during kick-motor burn. Something like that might be needed for a
rocketplane that's going to do major thrusting in air too thin for
aerodynamic control.
Henry
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