Re: Briefing on SRB based CEV at NPS with Scott Horowitz

Rand Simberg wrote:

> >Scott Horowitz was pretty convincing that these are not legitimate
> >concerns, for the following reasons:
> >1. Yes, but the explosion happened because hot gas burned through
the
> >LOX/H2 tank. Solid rockets don't explode.
>
> The people at the rocket lab, who lost half a mountain to a Titan
> booster test failure, will be surprised to hear this.
>
several people have mentioned that--we didn't discuss it, none of us
students knew enough to ask about it, but supposedly this kind of
explosive situation has never happened in 240 SRB flights.

> >5. Absolutely, in fact, it can launch under worse conditions than
the
> >shuttle. Finite element analysis modeling shows that with the
ker/lox
> >upperstage, CG, or rather cm is in about the same place as the
shuttle,
> >and even under worse case wind conditions, etc, the steerable nozzle
> >has more than enough control authority to handle it, and lots of
margin
> >to spare.
>
> How about roll control?

I didn't think to ask about it. Is there any reason it would be
different than pitch and yaw control? From what we discussed the SRB
has a steerable nozzle capable of about 8 deg deflection (on the
limiting end), with the max expected deflection (derived from F.E.M. of
the paper 'J-2' stacked ATK rocket)about 1-1.5 deg. We didn't discuss
the specific rates, but Mr. Horowitz said it had been initially
analyzed as being well within the capability of the current SRB
actuators.

How does the shuttle handle roll control? Is it handled by the orbiter
itself or the combined stack? I'm past the limits of my knowledge here.

Tom Merkle

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