[NRV Rocketry] LADEE Question (for VT Aerospace guys?)

[Brandon Smith]

Definitely not an expert, but here's my attempt since you included VT Aerospace guys in general. :-)

I can't speak for solid boosters, but on the liquids I've interacted with there are hydraulic struts (controlled with some of either the LOx or the RP-1 fuel in that case, can't remember which one) to gimbal the engine; I'd imagine something vaguely similar with a solid nozzle, just shoving it around here and there. Although obviously they wouldn't be able to rely on fuel to operate it...

As for varying thrust, you're right that solids are either "on or off," but from what I understand the internal "shape" of the solid fuel can be varied to alter burn rates--sounds like they did this in the Space Shuttle SRBs to account for different loading cases along the flight profile. Something about 11-point stars and truncated cones... See here: http://en.wikipedia.org/wiki/Space_Shuttle_Solid_Rocket_Booster#Propellant

Anyway, just my 2 cents... Anyone else feel free to chime in with more accurate/correct details.

Brandon Smith

Sent from my mobile. Please forgive any typos.

On Sep 8, 2013, at 12:32 AM, Thomas Weeks <tweeksjunk2 at theweeks.org> wrote:

> BTW...
> > Hey Dr. S, or other VT Aerospace Guys..
> >
> > So I've been watching LADEE footage from the launch last night and was just
> > wondering.. how do they stabilize large rockets like LADEE that obviously
> > have zero visible fins? Ballistically (if it flew passively) it should go
> > end over end.. no?
> Here's the photo I was staring at when I posed these questions:
> http://www.nasa.gov/content/ladee-launches-from-nasa-wallops/
> The boosters sections look as smooth as a Sono-Tube(tm).
> Just made me start wondering...
> Tweeks
> >
> > Are there ANY control surfaces on the LADEE boosters? I imagine they would
> > have to either use some sort of active vectored thrust, control surfaces,
> > or spin stabilization to keep it pointed up... no?
> >
> > And what about controlling the % thrust? They're using solid propulsion
> > motors (sort of like our HP ACP motors)... which are usually either 100%
> > on or burned out/off right? Do they have some sort of burn-rate or
> > oxidizer flow rate controls in their motors too?
> >
> > Hmm..
> >
> > Tweeks
> _______________________________________________
> NRVR mailing list
> NRVR at nrvr.org
> http://nrvr.org/mailman/listinfo/nrvr
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://nrvr.org/pipermail/nrvr/attachments/20130908/76911eb9/attachment-0001.html