Randall Clague wrote: > > On Fri, 27 Sep 2002 12:33:09 -0700, David Weinshenker > <[EMAIL PROTECTED]> wrote: > > >And when the H2O2 plumbing includes a catpack... sounds like we'll need an > >"oxidizer-trail" shutdown to be safe, keeping the engine running as a monoprop > >during the shutdown purge of the fuel passage. (Recycle procedures after an > >emergency "scram" of both propellants could get tricky.) > > A couple choices seem obvious(*) for what to do after an emergency > scram: > > 1) Pressurize to maybe 30 psi and crack the peroxide valve juuust a > hair, and let it run for a while. Crack it a little more, etc. > Useful procedure if you're in a hurry. > > 2) Tear down the entire plumbing system, passivate it, put it back > together, dry test it, water test it, monoprop test it, then return to > your regularly scheduled biprop test program. This procedure seems > the most rational to me, at least the first few times we have a > potential kerosene contamination problem. After all, if we have a > problem severe enough to an emergency scram in the first place, we > probably need to work on the plumbing anyway, to find the problem, or > to fix it, or both. > > I'm assuming emergency scram means dump both tanks under pressure?
By "emergency scram" I meant the rapid simultaneous shutdown of both propellants, without "sequencing down" through monoprop mode - i.e., a shutdown during which the catpack could not be kept operating while purging the fuel side of the plumbing. (A simultaneous cascade purge would help some, but would not provide the same degree of positive insurance against back-contaminating the catpack with fuel that a properly sequenced shutdown could.) -dave w . _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
