On Mon, 17 Feb 2003, Andrew Case wrote:
> > As I think I noted before, at that kind of operations pace, *nobody*
> > hooks up fuel and oxidizer lines -- they are part of the launch stand,
> > like all the other umbilicals, and are hooked up (and leak-tested)
> > automatically when the vehicle is positioned on the stand.
>
> ...There's a cost, of course, but at least in the case of propellant
> transfer, I would like human eyeballs looking at the connection as it
> is made and broken...
You misunderstand, I think. The connection is made as the vehicle is
moved onto the launch stand, which presumably involves humans on the spot.
It is broken at launch. There is no need for anything mechanical to
happen between those two events, and it is actively undesirable to add
mechanical events, especially ones which require human hands or attention.
> If the landing gear can't take liftoff weight (which it probably
> can't), then the first thing that happens after the landing engines are
> turned off is a service vehicle moving a support pedestal into position
> to take the ship's weight before it is fueled.
I think it is better to assume that the vehicle gets moved to the stand
from a separate landing pad. That permits built-in umbilicals in the
stand, removing a whole bunch of manual mechanical operations (which not
only eat man-hours, but are also error-prone), and making contamination-
sensitive oxidizer plumbing in particular considerably simpler. It also
makes landing guidance much less critical.
> > The "handler" will be a computer, or at least an automatic sequencer --
> > like the one that tanked operational V-2s...
>
> ...OTOH, I don't think it's a good idea to trust a machine to do it
> completely unsupervised...
There will probably be a human watching, at least for the first few
thousand times it gets done. Eventually, given careful fail-safe design
and thorough testing, people will no longer think it worth watching.
Nobody watches building thermostats or self-service elevators.
Routine monitoring is *exactly* the sort of task that machines do better
than humans. They don't get bored or distracted; they are just as
attentive the thousandth time as they were the first time.
> might make sense to have a fully automated set of pad services, with
> just a couple of guys who do nothing but walk around from one spot to
> another at the appropriate time and watch as critical automated
> functions are performed.
See note above about the undesirability of mechanical operations. They
won't be at the stand watching things move around; they'll be sitting in a
control room watching displays of pressure and valve status. There will
be nothing visible happening at the vehicle itself, other than swapping
the cargo pallets, which likely will be supervised by a human operator.
Henry Spencer
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