It was also a time when asbestos was everywhere, car makers would look at
you funny if you brought up “crumple zones,” and smoking was good for the
lungs.
The past is a foreign country, things change oftentimes for the better.
On Mon, Aug 30, 2021 at 3:17 PM Michael Kelly <dmarc-noreply@xxxxxxxxxxxxx>
wrote:
I once heard that the steel shutters on the Apollo Launch Control Center
windows had been designed to withstand an impact by a 100 pound chunk of
debris, which they figured was the heaviest mass that an exploding Saturn V
could hurl from the pad, 3.5 miles away. Yet the spectator stands were
just as close, and had no protection. I watched the Skylab Workshop launch
(the last Saturn V) from the edge of the crawler way, a position much
closer to the pad than the LCC or the spectator stands were. FAA/AST would
never issue a license for a commercial Saturn V launch under those
conditions.
On August 29, 2021 at 11:54 PM, Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Sun, 29 Aug 2021, roxanna Mason wrote:
A great example of sacrificing potential delta-V to g. Imagine the same
thing with a Saturn 5 and an F-1 out.
They did look at this. As of Apollo 8 (that being the Saturn V Flight
Manual I have handy), when the numbers are done carefully, an engine loss
this early -- a second or so after liftoff -- has a high probability of
pad fallback, and lesser probabilities of hold-down post collision or
tower collision.
After the short initial window (a few seconds) where such things can
happen, there's no immediate issue... except that the Saturn V did *not*
have closed-loop guidance during first-stage burn -- it just followed a
predesigned tilt schedule. According to a 1970 paper, the combination of
slower ascent and an uncorrected lateral force could make the impact
footprint (where it would hit if all thrust stopped) follow quite a
strange path. In particular, if it was just the wrong engine that failed,
the footprint could pass quite close to the VAB. Engine-out cases hadn't
really been considered when LC-39's layout was designed. The paper
suggested that for such cases, flight-termination criteria should factor
in which engine was out; I don't know whether that was ever done.
Henry
