Launch Costs

On 28/05/06, Robert wrote:
> there is a difference between "near" for a car and "near" for a
> rocket. when the columbia exploded it was almost a hundred miles down
> range many of the components could have killed ppl if they had not
> been above the ocean. even then the guidance system had been working
> and it was extreamly high. imagine if the guidance system went
> haywire in the first seconds of launch. it could easily hit a city a
> hundred miles away in a matter of seconds.

More garbage. Launch vehicles spend the first minute or so subsonic.
They can no more hit something a hundred miles away in seconds than a
747 can. If they tried to go faster than mach 1, the vehicle would
probably break up.

> military launches are
> designed to be destroyed if they go a short bit off course. would
> civilian's be so willing to have their precious cargo at risk of a
> deliberate explosion. would the ppl building them be willing to
> sacrifice the weight to carry the explosives when they were seldom
> used. the likely answer is no.

Garbage. Range control explosives weigh very little, and do not
significantly cut into payload.

> which means that when the rocket goes
> off course the only thing that will stop it is an impact with the
> earth. with that kind of rocket fuel, it would make a big impact on
> any kind of city.

Um. No.

Where range control isn't used they usually use thrust termination. In
other words the launch trajectory is along a corridor. If the vehicle
leaves the corridor, the vehicle switches off the engines and the
vehicle follows a ballistic trajectory into the ground.

The corridor is designed so that whichever way the vehicle leaves it,
within the detection time, the vehicle is guaranteed *not* to hit
significant areas of habitation i.e. cities.

This kind of thing is taken *very* seriously. You don't get a launch
license unless the chances of killing *someone* is below about 1 in a
million.

> > No. The production line is everything. If the production line is
> > engineered correctly you only test the rocket components to ensure
> > that the production line is working properly. If the production line
> > is working properly you can calculate the proportion of items coming
> > off the production line that are faulty.
>
> if its is something like cars, that is ok. if something is majorly
> wrong, its not difficult to issue a recall. its kind of hard to have
> a recall for a rocket that has turned a town of 10000 ppl into a
> swiming pool

No. Deaths away from the launch site have never happened in the west
(there was an accident in China, but they're comparatively reckless,
and I think there was an accident in the USSR- ditto); and a lot of
work is done to try to ensure they never will happen in the west.

Actually, aeroplanes are more dangerous; the fuel carried is more
energetic than rocket fuel, and they burn it far slower so more of it
ends up being burnt in a crash, they fly close to cities, and there's
far more aeroplanes than rockets.

--
-Ian Woollard

"Gravity is just a theory. We shouldn't be teaching it to children as
if were fact."
"The NSA would like to remind everyone to call their mothers this
Sunday. They need to calibrate their system."