Launch Costs

On 30/05/06, Robert wrote:
> --- In spacesettlers@yahoogroups.com, "Ian Woollard"
> wrote:
> >
> > No, for several reasons:
> >
> > a) 1 in 10,000 is an appallingly large risk- no launch vehicle would
> > ever be allowed to launch with a 1 in 10,000 risk of hitting a
> densely
> > populated area. IRC 1 in a million is the chance of *anyone* on the
> > ground dying you need to hit before they'll sign off on the launch.
> > You *do* need permission to launch- it's called a launch license.
>
> your forgetting bureaucracy and inertia. look at Challenger. every
> time they had a successful launch, they lowered the standards of what
> had to happen in the next launch, result was someone decided it was
> OK to launch under conditions that were not acceptable before. for
> the first 25 to 30 launches, everything would be scrutinized, then
> gradually over time, after success after success, the scrutiny would
> be a little less and a little less.

Yup. Then they have an accident. That doesn't mean that:

> then one day a rocket goes off course, and
> the range officer is not paying attention. since hes a salary
> employee, he has to have permission to put the key in the activator,
> but then, they have to find someone who is willing to face the boss
> with the news that he ordered the rocket destroyed. finally someone
> does. unfortunately its a little too late and the rocket is no longer
> within range.

Um. No.

Your scenarios are a total joke.

> > b) the chances of failure go down over time- the first space shuttle
> > had a 80% chance of success. The current space shuttle has a 98%
> > chance of success. That's after 200 flights. That's because they
> have
> > accidents, find the bug in the manufacture, operations or design,
> > repair it, and the reliability goes up.
>
> really, then what happen with Challenger and Columbia. sorry to tell
> you, but it does not work that way. systems start to fail. people
> fall under inertia. steps get shortcut-ted. result: failure.

That was the mechanism in action. Both vehicles had pre-existing
faults from day 1 that caused their destruction. Challenger had badly
designed seals, and Columbia had problems with the foam on the
external tank. The foam they're still working on; SRBs were reworked
and will not fail in the same way again.

Actually *all* launch vehicle designs have *many* faults. But as the
vehicle matures the number of faults goes down over time.

> > Duh huh. Then it isn't going very fast, and has gone very far, so
> > won't fall far from the launch point when you turn off the engines
> or
> > blow up the vehicle.
> >
> your assuming that some low paid salary employee that has been told
> that if he ever puts the key into the activator slot, without prior
> approval, that he will be terminated and likely sued for risking the
> rocket, is willing to put the key in in time. your also assuming that
> he is actually at the launch. very likely after many successes, he
> will be expected to be doing "more important work than babysitting an
> unneeded switch.

You're dreaming in technicolour. And even if he wasn't at the switch
(FFS it's his job to *be* at that switch, he deserves to be *executed*
if he's not at that switch, and if anyone stops him being there-
*they* deserve to be executed) the chances of hitting a city is
absolutely miniscule.

> OK which is it. first you tell me the rocket will be going mach
> three, then when i go with it, you tell me it will not. I'm basing
> its speed on what one of you have claimed to be the speed of the
> rocket.

It just can't happen. To get a really big explosion the rocket would
have to travel long distances *and* reach ground level with a lot of
propellant. To go long distances rockets *have* to leave the
atmosphere otherwise airdrag just uses up all the energy in the fuel.
The physics is that rockets only stay in the air for ~7 minutes before
running out of fuel. So a rocket *has* to go fast to get anywhere.

So, after leaving the atmosphere the tankage containing lots of
propellant isn't designed to survive reentry, so it would come bombing
into the atmosphere and promptly explode high up. You'd get some
debris falling. It would be like Columbia. Somebody could die, but
it's not very dangerous to a city (similar analogy- few people died
from the SCUD attacks on Israel).

> how often do businesses stay to regulation. how many times have they
> gotten into trouble in the last few years for ignoring them. ill name
> two big ones. Enron, and Valdez

That kind of corruption only works when everything is hidden.

If somebody starts launching rockets from the outskirts of a major
city, please sue their ass off.

It would take that level of demonstrable incompetence.

--
-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."