STS-133 LH2 and ET Problems

This is always a problem with expendable hardware. Every manufactured
thing has a 'bathtub' shaped failure curve. There are three
processes,

(1) Early failures - fall off exponentially from time of manufacture
(2) Random failures - constant
(3) Life time failures - rise exponentially from time of manufacture

Added together they make a 'bathtub curve'

http://en.wikipedia.org/wiki/Bathtub_curve

A highly reusable vehicle, with no throw away parts would have a far
higher reliability than an expendable. Especially after its test
flown a few times before entering service.

http://en.wikipedia.org/wiki/Flight_test

Part of the $8 billion to $12 billion development program I've
proposed to make a highly reusable launcher using an ET-derived
airframe is to carry out a flight test program to achieve far lower
hazard function for the flight hardware than is possible with the
Shuttle which as has been stated here, cannot generate the sort of
data needed to achieve the reliability levels we associated with
aircraft - because aircraft are highly reusable.

At present each shuttle is designed for 100 flights and has a failure
rate of about 2% largely because of the expendable components. So,
the odds of the shuttle getting to the end of its useful life
unscathed is about 14%.

There is every reason to believe with a well planned flight test
program flight elements will likely achieve survival figures similar
to that of rotary wing aircraft. These are 1,800 flight cycles and
2.7e-5 loss of vehicle accidents per flight. This means that there is
a 95.2% chance of getting to the end of its useful life without a loss
of vehicle accident. With 175 hour turn-around, this is a 35 year
life span for each of the elements.

http://docs.google.com/viewer?a=v&q=...esentation.pdf

So, with 35 elements flying 250x per year there is a 96.7% chance that
all will get through the year without loss of any element. The odds
are there will be 1 of the 35 elements lost per year at this flight
rate. At $250 million each this adds $1 million per launch. The cost
allocated to each launch (including insurance) is $1 billion. The
cost of the payload is $3.5 billion. The value of each payload is
$80.5 billion on orbit.

Over a 10 year period and 2,500 payloads there is a 71.3% chance all
the elements will survive unscathed. Likely that as many as 10 of the
35 elements will be lost over this period. Loss of element need not
mean loss of payload - which is a separate calculation.

For those who are unfamiliar with the system I've proposed here is a
review of it;

http://www.scribd.com/doc/30943696/ETDHLRLV
http://www.scribd.com/doc/31261680/Etdhlrlv-Addendum
http://www.scribd.com/doc/38432542/M...lement-Staging
http://www.scribd.com/doc/35439593/S...-Satellite-GEO

In article f2f219fd-a7e4-463a-bfe1-26def97ed1f7
@o4g2000yqd.googlegroups.com, says...

For those who are unfamiliar with the system I've proposed here is a
review of it;

http://www.scribd.com/doc/30943696/ETDHLRLV
http://www.scribd.com/doc/31261680/Etdhlrlv-Addendum
http://www.scribd.com/doc/38432542/M...lement-Staging
http://www.scribd.com/doc/35439593/S...-Satellite-GEO

Yet another thread jack, Mook? You can't help yourself, can you?

Jeff
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