At 01:32 03-03-01 +0000, you wrote:
>Joshua Bell wrote:
> >
> >>A reusable rocket is simply a waste of fuel.
> >>
> >>This might only be justified if the fuel was much more cheap than the
> >>circuitry etc.
> >
> >Is the fuel really that expensive?
> >
>"If I told you I would have to kill you" :-)
>
>Yes, it is. I can't precise how much, but just think that some rockets
>use Liquid Oxigen and Liquid Hydrogen, with high costs of production
>and high costs of storage.
>
> >The limiting factor doesn't seem to be cost of materials, but cost of
> labor.
> >Shuttle takes a team of hundreds several months to get ready.
> >
>And, of course, it's not 100% reusable. Lots of things have to be
>replaced, even with common cars!
>
> >(...) Each shuttle flight appears to cost $500 million, and surely
> >the fuel is only a tiny fraction of that.
> >
>Ok, I don't know how much of this is the cost of the fuel :-(
>
>Alberto Monteiro
A quick search turned up the following:
From <http://spaceflight.nasa.gov/shuttle/reference/basics/et/index.html>:
External Tank Statistics
Empty:
35,425 kilograms
(78,100 pounds)
Propellant:
719,115 kilograms
(1,585,379 pounds)
Gross:
756,445 kilograms
(1,667,677 pounds)
Propellant Weight *
Liquid oxygen:
616,496 kilograms
(1,359,142 pounds)
Liquid hydrogen:
102,619 kilograms
(226,237 pounds)
Gross: 719,115 kilograms
(1,585,379 pounds)
Propellant Volume *
Liquid oxygen tank:
143,060 gallons
(541,541 liters)
Liquid hydrogen tank:
1,450,063 liters
(383,066 gallons)
Gross: 1,991,604 liters
(526,126 gallons)
*Liquid oxygen is 16 times heavier than liquid hydrogen.
<http://www.dfrc.nasa.gov/PAO/PAIS/HTML/FS-015-DFRC.html>
External Tank: Each external tank is 154 feet long and 28.6 feet in
diameter. They are constructed primarily of aluminum alloys. Empty weight
of an external tank is 78,100 pounds. When filled and flight ready, each
has a gross weight of 1,667,677 pounds and contains nearly 1.6 million
pounds (143,060 gallons) of liquid oxygen and more than 226,000 pounds
(526,126 gallons) of liquid hydrogen. The external tank is the only major
part of the space shuttle system not reused after each flight.
Solid Rocket Boosters: The space shuttle solid rocket boosters are the
largest solid propellant motors ever built and the first to be used on a
manned spacecraft. Each motor is made of 11 individual weld-free steel
segments joined together with high-strength steel pins. Each assembled
motor is 116 feet long, 12 feet in diameter, and contains more than 1
million pounds of solid propellant. The propellant burns at a temperature
of 5,800 degrees (F) and generates a lift-off thrust of 2.65 million
pounds. The exhaust nozzles are gimbaled to provide yaw, pitch, and roll
control to help steer the orbiter on its ascent path. The solid propellant
is made of atomized aluminum powder (fuel), ammonium perchlorate
(oxidizer), iron oxide powder (catalyst), plus a binder and curing agent.
The boosters burn for two minutes in parallel with the main engines during
initial ascent and give the added thrust needed to achieve orbital
altitude. After two minutes of flight, at an altitude of about 24 miles,
the booster casings separate from the external tank. They descend by
parachute into the Atlantic Ocean where they are recovered by ship,
returned to land, and refurbished for reuse.
but nothing so far that gives the cost of the fuel.
-- Ronn! :)
