Fri, 22 October, 2010Orbital Warns Investors Prolonged U.S. Budget Battle Will Harm 2011 EarningsBy Peter B. de Selding PARIS — Satellite and launch-vehicle manufacturer Orbital Sciences Corp. on Oct. 21 reported double-digit increases in revenue, operating income and net profit but said its 2011 financial performance could drop by 6 percent to 8 percent from expected levels if the U.S. government does not conclude a final 2011 budget before spring. The Dulles, Va.-based company said its biggest ongoing investment — development of the Taurus 2 medium-lift rocket and the Cygnus cargo vehicle it will launch to the international space station — has encountered more delays. Its inaugural launch from Wallops Island, Va., is now set for between July and September. Whether that flight serves only to demonstrate Taurus 2’s abilities or also carries the Cygnus freighter will depend on whether the U.S. Congress appropriates the money for a rocket-only flight when it finally enacts NASA’s budget for 2011. If that money, which would come out of the additional $300 million NASA has requested for its Commercial Orbital Transportation Services program, is forthcoming, a successful Taurus 2-only demonstration could be followed, about three months later, with a Taurus 2 Cygnus launch to the space station.
some of use can still manage to figure out English units.
I have to wonder if that is the correct structural effect of over pressurization. It almost looks like it crumped inwards from low internal pressure. Strange effect, but I'll take your sources word on the cause.
"Deinde Advenimus Pontem Transierimus" - M. Antonius Eliseum
Quote from: robertross on 08/22/2010 01:06 pmI have to wonder if that is the correct structural effect of over pressurization. It almost looks like it crumped inwards from low internal pressure. Strange effect, but I'll take your sources word on the cause.Ahem... well, if you pressure-test a tank to destruction with a gas (say, air) most of the energy that is release when the tank fails is stored in the compressed gas. When this energy is released, it tends to distort the pieces of the tank outwards, and accelerate them to very large velocities with rather nasty consequences for the immediate surrounding.That is why people burst-test tanks with rather incompressible WATER. In that case, most of the energy stored pre-rupture is in the tank material, which is tensed taut like a balloon. When it fails, the water has little energy stored (it has not compressed a lot, even under high pressure), and the energy stored in the metal tends to drive the metal back to its original position: inwards. The resulting shape looks as if it "imploded" - but it's the opposite!
There is simpler explanation why the tank looks "imploded" - workers did it to fit ruptured and deformed tank on the transport platform.
you can see the water gushing out of the lower half of the tank (it was tested in a vertical position) while the top simply implodes.
Quote from: antonioe on 10/25/2010 06:02 pmyou can see the water gushing out of the lower half of the tank (it was tested in a vertical position) while the top simply implodes. Would sombody care to elaborate why this is also very logical (that the failure starts at the bottom)?
Thinking about it, since the pressures in the bottom of the tank (Due to the mass of the fluid above it) should be made stronger (more material) than the top of the tank. So the Top of the tank was made stronger than it needs to be, thus the top of your tank is mass inefficient. Antonioe, I am not impressed
What about pictures of the high pressure bursting of a soda can? Doesn't take much to burst them anymore, as one of my wet coworkers can attest.
Quote from: kevin-rf on 10/25/2010 06:48 pmThinking about it, since the pressures in the bottom of the tank (Due to the mass of the fluid above it) should be made stronger (more material) than the top of the tank. So the Top of the tank was made stronger than it needs to be, thus the top of your tank is mass inefficient. Antonioe, I am not impressed Hah! But the densities of LOX and kerosene are lower than that of water!!!
LOx is heavier than water,
as are the weighted averages of LOx and Kerosene.
Quote from: Robotbeat on 10/25/2010 09:12 pmLOx is heavier than water,Oops... 1.141 Kg/m3... my bad...
Perhaps Antonio can comment on (and hopefully retire) a rumor I heard a few months ago that has recently resurfaced. The story is there is an issue with the AJ26 (NK33) engine being used for the first time in a gimbaled mode. (Rocket historians will recall the NK was not moved for TVC in the N1 installation, but differentially throttled.) Apparently, the motion causes problems with the turbopump, type of problem unspecified but inferred to be binding or rubbing between rotating parts and the case.Any truth to this, and if so, is there a fix?