I have a counterpoint:
http://blogs.nasa.gov/cm/blog/J2X/posts/post_1297869180794.html
this is a duct for the J2-X rocket engine, produced using Direct Metal Laser Sintering (3D printed metal, in other words). it has to operate at insane temperatures and pressures... and it does, perfectly.
Most (if not all, Taurus II is yet to fly) of the engines in question are and will be brand new; sold profitably. Redesigned quite a few times. Put into production (or prepared for one) in "high labour cost" place.
they are cleaned, polished, given a new coat of paint and some new gaskets. a new wiring harness and modern electronics.. fired on a test stand to make sure they don't explode (and apparently a third of the NK-33s WILL explode when used.. without some fixes. that's why Taurus is delayed). but they are definitely not 'brand new'. none of those engines has been built new in decades.
But at least you, suddenly, insist that economy of rockets does matter after all...
the whole topic of discussion was about the price of *fuel*. which is insignificant compared to the rocket, engines, electronics, and payload. of course the cost of the engines makes a difference. a single engine costs ten or more times the fuel and oxidizer..
this would be the (one of) the reasons SpaceX designed a relatively simple, cheap to make, engine. it's not as efficient as the Soviet-era engines, but it's just as cheap, and can be mass produced now. that means you need to use more fuel. but guess what? the cost of the extra fuel is basically a rounding error.
for the upper stage, I absolutely agree with you - efficiency is king. but Soviet-era engines are not the best choice for that... a super high ISP kerolox engine is still 30% worse than an average hydrolox engine.
Why is that, why do ~half of US launch systems might end up with ex-Soviet / Russian engines? The staged combustion cycle, which only the Russians successfully implemented, is extremely efficient.
because they are cheap? they were built with Soviet labor, then left in warehouses to rot. found and sold to the US in the 90s for pennies on the dollar. they are VERY good engines.. but that's NOT why they're being used.
efficiency is only terribly useful for a rocket in a vacuum. that's why they're rebuilding the J2 for upper stage work (and even it's not particularly good).for first stages you need thrust. that's why the shuttle and the proposed Aries-V (cough) SLS needs expensive, dangerous solid rocket boosters strapped to it, because it's using hydrogen fueled engines which are good at ISP but not as good at thrust. Saturn-V used kerolox for the first stage for a very good reason. high thrust, not so good ISP.
When you have cheap Fuel and no Concerns about global warming. Making Bigger and Faster means transportation is easy. Fuel isn't cheap anymore. So we are trying to keep the same old stuff from the 60s but make them use less fuel a much harder engineering challenge. I want to make my car faster and fuel isn't a concern make the engine with more cylinders and grater gear ratios. But to make my car 10% more fuel efficient while keeping the existing power is much harder to do.
fuel (and oxidizer) is a TINY percentage of the cost of a rocket launch - usually less than 1% of the cost of the launch. launch vehicles are never optimized for fuel economy - they are optimized for performance above all else.
they are reusing components from the shuttle because they are still (just) available. components from Saturn V (engines, mostly) would do a far better job, but they haven't been built in decades and couldn't be reproduced for a sensible amount of money. NASA is half way through a project to reproduce a J-2 engine for the new vehicle's upper stage (the same engine was used for Saturn V upper stages 50 years ago), and it's cost a VERY large amount of money to get as far as they have.
there is also a huge dollop of politics and pork involved. re-using shuttle components keeps existing contractors (and jobs), rather than causing uncomfortable restructuring and job losses right before an election year.
that's just one. there are dozens of NASA 'human rating' standards documents that are expected to be followed, plus (possibly) some standards that are unofficial or just in the heads of certain managers.
SpaceX say they have adhered to every *published* NASA human rating requirement. they keep asking if there's anything else that's not published..
BTW the space shuttle did not follow several of those standards, but was 'waived'.
sigh. forgot to log in. parent article was me, if anyone cares.
took a while to find... it was from an interview with Aviation Week:
he says they're leaning towards a 1.7 million lbf engine, but they've also been looking at a 3.5 million lbf engine with a throttle setting for use in smaller rockets (back to 1.7, presumably).
the F-1 engine from the Saturn-V (Apollo), for reference, was only 1.5 million lbf, and still holds the title for 'largest rocket engine'.
that was their evolution plan - build a 'Merlin 2' sized to replace the 9 x Merlin 1s required for Falcon 9, then start building bigger rockets with multiple Merlin 2s.
BUT Elon has talked about building a Merlin 2 engine sized all the way up to 3 million lb/f (about three times bigger than the 'Falcon 9 replacement' size), which might be the route they took if there was suddenly a lot of money available to skip a step (and it would probably be sensible, if there was a tight deadline).
Falcon *XX*, not the current Falcon 9, or the planned Falcon 9-Heavy.
he offered it for $2.5 billion. any excess above that to be paid for by SpaceX, not the government. and the throw weight would be about 150 tons to LEO, so bigger than Ares-V (or the latest NASA plan)
smell like it, at least.. so probably taste like it to.
people on 'undercover missions' (special forces etc) usually eat the local diet for a couple of weeks before being deployed, so they don't smell like 'foreigners'.
ULA have done studies on extending the life of the Centaur upper stage past a few days, for example:
doesn't look cheap, or terribly easy. OTOH the technology would be re-usable for on-orbit fuel stores, so there's probably NASA $$ available for development.
this doesn't apply to Linus, but it's only a three year wait before you can apply for citizenship if your green card was allocated due to marriage to a US citizen
it's used quite a lot in some countries outside the US.. Australia is an example I think.
the main reason the US VOIP companies don't use it is that they hate the idea of it. it would short circuit them out of a huge number of their calls (peer-to-peer, direct between office PBXs), and they'd still get the blame for bad sounding calls (with no way of fixing them!)
comcast has two 'VOIP' offerings - one is basically an ISDN line on a different frequency ('Comcast Digital' I think) - it's not VOIP (actually, it's better, because faxes etc will work perfectly). it doesn't share bandwidth with your internet connection etc.
they also do a real 'VOIP' system. it should work perfectly because they control the QOS at both ends of the bandwidth bottleneck (the last couple of miles to your house). they do QOS at the headend to make sure your call gets priority, and also program your cable modem to do QOS outbound to prioritize your outgoing audio. the result is extremely low jitter (and hence, very small jitter buffer sizes).
my bet would be that the call is placed onto a circuit switched network as soon as it reaches the headend.. so there's only a very short run of 'VOIP'.
I guess I should have given a simple recipe for working (business) VOIP:
1) pick a provider who will give you a bundle of (a) VOIP lines, (b) bandwidth, and (c) phones. getting it all in one bundle makes finger pointing between providers impossible, and in theory they should have everything setup (QOS etc) to work properly. an example: speakeasy. there are others...
2) insist on a 60 day trial. don't let them bullshit you with "but we only do 30 day trials". the one person in your office most sensitive to audio problems will be on vacation in a thirty day window...
3) DON'T get rid of your old phone system. just forward the number(s) temporarily to the new system
4) HAMMER it for 60 days. download and upload as much as you can. get as many people on the phones at one time as you can. run some bittorrent clients and download some (legal) stuff - for example Linux install ISOs. bittorrent really stresses QOS. run a bunch of web-conference sessions if you use them. blast your LAN with a high rate of broadcast pings. *insist* that people tell you about audio problems (they still won't..). make them check whether the person they were talking to was on a cellphone or VOIP - if they were, it's hard to place the blame..
5) ??
6) profit
Real Programmers don't eat quiche. They eat Twinkies and Szechwan food.
