And yet their competitor, the Atlas rocket - uses a Russian engine ?
So it's apparently OK for strategic US rockets used to launch military payloads, to use Russian engines but not for a private company to employ Canadians.
As far as 'if,but, maybes' go, if us British had recognised the brilliance of both men... However, one man is continually overlooked. Without Tommy Flowers' engineering brilliance, the work of both Tutte and Turing would have had less impact.
If you were asked to bid on a contract to build the space shuttle, with conflicting and changing requirements from the NSA, Air Force and Nasa, with no guarantee on how many they will buy and no ability to sell to any other customer - you woudn't agree to a fixed price contract!
Especially when it would take years and billions of $ to even estimate what the cost to build it would be.
I don't know why this is getting downvoted. This is pretty much exactly why the government (mostly DOD) uses cost-plus in some cases.
The pendulum in government acquisitions tends to swing along multiple axis: sometimes the trend is towards the government do the integration itself, sometimes the trend is towards contracting out the integration to a prime contractor; sometimes the trend is towards cost-plus, sometimes the trend is towards firm-fixed price. Even though one way of doing things might be more popular at any given time, the other options are always considered and often used.
The choice of reimbursement structure (which is not just binary "cost-plus" or "fixed-price," but rather an entire continuum) is based on risk projections. If you insist on fixed price for a very risky project, contractors will bake that risk into their bids, pricing everything for the worst-case scenario. If you don't get the worst-case scenario, you'll still end up paying for it, in which case you would have been better off under a cost-plus contract. Conversely, if you pick the lowest bidder and they didn't bid conservatively enough, and then you do get the worst case scenario, they might very well run out of money, in which case you have a choice of either granting them more money or cancelling the project and eating the sunk costs when the contractor collapses. So, for high-risk projects, cost-plus is generally the best way to go.
I think that the swinging of the pendulum is due in part to a succession of over-corrections: "We used cost-plus too much and contractors wasted money! Lets use fixed-price as much as possible from now on!" Followed by "We used fixed-price too much and ended up paying too much on most contracts! Lets use cost-plus as much as possible from now on!" and then back the other way. However, I think that it's also driven by cycles of technological development: a lot of technology tends to go through phases where one generation of equipment really pushes the edge of what's feasible, and then the next generation mostly just matures and refines the technology used in the previous generation (e.g. Windows Vista and Windows 7). During those "pushing the edge" phases, risk is higher and so cost-plus gets used more; during the "mature and refine" phases, risk is lower and so fixed-price gets used more.
The only way out is to be crazy enough to build it and then sell it to the government. Risk is increased because you can't sell it any foreign one if your local one decides to make their own.
Then hope that the senator for <different state> doesn't block the purchase unless you agree to build it in their state. There is a reason that Nasa has facilities in 50states and it's not just for the airmiles
In other words it's the sort of testing a commercial aircraft engine maker would do - not what nasa would do.
The engines on your 777 are designed so that a 6ft long fan blade moving faster than the speed of sound can break off and not go through the engine cowling and into your lap. They blow up $30M engines in testing to prove this
> In other words it's the sort of testing a commercial aircraft engine maker would do - not what nasa would do.
I think that's a very good way to put it: nasa gets rockets built so they work, all of their engineering is built so it's as perfect as can be from the start. It's a huge cost, but it allows them not to blow up rockets in testing. SpaceX sees that as spaceworthy aircraft-building, they drive up-front costs lower by not focusing as much on design reliability and instead blow up engine to test how they behave.
This would be true if rockets actually never exploded. But it seems to me they actually do, and that's why it's useful to test very unfortunate scenarios as well. It's not like they design jet engines' blades to come loose and cause destruction, but they - or some aviation authority - have decided that the engines should not explode even in a case of blade separation. I find it a lot more comforting to know jet engine is tested to not explode in such situation than I would if I was told jet engines are designed perfect. Because perfection is not something engineering can achieve, only extremely small probabilities of failure.
I think the difference there is that when a 747 engine explodes, there are three other engines and the plane may well still be landable. When a Space Shuttle engine explodes, everybody is almost certainly dead and the Shuttle crashes.
I'm saying that pragmatically, unrecoverable errors don't need testing, and NASA's class of possible unrecoverable errors is much wider than any airline's. The fact that SpaceX feels the need to test so rigorously is a good sign about what they want to be "recoverable" and therefore about how safe their hardware is intended to be.
A lot more rocket failures are recoverable than you might think, though.
Engines can fail in many ways that don't destroy everything. Apollo 13 nearly became famous for exploding on launch due to massive resonant vibration, but a premature shutdown of the affected engine saved it. (Oddly, that shutdown was due to a mistaken fuel level reading, not the vibrations directly, so the save was something of an accident.) At least one Shuttle launch experienced an engine failure/shutdown as well. These engines didn't explode, of course, but there's a whole range of failures and many can be planned for.
Even when the entire thing does explode, you can still save your crew if you've planned properly. A Soyuz capsule's escape system saved its crew when the rocket exploded in 1983.
It appears to me that NASA's approach is to prefer systems which can't fail over systems which can fail safely. On the surface, this seems better, but when your foolproof system still fails and you haven't built it to withstand that, then you're in serious trouble.
I don't think there's any inherent reason why shedding a turbine blade during a rocket launch has to destroy the entire vehicle. Designing the system to withstand that makes it heavier and not perform as well, of course, but it seems like an overemphasis on performance while disregarding nearly everything else has really hurt space technology.
The use of solid rocket boosters for human space flight (as was planned for Ares I) is hugely controversial because they can't just be shut down in the event of a problem, as regular engines can, making survivability more difficult.
On the topic of aircraft turbine failures, there's the interesting case of a DC-10 engine that disintegrated in flight due to a pilot experiment, killing a passenger. For details see: http://en.wikipedia.org/wiki/National_Airlines_Flight_27
Finally, if you're interested in SpaceX, NASA budgeting, and so forth, I recommend http://nasawatch.com
Actually I think Nasa's approach is to design as best they can - then have layers of management each add a a factor of 10 to the assumed level of safety until it's sufficiently safe.
In the Challenger accident the engineers estimated the chance of a fatal accident at 1:100 , the next level of management 1:1000 senior management at 1:10,000 and the official Nasa press release 1:300,000
Presumably by adding more levels of management they could have made it even safer!
For those that don't click, Adobe published the (public domain) book and ran screaming away from the position implied by the parent. The file had some "don't read aloud" metadata that Adobe claimed was for devices and then removed in a subsequent version.
There was the company that sold the US a system to find hidden messages in Al Jazera videos - I think that got a few people a trip to the orange suited holiday camp before everybody discovered it was a con
> Data costs in canada are even higher than voice costs!
Most carriers have introduced a data-only plan, technically specifically to make iPad 3Gs work, that isn't nearly as gouging as the data plans for phones. You can get it set up for an arbitrary SIM card, then put that card into a phone: http://www.wifitalk.ca/iphone/ipad-3g-sim-gives-iphone-data-...
I had a t-mobile blackberry flip phone in the USA that could make calls over wifi. when it was connected to an access point I could turn off the carrier connection and just use the wifi, but it did still use my minutes and the quality was not good.
Does anyone know if a SIP soft phone app like X-lite and a smartphone that can use a wifi connection to so that at least outgoing calls could be made over data without long distance charges or ridiculous data rates?
I'm not sure if this is what you're asking about, but the Nokia business-oreinted phones E-series come with SIP capabilites natively (or one can use a third party client). I've used it on my E73.
