251–260 of 264 posts
Wonder if the boat didn't stray into the restricted area yesterday, things would have been different? I know we might never know but I did wonder if the draining and refueling the fuel caused an anomaly somewhere and lead to this? Such a big loss for us.
Or different in the other way - where had they launched with the boat there and it still had exploded. Then ORB/NASA would have to deal with a lot more than simply economic consequences.
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The CRS contract includes development costs, though. The marginal cost of one mission isn't anywhere near 1.9B/8.
Sort of. COTS was supposed to be the development costs, CRS was supposed to be the launches. Orbital got $288 Million for development of Antares/Cygnus from COTS. From wikipedia: > "COTS is related but separate from the Commercial Resupply Services (CRS) program.[3] COTS relates to the development of the vehicles, CRS to the actual deliveries. COTS involves a number of Space Act Agreements, with NASA providing milest…
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I think the generalization is overbroad. Risk of failure should be weighed against the consequences of failure. If I'm writing code for robots as a hobby and my robots behave exactly as I intended all of the time, then I'm probably not learning anything, and I should try to make the robots do more sophisticated tasks. The consequences of failure are minimal, so the optimum failure rate is high. If I'm at work writing…
That's also why research, prototyping and product development should often be done in ways where failure is a lot cheaper and your optimum failure rate can be much higher, accelerating progress hugely. For example at a smaller pilot scale or in test benches. Yet, if your test bench is very complicated, slow, costly and introduces errors of its own, it might not be wise. Also some "flying" test configurations can be a…
My entire physics lab watched this happen live. It started going up and everyone was cheering. Seconds later just caught fire, and fell to the ground and exploded. "That's what happens when you set 'a' to negative." a good lesson from my TA
What's 'a'?
The first stage engines that exploded were AJ-26 engines. These are remanufactured NK-33 or NK-43 engines built in the Soviet Union in the late-60s or early-70s for the N-1 moon rocket, but never used. In May, an AJ-26 exploded on the test stand at Stennis space center in Mississippi, severely damaging the test stand.
I wonder if this is going to be a pressing problem, given the Russian's lack of enthusiasm for supplying more rocket gear while under sanctions and the dwindling stock in the US. http://online.wsj.com/articles/david-a-deptula-the-russians-...
I happened upon this website as a result of a Google search re. yesterday's failed launch of the Orbital Sciences venture to resupply the ISS, and this URL appeared as the first search result. I've read your site guidelines, as well as the many comments on this news page, and as a lay person I humbly offer this question, which I hope someone will answer: Why was there no escape rocket atop the rocket's payload module…
Furthermore, adding a launch escape system would mean adding parachutes and flotation to a payload which otherwise doesn't need it.
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It seems so bizarre that we're using 40 year old, Russian-made engines. I'm sure there are plenty of smart folks who will say not too worry, but I wonder.
Most of those smart folks are probably retired now - need more immigrants: http://xkcd.com/984
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"The US has still yet to build anything matching its performance" The Space Shuttle Main Engines had an Isp of 452s and 500,000 lb of thrust, easily the most efficient rocket engines ever built.
NK-33 is RP/LOX, whereas SSME is LH2/LOX. LH2/LOX cryogenic engines have higher Isp compared to other solid and liquid engines. ISRO's CE-7.5 LH2/LOX engine[1] has an Isp of 454s. [1] http://en.wikipedia.org/wiki/CE-7.5
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Was anything about cromwellian's statement inaccurate, such that it should have been downvoted? I'm pretty sure I understand everything being discussed here but I don't understand THAT.
I didn't down vote it, but the difference between RP1 and Liquid Hydrogen engine performance is WELL known. Thus his assertion that SSME's are better, although true as comparison of rocket engines in general, is false when comparing LOX/RP1 engines specifically (since the SSME are NOT LOX/RP1), which the grandparent was clearly doing. Similarly, citing the 850 ISP of the experimental NERVA engines is equally out of c…
Let me qualify the SSME claim as "highest Isp/Thrust of any widely used engine". Prototypes or engines that haven't flown much IMHO aren't able to make this claim.
The NK-33 may beat a Merlin 1D, but what much do they cost to make and what is the reliability? If you make 100 NK-33s and 100 Merlin 1Ds, what's your total budget, and how many NK-33s will fail compared to the Merlin 1D?
One thing I get with SpaceX, is that their engines are not designed to push the performance envelope. They want them to be cheap and reliable.