231–240 of 264 posts
Right before the explosion you can hear launch control saying something like "Got engines at 108%". I was curious about it, but from Reddit discussion, apparently this is totally normal; "Yes, the engines have been upgraded many times. To avoid having to recalibrate the software each time engines are upgraded, they are simply rated at over 100 percent thrust over the first engine's thrust." Another interesting fact.…
Earlier quoted context omitted.
| If you're failing, you're doing something right. Wrong. This only goes on to emphasize the stigma associated with failures. This sentence is a cover up for the fact that someone did something wrong, or at the very least, things did not go as planned. Failures are bad and heartbreaking, and we should accept it in its entirety. | Don't fret the failures. Right. Instead of focusing on getting stressed and fretting, th…
A failure means you took risk, which is something you should do if you want to push the boundaries. So you did do something right. No one would suggest you did everything right. Conversely, absence of failure may mean you took a calculated amount of risk and it paid off. But it could also mean you were overly conservative, didn't push the boundaries, and took a minimum of risk. There's no way to tell the difference p…
Earlier quoted context omitted.
> I know the Shuttle carried DOD Secure comm equipment in addition to it's in the clear UHF and VHF Radios. I'm assuming that ISS has something similar. There's some obvious reasons why the International Space Station might be less likely to carry sensitive US military communications gear than the NASA Space Shuttles.
I don't think it is anything like that. It's for cases where they need to discuss something that they don't want every person with a HAM radio to hear. A discussion between an astronaut and the flight surgeon/spouse/clergy member. I'm sure the Russians have a system on ISS as well. Just having the hardware is not enough to crack into an enemies comms. It's more that they don't want stuff like that falling into the ha…
Using 50 year old Russian engines was a risky move on Orbital's part, but in fairness the NK-33's are a pretty amazing piece of technology. The US has still yet to build anything matching its performance: http://en.wikipedia.org/wiki/NK-33 297 seconds of Isp is huge. The Saturn V's F1 engine only had 263 seconds. And the closest we've come since to that level of performance in a Lox/RP-1 engine is the Merlin 1D which…
"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.
http://en.wikipedia.org/wiki/RD-0120
Although I don't believe we ever tested it on our own test stands, so it's impossible to know for sure.
By the way you are conflating vacuum Isp with sea level Isp (what I was using). The Sea level Isp of the SSME is 366 s.
The SSME is also a fuel-rich staged combustion cycle. The point I was making above is that the Russians were able to get an ox-rich staged combustion cycle working reliably. That's the key technology breakthrough that we have never duplicated.
Spacex had an engine explosion during a flight, yet their primary mission was successful. This is the benefit of modern rocket technology.
Earlier quoted context omitted.
The mission was insured, and it didn't cost "billions".
That means future cost of buying similar insurance will rise.
Therefore failure does not always occur when one is trying too hard because it is also feasible to fail when not trying hard enough.
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
Now imagine how people felt back in '86 when the challenger exploded with 7 people on board including a teacher. Shuttle launches were common by then but a lot of people were watching live due to the teacher on board aspect. It brings a whole different set of emotions to the event. Nobody made a joke that day.
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…
Earlier quoted context omitted.
As I've understood it, it means that the scale of your ambitions is right. Consider a continuum of things that you can do, divided up by difficulty. For some part of it, you allways succeed, for some part of it, it's a mix of sucess and failure, and for some even more difficult part, you always fail. Now in order to succeed at something consistently, you need to master it, which also means that the things you always…
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…
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 dead end.
So in the big "Battlestar galactica" NASA missions with lots of new technology, the cost of failure is very high. That's why they analyze a lot and test stuff in test benches. But those can be dead ends. It makes everything even more costly, making failure even more expensive, requiring more tests. Schedules slip while you have zero science return to show... It's a vicious circle.
It might make more sense to just for example launch many smaller probes, each one somewhat better than the previous one in some degrees. Some might crash, but if your audience understands that, it's not a political disaster. You're going to fly the next one again in two years. This way you also don't have to wait 20 years for your technology development to pay off.
So SpaceX launched Falcon 1 quite many times, and learned a lot about technology as well as matured as an organization. They crashed quite many times as well. But those were not nearly as expensive as Falcon 9 crashes were at this point.
That's also why they were flying different versions of Grasshopper and now Falcon 9 R. Retire risk. Allow crashes - when you can afford them. This will reduce crashes later when you can not allow them.
So it is a slightly complex issue but nothing very out of the ordinary. Usually in the real world things settle into a good compromise between conflicting goals.