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Could SpaceX Rocket Technology Put Lives At Risk? (chicagotribune.com)
In preparation for a crewed mission into orbit, NASA safety advisers are warning that the super-cold propellant SpaceX uses in their Falcon 9 rockets could be "a potential safety risk." When SpaceX is about to launch a rocket, they load it up with propellant at super-cold temperatures to shrink its size, allowing them to pack more of it into the tanks. "At those extreme temperatures, the propellant would need to be loaded just before takeoff -- while astronauts are aboard," reports Chicago Tribune. "An accident, or a spark, during this maneuver, known as 'load-and-go,' could set off an explosion." From the report: One watchdog group labeled load-and-go a "potential safety risk." A NASA advisory group warned in a letter that the method was "contrary to booster safety criteria that has been in place for over 50 years." The fueling issue is emerging as a point of tension between the safety-obsessed space agency and the maverick company run by Musk, a tech entrepreneur who is well known for his flair for the dramatic and for pushing boundaries of rocket science. The concerns from some at NASA are shared by others. John Mulholland, who oversees Boeing's contract to fly astronauts to the International Space Station and once worked on the space shuttle, said load-and-go fueling was rejected by NASA in the past because "we never could get comfortable with the safety risks that you would take with that approach. When you're loading densified propellants, it is not an inherently stable situation."
Greg Autry, a business professor at the University of Southern California, said the load-and-go procedures were a heated issue when he served on Trump's NASA transition team. "NASA is supposed to be a risk-taking organization," he said. "But every time we would mention accepting risk in human spaceflight, the NASA people would say, 'But, oh, you have to remember the scar tissue' -- and they were talking about the two shuttle disasters. They seemed to have become victims of the past and unwilling to try anything new, because of that scar tissue."
Greg Autry, a business professor at the University of Southern California, said the load-and-go procedures were a heated issue when he served on Trump's NASA transition team. "NASA is supposed to be a risk-taking organization," he said. "But every time we would mention accepting risk in human spaceflight, the NASA people would say, 'But, oh, you have to remember the scar tissue' -- and they were talking about the two shuttle disasters. They seemed to have become victims of the past and unwilling to try anything new, because of that scar tissue."
I actually disagree.
If you're in the capsule, and there's an explosion, the launch escape system fires and you're safe.
If you're outside the capsule (or getting into it, but not yet to the point that you're strapped in and the abort system has been activated), and there's an explosion, you're dead.
The question is: are the odds of an explosion with the rocket pre-fueled, during the crew loading time, less than the odds of the crew escape system working? If no, then the SpaceX approach is safer. If yes, then SpaceX needs to fix their bloody crew escape system.
"WANTED: Sinking ship seeks rats."
"There's always a risk that you're going to blow up if you climb in a rocket."
Of course. What's at issue is how great the risk is. Keep in mind that 133 of 135 Space Shuttle missions didn't kill anyone, but that the resulting 1.5% failure rate was generally felt to be unacceptable. It's a little hard to compute a failure rate for Falcon 9. Officially it's around 4% (two failures in 54 launches). But that doesn't count the vehicle that blew up on the launch pad in 2016 during static testing. OTOH, early lifetime failures for a new technology are probably more common than failures after the technology matures.
My gut feeling. Falcon 9 is fine for unmanned launches. For manned launches, it's maybe a bit iffy but it may get better over time.
You can't see ANYTHING from a car, You've got to get out of the goddamned contraption and walk...Edward Abbey
You know, the solid-fuel booster rockets on the shuttle that cannot be shut down once started? That's the NASA that is now so concerned over security problems?
Von Braun, back in the 60s, already knew that you cannot really man-rate those things exactly because you have zero control over them once they went off. And they now have a problem with "security concerns"?
I smell a government agency having a problem with seeing their last reason to exist vanish.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
The alternative to load and go is transporting the flight crew and personnel to the top of a rocket that's already fully fueled. Essentially personnel are working in areas with minimal protection and no ejection system standing next to a 230 foot tall bomb.
The way SpaceX does load and go, the flight crew is in a capsule with a functional abort system and the support personnel are a safe distance away.
Where would you rather be if there was an accident? In a crew capsule with an abort system or an elevator in the gantry? It's not rocket science...well, kinda is...but that's beside the point.
That's our life, the big wheel of shit. - The Fat Man, Blue Tango Salvage
Yes, there are valid concerns regarding densified propellants. Can those be mitigated, to a degree. SpaceX has now multiple years of handling densified propellants... However, just stating that they've done it a certain way because, well they've done it a certain way.
Let's think this out.
Scenario 1. Vehicle is dry. Astronauts and Techs ride up the elevator and get Astronauts situated the vehicle. Technicians then leave the pad. Abort system is verified and enabled. Propellant loading begins.
Scenario 2. Vehicle is loaded and oxidizer boil off is occuring, which means the Astronauts and support staff will be riding up an elevator next to a loaded rocket, plus the strong back will have be supplementing the vehicle so it's going to have a substantial amount of cryogenically cooled oxygen in it as well. Now, once the crew is loaded, the technicians need to safely get down the elevator and away while boil off and supplemental loading is occuring
Which of these scenarios seem more likely to be a recipe for disaster?
I called this a hit piece because this is looks from the outside like SpaceX is being forced to jump over much higher hurdles than ULA.
Yes Francis, the world has gone crazy.
Well.. Let's be fair about NASA's safety records...
NASA has demonstrated two things in their history. 1. They can be blind to obvious risks and become complacent about safety when what they are doing becomes too routine. 2. They can, and have, put excellent safety standards and practices in place and operate in very dangerous environments using very dangerous equipment in reasonably safe ways.
NASA has demonstrated both sides of the safety problem. They have made colossal mistakes, killed or nearly killed many people for stupid reasons AND they have learned from their mistakes, instituted safety practices that have allowed them to do amazing things with extremely few serious accidents and loss of life. They've made the stupid mistakes, and the hard decisions, in turn, and learned from the mistakes when they fell into complacency.
So, I think NASA is unique in it's qualifications for reviewing and determining space system's safety and their opinion carries a lot of weight. I also think that they are fallible as any other large organization, and they have a history of ignoring their risk management lessons learned in the name of expediency and efficiency.
So the question here is about SpaceX verses NASA in a discussion of risk management. I'm not sure we can dismiss either's opinions on the question. That means, we will need more information to decide. It may cost a lot of money to obtain the necessary information, it may take time and effort. I understand SpaceX is very sensitive to cost and schedule, but those pressures are what drove NASA into their various stupid mistakes. So I think NASA needs to be satisfied and SpaceX needs to prove what it needs to prove or change it's design.
"File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
The number of Falcon 9s lost is also two, and one of those was lost in a static fire test that would never have had people on board. Not sure what universe you're living in.
Of course, the Columbia disaster wasn't an exploding rocket either. That disaster would have to be compared with a Dragon heat shield failure, which hasn't happened yet.
The shuttle boosters did have a better non-explosion rate than SpaceX, 134/135 compared to SpaceX's 52 out of 53 or 54 (depending whether you include a static fire test, which would be equivalent to a space shuttle exploding during testing with nobody aboard, which never happened probably because you couldn't do static test fires of a space shuttle). But your "a lot" of explosions are imaginary unless you're talking about initial Falcon 1 tests, which case you should be comparing with NASAs early test rockets which were famed for exploding frequently.
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