Slashdot Mirror
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."
In the NASA scar tissue, there were known problems that NASA mgmt refused to honestly address before launches. In 1986, Challenger's freezeable, frozen seals. On Columbia, falling ice hits were a recurrent source of significant shuttle damage, that they specifically suspected a major hit on the fatal flight. Ice build up is an old problem with several solutions. Finally, NASA had a chance to image the fatal hole on Columbia in space, and didn't....
Too f'g many critical management failures...
While most people are not qualified to judge rocket safety risks, there is only one entity that has actually *demonstrated* that they are incompetent at judging rocket safety risks, and for that matter they did so spectacularly and totally, and then managed to stay in a position to continue judging rocket safety anyway and then did so again! That would of course be NASA, so I laugh when they judge someone else for being "too dangerous". It's still a hell of a lot safer than the deathtrap shuttle was. Next you'll be complaining it's too expensive...
Also, NASA used cryogenic propellants for many manned missions.
Cryogenic fuel and oxidiser loading was complete before the astronauts entered the capsule or the Shuttle. Some extra LH2 and LOX was added as a top-up process during the rest of the countdown due to losses from warming.
SpaceX's ultra-cold higher-density LOX has to be loaded almost immediately before launch as it will warm up and expand and negate the advantage of its increased density if it's left too long in the rocket's tank. That requires astronauts on a man-rated Falcon 9 using higher-density LOX to be on board the capsule when the oxygen tank starts being filled. This is an extra risk over and above all the other risks of flying the cheapest bidder's hardware.
A rocket involves many trade-offs between safety and efficiency.
Of course it does. That's not adequate justification for throwing caution to the wind. You use a new procedure because it is either more efficient (cost and/or performance) with similar safety or safer with comparable efficiency. In this case it is obviously a performance improvement but it isn't yet clear if that comes at an unacceptable increase in risk. To argue that astronauts should just shut up and strap in without appropriate investigation of the risks they are taking is a dumb way to run a space program. You don't change something that is working unless it is unambiguously better.
If you'd maximize safety in every case, it wouldn't be able to lift off.
Maximizing safety does not equal perfect safety and no one claimed otherwise. That does equate to carte blanche to implement every idea that pops into the minds of SpaceX engineers. If the idea is an improvement (price/performance/safety) then they should be able to prove it to the satisfaction of NASA. If it isn't then that's unfortunate but they'll have to figure something else out
Does anyone worry about an F-15 exploding during fueling? No? Then your example doesn't work. People stand right next to F-15s while they're fueling, and they're also fueled midair.
Indeed, the whole point is to get the vehicles to the point that nobody worries about them exploding.
Exactly. They're for emergencies only. Are you telling me than an explosion isn't an emergency? No, they're not comfortable, but they save lives.
What's your "emergency escape" for people standing outside a rocket or not yet strapped in when it explodes? None, that's what. They're dead.
No. And indeed, if that were the case, it wouldn't be an emergency escape, and wouldn't be approved.
Every system has a probability of failure. Period. The chance of a refueling failure will never be zero. Nor will the chance of a pre-fueled rocket exploding on the pad during crew failure. A proper analysis of failures has one metric: crew safety probabilities. And safety systems are very specifically a part of that. You cannot just discount the risk of people being killed during crew loading like you wish to. One obviously want the fuel loading risk to be as low as possible when crew is pre-loaded, just like one obviously wants the crew loading risk to be as low as possible when they're not. That doesn't mean you can just pretend that the former has all the risk and the latter has none, or that the availability vs. lack of emergency safety systems is irrelevant.
"WANTED: Sinking ship seeks rats."
What H1B holders work in SpaceX? ITAR requires that anyone who works on launch systems (due to the similarity to ICBM systems) to be a US citizen or green card holder.