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SpaceX Plan To Fuel Rockets With People Aboard Raises Alarm Bells (fortune.com)
Several space industry experts that advise NASA have told the US space agency there are safety risks in a proposal by Elon Musk's SpaceX to fuel its rockets while astronauts are on board. From a report on Fortune: "This is a hazardous operation," Space Station Advisory Committee Chairman Thomas Stafford, a former NASA astronaut and retired Air Force general, said during a conference call on Monday. Stafford said the group's concerns were heightened after an explosion of an unmanned SpaceX rocket while it was being fueled on Sept. 1. The causes of that explosion are still under investigation. Members of the eight-member group, which includes veterans of NASA's Gemini, Apollo and space shuttle programs noted that all previous rockets that have flown people into space were fueled before astronauts got to the launch pad. "It was unanimous ... Everybody there, and particularly the people who had experience over the years, said nobody is ever near the pad when they fuel a booster," Stafford said, referring to an earlier briefing the group had about SpaceX's proposed fueling procedure.
They're going to use the people aboard as the rocket fuel? How do the people feel about that?
With SpaceX's advanced high speed sensor suite they can react faster to problems, unlike those luddite NASA people. This means mistakes can be corrected immediately by the advanced SpaceX technology and the system shut down before any issues. Plus, they are going to add some cameras so they have video feeds of the snipers shooting at their rockets. What could possibly go wrong?
Musk is a software guy. If something fails, you can always issue a patch.
"Additional, unnecessary risk" would have been better wording, but the article was pretty scant on details. Some explanation as to why SpaceX feels it's necessary to go against 60 years of risk management recommendations would have been nice.
"Tell me doctor, with all of your defenses, are there any provisions for an attack by killer bees?"
Serious question. Everything about space travel is dangerous. But how many times have the rockets blown up during fueling vs the vehicle blowing up in travel?
I don't know the answer, but I'm sure someone does.
"A plan fiendishly clever in its intricacies"- Homer Simpson
That's not really fair. Of the set of things that can result in a rocket explosion "putting the explosive parts into the rocket" has to rate pretty highly.
If you can choose between fueling the rocket before the payload is aboard and fueling it after the payload is aboard, than all else being equal after is the obvious choice as that preserves the payload in the event of a fueling accident leading to loss of the rocket.
The Soviets lost a lot of their key technicians by having them hang around the rocket during fueling and tests.
Table-ized A.I.
They may have fueled the NASA rockets before crew arrival, but didn't they top them off continuously up until just a couple of minutes before flight? Is it safer if they only put in a little LOX, or a lot of LOX? Degrees of risk...
This is the kind of question that was asked after the Apollo 1 fire. Yes, there are risks in spaceflight. That doesn't mean that there isn't way to mitigate risks, or that undue risk has to be taken.
I imagine the benefit to fueling with the people already in the capsule is that you'll have less liquid oxygen boil off before launch, if you can launch as soon as the thing is fueled. Is that worth risking the lives of people? No, especially as you can likely fix it with a procedural change.
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What are you even talking about?
https://en.wikipedia.org/wiki/...
These systems have been around forever, SpaceX is (once again) doing nothing new or special. They only work when there is forewarning, and that is unlikely to be had during a fueling mishap. This isn't a cartoon or action movie, you can't just outrun an explosion in progress by jumping fast and wearing cool shades.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
That is all
Is it just my observation, or are there way too many stupid people in the world?
The only other way than to fuel the rocket with the crew on board would be to fuel it first and then let the crew board it. The latter would mean that the astronauts as well as pad crews would be near or on a fueled rocket with no way to escape if something goes wrong during boarding the capsule.
If the astronauts board the capsule on top of the empty rocket and the rocket is fueled only when they're safe and strapped in there, there is no point at which they couldn't fire the escape system and get away when something goes wrong. Look at the fueling accident they had: The payload sat up there for several seconds after the rocket was already falling down in flaming pieces. The Dragon 2 LES is within less than 1/10 second at full thrust, pulling the capsule away.
So yes, fueling the rocket with people aboard is dangerous but boarding an already fueled rocket would be even more dangerous.
SpaceX is using densified (highly cooled) LOX to increase peformance by cramming more fuel into the same-sized tank. That super-cooled LOX will only sit in the tank for so long before it starts to warm up and expand, so for best performance they need to be fueling up until just a few minutes before launch.
Probably the Falcon 9 could still lift the Dragon without supercooled LOX, but it would have lower launch margins.
NASA may have done the bulk of the fueling before loading astronauts, but they kept topping up the tanks against boil-off right up until a few minutes before launch, so there's a bit of an exaggeration here.
When the "old timers" are the ones who put people on the moon and the new kids on the block are having trouble making shit not explode on their way to LEO, then maybe you should listen to the "old timers". Especially when there's no fucking reason to fuel up while crew are aboard.
I find 60 or so years of experience by people who what watched friends die in launch pad accidents somewhat more credible than less than 15 years experience by people who have never launched a human being into space.
I know which group I'd like to have making safety decisions if I were sitting on top of that bomb.
Has any escape system ever deployed in practice?
Well... kind of. The Little Joe was set to test the Saturn V launch escape system by commanding it to set off at a certain point in the flight. However, a gyro on the Little Joe was attached the wrong way about, causing the rocket to go out of control during ascent and break apart in a completely unintentional and unplanned manner. This broke the continuity wires, which triggered the LES to fire in a real and unplanned breakup scenario, which worked perfectly.
...to refuel the Spaceship? If that's already the case, why not send up an empty Spaceship, refuel it robotically with Tankers, *then* send up the passengers? It's only one extra trip out of an already envisioned ~3-5 trips that his keynote talked about anyway.
This isn't about the interplanetary rocket on the drawing board, but about how SpaceX fuels all their rockets. They now use super-cooled fuel for maximum thrust, basically once fueled it either has to take off or be de-fueled again quite soon, it can't wait for long. So either the astronauts have to either be on board, arrive from a bunker real quick and get themselves strapped in or SpaceX will have to modify their launch method. And the latter is really unlikely in general for cargo/satellite launches, so it'd be a manned-only setting and less tested.
They'd still have the launch abort system that could hopefully get them out of harm's way just like a mid-launch problem, but sure in an ideal world it's best not to be around things that can go boom. But principally a construction site would be much safer without construction workers too, the only way to be really sure humans aren't hurt is to not send humans at all. It's a question of acceptable and necessary risk, but sometimes we do give up safety for progress. Lots of people have hurt themselves badly with chain saws, few have done the same with a hand saw. Still not going back for safety's sake.
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There's no boil-off here, just liquid expansion inside the tank, which could be dangerous with a fully fueled tank. If there were boil-off, it wouldn't be an issue.
Ezekiel 23:20
Plus if you load the crew before the fuel then the only people near the partially fueled rocket are the crew themselves.
If you load them after fueling then you're going to need a bunch of support stuff to also be near the "live" rocket.
Too bad the payload on that last rocket didn't have the Dragon escape system, to provide some real world data. Has any escape system ever deployed in practice?
Soyuz 7K-ST in 1983. Its launch escape system saved the crew; the rocket blew up on the launch pad.
Especially when there's no fucking reason to fuel up while crew are aboard.
Actually there are a number of reasons to fuel right before launch, some specific to SpaceX/Falcon 9 and some in practice.
1) If you fuel the rocket you have a lot of people that are working in and around the rocket when it's in a hazardous state for a long period of time, with no means of escape. Think of all the technicians in the white-room who are strapping the astronauts into the capsule etc... The astronauts, when strapped into the capsule, have a good escape system that will get them away from the fireball.
2) In the old days, it did take hours to load propellant into the rocket, and having your astronauts strapped into their seats that long was lunacy. With the Falcon 9, that process is down to 40 minutes.
3) The Falcon 9 requires this. The design as it stands depends on sub-chilled propellants to achieve the required performance. This means that the rocket can't sit for long on the pad fully loaded, certainly not long enough to strap in the astronauts.
All in all, with the way that the Falcon 9 works, and the reliability of the launch escape system, it's actually safer to load the propellants when the astronauts are already packed in.
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