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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?
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
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.