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NASA Space Science

SpaceX Plan To Fuel Rockets With People Aboard Raises Alarm Bells (fortune.com) 190

Posted by msmash from the space-hurdles dept.
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.
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SpaceX Plan To Fuel Rockets With People Aboard Raises Alarm Bells More

SpaceX Plan To Fuel Rockets With People Aboard Raises Alarm Bells

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  • People Fuel? (Score:5, Funny)

    by pubwvj ( 1045960 ) on Tuesday November 01, 2016 @04:24PM (#53194693)

    They're going to use the people aboard as the rocket fuel? How do the people feel about that?

  • Why? (Score:4, Funny)

    by 110010001000 ( 697113 ) on Tuesday November 01, 2016 @04:26PM (#53194709) Homepage Journal
    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?

    • 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?

      Until halfway through the first sentence I thought you were serious....... Yer, let's dispense with over fifty years of rocketry experience - a highly unstable vehicle to be getting into space in the first place.

  • Fueling is risky? Risky like sitting on top of a couple of hundred tons of propellant risky? Or risky like shooting people into outer space risky?

    What benefit would there be to fueling with people inside the ship? Would they save 30 minutes?

    • Musk is a software guy. If something fails, you can always issue a patch.
      • Technically, he's a physics guy.

    • Re:Fueling is risky? (Score:4, Interesting)

      by Scutter ( 18425 ) on Tuesday November 01, 2016 @04:31PM (#53194755) Journal

      "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.

      • Re:Fueling is risky? (Score:5, Informative)

        by Anonymous Coward on Tuesday November 01, 2016 @06:07PM (#53195371)

        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.

        • Which makes me immediately skeptical of the motives of anyone making those claims.

          Since they are saying that in order to carry crew, the falcon will most likely need to be flown in expendable mode, which will make it less financially competitive, which will benefit someone else...

          • Before distrusting others, consider who and why - who they are, and why they say what they say. Else others end up skeptical of what's making you skeptical.

            Musk has had problems rolling out beta products in his other transportation company. So its important to pay attention to known experts contradicting him.

        • They only switched to the supercooled fuel recently. They were launching fine before that. Seems wiser to me to go back to the regular old way for manned launches.

    • The current iteration of Falcon 9 is designed for very cold propellants.
      If the rocket sits on the pad too long the propellants warm up from the environment and expand, which necessitates venting them out so the tanks are not overpressured.
      The engines are also, presumably, tuned for a certain rate of flow at a certain density, so if the propellant is at a different density, it would reduce efficiency and might cause trouble.

      • The current iteration of Falcon 9 is designed for very cold propellants. If the rocket sits on the pad too long the propellants warm up from the environment and expand, which necessitates venting them out so the tanks are not overpressured.

        Then they need to get themselves better rocket technology and a better motor. Unfortunately this is corner cutting so they can get the rocket to do what it is barely on the edge of being able to do anyway.

        • They are working on a different engine and different architecture for their Mars plans, and it's quite reasonable to assume they'll scale that down for commercial use as well.

          As it stands, the Merlin engine is pretty damned good, they're just constrained by the size of rocket they can move by road and are therefore squeezing out some extra efficiency by resorting to methods that don't have as long a history of use and the edge cases have not been discovered.

          They could probably go back to using warmer propel

        • The Zenit launch vehicle did exactly the same thing despite having a much better engine than anything the US has even been able to produce, so I don't see how this alone helps you. You could say the same thing about mass fractions, safety margins, etc. etc. for virtually all launch vehicles. If the orbital velocity were just one or two kilometers per second lower, many of your problems would go away. We basically live on a planet from which spaceflight is borderline practical. (Could have been worse, though

        • Re: (Score:2)

          by Kremmy ( 793693 )
          Perhaps this is the better rocket technology and better motor, making it possible to use very cold propellants (higher fuel density) which would have caused previous rockets to fail on the pad every time while theirs has only done so once.

    • Re:Fueling is risky? (Score:5, Insightful)

      by MachineShedFred ( 621896 ) on Tuesday November 01, 2016 @04:47PM (#53194883) Journal

      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.

      • Re: (Score:2)

        by Guspaz ( 556486 )

        It's not just about how much boils off. The current revision of Falcon 9 uses sub-cooled liquid oxygen and fuel, which gives them additional performance (denser fuel, more thrust, more payload). If the fuel sits in the rocket for too long, it heats up and goes outside of the acceptable range. It's a relatively narrow window, so they only finish fueling ten minutes before the launch, and are forced to scrub the launch if there is any delay. That's not something that a procedural change would allow, it would

        • Alternatively for manned launches you don't use the supercooled fuel, and accept somewhat lower delta-v or payload. We know the rockets are capable of operating on non-supercooled fuel because SpaceX only started using supercooled fuel about a year ago. This seems a reasonable trade-off in a safety critical application.

          I'm not a rocket engineer, so I can't judge these trade-offs for myself, but we have quite a few real rocket engineers advocating this strategy.

          • Re: (Score:2)

            by Guspaz ( 556486 )

            > We know the rockets are capable of operating on non-supercooled fuel because SpaceX only started using supercooled fuel about a year ago.

            We don't know that, since the use of sub-cooled propellants only started with a new version of the rocket that is substantially different from the one that used regular temperatures. It's not even the same size as the previous vehicle, and we don't know what changes may have been made to the engines to enable them to hit their higher thrust with the sub-cooled fuel.

            Th

      • 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.

      • Keep in mind that the people in question are sitting in a fairly fireproof container with escape rockets. I mean, yeah, there's probably more risk sitting in the rocket while it's fueling than there is sitting in the rocket when the fuel has been sealed up. But as long as I can get away if something goes wrong, I'm sort of okay with it.

      • Is that worth risking the lives of people? No

        Some say no, some say yes. Risk is a function of the likelyhood and the consequence of a hazard. Accepting risk is a function of the benefit.

        Without being in the room where the decision was made You can't answer your own question.

    • It's in between those two. But additional to, since you are going to be doing both of them as well...

    • I've sat on planes as they've been refueled.

    • Re: (Score:2)

      by I4ko ( 695382 )

      What benefit would there be to fueling with people inside the ship? Would they save 30 minutes?

      They would have the people in outer space every time, even if the engines never leave the launch pad.

    • Risky like riding a unicycle down a mountain. Just walk down the mountain then ride the unicycle. Both are risky in their own right, but doing them together is just fucking stupid.

    • Re: (Score:2)

      by Ksevio ( 865461 )
      Just like how it's safer to be inside a car than outside during a car crash, it's safer to be in a capsule with a launch escape system than outside and walking into it.

  • Either provide some scientific insights, or sit down.
    https://www.youtube.com/watch?... [youtube.com]

    Also, anyone think Nasa is the right place to be asking whether Elon Musk can do whatever he wants?

  • How dangerous is it really? (Score:3)

    by acoustix ( 123925 ) on Tuesday November 01, 2016 @04:33PM (#53194769)

    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.

    • Re: (Score:2)

      by Calydor ( 739835 )

      But on the other hand, what would possibly be gained by loading the astronauts before the fuel?

      • Re: (Score:3, Funny)

        by Tablizer ( 95088 )

        But on the other hand, what would possibly be gained by loading the astronauts before the fuel?

        Reduces the chance of forgetting to put the astronauts in before launching. It's the same reason I put my pants on as soon as I wake up in the morning.

      • Others have mentioned it, but the fuel is very cold when loaded. Loading the fuel and then waiting a few hours to load the people will probably cause the fuel to warm and to expand which will change the pressure inside the fuel tanks which might things more dangerous.

        Loading the people, loading the fuel, and hitting the launch button might be safer than loading the fuel, loading the people while the fuel warms and expands, and then hitting the go button. Especially if the people are inside a fireproof con

    • Ever see someone put a Note 7 in their mouth? It's kind of like that, but 1000x more dangerous and you die instead of get a burned tongue.

      Space flight isn't about whether you die in a fire, but when. And the odds are not in your favor over the long term.

    • With one exception, it's been a while. Now, that one exception was a SpaceX flight last year, so of all the people to want to do this....

  • Those who don't know history... (Score:3, Interesting)

    by Tablizer ( 95088 ) on Tuesday November 01, 2016 @04:34PM (#53194777) Journal

    The Soviets lost a lot of their key technicians by having them hang around the rocket during fueling and tests.

  • Topping off (Score:3)

    by A10Mechanic ( 1056868 ) on Tuesday November 01, 2016 @04:38PM (#53194811)
    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...

    • It's the transient in temperature that has most of the risk. As things cool at different rates you get stresses, seals can fail, cryos rapidly boil. Once you are chilled and in replenish things are pretty calm.

  • ...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.

    • Re: (Score:2)

      by sconeu ( 64226 )

      So they're only going to use humans named Leo as their fuel? Quick change your name!!!

    • Re:Didn't Musk say multiple LEO trips were necessa (Score:4, Interesting)

      by Kjella ( 173770 ) on Tuesday November 01, 2016 @06:22PM (#53195483) Homepage

      ...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.

  • Do people in The British Commonwealth still celebrate Guy Fawkes Day

  • I wonder how many numbers men are placing bets on if this will work.

    at least that way LLoyds will make some money on it going BANG!

  • How else instead? (Score:5, Interesting)

    by joh ( 27088 ) on Tuesday November 01, 2016 @05:41PM (#53195217)

    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.

    • Re: (Score:2)

      by ender06 ( 913978 )
      False. As SpaceX demonstrated just 2 months ago, the fueling process is the dangerous part. You have 1 or more cryogenic liquids in very large quantities being loaded.

      Every vehicle that the US has launched with people loaded fuel before loading people. There are few concerns about problems due to boarding because the rocket is already powered up and in a known state. Fueling happens with few to no people at the pad for a reason.

    • So yes, fueling the rocket with people aboard is dangerous but boarding an already fueled rocket would be even more dangerous.

      The people who are actually rocket engineers, quoted in TFA, say you are wrong. Boarding an already fuelled rocket is how (nearly?) every manned flight up until now has been done.

      • Re: (Score:2)

        by joh ( 27088 )

        That's the people who build a spacecraft with no launch escape system at all, right?

  • using people for fuel. What else can we do with the 7B on the planet anyway?

    • using people for fuel. What else can we do with the 7B on the planet anyway?

      7 out of 10 people prefer soylent green.

  • "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."

    This has "bad ending" written all over it.

  • Have them sign an NDA...all is well.

  • Why is SpaceX wanting to do this??? To reduce the amount of fuel boil-off before launch?

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