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Elon Musk appeared on CNBC and offered a definitive explanation for his company's recent launch explosion:
SpaceX CEO Elon Musk says that his company has finally gotten to the bottom of the September 1st Falcon 9 explosion — claiming it was the "toughest puzzle" they've ever had to solve. And now that the problem is known, he expects SpaceX to return to flight in mid-December.
Speaking on CNBC yesterday, Musk said "it basically involves liquid helium, advanced carbon fiber composites, and solid oxygen. Oxygen so cold that it actually enters solid phase." So what does that mean exactly? Musk gave some hints a little while ago during a speech he gave to the National Reconnaissance Office. According to a transcript received by Space News, he argued that the supercooled liquid oxygen that SpaceX uses as propellant actually became so cold that it turned into a solid. And that's not supposed to happen.
This solid oxygen may have had a bad reaction with another piece of hardware — one of the vehicle's liquid helium pressure vessels. Three of these vessels sit inside the upper oxygen tank that holds the supercooled liquid oxygen propellant. They're responsible for filling and pressurizing the empty space that's left when the propellant leaves the tank. The vessels are also over wrapped with a carbon fiber composite material. The solid oxygen that formed could have ignited with the carbon, causing the explosion that destroyed the rocket.
Musk called the issue one that had "never been encountered before in the history of rocketry." One of SpaceX's customers, Inmarsat, may find an alternative for one of its upcoming satellite launches. SpaceX launches could resume mid-December.
For comparison's sake, at standard pressure:
- Liquid Helium: 4 K (about −269 °C or −452.2 °F).
- Solid Oxygen: 54.36 K (−218.79 °C, −361.82 °F).
- Solid Nitrogen: 63.15 K (−210.00 °C, −346.00 °F)
- Liquid Nitrogen: 77.355 K (−195.795 °C, −320.431 °F)
- Liquid Oxygen: 90.19 K (−182.96 °C; −297.33 °F)
- Dry Ice (Solid CO2): 194.65 K (−78.5 °C; −109.3 °F).
(Score: 3, Interesting) by khallow on Monday November 07 2016, @10:33AM
as fuelling with the standard rocket fuel?
It's not standard what they are doing. They are cooling LOX to near its freezing point so it's much easier to freeze than normal LOX would be. But in turn, they get higher density. The higher the density of propellant, the better thrust per weight they get and the more mass they can put in orbit. The problem appears to be that some LOX leaked out and froze due to the nearby helium tank.
The explanation seems little more than guesswork precisely because of the lack of footage, data or anything else.
They have a bunch of telemetry, data on the state of the rocket from a variety of sensors throughout the rocket. It's not perfect, but it does tell them a fair bit about what happens to the rocket.
We know oxygen is a factor. What we don't know is WHY IT IGNITED, and that's much more worrying.
It ignited because it's frozen oxygen mixed in with a burnable carbon fiber composite. Why is easy to understand.
Wasn't Musk at one point insinuating that someone could have shot the rocket from an nearby rival's rooftop? This sounds just as likely (i.e. not).
I understand they looked through a lot of video from people watching the launch to rule out such sabotage.